Sample records for diametral tensile strength

  1. Influence of different crosshead speeds on diametral tensile strength of a methacrylate based resin composite: An in-vitro study

    PubMed Central

    Sood, Anubhav; Ramarao, Sathyanarayanan; Carounanidy, Usha

    2015-01-01

    Aim: The aim was to evaluate the influence of different crosshead speeds on diametral tensile strength (DTS) of a resin composite material (Tetric N-Ceram). Materials and Methods: The DTS of Tetric N-Ceram was evaluated using four different crosshead speeds 0.5 mm/min (DTS 1), 1 mm/min (DTS 2), 5 mm/min (DTS 3), 10 mm/min (DTS 4). A total of 48 specimens were prepared and divided into four subgroups with 12 specimens in each group. Specimens were made using stainless steel split custom molds of dimensions 6 mm diameter and 3 mm height. The specimens were stored in distilled water at room temperature for 24 h. Universal testing machine was used and DTS values were calculated in MPa. Results: Analysis of variance was used to compare the four groups. Higher mean DTS value was recorded in DTS 2 followed by DTS 4, DTS 1, and DTS 3, respectively. However, the difference in mean tensile strength between the groups was not statistically significant (P > 0.05). Conclusion: The crosshead speed variation between 0.5 and 10 mm/min does not seem to influence the DTS of a resin composite. PMID:26069407

  2. Influence of powder/liquid ratio on the radiodensity and diametral tensile strength of glass ionomer cements

    PubMed Central

    FONSECA, Rodrigo Borges; BRANCO, Carolina Assaf; QUAGLIATTO, Paulo Sérgio; GONÇALVES, Luciano de Souza; SOARES, Carlos José; CARLO, Hugo Lemes; CORRER-SOBRINHO, Lourenço

    2010-01-01

    Objective To determine the influence of P/L ratio on the radiodensity and diametral tensile strength (DTS) of glass ionomer cements. Material and Methods There were 2 factors under study: P/L ratio (manufacturer's recommended P/L ratio and a 50% reduced P/L ratio), and materials (Vitro Molar, Vitro Fil, Vitro Cem conventional GICs and Vitro Fil LC, Ortho Glass LC RMGICs). Five 1-mm-thick samples of each material-P/L ratio were produced for radiodensity evaluation. Samples were x-ray exposed onto Digora phosphor plate and radiodensity was obtained using the software Digora for Windows 2.5 Rev 0. For DTS, five (4.0x8.0 mm) cylinder samples of each material were tested (0.5 mm/min). Data were subjected to one- and two-way ANOVA (5x2) followed by Tukey's HSD test, or Kruskal-Wallis and Dunn's method. For paired comparisons, t-test or Mann-Whitney test were used (a=0.05). Results There was a significant interaction (P=0.001) for the studied factors (materials vs. P/L ratio). Reduced P/L ratio resulted in significantly lower DTS for the RMGICs, but radiodensity was affected for all materials (P<0.05). Conclusions Reduced P/L ratio affected properties of the tested glass ionomer cements. RMGICs were more susceptible to lower values of DTS, but radiodensity decreased for all materials following P/L ratio reduction. PMID:21308288

  3. Tensile strength of dried gelcast green bodies

    SciTech Connect

    Nunn, S.D.; Omatete, O.O.; Walls, C.A.; Barker, D.L.

    1994-04-01

    Ceramic green bodies were prepared by three different techniques, dry pressing, slip casting, and gelcasting. The tensile strength of the green bodies was measured using a diametral compression test. It was found that the gelcast samples were from 2 to 20 times stronger than the conventionally formed green bodies. SEM examination of the gelcast samples revealed a homogeneous, brittle fracture surface indicating a very uniform distribution of the binder and excellent dispersion of the ceramic powder.

  4. Ultrasound transmission measurements for tensile strength evaluation of tablets.

    PubMed

    Simonaho, Simo-Pekka; Takala, T Aleksi; Kuosmanen, Marko; Ketolainen, Jarkko

    2011-05-16

    Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets. PMID:21356298

  5. Flexural vs. tensile strength in brittle materials

    NASA Astrophysics Data System (ADS)

    Leguillon, Dominique; Martin, Éric; Lafarie-Frenot, Marie-Christine

    2015-04-01

    The tests leading to the determination of the strength of brittle materials show a very wide scattering and a noticeable difference between flexural and tensile strengths. The corresponding statistics are usually described by the Weibull law, which only partly explained the observed difference. From a theoretical point of view, the coupled criterion reaches the same conclusion, the flexural strength is higher than the tensile one. It is shown that these two approaches complement to give a satisfying explanation of the difference between the flexural and tensile strengths. Moreover, according to the coupled criterion, the tensile strength appears to be the only material parameter.

  6. CHARACTERIZATION OF TENSILE STRENGTH OF GLOVEBOX GLOVES

    SciTech Connect

    Korinko, P.; Chapman, G.

    2012-02-29

    A task was undertaken to compare various properties of different glovebox gloves, having various compositions, for use in gloveboxes at the Savannah River Site (SRS). One aspect of this project was to determine the tensile strength (TS) of the gloves. Longitudinal tensile samples were cut from 15 different gloves and tensile tested. The stress, load, and elongation at failure were determined. All of the gloves that are approved for glovebox use and listed in the glovebox procurement specification met the tensile and elongation requirements. The Viton{reg_sign} compound gloves are not listed in the specification, but exhibited lower tensile strengths than permissible based on the Butyl rubber requirements. Piercan Polyurethane gloves were the thinnest samples and exhibited the highest tensile strength of the materials tested.

  7. Method and apparatus for determining tensile strength

    DOEpatents

    Ratigan, J.L.

    1982-05-28

    A method and apparatus is described for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.

  8. Tensile Strength Measurements on Biopolymer Films

    NASA Astrophysics Data System (ADS)

    Stevens, Eugene S.; Poliks, Mark D.

    2003-07-01

    An experiment is described in which students prepare biopolymer (agar, gelatin, and starch) films from aqueous solution and measure the tensile strengths of the films using easily constructed equipment. Agar and gelatin form moderately strong films. Starch forms weak films but the strength is increased by combining with agar and gelatin.

  9. Estimation of dynamic tensile strength of sandstone

    Microsoft Academic Search

    Shiro Kubota; Yuji Ogata; Yuji Wada; Ganda Simangunsong; Hideki Shimada; Kikuo Matsui

    2008-01-01

    A series of dynamic tests on Kimachi sandstone for measuring dynamic tensile strength are carried out using underwater shock waves. An emulsion explosive is used as the source of dynamic loading, and a pipe filled with water was arranged between the explosive and a cylindrical specimen. The length of the pipe is varied to produce different strengths of the incidence

  10. A comparison of pressure compaction and diametral compression tests for determining granule strengths

    NASA Astrophysics Data System (ADS)

    Glass, S. J.; Newton, C.

    Lightning strikes can cause structural damage, ignite flammable materials, and produce circuit malfunctions in missiles, aircraft, and ground systems. Lightning arrestor connectors (LAC's) are used to divert harmful lightning energy away from these systems by providing less destructive breakdown paths. Ceramic granules in the size range of 150-200 micrometers are used in LAC's to provide physical and electrical separation of contacts (pins) from the surrounding metal web, and to control the voltage breakdown level. Pressure compaction (P-C) tests were used to characterize the strength of ceramic granules. When compaction data are plotted as relative density of the compact versus the compaction pressure two linear regions are generally observed. The intersection of these regions, which is known as the 'breakpoint,' has been used as a semi-quantitative measure of granule strength. Comparisons were made between the P-C breakpoint and strengths of 150-200 micrometers diameter ZnO, TiO2 (rutile), and lead magnesium niobate-lead titanate (PMN-PT) granules, where the strengths were determined by diametral compression (D-C) tests. At high compaction pressures the compliance of the die itself is significant and was accounted for in the analyses. Tests were conducted at different compaction rates, and with different aspect ratio compacts. High aspect ratios and loading rates decrease the slope of the second linear portion of the compaction curve and produce higher apparent P-C breakpoints. Comparison of the P-C breakpoint to the average D-C strength indicates that the D-C strength is approximately fifty percent higher for PMN-PT granules. To eliminate the uncertainty in results due to irregular granules sizes and shapes, comparisons were made for uniform size (210 micrometers) glass spheres. In this case the average D-C strength coincided with a second breakpoint in the P-C data, which occurred after compaction by a mechanism of bridge formation and collapse had ceased.

  11. Strength Measurement of Ceramic Spheres Using a Diametrally Compressed "C-Sphere" Specimen

    SciTech Connect

    Wereszczak, Andrew A [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville; Kirkland, Timothy Philip [ORNL

    2007-01-01

    A "C-sphere" flexure strength specimen geometry was conceived and developed to measure the hoop tensile strength of bearing-grade silicon nitride (Si3N4) balls. Because such a strength can be measured, the important study of surface-located strength-limiting flaws in ceramic sphere is also enabled with this specimen. A slot is machined into the balls to a set depth to produce the C-sphere geometry. A simple, monotonically increasing uniaxial compressive force produces a hoop tensile stress at the C-sphere's outer surface that ultimately initiates fracture. The strength is determined using the combination of failure load, C-sphere geometry, and finite element analysis. Additionally, the stress field was used to determine C-sphere effective areas and effective volumes as a function of Weibull modulus. To demonstrate this new specimen, C-sphere flexure strength distributions were determined for three commercially available bearing-grade Si3N4 materials (NBD200, SN101C, and TSN-03NH), and differences among their characteristic strengths and Weibull moduli were found.

  12. A comparison of pressure compaction and diametral compression tests for determining granule strengths

    SciTech Connect

    Glass, S.J.; Newton, C.

    1994-12-31

    Lightning strikes can cause structural damage, ignite flammable materials, and produce circuit malfunctions in missiles, aircraft, and ground systems. Lightning arrestor connectors (LACs) are used to divert harmful lightning energy away from these systems by providing less destructive breakdown paths. Ceramic granules in the size range of 150--200 {micro}m are used in LACs to provide physical and electrical separation of contacts (pins) from the surrounding metal web, and to control the voltage breakdown level. Pressure compaction (P-C) tests were used to characterize the strength of ceramic granules. When compaction data are plotted as relative density of the compact versus the compaction pressure two linear regions are generally observed. The intersection of these regions, which is known as the ``breakpoint,`` has been used as a semi-quantitative measure of granule strength. Comparisons were made between the P-C breakpoint and strengths of 150--200 {micro}m diameter ZnO, TiO{sub 2} (rutile), and lead magnesium niobate-lead titanate (PMN-PT) granules, where the strengths were determined by diametral compression (D-C) tests. At high compaction pressures the compliance of the die itself is significant and was accounted for in the analyses. Tests were conducted at different compaction rates, and with different aspect ratio compacts. High aspect ratios and loading rates decrease the slope of the second linear portion of the compaction curve and produce higher apparent P-C breakpoints. Comparison of the P-C breakpoint to the average D-C strength indicates that the D-C strength is approximately fifty percent higher for PMN-PT granules. To eliminate the uncertainty in results due to irregular granules sizes and shapes, comparisons were made for uniform size (210 {micro}m) glass spheres. In this case the average D-C strength coincided with a second breakpoint in the P-C data, which occurred after compaction by a mechanism of bridge formation and collapse had ceased.

  13. Tensile strength analysis of midpontic soldering.

    PubMed

    Ferencz, J L

    1987-06-01

    A total of 120 three-unit fixed partial dentures were made by using a latex mold to produce uniform wax patterns. Four groups were used to compare the tensile strength of connectors with interproximal solder, midpontic vertical solder, midpontic diagonal solder, and a control of one-piece castings. Three different metals were tested and the tensile load required to fracture the samples as well as the fracture sites were recorded. The following was found: Soldering the interproximal connector area produced the weakest solder joints, regardless of metal tested, at p less than .001. There was no significant difference in the fracture loads between midpontic vertical soldering and midpontic diagonal soldering with all three metals at p less than .01. There was no significant difference in fracture loads between midpontic soldering and unit casting with all three metals at p less than .01. The extreme variations in fracture loads when soldering nickel-chrome-beryllium confirms the technique sensitivity of presoldering this alloy. PMID:2884306

  14. Aluminum/steel wire composite plates exhibit high tensile strength

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Composite plate of fine steel wires imbedded in an aluminum alloy matrix results in a lightweight material with high tensile strength. Plates have been prepared having the strength of titanium with only 85 percent of its density.

  15. Comparative Evaluation of Dimensional Accuracy and Tensile Strength of a Type IV Gypsum Using Microwave and Air Drying Methods.

    PubMed

    Sharma, Anuraag; Shetty, Manoj; Hegde, Chethan; Shetty, N Sridhar; Prasad, D Krishna

    2013-12-01

    To evaluate dimensional accuracy and tensile strength of a type IV gypsum product, at different time intervals, dried in air or a microwave oven. Eighty specimens prepared from a cylindrical mould were used for measuring tensile strength (group A). Twenty specimens from a master die mould were used for determining dimensional accuracy (group B). In group A, 40 specimens were dried in open air at room temperature (A1). The other 40 were removed after 30 min and air dried for 20 min. These were subjected to microwave oven drying for 5 min (A2). Ten specimens each were tested under diametral compression at each of the following time periods: 1, 2, 4 and 24 h after drying. In group B, ten specimens were dried in open air at room temperature (B1). Ten specimens were removed from the mould after 30 min and air dried for 20 min. These were then dried in a microwave oven for 5 min (B2). The data was statistically analyzed using students unpaired "t" test. At all time intervals, diametral tensile strength (DTS) values for specimens dried in microwave oven were significantly higher than for those dried in open air. There were no significant differences between the dimensional accuracy of the two groups. In this study, microwave oven drying had a positive effect on the DTS of a type IV gypsum and the microwave oven dried specimens were as accurate as the air dried specimens over the same time period. PMID:24431786

  16. Delamination strength of YBCO coated conductors under transverse tensile stress

    Microsoft Academic Search

    D. C. van der Laan; J. W. Ekin; C. C. Clickner; T. C. Stauffer

    2007-01-01

    We present a new experimental technique to measure the delamination strength under transverse tensile stress of YBa2Cu3O7-delta coated conductors for electric power applications. The delamination strength, defined as the tensile stress at which the ceramic layers delaminate from one another, is measured at 76 K for different sample configurations. The delamination strength is reduced by as much as 40% when

  17. Numerical simulation of microstructural damage and tensile strength of snow

    NASA Astrophysics Data System (ADS)

    Hagenmuller, Pascal; Theile, Thiemo C.; Schneebeli, Martin

    2014-01-01

    This contribution uses finite-element analysis to simulate microstructural failure processes and the tensile strength of snow. The 3-D structure of snow was imaged by microtomography. Modeling procedures used the elastic properties of ice with bond fracture assumptions as inputs. The microstructure experiences combined tensile and compressive stresses in response to macroscopic tensile stress. The simulated nonlocalized failure of ice lattice bonds before or after reaching peak stress creates a pseudo-plastic yield curve. This explains the occurrence of acoustic events observed in advance of global failure. The measured and simulated average tensile strengths differed by 35%, a typical range for strength measurements in snow given its low Weibull modulus. The simulation successfully explains damage, fracture nucleation, and strength according to the geometry of the microstructure of snow and the mechanical properties of ice. This novel method can be applied to more complex snow structures including the weak layers that cause avalanches.

  18. Tensile and shear strength of adhesives

    NASA Technical Reports Server (NTRS)

    Stibolt, Kenneth A.

    1990-01-01

    This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given.

  19. Correlation of Yield Strength and Tensile Strength with Hardness for Steels

    NASA Astrophysics Data System (ADS)

    Pavlina, E. J.; van Tyne, C. J.

    2008-12-01

    Hardness values as well as yield and tensile strength values were compiled for over 150 nonaustenitic, hypoeutectoid steels having a wide range of compositions and a variety of microstructures. The microstructures include ferrite, pearlite, martensite, bainite, and complex multiphase structures. The yield strength of the steels ranged from approximately 300 MPa to over 1700 MPa. Tensile strength varied over the range of 450-2350 MPa. Regression analysis was used to determine the correlation of the yield strength and the tensile strength to the diamond pyramid hardness values for these steels. Both the yield strength and tensile strength of the steels exhibited a linear correlation with the hardness over the entire range of strength values. Empirical relationships are provided that enable the estimation of strength from a bulk hardness measurement. A weak effect of strain-hardening potential on the hardness-yield strength relationship was also observed.

  20. Tensile Bond Strength of Latex-Modified Bonded Concrete Overlays

    NASA Astrophysics Data System (ADS)

    Dubois, Cameron; Ramseyer, Chris

    2010-10-01

    The tensile bond strength of bonded concrete overlays was tested using the in-situ pull-off method described in ASTM C 1583 with the goal of determining whether adding latex to the mix design increases bond strength. One slab of ductile concrete (f'c > 12,000 psi) was cast with one half tined, i.e. roughened, and one half steel-troweled, i.e. smooth. The slab surface was sectioned off and overlay mixtures containing different latex contents cast in each section. Partial cores were drilled perpendicular to the surface through the overlay into the substrate. A tensile loading device applied a direct tensile load to each specimen and the load was increased until failure occurred. The tensile bond strength was then calculated for comparison between the specimens.

  1. Relation between interfacial shear strength and tensile strength of carbon fiber\\/resin composite strands

    Microsoft Academic Search

    M. Shioya; S. Yasui; A. Takaku

    1998-01-01

    The dependence of the tensile strength of unidirectional carbon fiber\\/epoxy resin composite strand on the fiber-matrix interfacial shear strength was investigated. The interfacial shear strength was changed by applying different levels of liquid-phase oxidations to the carbon fibers. The tensile strength of the composite strands did not increase monotonically with increasing interfacial shear strength but showed a maximum at a

  2. Probability characterization of tensile strength of an aluminum casting

    Microsoft Academic Search

    X. Teng; H. Mae; Y. Bai

    2010-01-01

    The paper statistically studies fracture properties of an aluminum low-pressure die casting component on basis of 32 tensile tests on round bar specimens. It reveals that the probability distribution of both ultimate tensile strength and fracture strain can be described using either the Weibull or the Gaussian function. Goodness-of-fit tests based on the Anderson–Darling statistic fail to reject either of

  3. On the dynamic tensile strength of Zirconium

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, G. J.; Hameed, A.; Vignjevic, R.; Hazell, P. J.; Painter, J.; Cademartori, S.

    2014-05-01

    Despite its fundamental nature, the process of dynamic tensile failure (spall) is poorly understood. Spall initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to the spall response of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an ongoing in-house body of work investigating these highly complex materials. In particular, in this paper the effect of impact stress on spall in a commercially sourced Zr rod is considered, with apparent strain-rate softening highlighted.

  4. On the dynamic tensile strength of zirconium

    NASA Astrophysics Data System (ADS)

    Appleby-Thomas, Gareth; Hameed, Amer; Vignjevic, Rade; Siviour, Clive; Hazell, Paul; Painter, Jonathan

    2013-06-01

    Dynamic tensile failure (spall) initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to spall of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an on-going in-house body of work investigating this complex class of materials. In particular, in this paper the effects of impact stress, pulse duration and texture on spall have been interrogated using velocimetry techniques.

  5. Water's tensile strength measured using an optofluidic chip.

    PubMed

    Li, Z G; Xiong, S; Chin, L K; Ando, K; Zhang, J B; Liu, A Q

    2015-05-01

    In this paper, for the first time, the tensile strength of water is directly measured using an optofluidic chip based on the displacement of air-water interface deformation with homogeneous nucleation. When water in a microchannel is stretched dynamically via laser-induced shock reflection at the air-water interface, the shock pressures are determined by measuring the displacements of the deformed interface. Observation of the vapor bubbles is used as a probe to identify the cavitation threshold with a critical distance, and the tensile strength of water at 20 °C is measured to be -33.3 ± 2.8 MPa. This method can be extended to investigate the tensile strength of other soft materials such as glycerol, which is measured to be -59.8 ± 10.7 MPa at 20 °C. PMID:25812076

  6. Covalent Crosslinking of Carbon Nanotube Materials for Improved Tensile Strength

    NASA Technical Reports Server (NTRS)

    Baker, James S.; Miller, Sandi G.; Williams, Tiffany A.; Meador, Michael A.

    2013-01-01

    Carbon nanotubes have attracted much interest in recent years due to their exceptional mechanical properties. Currently, the tensile properties of bulk carbon nanotube-based materials (yarns, sheets, etc.) fall far short of those of the individual nanotube elements. The premature failure in these materials under tensile load has been attributed to inter-tube sliding, which requires far less force than that needed to fracture individual nanotubes.1,2 In order for nanotube materials to achieve their full potential, methods are needed to restrict this tube-tube shear and increase inter-tube forces.Our group is examining covalent crosslinking between the nanotubes as a means to increase the tensile properties of carbon nanotube materials. We are working with multi-walled carbon nanotube (MWCNT) sheet and yarn materials obtained from commercial sources. Several routes to functionalize the nanotubes have been examined including nitrene, aryl diazonium, and epoxide chemistries. The functional nanotubes were crosslinked through small molecule or polymeric bridges. Additionally, electron beam irradiation induced crosslinking of the non-functional and functional nanotube materials was conducted. For example, a nanotube sheet material containing approximately 3.5 mol amine functional groups exhibited a tensile strength of 75 MPa and a tensile modulus of 1.16 GPa, compared to 49 MPa and 0.57 GPa, respectively, for the as-received material. Electron beam irradiation (2.2x 1017 ecm2) of the same amine-functional sheet material further increased the tensile strength to 120 MPa and the modulus to 2.61 GPa. This represents approximately a 150 increase in tensile strength and a 360 increase in tensile modulus over the as-received material with only a 25 increase in material mass. Once we have optimized the nanotube crosslinking methods, the performance of these materials in polymer matrix composites will be evaluated.

  7. Effects of parachute-ribbon surface treatments on tensile strength

    Microsoft Academic Search

    I. Auerbach; L. D. Whinery; D. W. Johnson; K. E. Mead; D. D. Sheldon

    1986-01-01

    Routine quality-assurance evaluations of nylon ribbons used on test-deployed parachutes revealed tensile-strength degradation had occurred in some of the ribbons. The degradation occurred exclusively in some of the noncritical skirt ribbons with stenciled blue-ink identification markings. Although the strength loss was excessive, the reliability of the parachute was not affected. These results motivated an accelerated-aging study of the effects on

  8. Tensile strength of butt-joined epoxy-aluminum plates

    Microsoft Academic Search

    T. T. Wang; T. K. kwei; H. M. Zupko

    1970-01-01

    Tensile tests conducted on butt joined epoxy-aluminum plates containing single cracks along the bond surfaces showed that there exists a characteristic crack length below which the fracture strength of the composite is mainly influenced by the stress concentrations at the bond edges. For specimens with cracks longer than the characteristic length the fracture of the composite is entirely controlled by

  9. Effect of Microwave Disinfection on Compressive and Tensile Strengths of Dental Stones

    PubMed Central

    Robati Anaraki, Mahmood; Moslehifard, Elnaz; Aminifar, Soran; Ghanati, Hamed

    2013-01-01

    Background and aims Although microwave irradiation has been used for disinfection of dental stone casts, there are concerns regarding mechanical damage to casts during the process. The aim of this study was to evaluate the effect of microwave irradiation on the compressive strength (CS) and diametral tensile strength (DTS) of stone casts. Materials and methods In this in vitro study, 80 cylindrical type III and IV stone models (20 × 40 mm) were prepared and divided into 8 groups of 10. The DTS and CS of the specimens were measured by a mechanical testing machine at a crosshead speed of 0.5 cm/min after 7 times of frequent wetting, irradiating at an energy level of 600 W for 3 minutes and cooling. Data were analyzed by Student’s t-test. Results Microwave irradiation significantly increased DTS of type III and IV to 5.23 ± 0.64 and 8.17 ± 0.94, respectively (P < 0.01). Conclusion According to the results, microwave disinfection increases DTS of type III and IV stone casts without any effects on their CS. PMID:23487305

  10. Prediction of splitting tensile strength from the compressive strength of concrete using GEP

    Microsoft Academic Search

    Metin Hakan Severcan

    Splitting tensile strength is one of the important mechanical properties of concrete that is used in structural design. In\\u000a this paper, it is aimed to propose formulation for predicting cylinder splitting tensile strength of concrete by using gene\\u000a expression programming (GEP). The database used for training, testing, and validation sets of the GEP models is obtained from\\u000a the literature. The

  11. Delamination strength of YBCO coated conductors under transverse tensile stress

    NASA Astrophysics Data System (ADS)

    van der Laan, D. C.; Ekin, J. W.; Clickner, C. C.; Stauffer, T. C.

    2007-08-01

    We present a new experimental technique to measure the delamination strength under transverse tensile stress of YBa2Cu3O7-? coated conductors for electric power applications. The delamination strength, defined as the tensile stress at which the ceramic layers delaminate from one another, is measured at 76 K for different sample configurations. The delamination strength is reduced by as much as 40% when the conductor is slit to smaller width, a standard fabrication process, and this reduction is due to damage to the ceramic layers near the edges of the conductor. We found that the delamination strength of slit coated conductors can be raised significantly by reinforcing the conductor by laminating it with copper strips and adding solder fillets at the edges. In relatively strong conductors, where the delamination strength is as high as 15 MPa, the critical current does not degrade before actual delamination. This fact greatly simplifies sample characterization of practical high-strength conductors, since only mechanical measurements need to be made. The critical current does, however, degrade significantly as a function of transverse stress before delamination in weak conductors that have relatively low delamination strength below 15 MPa. We discuss how a soft metallic layer in YBCO coated conductors may limit the transverse stress that the superconducting layer experiences in applications. Contribution of NIST, a US Government Agency, not subject to copyright.

  12. Evaluation of micro-tensile, shear and tensile tests determining the bond strength of three adhesive systems

    Microsoft Academic Search

    Paulo E. C Cardoso; Roberto R Braga; Marcela R. O Carrilho

    1998-01-01

    Objectives. The aim of this study was to determine bond strength between dentin and three adhesive systems, by means of micro-tensile, shear and tensile tests.Methods. Extracted human molars were embedded in acrylic resin and had the dentin exposed on three of their smooth surfaces. On each surface a specimen was prepared to be submitted to either micro-tensile, shear or tensile

  13. Gigacycle fatigue behaviors of two SNCM439 steels with different tensile strengthes

    Microsoft Academic Search

    Zheng Duan; Xian-Feng Ma; Hui-Ji Shi; Ryosuke Murai; Eiichi Yanagisawa

    Gigacycle fatigue behaviors of two SNCM439 steels with different tensile strengthes were experimentally studied by rotating\\u000a bending tests, to investigate the effects of the tensile strength obtained by different heat treatment processes on very high\\u000a cycle fatigue failure mechanisms. The material with higher tensile strength of 1 710MPa exhibited typical gigacycle fatigue\\u000a failure characteristics, whereas one with lower tensile strength

  14. A novel indirect tensile test method to measure the biaxial tensile strength of concretes and other quasibrittle materials

    SciTech Connect

    Zi, Goangseup [Department of Civil, Environmental and Architectural Engineering, Korea, University, 5 Ga 1, An-Am Dong, Sung-Buk Gu, Seoul, 136-701 (Korea, Republic of)], E-mail: g-zi@korea.ac.kr; Oh, Hongseob [Department of Civil Engineering, Jinju National University, 150 Chilam Dong, Jinju, Kyongnam, 660-758 (Korea, Republic of); Park, Sun-Kyu [Department of Civil Engineering, Sungkyunkwan University, 300 Cheoncheon Dong, Jangan Gu, Suwon, Gyeonggi, 440-746 (Korea, Republic of)

    2008-06-15

    A novel indirect tensile test method, the biaxial flexure test (BFT) method, has been developed to measure the biaxial tensile strength of concretes. The classical modulus of rupture (MOR) test has been generalized to three dimensions. In this method, we use a circular plate as the new test specimen. This plate is supported by an annular ring. We apply an external load to this specimen through a circular edge. The centers of the specimen, the loading device and the support are identical. The biaxial tensile strength measured by this new method is about 19% greater than the uniaxial tensile strength obtained from the classical modulus of rupture test as reported by other researchers. However, at the same time, we also found that the stochastic deviation of the biaxial tensile strength is about 63% greater than the uniaxial strength.

  15. Effects of parachute-ribbon surface treatments on tensile strength

    SciTech Connect

    Auerbach, I.; Whinery, L.D.; Johnson, D.W.; Mead, K.E.; Sheldon, D.D.

    1986-01-01

    Routine quality-assurance evaluations of nylon ribbons used on test-deployed parachutes revealed tensile-strength degradation had occurred in some of the ribbons. The degradation occurred exclusively in some of the noncritical skirt ribbons with stenciled blue-ink identification markings. Although the strength loss was excessive, the reliability of the parachute was not affected. These results motivated an accelerated-aging study of the effects on tensile strength of not only the inks but also of the sizing chemicals that are used to coat fabrics in parachute construction. Nylon ribbons and Kevlar webbing were treated with these materials and stored both under ambient conditions and at 60/sup 0/C (140/sup 0/F) for periods of time up to eight months. Small increases in strength developed under ambient conditions whereas small decreases developed at elevated temperatures. Samples stored in glass degraded more than those stored in stainless steel. None of these laboratory results correlated with those obtained from parachutes. Possible explanations for the lack of a correlation are provided in this paper. Additional studies are in progress.

  16. Tensile strength of bilayered ceramics and corresponding glass veneers

    PubMed Central

    Champirat, Tharee; Jirajariyavej, Bundhit

    2014-01-01

    PURPOSE To investigate the microtensile bond strength between two all-ceramic systems; lithium disilicate glass ceramic and zirconia core ceramics bonded with their corresponding glass veneers. MATERIALS AND METHODS Blocks of core ceramics (IPS e.max® Press and Lava™ Frame) were fabricated and veneered with their corresponding glass veneers. The bilayered blocks were cut into microbars; 8 mm in length and 1 mm2 in cross-sectional area (n = 30/group). Additionally, monolithic microbars of these two veneers (IPS e.max® Ceram and Lava™ Ceram; n = 30/group) were also prepared. The obtained microbars were tested in tension until fracture, and the fracture surfaces of the microbars were examined with fluorescent black light and scanning electron microscope (SEM) to identify the mode of failure. One-way ANOVA and the Dunnett's T3 test were performed to determine significant differences of the mean microtensile bond strength at a significance level of 0.05. RESULTS The mean microtensile bond strength of IPS e.max® Press/IPS e.max® Ceram (43.40 ± 5.51 MPa) was significantly greater than that of Lava™ Frame/Lava™ Ceram (31.71 ± 7.03 MPa)(P<.001). Fluorescent black light and SEM analysis showed that most of the tested microbars failed cohesively in the veneer layer. Furthermore, the bond strength of Lava™ Frame/Lava™ Ceram was comparable to the tensile strength of monolithic glass veneer of Lava™ Ceram, while the bond strength of bilayered IPS e.max® Press/IPS e.max® Ceram was significantly greater than tensile strength of monolithic IPS e.max® Ceram. CONCLUSION Because fracture site occurred mostly in the glass veneer and most failures were away from the interfacial zone, microtensile bond test may not be a suitable test for bonding integrity. Fracture mechanics approach such as fracture toughness of the interface may be more appropriate to represent the bonding quality between two materials. PMID:25006377

  17. Through-the-thickness tensile strength of textile composites

    NASA Technical Reports Server (NTRS)

    Jackson, Wade C.; Ifju, Peter G.

    1994-01-01

    A series of tests was run to characterize the through-the-thickness tensile strength for a variety of composites that included 2D and 3D braids, 2D and 3D weaves, and prepreg tapes. A new test method based on a curved beam was evaluated. The through-the-thickness deformations were characterized using moire interferometry. Failures were significantly different between the 2D and 3D materials. The 2D materials delaminated between layers due to out-of-plane tensile stresses. The strength of the 2D textile composites did not increase relative to the tapes. The 3D materials failed due to the formation of radial cracks caused by high circumferential stresses along the inner radius. A circumferential crack similar to the 2D materials produced the final failure. Final failure in the 3D materials occurred at a lower bending moment than in other materials. The early failures were caused by radial crack formation rather than low through-the-thickness strength.

  18. Tensile strength and the mining of black holes.

    PubMed

    Brown, Adam R

    2013-11-22

    There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This Letter looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta, and puts a severe constraint on the operation of "space elevators" near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation, and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed. As a consequence of this limitation, the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings. PMID:24313473

  19. Tensile Strength and the Mining of Black Holes

    E-print Network

    Brown, Adam R

    2012-01-01

    There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta and puts a severe constraint on the operation of 'space elevators' near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed and that as a consequence of this limitation the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.

  20. Tensile Strength and the Mining of Black Holes

    E-print Network

    Adam R. Brown

    2012-07-13

    There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This paper looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta and puts a severe constraint on the operation of 'space elevators' near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed and that as a consequence of this limitation the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.

  1. Tensile Strength and the Mining of Black Holes

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.

    2013-11-01

    There are a number of important thought experiments that involve raising and lowering boxes full of radiation in the vicinity of black hole horizons. This Letter looks at the limitations placed on these thought experiments by the null energy condition, which imposes a fundamental bound on the tensile-strength-to-weight ratio of the materials involved, makes it impossible to build a box near the horizon that is wider than a single wavelength of the Hawking quanta, and puts a severe constraint on the operation of “space elevators” near black holes. In particular, it is shown that proposals for mining black holes by lowering boxes near the horizon, collecting some Hawking radiation, and dragging it out to infinity cannot proceed nearly as rapidly as has previously been claimed. As a consequence of this limitation, the boxes and all the moving parts are superfluous and black holes can be destroyed equally rapidly by threading the horizon with strings.

  2. Gigacycle fatigue behaviors of two SNCM439 steels with different tensile strengths

    NASA Astrophysics Data System (ADS)

    Duan, Zheng; Ma, Xian-Feng; Shi, Hui-Ji; Murai, Ryosuke; Yanagisawa, Eiichi

    2011-10-01

    Gigacycle fatigue behaviors of two SNCM439 steels with different tensile strengthes were experimentally studied by rotating bending tests, to investigate the effects of the tensile strength obtained by different heat treatment processes on very high cycle fatigue failure mechanisms. The material with higher tensile strength of 1 710MPa exhibited typical gigacycle fatigue failure characteristics, whereas one with lower tensile strength of 1 010MPa showed only traditional fatigue limit during the tests and no gigacycle failure could be found even when the specimen ran up to more than 108 cycles. Metallographic and fractographic analysis were carried out by an optical microscope (OM) and scanning electron microscope (SEM). It showed two different crack initiation mechanisms that for the specimen with lower tensile strength the crack prefers surface initiation and for that with higher strength the crack initiates from subsurface inclusions revealed by a fish-eye like microstructure.

  3. Tensile Strength of Glass Fiber-Reinforced Plastic by Fiber Orientation and Fiber Content Variations

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Woo; Kim, Hyoung-Seok; Lee, Dong-Gi

    For unidirectional composite material, there is a theoretical mixture rule equation to calculate the strength of composite from properties of matrix and fiber content. However, the equation for tensile strength with the fiber content and the fiber orientation is not available. Therefore, this study was investigated what affect fiber content and fiber orientation have on the strength of composites. Glass fiber-reinforced plastic by changing fiber orientation and fiber content was made. Tensile strength of 0° direction of composites increased being proportional fiber content and fiber orientation function as change from isotropy (J=0) to anisotropy (J=1). But, tensile strength of 90° direction by separation of fiber filament decreased when tensile load is imposed for width direction of reinforcement fiber length direction. In this study, empirical equation to estimate tensile strength out of fiber orientation and fiber content was proposed.

  4. Tensile testing of insulating thin films; humidity effect on tensile strength of SiO 2 films

    Microsoft Academic Search

    Toshiyuki Tsuchiya; Atsuko Inoue; Jiro Sakata

    2000-01-01

    Humidity effect on the strength of a plasma-enhanced chemical vapor deposition (CVD) SiO2 film is evaluated with new tensile testing method using an electrostatic force grip. This method can test insulating films without troublesome specimen preparation and careful handling. To measure the humidity effect, two thin film tensile testers are used. One can perform test in air, and the other

  5. Strain hardening and large tensile elongation in ultrahigh-strength nano-twinned copper

    Microsoft Academic Search

    E. Ma; Y. M. Wang; Q. H. Lu; M. L. Sui; L. Lu; K. Lu

    2004-01-01

    A high density of growth twins in pure Cu imparts high yield strength while preserving the capacity for efficient dislocation storage, leading to high strain hardening rates at high flow stresses, especially at 77 K. Uniform tensile deformation is stabilized to large plastic strains, resulting in an ultrahigh tensile strength of ~1 GPa together with an elongation to failure of

  6. Correlation of tensile and shear strengths of metals with their friction properties

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    The relation between the theoretical tensile and the shear strengths and the friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated. The relationship between the actual shear strength and the friction properties of the metal was also investigated. An estimate of the theoretical uniaxial tensile strength was obtained in terms of the equilibrium surface energy, interplanar spacing of the planes perpendicular to the tensile axis, and the Young's modulus of elasticity. An estimate of the theoretical shear strength for metals was obtained from the shear modulus, the repeat distance of atoms in the direction of shear of the metal and the interplanar spacing of the shear planes. The coefficient of friction for metals was found to be related to the theoretical tensile, theoretical shear, and actual shear strengths of metals. The higher the strength of the metal, the lower the coefficient of friction.

  7. Effect of strain rate on formability in warm deep drawing of high tensile strength steel sheet

    NASA Astrophysics Data System (ADS)

    Yoshihara, Shoichiro; Iwamatsu, Go

    2014-10-01

    In tensile test of the high tensile strength steel, tensile strength isdrastically decreased as the temperature is raised. Then, the strain rate sensitivity exponent of high tensile strength steel (SUS631) in this study is high at 800 degrees especially. Also, elongation is increased as the temperature is raised. In deep drawing, the maximum punch load of the high tensile strength steel is examined on difference punch speed at 600 and 800 degrees. On the other hand, finite element (FE) simulation was used for the possibility to evaluate the forming load on difference punch speed in warm deep drawing. In FE simulation, we have considered both the strain hardening exponent and the strain rate sensitivity exponent (m-value) because we cannot neglect m-value 0.184 at 800 degrees. The tendency of the forming load in the experiments agrees the results in FE simulation.

  8. Tensile bond strengths of an electrolytically and chemically etched base metal.

    PubMed

    Aquilino, S A; Diaz-Arnold, A M; Krueger, G E

    1990-01-01

    This study compared the tensile bond strengths of a Ni-Cr-Be alloy electrolytically etched and chemically etched with three commercially available gels. Etched metal cylinders were bonded end-to-end with a resin luting agent and subsequently tested for tensile strength. Mean bond strengths and the character of bond failure were recorded. Significant differences were found between the electrolytically and chemically etched specimens. PMID:2196897

  9. Tensile and flexural strength of commercially pure titanium submitted to laser and tungsten inert gas welds.

    PubMed

    Atoui, Juliana Abdallah; Felipucci, Daniela Nair Borges; Pagnano, Valéria Oliveira; Orsi, Iara Augusta; Nóbilo, Mauro Antônio de Arruda; Bezzon, Osvaldo Luiz

    2013-01-01

    This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (?=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84 ± 19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90 ± 37.76; laser=515.85 ± 62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations. PMID:24474361

  10. Specimen size effect on tensile strength of surface-micromachined polycrystalline silicon thin films

    Microsoft Academic Search

    Toshiyuki Tsuchiya; Osamu Tabata; Jiro Sakata; Yasunori Taga

    1998-01-01

    A new tensile tester using an electrostatic-force grip was developed to evaluate the tensile strength and the reliability of thin-film materials. The tester was constructed in a scanning electron microscope (SEM) chamber for in situ observation and was applied for tensile testing of polycrystalline silicon (poly-Si) thin films with dimensions of 30-300 ?m long, 2-5 ?m wide, and 2 ?m

  11. Tensile Strength of Single Lap Joint and Scarf Joint between CFRP and Carbon Steel

    Microsoft Academic Search

    Chiaki Sato; Kozo Ikegami

    1992-01-01

    The strength of single lap joints and scarf joints between carbon cloth laminated plastics (CFRP) and carbon steel bonded with epoxy resin was investigated both analytically and experimentally. The stress and strain distributions under tensile loads of the joints were analyzed by applying the elastic finite element method.The strength of the joints was predicted by applying the strength law of

  12. Sheave-bending and tensile fatigue of aramid-fiber strength members for communications cables

    Microsoft Academic Search

    Todd M Mower

    2000-01-01

    The influence of cyclic loading upon the residual strength of aramid-fiber strength members has been examined experimentally. Cyclic bending over sheaves, while under low tension, and tensile fatigue with low cyclic amplitude were studied. Residual strengths of the test specimens were measured as a function of number of cycles, and the tension and temperature during fatigue. It was found that

  13. Differential Tensile Strength and Collagen Composition in Ascending Aortic Aneurysms by Aortic Valve Phenotype

    PubMed Central

    Pichamuthu, Joseph E.; Phillippi, Julie A.; Cleary, Deborah A.; Chew, Douglas W.; Hempel, John; Vorp, David A.; Gleason, Thomas G.

    2014-01-01

    Background Ascending thoracic aortic aneurysm (ATAA) predisposes patients to aortic dissection and has been associated with diminished tensile strength and disruption of collagen. ATAA arising in patients with bicuspid aortic valve (BAV) develop earlier than those with tricuspid aortic valves (TAV) and have a different risk of dissection. The purpose of this study was to compare aortic wall tensile strength between BAV and TAV ATAAs and determine if the collagen content of the ATAA wall is associated with tensile strength and valve phenotype. Methods Longitudinally and circumferentially oriented strips of ATAA tissue obtained during elective surgery were stretched to failure and collagen content was estimated by hydroxyproline assay. Experimental stress-strain data were analyzed for failure strength and elastic mechanical parameters: ?, ? and maximum tangential stiffness. Results The circumferential and longitudinal tensile strengths were higher for BAV ATAA when compared with TAV ATAA. The ? and ? were lower for BAV ATAA when compared with TAV ATAA. The maximum tangential stiffness was higher for circumferential when compared with longitudinal orientation in both BAV and TAV ATAA. Amount of hydroxyproline was equivalent in BAV and TAV ATAA specimens. While there was a moderate correlation between the collagen content and tensile strength for TAV, this correlation is not present in BAV. Conclusion The increased tensile strength and decreased values of ? and ? in BAV ATAAs despite uniform collagen content between groups indicate that micro-structural changes in collagen contribute to BAV-associated aortopathy. PMID:24021768

  14. Experimental and numerical study on tensile strength of concrete under different strain rates.

    PubMed

    Min, Fanlu; Yao, Zhanhu; Jiang, Teng

    2014-01-01

    The dynamic characterization of concrete is fundamental to understand the material behavior in case of heavy earthquakes and dynamic events. The implementation of material constitutive law is of capital importance for the numerical simulation of the dynamic processes as those caused by earthquakes. Splitting tensile concrete specimens were tested at strain rates of 10(-7) s(-1) to 10(-4) s(-1) in an MTS material test machine. Results of tensile strength versus strain rate are presented and compared with compressive strength and existing models at similar strain rates. Dynamic increase factor versus strain rate curves for tensile strength were also evaluated and discussed. The same tensile data are compared with strength data using a thermodynamic model. Results of the tests show a significant strain rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain rate. In the quasistatic strain rate regime, the existing models often underestimate the experimental results. The thermodynamic theory for the splitting tensile strength of concrete satisfactorily describes the experimental findings of strength as effect of strain rates. PMID:24883355

  15. Tensile strength of carbon nanotubes under realistic temperature and strain rate Chenyu Wei,1,2

    E-print Network

    Srivastava, Deepak

    for yielding of multiwalled CNT's MWCNT Ref.6 to be as high as 12%. The yielding or failure of CNT's is mainly not readily explain the experimentally measured low tensile strength of SWCNT ropes or MWCNT's. On the other

  16. Increasing the tensile strength of HTPB with different isocyanates and chain extenders

    Microsoft Academic Search

    Niklas Wingborg

    2002-01-01

    The influence of the diols 1,4-butanediol, BDO, and 1,4-cyclohexane dimethanol, CHDM, on the mechanical properties of HTPB, cured with the diisocyanates, IPDI, HDI and H12MDI, was investigated. The highest tensile strength was obtained by using H12MDI and BDO. When adding the diols the tensile strength increases strongly up to 2 mol of diols per mole of HTPB. Above that point

  17. Small screw study: Interim report on fastener tensile strength and optimum thread depth

    Microsoft Academic Search

    K. V. Diegert; L. R. Dorrell; R. T. Reese; L. J. Lazarus

    1989-01-01

    This report summarizes about 1260 tests performed on small threaded fasteners (equal to or less than 1\\/4 inch in diameter and designated as 1\\/4-20 UNC, {number sign}4-40 UNC, {number sign}2-56 UNC, and 1.0 UNM). Tests determined the tensile strengths of the screws, the lengths of engagement needed to develop the full tensile strengths when the screws were engaged in 6061-T6

  18. Low-velocity impact and residual tensile strength analysis to carbon fiber composite laminates

    Microsoft Academic Search

    Shi-Xun Wang; Lin-Zhi Wu; Li Ma

    2010-01-01

    In this paper, low-velocity impact characteristics and residual tensile strength of carbon fiber composite laminates are investigated by experimentally and numerically. Low-velocity impact tests and residual tensile strength tests are performed using an instrumented drop-weight machine (Instron 9250HV) and static test machine (Instron 5569), respectively. The finite element (FE) software, ABAQUS\\/Explicit is employed to simulate low-velocity impact characteristics and predict

  19. Impact of a microwave curing process on tensile strength of selected carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Balzer, Brian B.

    The traditional process for curing carbon fiber (CF) composites has been the autoclave system. A review of recent research indicates curing CF composites in a microwave oven has the potential for reducing processing time. The problem statement of the experimental study was that the impact of a microwave curing process on tensile strength of selected CF composite specimens was unknown. The research study describes the statistical procedure and analysis of data to answer the specific question for the experimental trials: What is the effect on the tensile strength of cured CF composite samples due to the relationship of the autoclave and microwave curing process cycle time and temperature? ASTM International standard test method designation D 5083 - 02 was used for testing tensile strength of reinforced carbon fiber plastics using straight-sided specimens. Analytical data was obtained for evaluating the effects of process cycle time and temperature on tensile strength of the CF composite specimens. The result was that curing time of the autoclave system and microwave process had significant effects on the maximum tensile stress of CF composite specimen. Although 83% faster than the autoclave system, the microwave curing process had CF specimens with lower maximum tensile strength compared with the autoclave system results. The primary reason for the difference was that the microwave process did not use vacuum or pressure. Considering the cost/benefit ratio, the research study indicated that the microwave oven would be a viable and efficient process for curing CF composites.

  20. Biophotonic effect of diode laser irradiance on tensile strength of diabetic rats.

    PubMed

    Lau, Pik Suan; Bidin, Noriah; Krishnan, Ganesan; Nassir, Zaleha; Bahktiar, Hazri

    2015-04-01

    Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers-0.1 and 0.5 W/cm(2)-and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing. PMID:25260140

  1. A modified test for measuring the interlaminar tensile strength of fiber-reinforced ceramic composites

    E-print Network

    Zok, Frank

    to these planes. That is, they exhibit linear stress/strain response with complete loss of load bearing capacityA modified test for measuring the interlaminar tensile strength of fiber-reinforced ceramic) strength of ceramic composites with two-dimensional fiber architectures presents serious challenges

  2. Characterization of Optical Fiber Strength Under Applied Tensile Stress and Bending Stress

    SciTech Connect

    P.E. Klingsporn

    2011-08-01

    Various types of tensile testing and bend radius tests were conducted on silica core/silica cladding optical fiber of different diameters with different protective buffer coatings, fabricated by different fiber manufacturers. The tensile tests were conducted to determine not only the average fiber strengths at failure, but also the distribution in fracture strengths, as well as the influence of buffer coating on fracture strength. The times-to-failure of fiber subjected to constant applied bending stresses of various magnitudes were measured to provide a database from which failure times of 20 years or more, and the corresponding minimum bend radius, could be extrapolated in a statistically meaningful way. The overall study was done to provide an understanding of optical fiber strength in tensile loading and in applied bending stress as related to applications of optical fiber in various potential coizfgurations for weapons and enhanced surveillance campaigns.

  3. Specimen type and size effects on lithium hydride tensile strength distributions

    SciTech Connect

    Oakes, Jr, R E

    1991-12-01

    Weibull's two-parameter statistical-distribution function is used to account for the effects of specimen size and loading differences on strength distributions of lithium hydride. Three distinctly differing uniaxial specimen types (i.e., an elliptical-transition pure tensile specimen, an internally pressurized ring tensile, and two sizes of four-point-flexure specimens) are shown to provide different strength distributions as expected, because of their differing sizes and modes of loading. After separation of strengths into volumetric- and surface-initiated failure distributions, the Weibull characteristic strength parameters for the higher-strength tests associated with internal fracture initiations are shown to vary as predicted by the effective specimen volume Weibull relationship. Lower-strength results correlate with the effective area to much lesser degree, probably because of the limited number of surface-related failures and the different machining methods used to prepare the specimen. The strength distribution from the fourth specimen type, the predominantly equibiaxially stressed disk-flexure specimen, is well below that predicted by the two-parameter Weibull-derived effective volume or surface area relations. The two-parameter Weibull model cannot account for the increased failure probability associated with multiaxial stress fields. Derivations of effective volume and area relationships for those specimens for which none were found in the literature, the elliptical-transition tensile, the ring tensile, and the disk flexure (including the outer region), are also included.

  4. Thermal degradation of the tensile strength of unidirectional boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Grimes, H. H.; Lad, R. A.; Maisel, J. E.

    1977-01-01

    The variation of ultimate tensile strength with thermal treatment of B-Al composite materials and of boron fibers chemically removed from these composites in an attempt to determine the mechanism of the resulting strength degradation was studied. Findings indicate that thermally cycling B-Al represents a more severe condition than equivalent time at temperature. Degradation of composite tensile strength from about 1.3 GN/m squared to as low as 0.34 GN/m squared was observed after 3,000 cycles to 420 C for 203 micrometers B-1100 Al composite. In general, the 1100 Al matrix composites degraded somewhat more than the 6061 matrix material studied. Measurement of fiber strengths confirmed a composite strength loss due to the degradation of fiber strength. Microscopy indicated a highly flawed fiber surface.

  5. Environmental effects on the tensile strength of chemically vapor deposited silicon carbide fibers

    NASA Technical Reports Server (NTRS)

    Bhatt, R. T.; Kraitchman, M. D.

    1985-01-01

    The room temperature and elevated temperature tensile strengths of commercially available chemically vapor-deposited (CVD) silicon carbide fibers were measured after 15 min heat treatment to 1600 C in various environments. These environments included oxygen, air, argon and nitrogen at one atmosphere and vacuum at 10/9 atmosphere. Two types of fibers were examined which differed in the SiC content of their carbon-rich coatings. Threshold temperature for fiber strength degradation was observed to be dependent on the as-received fiber-flaw structure, on the environment and on the coating. Fractographic analyses and flexural strength measurements indicate that tensile strength losses were caused by surface degradation. Oxidation of the surface coating is suggested as one possible degradation mechanism. The SiC fibers containing the higher percentage of SiC near the surface of the carbon-rich coating show better strength retention and higher elevated temperature strength.

  6. The ideal tensile strength of tungsten and tungsten alloys by first-principles calculations

    NASA Astrophysics Data System (ADS)

    Giusepponi, Simone; Celino, Massimo

    2013-04-01

    The ideal tensile strength in the [0 0 1] direction of bcc crystal tungsten and its alloys (W-Re, W-Ta and W-V) has been investigated by using first-principles total energy method based on the density functional theory. Crystalline tungsten containing a single substitutional defect (concentration of defects about 2%) has been characterized in terms of structural and mechanical properties. The maximum tensile stress required to reach elastic instability under increasing load has been further computed.

  7. Treatment of bleached wool with trans-glutaminases to enhance tensile strength, whiteness, and alkali resistance.

    PubMed

    Montazer, Majid; Lessan, Fatemeh; Pajootan, Elmira; Dadashian, Fatemeh

    2011-09-01

    Trans-glutaminases is known as a cross-linking enzyme for proteins. Wool is a proteinous fiber conventionally is treated through several processes to obtain the desirable characteristics. Bleaching is also one of the most important processes usually carried out by using an oxidizing agent in a conventional method. The tensile strength of wool yarns was reduced as a consequence of oxidative bleaching. Here, with the help of microbial trans-glutaminases (m-TGases), a novel bleaching process was disclosed in a way to obtain a bleached wool yarn with no significant reduction in the tensile strength. The results confirmed that the bleached wool yarns with H(2)O(2) could be modified by m-TGases post-treatment. The m-TGases treatment on the bleached wool yarns improved the tensile strength and whiteness along with the higher alkali resistance. PMID:21638062

  8. Anastomotic tensile strength following in situ replacement of an infected abdominal aortic graft.

    PubMed

    Vetsch, R; Bandyk, D F; Schmitt, D D; Bergamini, T M; Storey, J D; Towne, J B

    1989-04-01

    The tensile strength and histologic features of anastomotic bonding were studied prior to and following in situ replacement of aortic vascular prostheses infected by Staphylococcus epidermidis. Sterile (n = 6) and infected (n = 19) Dacron grafts were used to replace the abdominal aorta of 25 dogs. After five weeks, grafts were explanted, and peak tensile force (measured in kilograms) required for anastomotic disruption was measured using a linear gain tensiometer. Anastomotic tensile strength (mean +/- SEM) of infected grafts (5.4 +/- 0.5 kg) was decreased when compared with that of sterile, control grafts (9.0 +/- 0.9 kg). The decreased anastomotic tensile strength of infected grafts was the result of an inflammatory aortitis adjacent to the suture line. Only grafts infected with the study strain of bacteria demonstrated signs of infection. In 19 dogs, the graft infection was treated by graft excision, antibiotic administration, and in situ graft replacement (Dacron or polytetrafluoroethylene prostheses). After five weeks and 12 weeks, anastomotic tensile strength of polytetrafluoroethylene (10.6 +/- 0.6 kg) and Dacron (10.8 +/- 0.5 kg) replacement grafts was similar to that of uninfected control grafts. In situ replacement of vascular prostheses infected by S epidermidis can result in graft healing with normal anastomotic bonding. PMID:2522764

  9. The effects of ZnO2 nanoparticles on split tensile strength of self-compacting concrete

    Microsoft Academic Search

    Ali Nazari; Shadi Riahi

    2012-01-01

    In this study, split tensile strength of self-compacting concrete (SCC) with different amounts of ZnO2 nanoparticles has been investigated. ZnO2 nanoparticles with the average particle size of 15?nm were added partially to SCC and split tensile strength of the specimens has been measured. The results indicate that ZnO2 nanoparticles are able to improve the split tensile strength of SCC and

  10. The effect of a compliant polyimide nanocoating on the tensile properties of a high strength PAN-based carbon fiber

    Microsoft Academic Search

    Tamaki Naganuma; Kimiyoshi Naito; Jenn-Ming Yang; Junro Kyono; Daisuke Sasakura; Yutaka Kagawa

    2009-01-01

    The effect of a compliant polyimide nanocoating on the tensile strength of a polyacrylonitrile-based high tensile strength (T1000GB) carbon fiber was investigated. The pyromellitic dianhydride\\/4-4?-oxydianiline polyimide nanocoating was deposited by high-temperature vapor deposition polymerization. The thickness of the polyimide coating was about 100nm. The tensile strength and Weibull modulus of nanocoated and uncoated fiber bundles were evaluated using a polyimide-impregnated

  11. Instrumented impact and residual tensile strength testing of eight-ply carbon eopoxy specimens

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1990-01-01

    Instrumented drop weight impact testing was utilized to examine a puncture-type impact on thin carbon-epoxy coupons. Four different material systems with various eight-ply lay-up configurations were tested. Specimens were placed over a 10.3-mm diameter hole and impacted with a smaller tup (4.2-mm diameter) than those used in previous studies. Force-time plots as well as data on absorbed energy and residual tensile strength were gathered and examined. It was found that a critical impact energy level existed for each material tested, at which point tensile strength began to rapidly decrease with increasing impact energy.

  12. Tensile strength of dome rocks and lavas at Santiaguito dome complex, Guatemala

    NASA Astrophysics Data System (ADS)

    Hornby, Adrian; Lamb, Oliver; Lamur, Anthony; Lavallée, Yan

    2015-04-01

    Lava domes are inherently unstable structures, subject to intense gas flux and rapid variations in the state of stress. At shallow depths confining stresses are minimal and deformation is dilatant, occurring predominantly through tensile fractures. This fracture mode facilitates outgassing and contributes to the development of gas-and-ash activity as well as vulcanian eruptions. However, there is a paucity of tensile strength data for volcanic materials in the published literature, and we know of no paper which addresses this at high temperatures. We study the tensile strength of dome rocks collected at the Santiaguito dome complex, Guatemala, over a porosity range of 3-25%. Indirect tensile (Brazilian) tests were conducted on 40-mm diameter cores, by imposing a compressive displacement rate (radial to the core) of 4 micron/s at room temperature as well as an eruptive temperature of ca. 850 °C. An acoustic monitoring system is employed to track the nucleation, propagation and coalescence of fractures leading to complete sample failure. We find that the rocks' tensile strength exhibits a nonlinear decrease with porosity. Preliminary tests at high temperature indicate that some rocks exhibit a higher tensile strength (than at room temperature); in these experiments, samples containing a higher fraction of interstitial melt revealed an additional component of viscous flow. Further experiments conducted at higher strain rates will define the brittle response of the liquid during tensile failure. The data is compared against similar datasets for volcanic rocks. We will discuss implications for shallow volcanic processes ranging from dilation bands and tuffisite formation to gas-and-ash explosions and dome structural stability.

  13. SIZE EFFECTS IN THE TENSILE STRENGTH OF UNIDIRECTIONAL FIBER COMPOSITES

    SciTech Connect

    M. SIVASAMBU; ET AL

    1999-08-01

    Monte Carlo simulation and theoretical modeling are used to study the statistical failure modes in unidirectional composites consisting of elastic fibers in an elastic matrix. Both linear and hexagonal fiber arrays are considered, forming 2D and 3D composites, respectively. Failure is idealized using the chain-of-bundles model in terms of {delta}-bundles of length {delta}, which is the length-scale of fiber load transfer. Within each {delta}-bundle, fiber load redistribution is determined by local load-sharing models that approximate the in-plane fiber load redistribution from planar break clusters as predicted from 2D and 3D shear-lag models. As a result these models are 1D and 2D, respectively. Fiber elements have random strengths following either the Weibull or the power-law distribution with shape and scale parameters {rho} and {sigma}{sub {delta}}, respectively. Simulations of {delta}-bundle failure, reveal two regimes. When fiber strength variability is low (roughly {rho} > 2) the dominant failure mode is by growing clusters of fiber breaks up to instability. When this variability is high (roughly 0 < {rho} < 1) cluster formation is suppressed by a dispersed fiber failure mode. For these two cases, closed-form approximations to the strength distribution of a {delta}-bundle are developed under the local load-sharing model and an equal load-sharing model of Daniels, respectively. The results compare favorably with simulations on {delta}-bundles with up to 1500 fibers. The location of the transition in terms of {rho} is affected by the upper tail properties of the fiber strength distributions as well as the number of fibers.

  14. Effective Size Analysis of the Diametral Compression (Brazil) Test Specimen

    SciTech Connect

    Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL

    2009-04-01

    This study considers the finite element analysis (FEA) simulation and Weibull effective size analysis for the diametral compression (DC) or Brazil specimen loaded with three different push-rod geometries. Those geometries are a flat push-rod, a push-rod whose radius of curvature is larger than that for the DC specimen, and a push-rod whose radius of curvature matches that of the DC specimen. Such established effective size analysis recognizes that the tensile strength of structural ceramics is typically one to two orders of magnitude less than its compressive strength. Therefore, because fracture is much more apt to result from a tensile stress than a compressive one, this traditional analysis only considers the first principal tensile stress field in the mechanically loaded ceramic component for the effective size analysis. The effective areas and effective volumes were computed as function of Weibull modulus using the CARES/Life code. Particular attention was devoted to the effect of mesh sensitivity and localized stress concentration. The effect of specimen width on the stress state was also investigated. The effects of push-rod geometry, the use of steel versus WC push-rods, and considering a frictionless versus no-slip interface between push-rod and specimen on the maximum stresses, where those stresses are located, and the effective area and effective volume results are described. Of the three push-rod geometries, it is concluded that the push-rod (made from WC rather than steel) whose radius of curvature matches that of the DC specimen is the most apt to cause fracture initiation within the specimen's bulk rather than at the loading interface. Therefore, its geometry is the most likely to produce a valid diametral compression strength test. However, the DC specimen remains inefficient in terms of its area and volume efficiencies; namely, the tensile strength of only a few percent of the specimen's entire area or volume is sampled. Given the high probability that a valid (or invalid) test can be proven by ceramic fractographic practices suggests that this test method and specimen is questionable for use with relatively strong structural ceramics.

  15. Development of Yield and Tensile Strength Design Curves for Alloy 617

    SciTech Connect

    Nancy Lybeck; T. -L. Sham

    2013-10-01

    The U.S. Department of Energy Very High Temperature Reactor Program is acquiring data in preparation for developing an Alloy 617 Code Case for inclusion in the nuclear section of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. A draft code case was previously developed, but effort was suspended before acceptance by ASME. As part of the draft code case effort, a database was compiled of yield and tensile strength data from tests performed in air. Yield strength and tensile strength at temperature are used to set time independent allowable stress for construction materials in B&PV Code, Section III, Subsection NH. The yield and tensile strength data used for the draft code case has been augmented with additional data generated by Idaho National Laboratory and Oak Ridge National Laboratory in the U.S. and CEA in France. The standard ASME Section II procedure for generating yield and tensile strength at temperature is presented, along with alternate methods that accommodate the change in temperature trends seen at high temperatures, resulting in a more consistent design margin over the temperature range of interest.

  16. Tensile, flexural and compressive strength studies on natural and artificial phosphate urinary stones.

    PubMed

    Mohamed Ali, A; Arunai Nambi Raj, N

    2008-12-01

    Mechanical properties of renal calculi dictate how a stone interacts and disintegrates by shock wave or intracorporeal lithotripsy techniques. Renal stones of different compositions have large variation in their mechanical strength and susceptibilities to shock waves. Operated urinary stones and artificially developed stones using pharmaceutical methods, composed of phosphates were subjected to tensile, flexural and compressive strength studies using universal testing machine. The infrared spectra confirmed the presence of hydroxyapatite in both the natural stones and struvite with calcium oxalate trihydrate in one stone and struvite with uric acid in the other. The X-ray diffraction analyses confirmed their crystalline nature. It has been observed that the flexural properties depend on the size of the sample even for the samples cut from a single stone. The compressive strengths were almost 25 times larger than the tensile strengths of the respective natural stones as well as the artificial stones prepared. PMID:18987852

  17. DEVELOPMENT OF TENSILE STRENGTH DURING DISTRACTION OSTEOGENESIS IN A RAT MODEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    These studies were designed to determine the reliability of in vitro tensile testing to measure the temporal development of regenerate bone strength in rats during limb lengthening (distraction osteogenesis, DO). External fixators were placed on the right tibiae of 36 virus-free, 400-450 g male Spr...

  18. Melt reaction of zein with glyoxal to improve tensile strength and reduce solubility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glyoxal, in the presence of base, has been used to crosslink zein in a melt process, involving reaction in a melt state combined with compression molding. The resulting zein articles had improved tensile strength, increasing from 34.3 to 40.6 MPa, when the amount of glyoxal was 6% by zein weight. ...

  19. Tensile properties of carbon nanotubes grown on ultrahigh strength polyacrylonitrile-based and ultrahigh modulus pitch-based carbon fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi; Yang, Jenn-Ming; Tanaka, Yoshihisa; Kagawa, Yutaka

    2008-06-01

    The tensile properties and fracture behavior of carbon nanotubes (CNTs) grown on ultrahigh tensile strength polyacrylonitrile (PAN)-based (T1000GB) and ultrahigh modulus pitch-based (K13D) carbon fibers have been investigated. The CNTs were grown on the carbon fiber surface using chemical vapor deposition. The statistical scattering of the tensile strength was also evaluated. The results clearly show that grafting of CNTs improves the mechanical properties and the Weibull modulus of ultrahigh tensile strength PAN-based and ultrahigh modulus pitch-based carbon fibers.

  20. Correlation of Fiber Composite Tensile Strength with the Ultrasonic Stress Wave Factor

    NASA Technical Reports Server (NTRS)

    Vary, A.; Lark, R. F.

    1978-01-01

    An ultrasonic-acoustic technique was used to indicate the strength variations of tensile specimens of a graphite-epoxy composite. A stress wave factor was determined and its value was found to depend on variations of the fiber-resin bonding as well as fiber orientation. The fiber orientations studied were 0 deg (longitudinal), 10 deg (off-axis), 90 deg (transverse), 0 deg + or - 45 deg/0 deg symmetrical, and + or - 45 deg] symmetrical. The stress wave factor can indicate variations of the tensile and shear strengths of composite materials. The stress wave factor was also found to be sensitive to strength variations associated with microporosity and differences in fiber-resin ratio.

  1. Anomalous ideal tensile strength of ferromagnetic Fe and Fe-rich alloys

    NASA Astrophysics Data System (ADS)

    Li, Xiaoqing; Schönecker, Stephan; Zhao, Jijun; Johansson, Börje; Vitos, Levente

    2014-07-01

    Within the same failure mode, iron has the lowest ideal tensile strength among the transition metals crystallizing in the body-centered cubic structure. Here, we demonstrate that this anomalously low strength of Fe originates partly from magnetism and is reflected in unexpected alloying effects in dilute Fe(M) (M =Al, V, Cr, Mn, Co, Ni) binaries. We employ the structural energy difference and the magnetic pressure to disentangle the magnetic effect on the ideal tensile strength from the chemical effect. We find that the investigated solutes strongly alter the magnetic response of the Fe host from the weak towards a stronger ferromagnetic behavior, which is explained based on single-particle band energies.

  2. Effects of processing induced defects on laminate response - Interlaminar tensile strength

    NASA Technical Reports Server (NTRS)

    Gurdal, Zafer; Tomasino, Alfred P.; Biggers, S. B.

    1991-01-01

    Four different layup methods were used in the present study of the interlaminar tensile strength of AS4/3501-6 graphite-reinforced epoxy as a function of defects from manufacturing-induced porosity. The methods were: (1) baseline hand layup, (2) solvent wipe of prepreg for resin removal, (3) moisture-introduction between plies, and (4) a low-pressure cure cycle. Pore characterization was conducted according to ASTM D-2734. A significant reduction is noted in the out-of-plane tensile strength as a function of increasing void content; the porosity data were used in an empirical model to predict out-of-plane strength as a function of porosity.

  3. A comparison of electrolytic and chemical etch systems on the resin-to-metal tensile bond strength.

    PubMed

    Krueger, G E; Diaz-Arnold, A M; Aquilino, S A; Scandrett, F R

    1990-11-01

    This investigation compared the tensile bond strengths of a nickel-chromium-beryllium alloy etched electrolytically and etched with a commercially available chemical gel. The number of applications and the thermal conditions of the chemical etchant were varied to assess their influence on the composite-to-metal tensile bond strength. Etched metal cylinders were bonded end-to-end with a resin luting agent and were subsequently tested for tensile strength. Etch patterns, mean bond strengths, and mode of failure were recorded. Significant differences relating to the application number and the thermal conditions of the chemically etched specimens were noted. PMID:2090823

  4. Predictive model for tensile strength of pharmaceutical tablets based on local hardness measurements.

    PubMed

    Juban, Audrey; Nouguier-Lehon, Cécile; Briancon, Stéphanie; Hoc, Thierry; Puel, François

    2015-07-25

    In the pharmaceutical field, tablets are the most common dosage forms for oral administration. During the manufacture of tablets, measures are taken to assure that they possess a suitable mechanical strength to avoid crumbling or breaking when handling while ensuring disintegration after administration. Accordingly, the tensile strength is an essential parameter to consider. In the present study, microscopic hardness and macroscopic tensile strength of binary tablets made from microcrystalline cellulose and caffeine in various proportions were measured. A relationship between these two mechanical properties was found for binary mixture. The proposed model was based on two physical measurements easily reachable: hardness and tablet density. Constants were determined from the two extreme compositions of this given system. This model was validated with experimental results, and a comparison was made with the one developed by Wu et al. (2005). Both models are relevant for this studied system. Nonetheless, with this model, the tablet tensile strength can be connected with a tablet characteristic at microscopic scale in which porosity is not needed. PMID:26043825

  5. Effects of porosity on weld-joint tensile strength of aluminum alloys

    NASA Technical Reports Server (NTRS)

    Lovoy, C. V.

    1974-01-01

    Tensile properties in defect-free weldments of aluminum alloys 2014-T6 and 2219-T87 (sheet and plate) are shown to be related to the level or concentration of induced simulated porosity. The scatter diagram shows that the ultimate tensile strength of the weldments displays the most pronounced linear relationship with the level of porosity. The relationships between yield strength or elongation and porosity are either trivial or inconsequential in the lower and intermediate levels of porosity content. In highly concentrated levels of porosity, both yield strength and elongation values decrease markedly. Correlation coefficients were obtained by simple straight line regression analysis between the variables of ultimate tensile strength and pore level. The coefficients were greater, indicating a better correlation, using a pore area accumulation concept or pore volume accumulation than the accumulation of the pore diameters. These relationships provide a useful tool for assessing the existing aerospace radiographic acceptance standards with respect to permissible porosity. In addition, these relationships, in combination with known design load requirements, will serve as an engineering guideline in determining when a weld repair is necessary based on accumulative pore level as detected by radiographic techniques.

  6. Laser solder repair technique for nerve anastomosis: temperatures required for optimal tensile strength

    NASA Astrophysics Data System (ADS)

    McNally-Heintzelman, Karen M.; Dawes, Judith M.; Lauto, Antonio; Parker, Anthony E.; Owen, Earl R.; Piper, James A.

    1998-01-01

    Laser-assisted repair of nerves is often unsatisfactory and has a high failure rate. Two disadvantages of laser assisted procedures are low initial strength of the resulting anastomosis and thermal damage of tissue by laser heating. Temporary or permanent stay sutures are used and fluid solders have been proposed to increase the strength of the repair. These techniques, however, have their own disadvantages including foreign body reaction and difficulty of application. To address these problems solid protein solder strips have been developed for use in conjunction with a diode laser for nerve anastomosis. The protein helps to supplement the bond, especially in the acute healing phase up to five days post- operative. Indocyanine green dye is added to the protein solder to absorb a laser wavelength (approximately 800 nm) that is poorly absorbed by water and other bodily tissues. This reduces the collateral thermal damage typically associated with other laser techniques. An investigation of the feasibility of the laser-solder repair technique in terms of required laser irradiance, tensile strength of the repair, and solder and tissue temperature is reported here. The tensile strength of repaired nerves rose steadily with laser irradiance reaching a maximum of 105 plus or minus 10 N.cm-2 at 12.7 W.cm-2. When higher laser irradiances were used the tensile strength of the resulting bonds dropped. Histopathological analysis of the laser- soldered nerves, conducted immediately after surgery, showed the solder to have adhered well to the perineurial membrane, with minimal damage to the inner axons of the nerve. The maximum temperature reached at the solder surface and at the solder/nerve interface, measured using a non-contact fiber optic radiometer and thermocouple respectively, also rose steadily with laser irradiance. At 12.7 W.cm-2, the temperatures reached at the surface and at the interface were 85 plus or minus 4 and 68 plus or minus 4 degrees Celsius respectively. This study demonstrates the feasibility of the laser-solder repair technique for nerve anastomosis resulting in improved tensile strength. The welding temperature required to achieve optimal tensile strength has been identified.

  7. Enhancement of tensile strength of lignocellulosic jute fibers by alkali-steam treatment.

    PubMed

    Saha, Prosenjit; Manna, Suvendu; Chowdhury, Sougata Roy; Sen, Ramkrishna; Roy, Debasis; Adhikari, Basudam

    2010-05-01

    The physico-chemical properties of jute fibers treated with alkali (NaOH) solution have been investigated in this study. The treatments were applied under ambient and elevated temperatures and high pressure steaming conditions. To the knowledge of these authors the influence of alkali-steam treatment on the uniaxial tensile strength of natural ligno-cellulosic fibers, such as jute, has not been investigated earlier. The results from this investigation indicate that a 30 min dipping of the fibers in 0.5% alkali solution followed by 30 min alkali-steam treatment leads to an increase in the tensile strength of up to 65%. The increase appears to be due to fiber separation and removal of non-cellulosic materials, which, in turn, resulted in an increased crystallinity. PMID:20074944

  8. Tensile strength of simulated and welded butt joints in W-Cu composite sheet

    NASA Technical Reports Server (NTRS)

    Moore, Thomas J.; Watson, Gordon K.

    1994-01-01

    The weldability of W-Cu composite sheet was investigated using simulated and welded joints. The welded joints were produced in a vacuum hot press. Tensile test results showed that simulated joints can provide strength and failure mode data which can be used in joint design for actual weldments. Although all of the welded joints had flaws, a number of these joints were as strong as the W-Cu composite base material.

  9. Tensile strength of sand, palygorskite and calcium carbonate mixtures and interpretation with the effective stress theory

    Microsoft Academic Search

    M. R. Mosaddeghi; M. A. Hajabbasi; H. Khademi

    2006-01-01

    Many soils in arid regions of the world including those of central Iran contain palygorskite and carbonates in their mineral fraction. There is, however, little information on the effects of these minerals on soil physical and mechanical behaviour. A laboratory experiment was carried out to evaluate tensile strength of artificial mixtures of sand–palygorskite–calcium carbonate (CaCO3). Palygorskite and calcium carbonate were

  10. Effect of dimethylpolysiloxane liquid on the cryogenic tensile strength and thermal contraction behavior of epoxy resins

    NASA Astrophysics Data System (ADS)

    Yi, Jin Woo; Lee, Yu Jin; Lee, Sang Bok; Lee, Wonoh; Um, Moon Kwang

    2014-05-01

    Dimethylpolysiloxane liquid was blended with diglycidyl ether of bisphenol-A epoxy resin including anhydride curing agent to improve the tensile strength of the epoxy resin at 77 K without any increase in its coefficient of thermal expansion (CTE). A bifunctional polymer, silicone-modified epoxy resin (SME), was also added to the mixture as a compatibilizer. The results of UV transmittance for the blend resin showed that the incorporation of the SME could stabilize effectively spherical domains of the siloxane liquid which was immiscible with the epoxy matrix. The tensile strengths of the blend resins at both room temperature and 77 K were measured and SEM analysis for the fractured cross sections was carried out to verify the toughening behavior of the liquid droplets. The results indicated that even small amount of addition of the siloxane liquid (0.05 phr) coupled with SME (20 phr) could enhance the tensile strength at 77 K by 77.6% compared to that of the neat epoxy resin. This improvement is attributed to the fact that the solid and s droplets can disperse the localized stress and interrupt the crack propagation by cavitation mechanism followed by multiple generation of numerous micro-deformation. From the CTE measurement, the siloxane liquid has no influence on the thermal contraction behavior of the blend resin.

  11. Effects of HF Treatments on Tensile Strength of Hi-Nicalon Fibers

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1998-01-01

    Tensile strengths of as-received Hi-Nicalon fibers and those having a dual BN/SiC surface coating, deposited by chemical vapor deposition, have been measured at room temperature. These fibers were also treated with HF for 24 h followed by tensile strength measurements. Strengths of uncoated and BN/SiC coated Hi-Nicalon fibers extracted from celsian matrix composites, by dissolving away the matrix in HF for 24 h, were also determined. The average tensile strength of uncoated Hi-Nicalon was 3.19 +/- 0.73 GPa with a Weibull modulus of 5.41. The Hi-Nicalon/BN/SiC fibers showed an average strength of 3.04 q 0.53 GPa and Weibull modulus of 6.66. After HF treatments, the average strengths of the uncoated and BN/SiC coated Hi-Nicalon fibers were 2.69 +/- 0.67 GPa and 2.80 +/- 0.53 GPa and the Weibull moduli were 4.93 and 5.96, respectively. The BN/SiC coated fibers extracted from the celsian matrix composite exhibited a strength of 2.38 +/- 0.40 GPa and a Weibull modulus of 7.15. The strength of the uncoated Hi-Nicalon fibers in the composite was so severely degraded that they disintegrated into small fragments during extraction with HF. The uncoated fibers probably undergo mechanical surface damage during hot pressing of the composites. Also, the BN layer on the coated fibers acts as a compliant layer which protects the fibers from mechanical damage during composite processing. The elemental composition and thickness of the fiber coatings were deten-nined using scanning Auger analysis. Microstructural analyses of the fibers and the coatings were done by scanning electron microscopy and transmission electron microscopy. Strengths of fibers calculated using average and measured fiber diameters were in good agreement. Thus, the strength of fibers can be evaluated using an average fiber diameter instead of the measured diameter of each filament.

  12. In situ neutron diffraction of heavily drawn steel wires with ultra-high strength under tensile loading

    SciTech Connect

    Tomota, Y. [Graduate School of Science and Engineering, Institute of Applied Beam Science, Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan)]. E-mail: tomota@mx.ibaraki.ac.jp; Suzuki, T. [Faculty of Engineering, Research Center for Superplasticity, Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Kanie, A. [Graduate student of Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Shiota, Y. [Graduate student of Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Uno, M. [Graduate student of Ibaraki University, Hitachi, Ibaraki 316-8511 (Japan); Moriai, A. [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1196 (Japan); Minakawa, N. [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1196 (Japan); Morii, Y. [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1196 (Japan)

    2005-01-10

    To make clear the strengthening mechanism of heavily drawn steel wires exhibiting ultra-high strength, in situ neutron diffraction during tensile loading was performed. A ferrite steel (FK) subjected to a true strain of 6.6 and a pearlite steel (PS) subjected to 4.0 were extended on a tensile tester and (1 1 0) diffraction profiles were measured at various holding stresses. Tensile strengths of steel FK and PS are 1.7 and 3.7 GPa, respectively. The change in (1 1 0) spacing with tensile stress is reversible, i.e., elastic, close to the relevant tensile strength. A stress versus (1 1 0) lattice plane strain is linear for steel FK while evidently nonlinear at higher stresses for steel PS. In steel PS in which cementite peaks were hardly observed, the strengthening mechanism is postulated to be different from that for as-patented pearlite steels.

  13. The effects of laser trimming on the tensile strength and fatigue resistance properties of titanium - 6Al-4V 

    E-print Network

    Whitesel, Dean Adam

    1994-01-01

    The effect of laser trimming on the tensile strength and fatigue resistance of titanium-6% aluminum-4% vanadium specimens was investigated. Due to the nature of laser processing, the microstructure of the titanium alloy ...

  14. The effects of laser trimming on the tensile strength and fatigue resistance properties of titanium - 6Al-4V

    E-print Network

    Whitesel, Dean Adam

    1994-01-01

    The effect of laser trimming on the tensile strength and fatigue resistance of titanium-6% aluminum-4% vanadium specimens was investigated. Due to the nature of laser processing, the microstructure of the titanium alloy was altered in an area local...

  15. Low-velocity impact characteristics and residual tensile strength of carbon fiber composite lattice core sandwich structures

    Microsoft Academic Search

    Bing Wang; Lin-Zhi Wu; Li Ma; Ji-Cai Feng

    2011-01-01

    In this paper, low-velocity impact characteristics and residual tensile strength of carbon fiber composite lattice core sandwich structures are investigated by experimentally and numerically. Low-velocity impact tests and residual tensile strength tests are performed using an instrumented drop-weight machine (Instron 9250HV) and static test machine (Instron 5569), respectively. The FE (finite element) software, ABAQUS\\/Explicit is employed to simulate low-velocity impact

  16. A novel melt stable and high tensile strength biopolymer (polyhydroxyalkanoates) from Bacillus megaterium (MTCC10086) and its characterization.

    PubMed

    Bora, Limpon; Das, Reshmi; Gohain, Dibakar

    2014-09-01

    In the present investigation, we have defined a novel biopolymer from Bacillus megaterium strain with novel melt stability, high tensile strength, and elongation to break properties higher to polypropylene and similar to polyethylene the polymers available commercially. The polymer was characterized with FTIR and XRD. The percent crystalinity was found to 44.09% with tensile strength 42 (Mpa) and elongation to break (%) 142 higher than polypropylene. The polymeric properties were confirmed by differential scanning calorimeter and universal testing. PMID:23744753

  17. Effect of strain rate on the tensile strength of copper shaped charge jet

    SciTech Connect

    Silvestrov, V.V.; Gorshkov, N.N. [Lavrentyev Institute of Hydrodynamics, Novosibirsk, 630090 (Russia)

    1996-05-01

    The jet is produced by a cylindrical 45-mm shaped charge inside a conical copper liner with 120{degree} apex angle. The data on rotating shaped charge penetration are used to estimate the strength of a copper jet under radial tension due to the action of centrifugal force. The value of 0.07 to 0.15 GPa is obtained, which is close to the static yield strength for deformed copper. The strength of the jet estimated when the jet breaks into separate fragments under tensile load along the axis with the strain rate {approximately}2{center_dot}10{sup 4}s{sup {minus}1} achieves substantially higher value from 1.5 GPa. {copyright} {ital 1996 American Institute of Physics.}

  18. Bulk metallic glass composite with good tensile ductility, high strength and large elastic strain limit

    PubMed Central

    Wu, Fu-Fa; Chan, K. C.; Jiang, Song-Shan; Chen, Shun-Hua; Wang, Gang

    2014-01-01

    Bulk metallic glasses exhibit high strength and large elastic strain limit but have no tensile ductility. However, bulk metallic glass composites reinforced by in-situ dendrites possess significantly improved toughness but at the expense of high strength and large elastic strain limit. Here, we report a bulk metallic glass composite with strong strain-hardening capability and large elastic strain limit. It was found that, by plastic predeformation, the bulk metallic glass composite can exhibit both a large elastic strain limit and high strength under tension. These unique elastic mechanical properties are attributed to the reversible B2?B19? phase transformation and the plastic-predeformation-induced complicated stress state in the metallic glass matrix and the second phase. These findings are significant for the design and application of bulk metallic glass composites with excellent mechanical properties. PMID:24931632

  19. Relationship between the ideal tensile strength and the friction properties of metals in contact with nonmetals and themselves

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1981-01-01

    The adhesion and friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated. An estimate of the ideal uniaxial tensile was obtained in terms of the equilibrium surface energy, interplanar spacing of the planes perpendicular to the tensile axis, and the Young's modulus of elasticity. The coefficient of friction for metals was found to be related to the ideal tensile strength of metals. The higher the strength of the metal, the lower the coefficient of friction.

  20. Tensile and fatigue strength properties of Kevlar 29 aramid/epoxy unidirectional composites

    SciTech Connect

    Zweben, C.

    1981-07-22

    Static and fatigue tensile strength properties of filament wound undirectional Kevlar 29/epoxy, typical of filament wound material used in flywheel rotors, were studied. Machining techniques were developed to minimize fiber fuzzing on edges. The static modulus, normalized to 70% fiber volume fraction is 8.87 x 10/sup 6/ psi. The major Poisson's ratio is 0.37. The static composite tensile strength, normalized to 70% fiber volume fraction is 200 x 10/sup 3/ psi, corresponding to a fiber stress at failure of 286 x 10/sup 3/ psi, which is good for materials having a very high fiber volume fraction. The S-N curve for R = 0.7 was found to be quite flat. Although the techniques used in this program had previously been employed successfully to study the fatigue behavior of Kevlar 29/epoxy and Kevlar 49/epoxy unidirectional materials, we were unable to overcome the persistent problem of cohesive material failure in the tab regions. The apparent reason for this is the very low interlaminar shear strength of the filament wound material. 16 figures.

  1. Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.

    PubMed

    Podczeck, Fridrun; Newton, J Michael; Fromme, Paul

    2014-12-30

    Flat, round tablets may have a breaking ("score") line. Pharmacopoeial tablet breaking load tests are diametral in their design, and industrially used breaking load testers often have automatic tablet feeding systems, which position the tablets between the loading platens of the machine with the breaking lines in random orientation to the applied load. The aim of this work was to ascertain the influence of the position of the breaking line in a diametral compression test using finite element methodology (FEM) and to compare the theoretical results with practical findings using commercially produced bevel-edged, scored tablets. Breaking line test positions at an angle of 0°, 22.5°, 45°, 67.5° and 90° relative to the loading plane were studied. FEM results obtained for fully elastic and elasto-plastic tablets were fairly similar, but they highlighted large differences in stress distributions depending on the position of the breaking line. The stress values at failure were predicted to be similar for tablets tested at an angle of 45° or above, whereas at lower test angles the predicted breaking loads were up to three times larger. The stress distributions suggested that not all breaking line angles would result in clean tensile failure. Practical results, however, did not confirm the differences in the predicted breaking loads, but they confirmed differences in the way tablets broke. The results suggest that it is not advisable to convert breaking loads obtained on scored tablets into tablet tensile strength values, and comparisons between different tablets or batches should carefully consider the orientation of the breaking line with respect to the loading plane, as the failure mechanisms appear to vary. PMID:25455775

  2. Enzymatic Surface Erosion of High Tensile Strength Polycarbonates Based on Natural Phenols

    PubMed Central

    2015-01-01

    Surface erosion has been recognized as a valuable design tool for resorbable biomaterials within the context of drug delivery devices, surface coatings, and when precise control of strength retention is critical. Here we report on high tensile strength, aromatic–aliphatic polycarbonates based on natural phenols, tyrosol (Ty) and homovanillyl alcohol (Hva), that exhibit enzymatic surface erosion by lipase. The Young’s moduli of the polymers for dry and fully hydrated samples are 1.0 to 1.2 GPa and 0.8 to 1.2 GPa, respectively. Typical characteristics of enzymatic surface erosion were confirmed for poly(tyrosol carbonate) films with concomitant mass-loss and thickness-loss at linear rates of 0.14 ± 0.01 mg cm–2 d–1 and 3.0 ± 0.8 ?m d–1, respectively. The molecular weight and the mechanical properties of the residual films remained constant. Changing the ratio of Ty and Hva provided control over the glass transition temperature (Tg) and the enzymatic surface erosion: increasing the Hva content in the polymers resulted in higher Tg and lower enzymatic erosion rate. Polymers with more than 50 mol % Hva were stable at 37 °C in enzyme solution. Analysis on thin films using quartz crystal microbalance with dissipation (QCM-D) demonstrated that the onset temperature of the enzymatic erosion was approximately 20 °C lower than the wet Tg for all tested polymers. This new finding demonstrates that relatively high tensile strength polycarbonates can undergo enzymatic surface erosion. Moreover, it also sheds light on the connection between Tg and enzymatic degradation and explains why few of the high strength polymers follow an enzyme-meditated degradation pathway. PMID:24432806

  3. Effect of Preparation Methods on Crystallization Behavior and Tensile Strength of Poly(vinylidene fluoride) Membranes

    PubMed Central

    Liu, Jie; Lu, Xiaolong; Wu, Chunrui

    2013-01-01

    Poly(vinylidene fluoride) (PVDF) membranes were prepared by non solvent induced phase separation (NIPS), melt spinning and the solution-cast method. The effect of preparation methods with different membrane formation mechanisms on crystallization behavior and tensile strength of PVDF membranes was investigated. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and X-ray diffraction (XRD) were employed to examine the crystal form of the surface layers and the overall membranes, respectively. Spherulite morphologies and thermal behavior of the membranes were studied by polarized light optical microscopy (PLO) and differential scanning calorimetry (DSC) separately. It was found that the crystallization behavior of PVDF membranes was closely related to the preparation methods. For membranes prepared by the NIPS method, the skin layers had a mixture of ? and ? phases, the overall membranes were predominantly ? phase, and the total crystallinity was 60.0% with no spherulite. For melt spinning membranes, the surface layers also showed a mixture of ? and ? phases, the overall membranes were predominantly ? phase. The total crystallinity was 48.7% with perfect spherulites. Whereas the crystallization behavior of solution-cast membranes was related to the evaporation temperature and the additive, when the evaporation temperature was 140 °C with a soluble additive in the dope solution, obvious spherulites appeared. The crystalline morphology of PVDF exerted a great influence on the tensile strength of the membranes, which was much higher with perfect spherulites. PMID:24957064

  4. Change of Tensile Strength due to Non-uniform Thermal Deterioration of XLPE Sheets

    NASA Astrophysics Data System (ADS)

    Kurihara, Takashi; Takahashi, Toshihiro; Homma, Hiroya; Okamoto, Tatsuki

    Cross-linked polyethylene (XLPE) sheets were thermally deteriorated in atmospheric air at 180°C for at most 100 hours, and their depth profiles of the oxidation degrees were investigated with a micro FT-IR, and the relationships between the oxidation degree and mechanical properties such as tensile strength and elongation at break were examined. The oxidation degree was defined as the ratio of the IR absorption peak for the C=O bond to that for the C-H bond. When tensile strength and elongation at break of XLPE sheets decreased, the oxidation degree increased and the oxidation degree distributed non-uniformly with depth. That is, the oxidation degree was the largest on the upper surface of XLPE sheets where air supply was sufficient during heating, and it was the smallest on the lower surface that contacted with a metal plate during heating. Since the mechanical characteristics such as the hardness and the Young's modulus decreased in the oxidized region of XLPE sheets, it was pointed out that the oxidized region became a weak point against the mechanical stress. It was also pointed out that the micro FT-IR was useful in evaluating the depth profile of oxidation in polymer materials.

  5. Effects of fiber length and fiber orientation distributions on the tensile strength of short-fiber-reinforced polymers

    Microsoft Academic Search

    Shao-Yun Fu; Bernd Lauke

    1996-01-01

    This paper presents an analytical method considering the effects of fiber length and fiber orientation distributions for predicting the tensile strength (TS) of short-fiber-reinforced polymers (SFRP). Two probability density functions are used for modelling the distributions of fiber length and fiber orientation. The strength of SFRP is derived as a function of fiber length and fiber orientation distribution taking into

  6. Origin of tensile strength of a woven sample cut in bias directions

    PubMed Central

    Pan, Ning; Kovar, Radko; Dolatabadi, Mehdi Kamali; Wang, Ping; Zhang, Diantang; Sun, Ying; Chen, Li

    2015-01-01

    Textile fabrics are highly anisotropic, so that their mechanical properties including strengths are a function of direction. An extreme case is when a woven fabric sample is cut in such a way where the bias angle and hence the tension loading direction is around 45° relative to the principal directions. Then, once loaded, no yarn in the sample is held at both ends, so the yarns have to build up their internal tension entirely via yarn–yarn friction at the interlacing points. The overall fabric strength in such a sample is a result of contributions from the yarns being pulled out and those broken during the process, and thus becomes a function of the bias direction angle ?, sample width W and length L, along with other factors known to affect fabric strength tested in principal directions. Furthermore, in such a bias sample when the major parameters, e.g. the sample width W, change, not only the resultant strengths differ, but also the strength generating mechanisms (or failure types) vary. This is an interesting problem and is analysed in this study. More specifically, the issues examined in this paper include the exact mechanisms and details of how each interlacing point imparts the frictional constraint for a yarn to acquire tension to the level of its strength when both yarn ends were not actively held by the testing grips; the theoretical expression of the critical yarn length for a yarn to be able to break rather than be pulled out, as a function of the related factors; and the general relations between the tensile strength of such a bias sample and its structural properties. At the end, theoretical predictions are compared with our experimental data.

  7. Correlation analysis of the variation of weld seam and tensile strength in laser welding of galvanized steel

    NASA Astrophysics Data System (ADS)

    Sinha, Amit Kumar; Kim, Duck Young; Ceglarek, Darek

    2013-10-01

    Many advantages of laser welding technology such as high speed and non-contact welding make the use of the technology more attractive in the automotive industry. Many studies have been conducted to search the optimal welding condition experimentally that ensure the joining quality of laser welding that relies both on welding system configuration and welding parameter specification. Both non-destructive and destructive techniques, for example, ultrasonic inspection and tensile test are widely used in practice for estimating the joining quality. Non-destructive techniques are attractive as a rapid quality testing method despite relatively low accuracy. In this paper, we examine the relationship between the variation of weld seam and tensile shear strength in the laser welding of galvanized steel in a lap joint configuration in order to investigate the potential of the variation of weld seam as a joining quality estimator. From the experimental analysis, we identify a trend in between maximum tensile shear strength and the variation of weld seam that clearly supports the fact that laser welded parts having larger variation in the weld seam usually have lower tensile strength. The discovered relationship leads us to conclude that the variation of weld seam can be used as an indirect non-destructive testing method for estimating the tensile strength of the welded parts.

  8. Galactans and cellulose in flax fibres: putative contributions to the tensile strength.

    PubMed

    Girault, R; Bert, F; Rihouey, C; Jauneau, A; Morvan, C; Jarvis, M

    1997-08-01

    The proton spin-spin relaxation time, T2, measured from solid-state NMR, indicates a greater rigidity for cellulose than for the adhesive matrix between the microfibrils of flax ultimate fibres. Cytochemical and biochemical analyses allow the identification of: (1) EDTA-soluble RG I-polymers in the primary walls and cell junctions of fibres; (2) long 1 --> 4-beta-D-galactan chains between primary and secondary wall layers; and (3) arabinogalactan-proteins throughout the secondary walls. These polymers in the adhesive matrix between microfibrils and/or cellulose layers ensure that cracks propagate along the matrix rather than across the fibres and play an important role in allowing flax fibres to approach the tensile strength of advanced synthetic fibres like carbon and Kevlar. PMID:9283034

  9. Analysis of Ninety Degree Flexure Tests for Characterization of Composite Transverse Tensile Strength

    NASA Technical Reports Server (NTRS)

    OBrien, T. Kevin; Krueger, Ronald

    2001-01-01

    Finite element (FE) analysis was performed on 3-point and 4-point bending test configurations of ninety degree oriented glass-epoxy and graphite-epoxy composite beams to identify deviations from beam theory predictions. Both linear and geometric non-linear analyses were performed using the ABAQUS finite element code. The 3-point and 4-point bending specimens were first modeled with two-dimensional elements. Three-dimensional finite element models were then performed for selected 4-point bending configurations to study the stress distribution across the width of the specimens and compare the results to the stresses computed from two-dimensional plane strain and plane stress analyses and the stresses from beam theory. Stresses for all configurations were analyzed at load levels corresponding to the measured transverse tensile strength of the material.

  10. Effects of solution treatment and test temperature on tensile properties of high strength high Mn austenitic steels

    Microsoft Academic Search

    W. Bleck; A. Schwedt; J. Mayer

    Tensile properties of high strength high Mn austenitic Fe-26.5%Mn-3.6%Al-2.2%Si-0.38%C-0.005%B and Fe-18.9%Mn-0.62%C-0.02%Ti-0.005%B-0.11%N\\u000a steels were investigated after different solution treatments. The results show that the solution treatment has a significant\\u000a influence on microstructure and mechanical properties of the investigated steels. By appropriate solution treatment the product\\u000a of tensile strength (Rm) and total elongation (A50) of the hot rolled steel can be improved

  11. Tensile strength as a function of thermal history of Inconel 718 and Inconel 625 alloys for glass-ceramic headers

    SciTech Connect

    Rey, M.C.; Henderson, W.R.

    1982-06-11

    Tensile strength tests were conducted on Inconel 718 specimens following a variety of heat treatments, and on as-received and heat-treated specimens of Inconel 625. A heat treatment cycle for Inconel 718 was found that represents an acceptable compromise between a thermal cycle that yields the strongest metal and one that least taxes a glass-ceramic material to which the Inconel 718 is bonded. Heat treating resulted in a moderate decrease in the tensile strength of the as-received Inconel 625.

  12. Dimensional stability and tensile strength of irradiated Nicalon-CG and Hi-Nicalon SiC fibers

    SciTech Connect

    Youngblood, G.E.; Henager, C.H. Jr.; Senor, D.J. [Pacific Northwest National Lab., Richland, WA (United States); Newsome, G.A.; Woods, J.J. [Lockheed Martin, Schenectady, NY (United States)

    1997-05-01

    Nicalon-CG and Hi-Nicalon fibers were characterized by measuring their length, density, and tensile strength in the unirradiated, thermal annealed, and irradiated conditions. The irradiation was conducted in the EBR-II to a dose of 43 dpa-SiC at a nominal irradiation temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. The results indicate the fibers that perform best in an irradiation environment are those that approach stoichiometric and crystalline SiC. Hi-Nicalon exhibited negligible densification, accompanied by an increase in tensile strength after irradiation. Nicalon-CG possessed a higher tensile strength than hi-Nicalon in the unirradiated condition, but was significantly weakened in the annealed and irradiated conditions. In addition, Nicalon-CG exhibited unacceptable irradiation-induced shrinkage. Loss o fiber tensile strength after irradiation is shown to reduce the flexural strength of irradiated composites and Nicalon-CG fiber shrinkage observed in irradiated composites.

  13. In situ tensile strength measurement and Weibull analysis of thick film and thin film micromachined polysilicon structures

    Microsoft Academic Search

    Staffan Greek; Fredric Ericson; Stefan Johansson; Jan-Åke Schweitz

    1997-01-01

    A method is introduced in which tensile tests can be performed in situ on micromachined structures. The testing equipment consists of a testing unit mounted on a micromanipulator in a scanning electron microscope. The fracture loads of micromachined beam structures made from thick and thin film polysilicon were measured, and the fracture strengths were then calculated via measurements of the

  14. Effects of red yeast inclusions in diets for salmonids and extrusion temperature on pellet tensile strength: Weibull analysis

    Microsoft Academic Search

    K. A. Aarseth; M. Sørensen; T. Storebakken

    2006-01-01

    Enhancement of fish feed extrusion-technology and improvements of technical pellet quality requires knowledge about causal connections amongst variables of processing condition and raw materials, and how these connections can be elucidated by measurements. Weibull analysis of feed pellet tensile strengths may represent one possible measurement tool for this purpose; this analysis is evaluated here and compared with the Holmen durability

  15. Optical absorption as a sensitive monitor of tensile strength loss in thermally aged nylon 6,6

    Microsoft Academic Search

    1985-01-01

    Chemical changes which take place in polymers during thermal aging often adversely affect the bulk physical properties of the material. Aging rates under ambient conditions are usually so slow as to require extremely long aging cycles to achieve measurable losses in such properties as tensile strength. Therefore, accelerated aging under more stressful conditions (e.g., higher temperatures) with Arrhenius-plot extrapolations to

  16. Effect of replacement of lateritic soils with granite fines on the compressive and tensile strengths of laterized concrete

    Microsoft Academic Search

    J. A Osunade

    2002-01-01

    Over the years, research works have been carried out on lateritic soils with a view to investigating their usefulness wholly as a construction material or partly as a substitute for fine aggregate component of concrete.This paper presents the results of investigations carried out on how lateritic soils replaced with varying percentages of granite fines affect the compressive and tensile strengths

  17. Developmental Exposure to Xenoestrogens at Low Doses Alters Femur Length and Tensile Strength in Adult Mice1

    PubMed Central

    Pelch, Katherine E.; Carleton, Stephanie M.; Phillips, Charlotte L.; Nagel, Susan C.

    2011-01-01

    ABSTRACT Developmental exposure to high doses of the synthetic xenoestrogen diethylstilbestrol (DES) has been reported to alter femur length and strength in adult mice. However, it is not known if developmental exposure to low, environmentally relevant doses of xenoestrogens alters adult bone geometry and strength. In this study we investigated the effects of developmental exposure to low doses of DES, bisphenol A (BPA), or ethinyl estradiol (EE2) on bone geometry and torsional strength. C57BL/6 mice were exposed to DES, 0.1 ?g/kg/day, BPA, 10 ?g/kg/day, EE2, 0.01, 0.1, or 1.0 ?g/kg/day, or vehicle from Gestation Day 11 to Postnatal Day 12 via a mini-osmotic pump in the dam. Developmental Xenoestrogen exposure altered femoral geometry and strength, assessed in adulthood by micro-computed tomography and torsional strength analysis, respectively. Low-dose EE2, DES, or BPA increased adult femur length. Exposure to the highest dose of EE2 did not alter femur length, resulting in a nonmonotonic dose response. Exposure to EE2 and DES but not BPA decreased tensile strength. The combined effect of increased femur length and decreased tensile strength resulted in a trend toward decreased torsional ultimate strength and energy to failure. Taken together, these results suggest that exposure to developmental exposure to environmentally relevant levels of xenoestrogens may negatively impact bone length and strength in adulthood. PMID:22088916

  18. In vitro Comparative Evaluation of Tensile Bond Strength of 6th, 7th and 8th Generation Dentin Bonding Agents

    PubMed Central

    Kamble, Suresh S; Kandasamy, Baburajan; Thillaigovindan, Ranjani; Goyal, Nitin Kumar; Talukdar, Pratim; Seal, Mukut

    2015-01-01

    Background: Newer dentin bonding agents were developed to improve the quality of composite restoration and to reduce time consumption in its application. The aim of the present study was to evaluate tensile bond strength of 6th, 7th and 8th generation bonding agents by in vitro method. Materials and Methods: Selected 60 permanent teeth were assigned into 20 in each group (Group I: 6th generation bonding agent-Adper SE plus 3M ESPE, Group II: 7th generation bonding agent-G-Bond GC Corp Japan and Group III: 8th generation dentin adhesives-FuturaBond, DC, Voco, Germany). With high-speed diamond disc, coronal dentin was exposed, and selected dentin bonding agents were applied, followed by composite restoration. All samples were saved in saline for 24 h and tensile bond strength testing was done using a universal testing machine. The obtained data were tabulated and statistically analyzed using ANOVA test. Results: The tensile bond strength readings for 6th generation bonding agent was 32.2465, for 7th generation was 31.6734, and for 8th-generation dentine bonding agent was 34.74431. The highest tensile bond strength was seen in 8th generation bonding agent compared to 6th and 7th generation bonding agents. Conclusion: From the present study it can be conclude that 8th generation dentine adhesive (Futura DC, Voco, Germany) resulted in highest tensile bond strength compared to 6th (Adper SE plus, 3M ESPE) and 7th generation (G-Bond) dentin bonding agents. PMID:26028901

  19. Energy Landscape and Isotropic Tensile Strength of n-Alkane Glasses Vincent K. Shen, Pablo G. Debenedetti,* and Frank H. Stillinger

    E-print Network

    Stillinger, Frank

    the equation of state of energy landscape for this homologous series. The tensile strength depends deformation procedure. Although the ultimate isotropic tensile strength maximum at n ) 3 would seem deformation. In other words, glasses exhibit proportionality between stress and deformation: they deform

  20. The influence of heat treatment temperature on room temperature and high temperature tensile strength of unidirectional carbon fibre reinforced carbon

    SciTech Connect

    Luedenbach, G.; Peters, P.W.M. [Institute of Materials Research, Koeln (Germany)

    1995-12-01

    The influence of process parameters (particularly the final heat treatment temperature) as well as test temperature up to 1800{degrees}C on the mechanical properties of two types of unidirectional phenolic resin based carbon/carbon (UD C/C) were investigated. The room temperature tensile strength of HT and HM-fibre reinforced carbon dropped to a minimum value after a carbonization temperature of 920{degrees}C and a following heat treatment at 1000{degrees}C. Higher heat treatment temperatures up to 2100{degrees}C led to improved tensile strengths. In contradiction to the heat treatment temperature the test temperature (RT to 1800{degrees}C) was found to have little influence on the strength.

  1. First-principles study of the tensile strength and failure of ?-Al2O3(0001)/Ni(111) interfaces

    NASA Astrophysics Data System (ADS)

    Shi, Siqi; Tanaka, Shingo; Kohyama, Masanori

    2007-08-01

    Tensile strength and failure of Al2O3(0001)/Ni(111) interfaces have been examined by the first-principles pseudopotential method, and compared with Al2O3(0001)/Cu(111) interfaces, and effects of the interface stoichiometry, configurations, and metal species have been analyzed. From rigid-type tensile tests, the Ni-O interfaces at the O-terminated interfaces are much stronger than the back Ni-Ni interlayers, while the strength of the Ni-Al interfaces at the Al-terminated ones is less than half of the back Ni-Ni interlayers. Relaxed-type tensile tests have been applied to the most stable configurations (Al-site and O-site models of the O-terminated and Al-terminated interfaces, respectively) to examine the behavior of atoms and electrons at the failure. For the Al-terminated interface, the Ni-Al interface is naturally broken under lower stress, while catastrophic failure occurs within the interface Ni layer for the O-terminated interface because of the irregular configuration of the interface Ni layer of the Al-site model. Tensile strength and interfacial Young’s moduli of Al2O3/Ni interfaces are larger than those of the Al2O3/Cu interfaces due to stronger Ni-O and Ni-Al interactions.

  2. Tensile and shear strength measurements on brazed "T" joints used in construction of intra- and intermaxillary hooks.

    PubMed

    Davies, E H; Kuhn, A T; Oleschenko, S V

    1982-10-01

    Silver-brazed "T" joints, representing the first stage in the construction of intermaxillary hooks were fabricated under rigorously controlled conditions. Their tensile and shear strengths were then measured using specially developed test jigs. It was found that the braze joint itself was stronger than the component wires (under tensile load) while in shear mode, fracture occurred in one of a number of well-defined ways. The effect of prolonged heating was investigated using microhardness measurements and recommendations are made for the optimum brazing conditions. PMID:6958322

  3. Thermal dilatation, density, porosity and tensile strength of porous Miocene limestone

    NASA Astrophysics Data System (ADS)

    Pápay, Zita; Török, Ákos

    2015-04-01

    Porous Miocene limestone is one of the most important stone that have been used as in the monuments from Roman times in the present territory of Hungary. Thermal behaviour of these structures plays an important role in the structural integrity of the monument. Very limited data is available on the thermal dilatation of porous limestone and to bridge this information gap limestone from Sóskút quarry was analyzed. The present study focuses on the thermal dilatation and its relationship with other physical properties and fabric. Three different lithotypes were tested: i) fine-grained, ii) medium-grained and iii) coarse-grained porous limestone. Prismatic test specimens were placed in thermal dilatometers and were subjected to thermal cycles within the temperature range of 20°C - 100°C. Thermal dilation and shrinkage was recorded. Measurements on bulk density, porosity and indirect tensile strength of the three different lithologies were also made. Data set suggests that the thermal dilatation of porous limestone is in the order of 0.2-0.8 mm/m. The differences are related to different fabric and also suggest an oriented micro-fabric, since thermal expansion in the X,Y Z direction is different.

  4. The effect of custom tray material type and fabrication technique on tensile bond strength of impression material adhesive systems.

    PubMed

    Abdullah, M A; Talic, Y F

    2003-03-01

    The purpose of this investigation was to evaluate the tensile bond strengths of two impression material systems (polysulphide and polyvinyl siloxane) to two custom tray materials [autopolymerizing and visible light-cured (VLC) acrylic resin]. The effect of polymerizing the tray materials directly against wax spacer and tin foil was evaluated for each material. Polymerizing tray materials against tin foil significantly increased the bond strengths of polysulphide and polyvinyl siloxane impression materials to VLC and autopolymerizing acrylic resin tray materials. Polyvinyl siloxane VLC cured against tin foil combination produced the strongest bond. The VLC resin tray material generated greater bond strength than autopolymerizing acrylic resin when polymerized against tin foil. PMID:12588506

  5. Open and filled hole static tensile strength characterization of metal matrix composite SCS-9/Beta21s. Master's thesis

    SciTech Connect

    Roush, J.T.

    1992-12-01

    SCS-9/Beta 21s has a reduced gauge thickness, in comparison with other metal matrix composites, due to a smaller diameter fiber. This reduced gauge thickness makes it an attractive candidate for the skin of hypersonic vehicles. Tensile testing of (0/90) sub 2s and (O/+ or -45/90) sub s laminates was performed at room temperature, 482 deg C, and 650 deg C. Both notched and unnotched specimens were tested. Notched specimens, open and filled hole, had a width-to-diameter ratio of six. Materials 7075-T6 and Mar-m-246 were used as pins in the filled hole tensile testing. Analytical work was completed to predict material properties, elastic and plastic stress concentration factors, residual stresses, and failure strengths. Damage was documented in the form of fiber-matrix debonding, matrix cracking, fiber failure, and plasticity.... SCS-9, Beta 21s, Open Hole, Filled Hole, Metal Matrix Composite, Notch, Static Tensile.

  6. Delamination strength of YBCO coated conductors under transverse tensile stressContribution of NIST, a US Government Agency, not subject to copyright

    Microsoft Academic Search

    D C van der Laan; J W Ekin; C C Clickner; T C Stauffer

    2007-01-01

    We present a new experimental technique to measure the delamination strength under transverse tensile stress of YBa2Cu3O7?? coated conductors for electric power applications. The delamination strength, defined as the tensile stress at which the ceramic layers delaminate from one another, is measured at 76 K for different sample configurations. The delamination strength is reduced by as much as 40% when

  7. A Unified Model for Predicting the Open Hole Tensile and Compressive Strengths of Composite Laminates for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Davidson, Paul; Pineda, Evan J.; Heinrich, Christian; Waas, Anthony M.

    2013-01-01

    The open hole tensile and compressive strengths are important design parameters in qualifying fiber reinforced laminates for a wide variety of structural applications in the aerospace industry. In this paper, we present a unified model that can be used for predicting both these strengths (tensile and compressive) using the same set of coupon level, material property data. As a prelude to the unified computational model that follows, simplified approaches, referred to as "zeroth order", "first order", etc. with increasing levels of fidelity are first presented. The results and methods presented are practical and validated against experimental data. They serve as an introductory step in establishing a virtual building block, bottom-up approach to designing future airframe structures with composite materials. The results are useful for aerospace design engineers, particularly those that deal with airframe design.

  8. Optical absorption as a sensitive monitor of tensile strength loss in thermally aged nylon 6,6

    SciTech Connect

    Renschler, C.L.

    1985-01-01

    Chemical changes which take place in polymers during thermal aging often adversely affect the bulk physical properties of the material. Aging rates under ambient conditions are usually so slow as to require extremely long aging cycles to achieve measurable losses in such properties as tensile strength. Therefore, accelerated aging under more stressful conditions (e.g., higher temperatures) with Arrhenius-plot extrapolations to ambient conditions is often employed. Since this scheme requires that there is no change in the predominate aging mechanism at higher temperatures, one would prefer to increase the sensitivity of aging detection so one could measure aging at lower temperatures on a reasonable time scale. We describe here the use of optical absorption spectrophotometry as a sensitive monitor of thermal aging in nylon 6,6 which correlates with tensile strength loss. 8 refs., 3 figs.

  9. Tensile strength of radio frequency cold plasma treated PET fibers—Part I: Influence of environment and treatment time

    Microsoft Academic Search

    M. O. H. Cioffi; H. J. C. Voorwald; V. Ambrogi; T. Monetta; F. Bellucci; L. Nicolais

    2002-01-01

    This article reports on a series of experiments with polyethylene terepthalate (PET) treated in a radio frequency plasma reactor\\u000a using argon and oxygen as a gas fuel, for treatment times equal to 5 s, 20 s, 30 s, and 100 s. The mechanical strength modification\\u000a of PET fibers, evaluated by tensile tests on monofilaments, showed that oxygen and argon plasma

  10. Modelling and Simulation of Tensile Fracture in High Velocity Compacted Metal Powder

    NASA Astrophysics Data System (ADS)

    Jonsén, P.; Häggblad, H.-A.?.

    2007-05-01

    In cold uniaxial powder compaction, powder is formed into a desired shape with rigid tools and a die. After pressing, but before sintering, the compacted powder is called green body. A critical property in the metal powder pressing process is the mechanical properties of the green body. Beyond a green body free from defects, desired properties are high strength and uniform density. High velocity compaction (HVC) using a hydraulic operated hammer is a production method to form powder utilizing a shock wave. Pre-alloyed water atomised iron powder has been HVC-formed into circular discs with high densities. The diametral compression test also called the Brazilian disc test is an established method to measure tensile strength in low strength material like e.g. rock, concrete, polymers and ceramics. During the test a thin disc is compressed across the diameter to failure. The compression induces a tensile stress perpendicular to the compressed diameter. In this study the test have been used to study crack initiation and the tensile fracture process of HVC-formed metal powder discs with a relative density of 99%. A fictitious crack model controlled by a stress versus crack-width relationship is utilized to model green body cracking. Tensile strength is used as a failure condition and limits the stress in the fracture interface. The softening rate of the model is obtained from the corresponding rate of the dissipated energy. The deformation of the powder material is modelled with an elastic-plastic Cap model. The characteristics of the tensile fracture development of the central crack in a diametrically loaded specimen is numerically studied with a three dimensional finite element simulation. Results from the finite element simulation of the diametral compression test shows that it is possible to simulate fracturing of HVC-formed powder. Results from the simulation agree reasonably with experiments.

  11. Effects of Cyclic Tensile Forces on the Strength of Fibrous Tissue Examined in an in Vivo Model

    NASA Astrophysics Data System (ADS)

    Takakuda, Kazuo; Koyama, Yoshihisa; Matsumoto, Hiroko N.; Katakura, Hiroshi; Muneta, Takeshi

    Adaptive remodeling of soft fibrous tissues under cyclic tensile forces was investigated. Patellar tendons of rat’s knee were harvested and mounted on apparatuses for mechanical stimuli. They were transplanted into the subcutaneous tissues and experienced mechanical stimuli of cyclic tensile forces (1N, 1Hz). Then the tendons were retrieved and their mechanical properties were evaluated with a tensile tester. Four experimental groups were examined in which loading conditions were (1) three times a day (2700 cycles a day) throughout 4 weeks, (2) twice a week (1800 cycles a week) throughout 4 weeks, (3) load-free throughout 4 weeks, or (4) control. Comparing to control group, the tendons in load-free conditions were very weak and shown statistically significant decrease in maximum load, strength and tangent modulus. Contrarily, the tendons in frequent loadings (three times a day) nearly maintained their mechanical properties. Thus the present study clearly elucidated the fact that cyclic tensile forces have significant effects on the mechanical properties of transplanted fibrous tissues.

  12. Effects of polymerization and briquetting parameters on the tensile strength of briquettes formed from coal coke and aniline-formaldehyde resin

    SciTech Connect

    Demirbas, A.; Simsek, T. [Selcuk University, Konya (Turkey)

    2006-10-15

    In this work, the utilization of aniline (C{sub 6}H{sub 7}N) formaldehyde (HCHO) resins as a binding agent of coke briquetting was investigated. Aniline (AN) formaldehyde (F) resins are a family of thermoplastics synthesized by condensing AN and F in an acid solution exhibiting high dielectric strength. The tensile strength sharply increases as the ratio of F to AN from 0.5 to 1.6, and it reaches the highest values between 1.6 and 2.2 F/AN ratio; it then slightly decreases. The highest tensile strength of F-AN resin-coke briquette (23.66 MN/m{sup 2}) was obtained from the run with 1.5 of F/AN ratio by using (NH4){sub 2}S{sub 2}O{sub 8} catalyst at 310 K briquetting temperature. The tensile strength of F-AN resin-coke briquette slightly decreased with increasing the catalyst percent to 0.10%, and then it sharply decreased to zero with increasing the catalyst percent to 0.2%. The effect of pH on the tensile strength is irregular. As the pH of the mixture increases from 9.0 to 9.2, the tensile strength shows a sharp increase, and the curve reaches a plateau value between pH 9.3 and 9.9; then the tensile strength shows a slight increase after pH = 9.9.

  13. Influence of different brazing and welding methods on tensile strength and microhardness of orthodontic stainless steel wire.

    PubMed

    Bock, Jens Johannes; Fraenzel, Wolfgang; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner

    2008-08-01

    The aim of this study was to compare the mechanical strength and microhardness of joints made by conventional brazing and tungsten inert gas (TIG) and laser welding. A standardized end-to-end joint configuration of the orthodontic wire material in spring hard quality was used. The joints were made using five different methods: brazing (soldering > 450 degrees C) with universal silver solder, two TIG, and two laser welders. Laser parameters and welding conditions were used according to the manufacturers' guidance. The tensile strengths were measured with a universal testing machine (Zwick 005). The microhardness measurements were carried out with a hardness tester (Zwick 3202). Data were analysed using one-way analysis of variance and Bonferroni's post hoc correction (P < 0.05). In all cases, brazing joints ruptured at low levels of tensile strength (198 +/- 146 MPa). Significant differences (P < 0.001) between brazing and TIG or laser welding were found. The highest means were observed for TIG welding (699-754 MPa). Laser welding showed a significantly lower mean tensile strength (369-520 MPa) compared with TIG welding. Significant differences (P < 0.001) were found between the original orthodontic wire and the mean microhardness at the centre of the welded area. The mean microhardness differed significantly between brazing (1.99 GPa), TIG (2.22-2.39 GPa) and laser welding (2.21-2.68 GPa). For orthodontic purposes, laser and TIG welding are solder-free alternatives to joining metal. TIG welding with a lower investment cost is comparable with laser welding. However, while expensive, the laser technique is a sophisticated and simple method. PMID:18617503

  14. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    NASA Technical Reports Server (NTRS)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  15. Ultimate Tensile Strength as a Function of Test Rate for Various Ceramic Matrix Composites at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Bansal, Narottam P.; Gyekenyesi, John P.

    2002-01-01

    Ultimate tensile strength of five different continuous fiber-reinforced ceramic composites, including SiC/BSAS (2D 2 types), SiC/MAS-5 (2D), SiC/SiC (2D enhanced), and C/SiC(2D) was determined as a function of test rate at I 100 to 1200 'C in air. All five composite materials exhibited a significant dependency of ultimate strength on test rate such that the ultimate strength decreased with decreasing test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress rate) to another (constant stress loading) for SiC/BSAS suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics.

  16. On the tensile and shear strength of nano-reinforced composite interfaces

    Microsoft Academic Search

    S. A Meguid; Y Sun

    2004-01-01

    The tensile debonding and shear properties of composite interfaces reinforced by two different homogeneously dispersed nanofillers, carbon nanotubes and alumina nanopowder, are investigated. The composite adherends used are made of carbon fibre\\/epoxy laminate and aluminium alloy 6061-T6. The results reveal that varying the weight percentage of the nanofillers into the epoxy matrix adhesive favourably influences the debonding and shear characteristics

  17. The Value Compressive Strength and Split Tensile Strength on Concrete Mixture With Expanded Polystyrene Coated by Surfactant Span 80 as a Partial Substitution of Fine Aggregate

    NASA Astrophysics Data System (ADS)

    Hidayat, Irpan; Siauwantara, Alice

    2014-03-01

    The value of the density normal concrete which ranges between 2200-2400 kg/m3. Therefore the use of Expanded Polystyrene (EPS) as a subitute to fine aggregate can reduce the density of concrete. The purpose this research is to reduce the density of normal concrete but increase compressive strength of EPS concrete, with use surfactant as coating for the EPS. Variables of substitution percentage of EPS and EPS coated by surfactant are 5%,10%,15%,20%,25%. Method of concrete mix design based on SNI 03-2834-2000 "Tata Cara Pembuatan Rencana Campuran Beton Normal (Provisions for Proportioning Normal Concrete Mixture)". The result of testing, every increase percentage of EPS substitution will decrease the compressive strength around 1,74 MPa and decrease density 34,03 kg/m3. Using Surfactant as coating of EPS , compressive strength increase from the EPS's compressive strength. Average of increasing compressive strength 0,19 MPa and increase the density 20,03 kg/m3,average decrease of the tensile split strength EPS coated surfaktan is 0,84 MPa.

  18. Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing**

    PubMed Central

    Kiener, Daniel; Kaufmann, Petra; Minor, Andrew M.

    2012-01-01

    We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100–200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu. PMID:23447712

  19. Reduction in tensile strength of cartilage precedes surface damage under repeated compressive loading in vitro

    Microsoft Academic Search

    Triona McCormack; Joseph M. Mansour

    1997-01-01

    An experimental protocol for the fatiguing and tensile testing of articular cartilage has been established. Samples were taken from the interpatellar groove of bovine femurs collected post-slaughter, split into two test groups and subjected to a cyclically varying compressive load of approximately 65N for 64,800 cycles or 97,200 cycles. The cartilage was then removed from the underlying bone and two

  20. Tensile Strength and Microstructure of Al2O3-ZrO2 Hypo-Eutectic Fibers Studied

    NASA Technical Reports Server (NTRS)

    Farmer, Serene C.; Sayir, Ali

    2001-01-01

    Oxide eutectics offer high-temperature strength retention and creep resistance in oxidizing environments. Al2O3-ZrO2 eutectic strengths have been studied since the 1970's. Directionally solidified oxide eutectics exhibit improved resistance to slow crack growth and excellent strength retention at high temperatures up to 1400 C. Materials studied typically contain Y2O3 to metastably retain the high-temperature cubic and tetragonal polymorphs at room temperature. Al2O3-ZrO2 is of fundamental interest for creep studies because it combines a creep-resistant material, Al2O3, with a very low creep resistance material, ZrO2. Results on mechanical properties and microstructures of these materials will be used to define compositions for creep testing in future work. Substantial variations from the eutectic alumina to zirconia ratio can be tolerated without a loss in room-temperature strength. The effect of increasing Y2O3 addition on the room-temperature tensile strength of an Al2O3-ZrO2 material containing excess Al2O3 was examined at the NASA Glenn Research Center, where the materials were grown using Glenn's world-class laser growth facilities.

  1. Validity of using average diameter for determination of tensile strength and Weibull modulus of ceramic filaments

    SciTech Connect

    Petry, M.D.; Mah, T.I. [UES Inc., Dayton, OH (United States); Kerans, R.J. [Materials Directorate, Wright-Patterson AFB, OH (United States). Wright Lab.

    1997-10-01

    Strengths and Weibull moduli for alumina/yttrium aluminum garnet eutectic (AYE) filaments and for Si-C-O (Nicalon) filaments were calculated using measured and average filament diameters. The strengths agreed closely. Thus an average filament diameter could be used instead of the measured filament diameter in calculating strengths. The Weibull modulus obtained from an average filament diameter approximates the Weibull modulus obtained using the measured filament diameter.

  2. Measurement of ultimate tensile strength and Young modulus in LYSO scintillating crystals

    Microsoft Academic Search

    Lorenzo Scalise; Daniele Rinaldi; Fabrizio Davì; Nicola Paone

    2011-01-01

    Scintillating crystals are employed in high energy physics, in medical imaging, diagnostic and security. Two mechanical properties of lutetium–yttrium oxyorthosilicate cerium-doped Lu2(1?x)Y2xSiO5:Ce with x=0.1 (LYSO) crystals have been measured: the ultimate tensile stress (?UTS) and the Young elastic modulus (E). Measurements are made by means of a 4-points loading device and the experimental results account for an elastic–brittle stress–strain relation,

  3. Effect on the tensile strength of human acellular dermis (Epiflex®) of in-vitro incubation simulating an open abdomen setting

    PubMed Central

    2014-01-01

    Background The use of human acellular dermis (hAD) to close open abdomen in the treatment process of severe peritonitis might be an alternative to standard care. This paper describes an investigation of the effects of fluids simulating an open abdomen environment on the biomechanical properties of Epiflex® a cell-free human dermis transplant. Methods hAD was incubated in Ringers solution, blood, urine, upper gastrointestinal (upper GI) secretion and a peritonitis-like bacterial solution in-vitro for 3 weeks. At day 0, 7, 14 and 21 breaking strength was measured, tensile strength was calculated and standard fluorescence microscopy was performed. Results hAD incubated in all five of the five fluids showed a decrease in mean breaking strength at day 21 when compared to day 0. However, upper GI secretion was the only incubation fluid that significantly reduced the mechanical strength of Epiflex after 21days of incubation when compared to incubation in Ringer’s solution. Conclusion hAD may be a suitable material for closure of the open abdomen in the absence of upper GI leakage and pancreatic fistulae. PMID:24468201

  4. Measurement of ultimate tensile strength and Young modulus in LYSO scintillating crystals

    NASA Astrophysics Data System (ADS)

    Scalise, Lorenzo; Rinaldi, Daniele; Davì, Fabrizio; Paone, Nicola

    2011-10-01

    Scintillating crystals are employed in high energy physics, in medical imaging, diagnostic and security. Two mechanical properties of lutetium-yttrium oxyorthosilicate cerium-doped Lu 2(1- x) Y 2 xSiO 5:Ce with x=0.1 (LYSO) crystals have been measured: the ultimate tensile stress ( ?UTS) and the Young elastic modulus ( E). Measurements are made by means of a 4-points loading device and the experimental results account for an elastic-brittle stress-strain relation, which depends heavily on the specimen preparation and the material defects. ?UTS along the [0 1 0] tensile direction ranges within 68.14 and 115.61 MPa, which, in the lowest case, is more than twice with respect to those measured for PbWO 4 (PWO), exhibiting a marked difference between the annealed and the not-annealed samples. The mean elastic modulus ( E), along the same direction, is E=1.80×10 11 (±2.15×10 10) N/m 2, with lower dispersion respect to UTS data. This type of analysis and study can be included into quality control procedures of crystals, based on samples taken out of production; such procedures can be established for industrial processing of crystals aimed to the high energy physics (calorimeters) and medical imaging (PET, etc.) applications.

  5. Tensile strength and work hardening of ultrafine-grained high-purity copper

    Microsoft Academic Search

    M. D. Merz; S. D. Dahlgren

    1975-01-01

    Sputter-deposited high-purity copper specimens with grain sizes from 8.4 to 0.056 mum were tested in tension to investigate the influence of grain size on yield strength for small grain sizes. The smallest grain size in the sputter-deposited copper was a factor of 40 smaller than the smallest grain size previously available for yield-strength-grain-size studies of high-purity copper. The 0.2% offset

  6. Effect of the strain rate on the tensile strength of a copper shaped-charge jet

    Microsoft Academic Search

    V. V. Silvestrov; N. N. Gorshkov

    1997-01-01

    The data on the penetration depth of a rotating shaped-charge jet were used to estimate the strength of the material of a\\u000a copper jet formed from a “low” conical linear with an apex angle of120° under the action of centrifugal forces. The estimates0.07–0.15 GPa obtained are close to the static yield point of deformed copper. The jet strength, which is

  7. Relevance of impacter shape to nonvisible damage and residual tensile strength of a thick graphite/epoxy laminate

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1990-01-01

    A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm (1.4 in.) thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, a sharp corner, and a 6.3 mm (0.25 in.) diameter bolt-like rod. The investigation revealed that damage initiated when the contact pressure exceeded a critical level. However, the damage was not visible on the surface until an even higher pressure was exceeded. The damage on the surface consisted of a crater shaped like the impacter, and the damage below the surface consisted of broken fibers. The impact energy to initiate damage or cause visible damage on the surface increased approximately with impacter diameter to the third power. The reduction in strength for nonvisible damage increased with increasing diameter, 9 and 30 percent for the 12.7 mm (0.5 in.) and 25.4 mm (1.0 in.) diameter hemispheres, respectively. The corner impacter made visible damage on the surface for even the smallest impact energy. The rod impacter acted like a punch and sliced through the composite. Even so, the critical level of pressure to initiate damage was the same for the rod and hemispherical impacters. Factors of safety for nonvisible damage increased with increasing kinetic energy of impact. The effects of impacter shape on impact force, damage size, damage visibility, and residual tensile strength were predicted quite well assuming Hertzian contact and using maximum stress criteria and a surface crack analysis.

  8. Tensile bond strength of indirect composites luted with three new self-adhesive resin cements to dentin

    PubMed Central

    TÜRKMEN, Cafer; DURKAN, Meral; C?M?LL?, Hale; ÖKSÜZ, Mustafa

    2011-01-01

    Objective The aims of this study were to evaluate the tensile bond strengths between indirect composites and dentin of 3 recently developed self-adhesive resin cements and to determine mode of failure by SEM. Material and Methods Exposed dentin surfaces of 70 mandibular third molars were used. Teeth were randomly divided into 7 groups: Group 1 (control group): direct composite resin restoration (Alert) with etch-and-rinse adhesive system (Bond 1 primer/adhesive), Group 2: indirect composite restoration (Estenia) luted with a resin cement (Cement-It) combined with the same etch-and-rinse adhesive, Group 3: direct composite resin restoration with self-etch adhesive system (Nano-Bond), Group 4: indirect composite restoration luted with the resin cement combined with the same self-etch adhesive, Groups 5-7: indirect composite restoration luted with self-adhesive resin cements (RelyX Unicem, Maxcem, and Embrace WetBond, respectively) onto the non-pretreated dentin surfaces. Tensile bond strengths of groups were tested with a universal testing machine at a constant speed of 1 mm/min using a 50 kgf load cell. Results were statistically analyzed by the Student's t-test. The failure modes of all groups were also evaluated. Results The indirect composite restorations luted with the self-adhesive resin cements (groups 5-7) showed better results compared to the other groups (p<0.05). Group 4 showed the weakest bond strength (p>0.05). The surfaces of all debonded specimens showed evidence of both adhesive and cohesive failure. Conclusion The new universal self-adhesive resins may be considered an alternative for luting indirect composite restorations onto non-pretreated dentin surfaces. PMID:21710095

  9. Effect of laser welding on the titanium composite tensile bond strength.

    PubMed

    Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Pagnano, Valéria de Oliveira; de Mattos, Maria da Glória Chiarello

    2009-01-01

    The aim of this study was to analyze the shear bond strength between commercially pure titanium, with and without laser welding, after airbone-particle abrasion (Al(2)O(3)) and 2 indirect composites. Sixty-four specimens were cast and divided into 2 groups with and without laser welding. Each group was divided in 4 subgroups, related to Al(2)O(3) grain size: A - 250 microm; B - 180 microm; C- 110 microm; and D - 50 microm. Composite rings were formed around the rods and light polymerized using UniXS unit. Specimens were invested and their shear bond strength at failure was measured with a universal testing machine at a crosshead speed of 2.0 mm/min. Statistical analysis was carried out with ANOVA and Tukey's test (alpha=0.05). The highest bond strength means were recorded in 250 microm group without laser welding. The lowest shear bond strength means were recorded in 50 microm group with laser welding. Statistically significant differences (p<0.05) were found between all groups. In conclusion, airborne particle abrasion yielded significantly lower bond strength as the Al(2)O(3) particle size decreased. Shear bond strength decreased in the laser welded specimens. PMID:20126909

  10. The effect of three different surface treatments on the tensile strength of the resin bond to nickel-chromium-beryllium alloy.

    PubMed

    Kohli, S; Levine, W A; Grisius, R J; Fenster, R K

    1990-01-01

    The effect of three different metal surface treatments on the tensile strength of the resin bond to non-noble nickel-chromium-beryllium alloy was studied by bonding metal to metal. Chemical etching of the metal for 1 hour obtained the highest strength, followed by air-abraded bond specimens. Lowest strength was obtained with the gel-etch method. All resulted in clinically acceptable values. PMID:2404105

  11. Effects on stress rupture life and tensile strength of tin additions to Inconel 718

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.; Johnson, W.

    1982-01-01

    Because Inconel 718 represents a major use of columbium and a large potential source of columbium for aerospace alloys could be that of columbium derived from tin slags, the effects of tin additions to Inconel 718 at levels which might be typical of or exceed those anticipated if tin slag derived columbium were used as a melting stock were investigated. Tin was added to 15 pound Inconel 718 heats at levels varying from none added to approximately 10,000 ppm (1 wt%). Limited 1200 F stress rupture testing was performed at stresses from 68,000 to 115,000 psi and a few tensile tests were performed at room temperature, 800 and 1200 F. Additions of tin in excess of 800 ppm were detrimental to ductility and stress rupture life.

  12. Tensile bond strength of a composite resin cement for bonded prosthesis to various dental alloys.

    PubMed

    Rubo, J H; Pegoraro, L F

    1995-09-01

    The development of composite resin cements that chemically bond to dental alloys has improved the construction of resin-bonded prostheses. Composite resins can be selected for various situations, but specific clinical situations may require different alloys. This study evaluated the ability of a composite resin cement to bond to various dental alloys of different compositions. Ten pairs of disks for each alloy (two NiCr, two NiCrBe, one CuAl, one gold type IV, and one gold for metal ceramic) were bonded to a composite resin cement after air abrasion was performed with aluminum oxide. The disks were then rinsed in tap water and were ultrasonically cleaned in distilled water for 2 minutes. The tensile tests exhibited greater values for alloys ultrasonically cleaned, and the best results were recorded by NiCr and NiCrBe alloys. PMID:7473275

  13. Tensile strength of composite sheets with unidirectional stringers and crack-like damage: A brief report

    NASA Technical Reports Server (NTRS)

    Poe, C. C., Jr.

    1984-01-01

    The residual strength of composite sheets with bonded composite stringers loaded in tension was determined. The results are summarized. About 50 graphite/epoxy composite panels with crack-like slots were monotonically loaded in tension to failure. Both sheet layup and stringer configuration were varied. The composite panels have considerable damage tolerance. The stringers arrested cracks that ran from the crack-like slots, and the residual strengths were considerably greater than those of unstiffened composite sheets. A stress-intensity factor analysis was developed to predict the failing strains of the stiffened panels. Using the analysis, a single design curve was produced for composite sheets with bonded stringers of any configuration.

  14. Effect of surface treatment on the hydrolytic stability of E-glass fiber bundle tensile strength

    E-print Network

    Sottos, Nancy R.

    on flaw nucleation and growth from contact abrasion and hydro- lytic degradation. The effect of fiber and silane, starch and wax, and epoxy surface treatments are tested following exposure to 10%, 40%, 80 degradation significantly reduce the realizable strength of commercial fibers used for manufacturing [2]. Mois

  15. Gas bubble retention and its effect on waste properties: Retention mechanisms, viscosity, and tensile and shear strengths

    SciTech Connect

    Gauglitz, P.A.; Rassat, S.D.; Powell, M.R. [and others

    1995-08-01

    Several of the underground nuclear storage tanks at Hanford have been placed on a flammable gas watch list, because the waste is either known or suspected to generate, store, and episodically release flammable gases. Because retention and episodic release of flammable gases from these tanks containing radioactive waste slurries are critical safety concerns, Pacific Northwest Laboratory (PNL) is studying physical mechanisms and waste properties that contribute to the episodic gas release from these storage tanks. This study is being conducted for Westinghouse Hanford Company as part of the PNL Flammable Gas project. Previous investigations have concluded that gas bubbles are retained by the slurry or sludge that has settled at the bottom of the tanks; however, the mechanisms responsible for the retention of these bubbles are not well understood. Understanding the rheological behavior of the waste, particularly of the settled sludge, is critical to characterizing the tendency of the waste to retain gas bubbles and the dynamics of how these bubbles are released from the waste. The presence of gas bubbles is expected to affect the rheology of the sludge, specifically its viscosity and tensile and shear strengths, but essentially no literature data are available to assess the effect of bubbles. The objectives of this study were to conduct experiments and develop theories to understand better how bubbles are retained by slurries and sludges, to measure the effect of gas bubbles on the viscosity of simulated slurries, and to measure the effect of gas bubbles on the tensile and shear strengths of simulated slurries and sludges. In addition to accomplishing these objectives, this study developed correlations, based on the new experimental data, that can be used in large-scale computations of waste tank physical phenomena.

  16. Weibull statistical analysis of tensile strength of vascular bundle in inner layer of moso bamboo culm in molecular parasitology and vector biology.

    PubMed

    Le, Cui; Wanxi, Peng; Zhengjun, Sun; Lili, Shang; Guoning, Chen

    2014-07-01

    Bamboo is a radial gradient variation composite material against parasitology and vector biology, but the vascular bundles in inner layer are evenly distributed. The objective is to determine the regular size pattern and Weibull statistical analysis of the vascular bundle tensile strength in inner layer of Moso bamboo. The size and shape of vascular bundles in inner layer are similar, with an average area about 0.1550 mm2. A statistical evaluation of the tensile strength of vascular bundle was conducted by means of Weibull statistics, the results show that the Weibull modulus m is 6.1121 and the accurate reliability assessment of vascular bundle is determined. PMID:25016270

  17. Effect of strain rate on the tensile strength of copper shaped charge jet

    Microsoft Academic Search

    V. V. Silvestrov; N. N. Gorshkov

    1996-01-01

    The jet is produced by a cylindrical 45-mm shaped charge inside a conical copper liner with 120° apex angle. The data on rotating shaped charge penetration are used to estimate the strength of a copper jet under radial tension due to the action of centrifugal force. The value of 0.07 to 0.15 GPa is obtained, which is close to the

  18. An investigation of the reduction in tensile strength and fatigue life of pre-corroded 7075-T6 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Obert, B.; Ngo, K.; Hashemi, J.; Ekwaro-Osire, S.; Sivam, T. P.

    2000-08-01

    In aging aircraft, the synergetic interaction between corrosion and fatigue has been shown to reduce the life expectancy of aluminum alloys. The objective of this study was to quantify the effects of corrosion, in terms of mass loss per unit area, on the static strength and fatigue life of 7075-T6 aluminum alloy. This was an experimental study in which test specimens were corroded in a laboratory environment. The corrosion process was accelerated by use of a corrosion cell. Test specimens were cut from flat sheets of aluminum and covered with masking material to restrict corrosion to a confined area. After testing, the fatigue life, ultimate tensile strength (UTS), and hardness of the specimens were observed to drop significantly with small amounts of corrosion. After the initial decrease, the UTS was observed to decrease linearly with increasing corrosion levels. The fatigue life of the specimens decreased in an inverse exponential fashion as mass loss per unit area increased. The hardness values of the corroded surfaces were also observed to drop. The topology of the pits and the related subsurface damage produced areas of high stress concentration resulting in the immediate reduction of UTS and fatigue life of the specimens. Subsurface corrosion damage was responsible for the reduction in hardness.

  19. The influence of impurities in Titan ice bedrock on tensile strength and resistance to fluvial erosion: experimental results

    NASA Astrophysics Data System (ADS)

    Litwin, K. L.; Polito, P.; Zygielbaum, B.; Sklar, L. S.; Collins, G. C.

    2010-12-01

    Images of the surface of Titan returned by the Cassini-Huygens mission show extensive fluvial drainage networks, which may be eroded by low-velocity impacts by ice clasts moving as bedload in rivers of liquid methane. Recent work has shown that the strength of polycrystalline water ice at Titan surface temperature of 93K is comparable to moderate strength rocks on Earth, and is significantly stronger than ice at terrestrial temperatures. However, the ice bedrock on Titan is likely to contain impurities such as silicates, atmospherically-derived hydrocarbon polymers and compounds of cryovolcanic origin. In this laboratory investigation, we examine the dependence of ice erosion resistance on the concentration of impurities, across a wide range of temperatures. The polycrystalline ice is made from a log-normally distributed seed crystal material with a median size of 1.4mm, which we combine with particles of basalt, ammonium-sulfate, and a urea polymer. We use the Brazilian tensile splitting test to measure the strength of the ice as a function of the concentration of each impurity. We erode 57-cm diameter drums of ice by repeatedly dropping a clast of known mass from a constant height and measure volume eroded with a topographic scanning technique where photographs are taken at an oblique angle to a vertically-oriented laser sheet. We control the temperature of the ice with dry ice and liquid nitrogen, as well as by conducting experiments in a walk-in freezer. The strength tests indicate that the ice strengthens with decreasing temperature and increasing concentration of impurity, for all impurity types. Additionally, the grain size of the added impurities is a strongly influences ice strength. The results of the erosion tests indicate that ice, regardless of composition, becomes stronger, and becomes more resistant to erosion, as it gets colder. However, the ice containing impurities is more resistant to erosion as compared to pure ice. Combining the results of both the strength tests and erosion experiments, we conclude that the resistance to erosion of the ice increases with increasing concentration of each impurity. These results will help constrain estimates of ice resistance to erosion, and possible erosion rates, that may occur on Titan and other icy satellites.

  20. Influence of the core-sheath weight ratio and twist on the tensile strength of the ring core yarns with high tenacity filaments

    Microsoft Academic Search

    Hyung J. Kim; Hee W. Yang; Cheng Y. Zhu; You Huh

    2009-01-01

    Core spun yarns are applied for various purposes that especially require the multi-functional performance. This research reports\\u000a on the core spinning effect on the yarn strength. We prepared various core yarns by combining different kinds of high tenacity\\u000a filaments in core with cotton staples in sheath with various twist levels in the ring spin system. And the tensile strength\\u000a was

  1. The effect of pre-operative conventional and hyperfractionated radiotherapy schedules on wound healing and tensile strength in rats: an experimental study.

    PubMed

    Ozbek, N; Guneren, E; Yildiz, L; Meydan, D; Cakir, S; Coskun, M

    2005-03-01

    We examined the effects of pre-operative conventional and hyperfractionated radiotherapy schedules on wound healing and tensile strength in 90 female Wistar rats weighing between 182 and 240 g. The animals were randomized into three groups (n = 30 each). Group I was sham-irradiated. Group II (conventional) received 20 daily fractions of 200 cGy, to a total dose of 4000 cGy. Group III (hyperfractionated) received 40 fractions of 120 cGy, twice daily, to a total dose of 4800 cGy. Four weeks after radiotherapy, incision and primary repair with simple suturing was performed on one side of the neck. Twenty-one days after wounding, all the rats were sacrificed. Non-parametric Kruskal-Wallis and Mann-Whitney U-tests were used for the statistical analysis of wound tensile strength. The chi-squared test was used for the statistical analysis of the histopathologic findings. The hyperfractionated group had a significantly lower tensile strength than that of the control group (P = 0.03, z = -2.18). According to the histopathologic findings, fibrosis was increased significantly in the hyperfractionated group as compared to the other groups (P = 0.038, chi2 = 6.52). Hyperfractionated radiotherapy significantly reduced the wound tensile strength in the early evaluation period as compared to the control group. PMID:15695049

  2. Multivariate analysis of relationships between material properties, process parameters and tablet tensile strength for alpha-lactose monohydrates.

    PubMed

    Haware, Rahul V; Tho, Ingunn; Bauer-Brandl, Annette

    2009-11-01

    The present work describes an approach to quantify relationships between the material properties of various alpha-lactose monohydrate grades (alphaLM), process parameters (punch velocity, lubricant fraction) and the tablet tensile strength (TS). Milled, sieved, agglomerated and spray-dried alphaLMs were studied. Each material was tableted (11 mm flat punches, constant true volume of 0.2833 cm(3)) on a compaction simulator at a pressure of 104.4+/-0.1 MPa. The force-displacement data was analyzed by applying a combination of compression descriptors (derived from Kawakita and Heckel equations, work-related parameters). The relationships were evaluated and quantified by principal component analysis (PCA) and partial least square regression (PLS-1). PCA verified fundamental relationships between different powder and compression properties of studied materials. It was found that the compression descriptors Kawakita '1/b' and WoC were sufficient to distinguish the tested alphaLM-grades, even in combination with different lubricant fraction or by utilizing different punch velocities; the identified descriptors correlated with TS. These relationships were quantified by PLS-1. Finally, TS were successfully predicted for all alphaLM with the help of separate optimized PLS-1 models. The present study shows an approach how to extract relevant information about tableting behavior from a limited amount of material. PMID:19698784

  3. Effects of excipients on the tensile strength, surface properties and free volume of Klucel® free films of pharmaceutical importance

    NASA Astrophysics Data System (ADS)

    Gottnek, Mihály; Süvegh, Károly; Pintye-Hódi, Klára; Regdon, Géza

    2013-08-01

    The physicochemical properties of polymers planned to be applied as mucoadhesive films were studied. Two types of Klucel® hydroxypropylcellulose (LF and MF) were used as film-forming polymers. Hydroxypropylcellulose was incorporated in 2 w/w% with glycerol and xylitol as excipients and lidocaine base as an active ingredient at 5, 10 or 15 w/w% of the mass of the film-forming polymer. The free volume changes of the films were investigated by positron annihilation lifetime spectroscopy, the mechanical properties of the samples were measured with a tensile strength tester and contact angles were determined to assess the surface properties of the films. It was found that the Klucel® MF films had better physicochemical properties than those of the LF films. Klucel® MF as a film-forming polymer with lidocaine base and both excipients at 5 w/w% exhibited physicochemical properties and good workability. The excipients proved to exert strong effects on the physicochemical properties of the tested systems and it is very important to study them intensively in preformulation studies in the pharmaceutical technology in order to utilise their benefits and to avoid any disadvantageous effects.

  4. Diametric gene-dosage effects as windows into neurogenetic architecture

    E-print Network

    Crespi, Bernard J.

    Diametric gene-dosage effects as windows into neurogenetic architecture Bernard Crespi Gene diametric changes in gene dosage influence neurological development and function? Recent studies of transgenic and knockout mouse models, genomic copy-number variants, imprinted- gene expression alterations

  5. Diametric Quadrilaterals with Two Equal Sides

    ERIC Educational Resources Information Center

    Beauregard, Raymond A.

    2009-01-01

    If you take a circle with a horizontal diameter and mark off any two points on the circumference above the diameter, then these two points together with the end points of the diameter form the vertices of a cyclic quadrilateral with the diameter as one of the sides. We refer to the quadrilaterals in question as diametric. In this note we consider…

  6. To evaluate and compare the effect of different Post Surface treatments on the Tensile Bond Strength between Fiber Posts and Composite Resin.

    PubMed Central

    Shori, Deepa; Pandey, Swapnil; Kubde, Rajesh; Rathod, Yogesh; Atara, Rahul; Rathi, Shravan

    2013-01-01

    Background: Fiber posts are widely used for restoration of mutilated teeth that lack adequate coronal tooth structure to retain a core for definitive restoration, bond between the fiber post and composite material depends upon the chemical reaction between the post surface and the resin material used for building up the core. In attempt to maximize the resin bonding with fiber post, different post surface conditioning is advocated. Therefore the purpose of the study is to examine the interfacial strength between fiber post and composite, as core build-up material after different surface treatments of fiber posts. Materials & Methods:Twenty fiber posts were split into four groups off five each according to different surface treatments viz. Group I-(Negative Control), Group II-Silanization (Positive control), Group III-(37% Phosphoric Acid & Silanization) ,Group IV- (10% Hydrogen Peroxide and Silanization). With the preformed plastic mould, a core of dual cure composite resin around the fiber post having the uniform thickness was created. Tensile bond strength of each specimen was measured under Universal Testing Machine (UTM) at the cross head speed of 3mm/min. Results: The results achieved with 10% Hydrogen peroxide had a marked effect on micro tensile bond strength values between the tested materials. Conclusion: Immense enhancement in the silanization efficiency of quartz fiber phase was observed with different surface chemical treatment of the resin phase of fiber posts with the marked increase in the micro-tensile bond strength between fiber post and composite core. How to cite this article: Shori D, Pandey S, Kubde R, Rathod Y, Atara R, Rathi S. To evaluate and compare the effect of different Post Surface treatments on the Tensile Bond Strength between Fiber Posts and Composite Resin. J Int Oral Health 2013; 5(5):27-32. PMID:24324301

  7. Molecular-Level Study of the Effect of Prior Axial Compression/Torsion on the Axial-Tensile Strength of PPTA Fibers

    NASA Astrophysics Data System (ADS)

    Grujicic, M.; Yavari, R.; Ramaswami, S.; Snipes, J. S.; Yen, C.-F.; Cheeseman, B. A.

    2013-11-01

    A comprehensive all-atom molecular-level computational investigation is carried out in order to identify and quantify: (i) the effect of prior longitudinal-compressive or axial-torsional loading on the longitudinal-tensile behavior of p-phenylene terephthalamide (PPTA) fibrils/fibers; and (ii) the role various microstructural/topological defects play in affecting this behavior. Experimental and computational results available in the relevant open literature were utilized to construct various defects within the molecular-level model and to assign the concentration to these defects consistent with the values generally encountered under "prototypical" PPTA-polymer synthesis and fiber fabrication conditions. When quantifying the effect of the prior longitudinal-compressive/axial-torsional loading on the longitudinal-tensile behavior of PPTA fibrils, the stochastic nature of the size/potency of these defects was taken into account. The results obtained revealed that: (a) due to the stochastic nature of the defect type, concentration/number density and size/potency, the PPTA fibril/fiber longitudinal-tensile strength is a statistical quantity possessing a characteristic probability density function; (b) application of the prior axial compression or axial torsion to the PPTA imperfect single-crystalline fibrils degrades their longitudinal-tensile strength and only slightly modifies the associated probability density function; and (c) introduction of the fibril/fiber interfaces into the computational analyses showed that prior axial torsion can induce major changes in the material microstructure, causing significant reductions in the PPTA-fiber longitudinal-tensile strength and appreciable changes in the associated probability density function.

  8. Ab initio study of the tensile strength and fracture of coincidence tilt boundaries in cubic SiC: Polar interfaces of the \\\\{122\\\\} Sigma=9 boundary

    Microsoft Academic Search

    Masanori Kohyama

    2002-01-01

    The tensile strength and fracture of polar interfaces of the \\\\{122\\\\} Sigma=9 coincidence tilt grain boundary in cubic SiC have been examined through the behavior of electrons and ions using the ab initio pseudopotential method based on the local density-functional theory. The results are compared with previous results for the nonpolar interface of this boundary [M. Kohyama, Philos. Mag. Lett.

  9. Computer-aided prediction of the Al 2 O 3 nanoparticles’ effects on tensile strength and percentage of water absorption of concrete specimens

    Microsoft Academic Search

    Ali Nazari; Shadi Riahi

    In the present paper, two models based on artificial neural networks and genetic programming for predicting split tensile\\u000a strength and percentage of water absorption of concretes containing Al2O3 nanoparticles have been developed at different ages of curing. For purpose of building these models, training and testing\\u000a using experimental results for 144 specimens produced with 16 different mixture proportions were conducted.

  10. Determination of In-plane Shear Strength of Unidirectional Composite Materials Using the Off-axis Three-point Flexure and Off-axis Tensile Tests

    Microsoft Academic Search

    G. Vargas; F. Mujika

    2010-01-01

    The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports

  11. Effect of pretreatment with ethanol containing fluoride on etched enamel surface as evaluated by scanning electron microscopy, optical microscopy, and tensile bond strength measurement.

    PubMed

    Takahashi, Y; Otsuki, A; Takeuchi, M

    1977-06-01

    The effects of pretreatment with a fluoride-containing ethanol solution on etched enamel surfaces before application of sealant were examined using scanning electron microscopy, optical microscopy, and tensile bond strength determinations. The results suggested that when etched enamel surfaces are treated with ethanol containing no more than 250 ppm fluorine in potassium fluoride, there is no interference with the bonding of the sealant to the treated, etched anamel surface. PMID:330585

  12. pGlcNAc Nanofiber Treatment of Cutaneous Wounds Stimulate Increased Tensile Strength and Reduced Scarring via Activation of Akt1

    PubMed Central

    Lindner, Haley Buff; Felmly, Lloyd McPherson; Demcheva, Marina; Seth, Arun; Norris, Russell; Bradshaw, Amy D.; Vournakis, John; Muise-Helmericks, Robin C.

    2015-01-01

    Treatment of cutaneous wounds with poly-N-acetyl-glucosamine containing nanofibers (pGlcNAc), a novel polysaccharide material derived from a marine diatom, results in increased wound closure, antibacterial activities and innate immune responses. We have shown that Akt1 plays a central role in the regulation of these activities. Here, we show that pGlcNAc treatment of cutaneous wounds results in a smaller scar that has increased tensile strength and elasticity. pGlcNAc treated wounds exhibit decreased collagen content, increased collagen organization and decreased myofibroblast content. A fibrin gel assay was used to assess the regulation of fibroblast alignment in vitro. In this assay, fibrin lattice is formed with two pins that provide focal points upon which the gel can exert force as the cells align from pole to pole. pGlcNAc stimulation of embedded fibroblasts results in cellular alignment as compared to untreated controls, by a process that is Akt1 dependent. We show that Akt1 is required in vivo for the pGlcNAc-induced increased tensile strength and elasticity. Taken together, our findings suggest that pGlcNAc nanofibers stimulate an Akt1 dependent pathway that results in the proper alignment of fibroblasts, decreased scarring, and increased tensile strength during cutaneous wound healing. PMID:25955155

  13. Root tensile strength of grey alder and mountain maple grown on a coarse grained eco-engineered slope in the Swiss Alps related to wood anatomical features

    NASA Astrophysics Data System (ADS)

    Kink, Dimitri; Bast, Alexander; Meyer, Christine; Meier, Wolfgang; Egli, Markus; Gärtner, Holger

    2014-05-01

    Steep, vegetation free slopes are a common feature in alpine areas. The material covering these slopes is prone to all kind of erosional processes, resulting in a high risk potential for population and infrastructure. This risk potential is likely to increase with the predicted change in the spatiotemporal distribution of precipitation events. A potential increase in extreme precipitation events will also result in a higher magnitude and frequency of erosional processes. In the Swiss Alps as in many other mountainous areas, there is a need to stabilize these slopes to reduce their direct or indirect hazard potential. In this regard, eco-engineering is a very promising and sustainable approach for slope stabilization. Planting trees and shrubs is a central task in eco-engineering. A developing vegetation cover will on one hand reduce the mechanical effects of rainfall by an increased interception, on the other hand, the root systems cause modifications of soil properties. Roots not only provide anchorage for the plants, they also promote soil aggregation and are able to penetrate possible shear horizons. Overall, anchorage of plants is at the same extend also stabilizing the near subsurface. When rainfall occurs, the saturated soil exerts downhill pressure to a tree or shrub. As long as the root distribution supports anchorage, the respective slope area remains stable. At this point, the tensile strength of the roots is a critical measure, because it is more likely that the supporting roots break than the entire root system being pulled out of the soil completely. As a consequence, root tensile strength is an important parameter in characterizing the soil stabilization potential of trees and shrubs. It is known that tree roots show a high variability in their anatomical structure depending on their depth below soil surface as well as their distance to the main stem. Therefore, we assume that these structural changes affect the tensile strength of every single root. In order to confirm this assumption and possibly find more important root properties which have an influence on soil stabilization, the root systems of seven trees (three grey alder, four mountain maple) were excavated and analyzed. The study site is a catchment, where shallow landslides are common. It is located in the Prättigau valley in the Eastern Swiss Alps and was eco-engineered in 1997. The substrate is coarse-grained morainic material, mean annual air temperature reaches 4.64°C, average precipitation is 1170 mm, and the altitude is about 1000 m a.s.l.. The root system of each tree was uncovered carefully by hand to keep the roots undamaged, before removal it was photographed in situ to document the root distribution. The root systems were then cut into single root pieces of about 20 cm length and the position of each sample was documented. The root samples were then hierarchically classified in several root classes. The tensile strength of more than 500 samples was determined. In addition, the values for age, diameter, and root moisture were ascertained. Since it was assumed, that the cellular structure of the roots has an influence on the tensile strength, two microscopic thin-sections were prepared from all successfully tested root samples. The microscopic analysis focused on anatomical parameters such as the size and number of vessels, their distribution as well as their conductivity. The results for the final correlation between the anatomical characteristics and the root's tensile strength are presented for both tree species.

  14. Effects of surface treatments and storage times on the tensile bond strength of adhesive cements to noble and base metal alloys.

    PubMed

    Burmann, Paulo Afonso; Santos, Jose Fortunato Ferreira; May, Liliana Gressler; Pereira, Joao Eduardo da Silva; Cardoso, Paulo Eduardo Capel

    2008-01-01

    This work evaluated two resin cements and a glass-ionomer cement and their bond strength to gold-palladium (Au-Pd), silver-palladium (Ag-Pd), and nickel-chromium-beryllium (Ni-Cr-Be) alloys, utilizing three surface treatments over a period of six months. Eight hundred ten pieces were cast (in a button shape flat surfaces) in one of three alloys. Each alloy group was assigned to three other groups, based on the surface treatment utilized. Specimens were fabricated by bonding similar buttons in using one of three adhesive cements. The 405 pairs were thermocycled and stored in saline solution (0.9% NaCl) at 37 degrees C. The tensile bond strengths were measured in a universal testing machine after storage times of 2, 90, or 180 days. The highest mean bond strength value was obtained with the base metal alloy (10.9 +/- 8.6 MPa). In terms of surface treatment, oxidation resulted in the highest mean bond strength (13.7 +/- 7.3 MPa), followed by sandblasting (10.3 +/- 5.5 MPa) and polishing (3.0 +/- 6.4 MPa). Panavia Ex (13.2 +/- 9.3 MPa) showed significantly higher bond strengths than the other two cements, although the storage time reduced all bond strengths significantly. PMID:18348374

  15. Reactor irradiation effects on the ultimate tensile and the interlaminar shear strength of carbon fibre reinforced epoxies at 77 K

    Microsoft Academic Search

    S. M Spießberger; K Humer; E. K Tschegg; H. W Weber; H Gerstenberg

    1998-01-01

    A carbon fibre reinforced plastics material (CFRP) `TORAYCA T300 3K', which was developed for various applications, including cryogenics, was irradiated at 5K and 340K with different reactor spectra up to a fast neutron fluence of 5×1022m?2 (E>0.1MeV). All investigations in the interlaminar shear mode as well as the tensile tests were made at 77K, the samples subjected to 5K irradiation

  16. A Comparative Evaluation of the Effect of Bonding Agent on the Tensile Bond Strength of Two Pit and Fissure Sealants Using Invasive and Non-invasive Techniques: An in–vitro Study

    PubMed Central

    Singh, Shamsher; Adlakha, Vivek; Babaji, Prashant; Chandna, Preetika; Thomas, Abi M.; Chopra, Saroj

    2013-01-01

    Background: Newer technologies and the development of pit and fissure sealants have shifted the treatment philosophy from ‘drill and fill’ to that of ‘seal and heal’. Aims: The purpose of this in–vitro study was to evaluate the effects of bonding agents on the tensile bond strengths of two pit and fissure sealants by using invasive and non-invasive techniques. Study Design and Methods: One hundred and twenty bicuspids were collected and teeth were divided into two groups: Group-I (Clinpro) and Group-II (Conseal f) with 60 teeth in each group. For evaluating tensile bond strengths, occlusal surfaces of all the teeth were flattened by reducing buccal and lingual cusps without disturbing fissures. Standardised polyvinyl tube was bonded to occlusal surfaces with respective materials. Sealants were applied, with or without bonding agents, in increments and they were light cured. Tensile bond strengths were determined by using Universal Testing Machine. Statistical Analysis: Data were then statistically analysed by using Student t–test for comparison. Results: A statistically significant difference was found in tensile bond strength in invasive with bonding agent group than in non-invasive with bonding agent group. Conclusion: This study revealed that invasive techniques increase the tensile bond strengths of sealants as compared to non- invasive techniques and that the use of a bonding agent as an intermediate layer between the tooth and fissure sealant is beneficial for increasing the bond strength. PMID:24298525

  17. Data Qualification and Data Summary Report: Intact Rock Properties Data on Tensile Strength, Schmidt Hammer Rebound Hardness, and Rock Triaxial Creep

    SciTech Connect

    E.M. Cikanek; R.J. Blakely; T.A. Grant; L.E. Safley

    2003-07-29

    This report presents a systematic review of the available data in the TDMS that are relevant to the following intact rock properties: rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep. Relevant data are compiled from qualified and unqualified sources into the summary DTNs and these DTNs are evaluated for qualification using the method of corroborating data as defined in AP-SIII.2Q, ''Qualification of Unqualified Data''. This report also presents a summary of the compiled information in the form of descriptive statistics and recommended values that will be contained in a Reference Information Base (RIB) item prepared in accordance with AP-SIII.4Q, ''Development, Review, Online Placement, and Maintenance of Individual Reference Information Base Data Items''. The primary purpose of this report is to produce qualified sets of data that include all relevant intact rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep testing done over the course of the Yucca Mountain Project (YMP). A second purpose is to provide a qualified summary (i.e., a RIB data item) of the test results using descriptive statistics. The immediate purpose of the report is to support the data needs of repository design; however, the products are designed to be appropriate for general use by the YMP. The appropriateness and limitations, if any, of the data, with respect to the intended use, are addressed in this report.

  18. Root tensile strength assessment of Dryas octopetala L. and implications for its engineering mechanism on lateral moraine slopes (Turtmann Valley, Switzerland)

    NASA Astrophysics Data System (ADS)

    Eibisch, Katharina; Eichel, Jana; Dikau, Richard

    2015-04-01

    Geomorphic processes and properties are influenced by vegetation. It has been shown that vegetation cover intercepts precipitation, enhances surface detention and storage, traps sediment and provides additional surface roughness. Plant roots impact the soil in a mechanical and hydrological manner and affect shear strength, infiltration capacity and moisture content. Simultaneously, geomorphic processes disturb the vegetation development. This strong coupling of the geomorphic and ecologic system is investigated in Biogeomorphology. Lateral moraine slopes are characterized by a variety of geomorphic processes, e. g. sheet wash, solifluction and linear erosion. However, some plant species, termed engineer species, possess specific functional traits which allow them to grow under these conditions and also enable them to influence the frequency, magnitude and even nature of geomorphic processes. For lateral moraine slopes, Dryas octopetala L., an alpine dwarf shrub, was identified as a potential engineer species. The engineering mechanism of D. octopetala, based on its morphological (e.g., growth form) and biomechanical (e.g., root strength) traits, yet remains unclear and only little research has been conducted on alpine plant species. The objectives of this study are to fill this gap by (A) quantifying D. octopetala root tensile strength as an important trait considering anchorage in and stabilization of the slope and (B) linking plant traits to the geomorphic process they influence on lateral moraine slopes. D. octopetala traits were studied on a lateral moraine slope in Turtmann glacier forefield, Switzerland. (A) Root strength of single root threads of Dryas octopetala L. were tested using the spring scale method (Schmidt et al., 2001; Hales et al., 2013). Measurement equipment was modified to enable field measurements of roots shortly after excavation. Tensile strength of individual root threads was calculated and statistically analyzed. First results show that Dryas roots appear to be quite strong compared to other alpine species with a mean tensile strength of 22,63 N mm -². (B) On a micro scale, morphological and biomechanical features of above and below-ground biomass were qualitatively studied through field observations on D. octopetala individuals. Findings indicate that D. octopetala's dense cushions, covering many square meters of the moraines surface, traps fine sediment, stores moisture and significantly reduces erosion through wind and water. Furthermore, Dryas is well adapted to rock fall or burial by forming stabilized patches of ground despite steep slope inclinations and strong, episodic surface runoff and creep processes. Anchorage is provided by its strong root, which in all studied cases grew upslope parallel to the moraines surface. Insights from this study allow to relate root tensile strength and other specific plant traits of Dryas octopetala to an engineering mechanism and effect on geomorphic processes on lateral moraine slopes. Knowledge about Dryas as an engineering species may help to understand its biotic influence on the geomorphic system of a lateral moraine and aid in the selection of species for erosion control or rehabilitation of ecosystems, where Dryas is native.

  19. Role of matrix microstructure on room-temperature tensile properties and fiber-strength utilization of an orthorhombic ti-alloy-based composite

    NASA Astrophysics Data System (ADS)

    Boehlert, C. J.; Majumdar, B. S.; Krishnamurthy, S.; Miracle, D. B.

    1997-02-01

    Microstructure-property understanding obtained for a nominally Ti-25Al-17Nb (at. pct) monolithic sheet alloy was used to heat treat a unidirectional four-ply SCS-6/Ti-25Al-17Nb metal-matrix composite (MMC) and a fiberless “neat” material of the same alloy for enhancing mechanical properties. The unreinforced alloy and [0]4 composite recorded significant improvements in ductility and strength, which were related to the microstructural condition. Modeling of the tensile strength based on fiber fracture statistics helped in understanding how improved matrix microstructure provided more efficient utilization of fiber strength. In comparison to the [0]4 MMC, improvement of the [90]4 response was negligible, which was related to an ?2 stabilized zone around the fiber. A Nb coating on the fiber was used to modify the local microstructure, and it produced a modest improvement in strength and ductility in the transverse direction. Structure-property relations of the matrix under different heat-treatment conditions are described in terms of deformation and failure mechanisms of the constituent phases; ?2 (ordered hexagonal close-packed), B2 (ordered body-centered cubic), and O (ordered orthorhombic based on Ti2AlNb).

  20. Comparative Evaluation of Tensile – Bond Strength of An Orthodontic Adhesive with and without Fluoride Application, After Acid Etching -An Invitro Study

    PubMed Central

    Yugandhar, G; Ramana, I Venkata; Srinivas, K; Yadav, S. Sarjeev Singh

    2015-01-01

    Background Fixed appliances hinder the effective control of plaque accumulation and white spot lesions may develop under the ill fitting bands or adjacent to the stainless steel brackets during orthodontic treatment particularly the etching process. Aims and Objectives Comparative study of tensile bond strength of an orthodontic adhesive with and without fluoride application after acid etching to know the effect of fluoride on bond strength. Materials and Methods This study is carried out on 90 non carious human premolar teeth, and divided in 6 groups with each group of 15 specimens. In those Groups I and IV were control group acid etch treatment, Group II and V is 1.23% APF gel (acid etch plus APF gel treatment,) and group III and VI is 8% SnF2 (acid etch plus SnF2 treatment). Samples of Group I, II and III bond strength were tested after 24 h and groups IV, V and VI after one month on microtechtensometer machine. The scanning electron microscope (SEM) investigation was carried out for the 2 specimens for the control group after acid etch and 4 specimens after acid etch with fluoride application for fluoride groups. Results Control and SnF2 treated groups was found to be nearly similar to the control group whereas APF treated group showed less focal holes than the other 2 groups. Conclusion Fluoride application after acid etching without having an adverse effect on bond strength but we can prevent the white spot lesions and caries. PMID:26023648

  1. Mechanical strength and stability of lithium aluminate

    SciTech Connect

    Brimhall, J.L.

    1992-06-01

    Pacific Northwest Laboratory (PNL) investigated the strength and resistance to thermal shock of lithium aluminate annular pellets. The room temperature, axial compressive fracture strength of pellets made at Westinghouse Advanced Energy Systems (WAES) varied from 80 to 133 ksi. The strength at 430{degrees}C (806{degrees}F) was to 30 to 40% lower. The strength at 900{degrees}C (1652{degrees}F) showed a wide variation with one measurement near 90 ksi. These strength values are consistent with other data and predictions made in the literature when the grain size and porosity of the microstructure are taken into account. In diametral compression tests, the fracture strengths were much lower due to the existence of tensile stresses in some pellet regions from this type of loading. However, the fracture stresses were still generally higher than those reported in the literature; this fracture resistance probably reflects the better quality of the pellets tested in this study. Measurements on pellets made at PNL indicated lower strengths compared to the WAES material. This strength difference could be accounted for by different processing technologies: material made at PNL was cold-pressed and sintered with high porosity whereas the WAES material was isostatically hot-pressed with high density. Thermal shocking of the material by ramping to 900{degrees}C in two minutes did not have an observable effect on the microstructure or the strength of any of the pellets.

  2. Mechanical Strength and Failure Characteristics of Cast Mg-9 pctAl-1 pctZn Alloys Produced by a Heated-Mold Continuous Casting Process: Tensile Properties

    NASA Astrophysics Data System (ADS)

    Okayasu, Mitsuhiro; Takeuchi, Shuhei; Ohfuji, Hiroaki

    2014-11-01

    The mechanical properties and failure characteristics of a cast Mg alloy (AZ91: Mg-Al8.9-Zn0.6-Mn0.2) produced by a heated-mold continuous casting process (HMC) are investigated. In a modification of the original HMC process, the cooling of the liquid alloy by direct water spray is carried out in an atmosphere of high-purity argon gas. The HMC-AZ91 alloy exhibits excellent mechanical properties (high strength and high ductility) that are about twice as high as those for the same alloy produced by conventional gravity casting. The increased material strength and ductility of the HMC sample are attributed to nanoscale and microscale microstructural characteristics. The fine grains and tiny spherical eutectic structures ( e.g., Mg17Al12 and Al6Mn) distributed randomly in the matrix of the HMC alloy result in resistance to dislocation movement, leading to high tensile strength. Basal slip on (0001) planes in the relatively organized crystal orientation of the HMC alloy, as well as grain boundary sliding through tiny spherical eutectic structures, results in high ductility. Details of the failure mechanism under static loading in the HMC alloy are also discussed using failure models.

  3. Prediction of tensile strength of friction stir welded aluminium matrix TiC p particulate reinforced composite

    Microsoft Academic Search

    S. Gopalakrishnan; N. Murugan

    2011-01-01

    The usage of particulate reinforced metal matrix composite (MMC) is steadily increasing due to its properties such as high specific strength, high specific modulus and good wear resistance. Aluminium matrix composite (AMC) plays an important role to meet the above requirements. Effective utilization of AMC is based on not only its production but also on fabrication methods. Among AMCs, those

  4. Infl uence of different brazing and welding methods on tensile strength and microhardness of orthodontic stainless steel wire

    Microsoft Academic Search

    Jens Johannes Bock; Wolfgang Fraenzel; Jacqueline Bailly; Christian Ralf Gernhardt; Robert Andreas; Werner Fuhrmann

    SUMMARY The aim of this study was to compare the mechanical strength and microhardness of joints made by conventional brazing and tungsten inert gas (TIG) and laser welding. A standardized end-to-end joint confi guration of the orthodontic wire material in spring hard quality was used. The joints were made using fi ve different methods: brazing (soldering > 450°C) with universal

  5. Effect of metal as part of fillet on the tensile shear strength of adhesively bonded single lap joints

    Microsoft Academic Search

    Min You; Yong Zheng; Xiao-Ling Zheng; Wen-Jun Liu

    2003-01-01

    The effect of fillet containing metallic components on the strength of adhesively bonded single lap joints has been undertaken by alternating the shape and size of metallic components as a part of fillet or whole fillet at the end of the joints. Mild carbon steel and epoxy structural adhesive were used to prepare single lap-shear joints. Three types of steel

  6. Time/Temperature Dependent Tensile Strength of SiC and Al2O3-Based Fibers

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; DiCarlo, James A.

    1997-01-01

    In order to understand and model the thermomechanical behavior of fiber-reinforced composites, stress-rupture, fast-fracture, and warm-up rupture studies were conducted on various advanced SiC and Al2O3-based fibers in the,temperature range from 20 to 1400 C in air as well as in inert environments. The measured stress-rupture, fast fracture, and warm-up rupture strengths were correlated into a single master time/temperature-dependent strength plot for each fiber type using thermal activation and slow crack growth theories. It is shown that these plots are useful for comparing and selecting fibers for CMC and MMC reinforcement and that, in comparison to stress rupture tests, the fast-fracture and warm-up tests can be used for rapid generation of these plots.

  7. Investigation of the C-ring test for measuring hoop tensile strength of nuclear grade ceramic composites

    NASA Astrophysics Data System (ADS)

    Jacobsen, G. M.; Stone, J. D.; Khalifa, H. E.; Deck, C. P.; Back, C. A.

    2014-09-01

    Silicon carbide (SiC) and silicon carbide fiber reinforced composites (SiC/SiCf) are currently being evaluated as a high temperature material for use in nuclear reactors. While methods to determine the mechanical properties of SiC/SiCf on planar test specimens are well established, mechanical testing methods for tubular SiC/SiCf are still being developed. In this study the C-ring test is evaluated for use with nuclear grade SiC/SiCf as a method of measuring hoop strength. For the samples tested in this work, hoop strengths from C-ring testing are shown to agree within 6% to those obtained using expanding plug testing and analysis shows that the expected composite behavior is observed during testing. While other techniques may give more accurate values for hoop stress, the small specimen requirements and ease of testing makes C-ring testing a valuable tool.

  8. An investigation of the reduction in tensile strength and fatigue life of pre-corroded 7075-T6 aluminum alloy

    Microsoft Academic Search

    B. Obert; K. Ngo; J. Hashemi; S. Ekwaro-Osire; T. P. Sivam

    2000-01-01

    In aging aircraft, the synergetic interaction between corrosion and fatigue has been shown to reduce the life expectancy of\\u000a aluminum alloys. The objective of this study was to quantify the effects of corrosion, in terms of mass loss per unit area,\\u000a on the static strength and fatigue life of 7075-T6 aluminum alloy. This was an experimental study in which test

  9. High-strain rate tensile characterization of graphite platelet reinforced vinyl ester based nanocomposites using split-Hopkinson pressure bar

    NASA Astrophysics Data System (ADS)

    Pramanik, Brahmananda

    The dynamic response of exfoliated graphite nanoplatelet (xGnP) reinforced and carboxyl terminated butadiene nitrile (CTBN) toughened vinyl ester based nanocomposites are characterized under both dynamic tensile and compressive loading. Dynamic direct tensile tests are performed applying the reverse impact Split Hopkinson Pressure Bar (SHPB) technique. The specimen geometry for tensile test is parametrically optimized by Finite Element Analysis (FEA) using ANSYS Mechanical APDLRTM. Uniform stress distribution within the specimen gage length has been verified using high-speed digital photography. The on-specimen strain gage installation is substituted by a non-contact Laser Occlusion Expansion Gage (LOEG) technique for infinitesimal dynamic tensile strain measurements. Due to very low transmitted pulse signal, an alternative approach based on incident pulse is applied for obtaining the stress-time history. Indirect tensile tests are also performed combining the conventional SHPB technique with Brazilian disk test method for evaluating cylindrical disk specimens. The cylindrical disk specimen is held snugly in between two concave end fixtures attached to the incident and transmission bars. Indirect tensile stress is estimated from the SHPB pulses, and diametrical transverse tensile strain is measured using LOEG. Failure diagnosis using high-speed digital photography validates the viability of utilizing this indirect test method for characterizing the tensile properties of the candidate vinyl ester based nanocomposite system. Also, quasi-static indirect tensile response agrees with previous investigations conducted using the traditional dog-bone specimen in quasi-static direct tensile tests. Investigation of both quasi-static and dynamic indirect tensile test responses show the strain rate effect on the tensile strength and energy absorbing capacity of the candidate materials. Finally, the conventional compressive SHPB tests are performed. It is observed that both strength and energy absorbing capacity of these candidate material systems are distinctively less under dynamic tension than under compressive loading. Nano-reinforcement appears to marginally improve these properties for pure vinyl ester under dynamic tension, although it is found to be detrimental under dynamic compression.

  10. Temperature-dependent tensile strength, surface roughness diagnostics, and magnetic support and positioning of polymer ICF shells. Final report, October 1, 1993--April 30, 1995

    SciTech Connect

    Honig, A.

    1995-12-15

    During the course of this grant, we perfected emissivity and accommodation coefficient measurements on polymer ICF shells in the temperature range 250 to 350 K. Values for polystyrene shells are generally between 10{sup -2} and 10{sup -3}, which are very advantageous for ICF at cryogenic temperatures. Preliminary results on Br doped target shells indicate an accommodation coefficient, presumably associated with surface roughness on an atomic scale, about an order of magnitude larger than for ordinary polystyrene target shells. We also constructed apparatus with optical access for low temperature tensile strength and emissivity measurements, and made preliminary tests on this system. Magnetic shells were obtained both from GDP coating and from doping styrene with 10 manometer size ferromagnetic particles. The magnetic properties were measured through electron spin resonance (ESR). These experiments confirm the applicability of the Curie law, and establish the validity of using ESR measurements to determine shell temperature in the low temperature regime from 4K to 250K, thus complementing our presently accessible range. The high electron spin densities (> 10{sup 20}/CM{sup 3}) suggest magnetic levitation should be feasible at cryogenic temperatures. This work has resulted in two conference presentations, a Technical Report, a paper to be published in Fusion Technology, and a Master`s Thesis.

  11. Comparison of J[sub Ic] and J--R curves for short crack and tensilely loaded specimen geometries of a high strength structural steel

    SciTech Connect

    Joyce, J.A. (Naval Academy, Annapolis, MD (United States)); Hackett, E.M. (Nuclear Regulatory Commission, Washington, DC (United States)); Roe, C. (Naval Surface Warfare Center, Annapolis, MD (United States))

    1992-11-01

    This paper describes an experimental program which had the objective of developing a series of J-R curve data from laboratory specimens of varied constraint. Constraint was varied by testing specimens with different thicknesses, crack lengths, and mode of loading. All specimens were relatively small and were kept simple in geometry and loading to allow estimation of the applied J integral. All tests were conducted on high strength structural steel, at ambient temperature, on the ductile upper shelf for this alloy. Results of these tests have shown that different constraint condition can dramatically affect the J[sub Ic] and the J-R curve for the full range of crack lengths and loading modes studied here. The results are compared in terms of the T Stress'' (T[sub sigma]) parameter and the Q constraint parameter, but the trends in the data do not seem to correlate well with either parameter. Although both the T[sub sigma] and Q parameters predict that the single edge notched tensile bar (SE(T)) would have relatively high constraint, this geometry .,demonstrated the highest J[sub Ic] properties. The double edge notched bars were predicted by the T[sub sigma] or Q parameters to be a low constraint geometry, however this geometry resulted in J[sub Ic] results lower than those measured on standard deeply crack bend bars.

  12. Comparison of J{sub Ic} and J--R curves for short crack and tensilely loaded specimen geometries of a high strength structural steel

    SciTech Connect

    Joyce, J.A. [Naval Academy, Annapolis, MD (United States); Hackett, E.M. [Nuclear Regulatory Commission, Washington, DC (United States); Roe, C. [Naval Surface Warfare Center, Annapolis, MD (United States)

    1992-11-01

    This paper describes an experimental program which had the objective of developing a series of J-R curve data from laboratory specimens of varied constraint. Constraint was varied by testing specimens with different thicknesses, crack lengths, and mode of loading. All specimens were relatively small and were kept simple in geometry and loading to allow estimation of the applied J integral. All tests were conducted on high strength structural steel, at ambient temperature, on the ductile upper shelf for this alloy. Results of these tests have shown that different constraint condition can dramatically affect the J{sub Ic} and the J-R curve for the full range of crack lengths and loading modes studied here. The results are compared in terms of the ``T Stress`` (T{sub sigma}) parameter and the Q constraint parameter, but the trends in the data do not seem to correlate well with either parameter. Although both the T{sub sigma} and Q parameters predict that the single edge notched tensile bar (SE(T)) would have relatively high constraint, this geometry .,demonstrated the highest J{sub Ic} properties. The double edge notched bars were predicted by the T{sub sigma} or Q parameters to be a low constraint geometry, however this geometry resulted in J{sub Ic} results lower than those measured on standard deeply crack bend bars.

  13. Evaluation of nondestructive tensile testing

    NASA Technical Reports Server (NTRS)

    Bowe, J. J.; Polcari, S. M.

    1971-01-01

    The results of a series of experiments performed in the evaluation of nondestructive tensile testing of chip and wire bonds are presented. Semiconductor devices were subjected to time-temperature excursions, static-load life testing and multiple pre-stressing loads to determine the feasibility of a nondestructive tensile testing approach. The report emphasizes the importance of the breaking angle in determining the ultimate tensile strength of a wire bond, a factor not generally recognized nor implemented in such determinations.

  14. Experimental stress analysis of a sphere under a diametral load

    E-print Network

    Noyes, Theodore Alvan

    1957-01-01

    LIBRA&V tk M COLLEQE OF YfXAS EXPERIMENTAL STRESS ANALYSIS OF A SPHERE UNDER A DIAMETRAL LOAD A Thesis By THEODORE ALVAN NOYFS Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May 1957 Ma)or Subject: Mechanical Engineering EXPERINENTAL STRESS ANALYSIS OF A SPHERE UNDER A DIAMETRAL LOAD A Thesis THEODORE ALVAN NOYES Approved as to Style and Content by: Chairman of Committee...

  15. Improved Tensile Test for Ceramics

    NASA Technical Reports Server (NTRS)

    Osiecki, R. A.

    1982-01-01

    For almost-nondestructive tensile testing of ceramics, steel rod is bonded to sample of ceramic. Assembly is then pulled apart in conventional tensile-test machine. Test destroys only shallow surface layer which can be machined away making specimen ready for other uses. Method should be useful as manufacturing inspection procedure for low-strength brittle materials.

  16. Tensile properties of impact ices

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Kellackey, C. J.

    1992-01-01

    A special test apparatus was developed to measure the tensile strength of impact ices perpendicular to the direction of growth. The apparatus consists of a split tube carefully machined to minimize the effect of the joint on impact ice strength. The tube is supported in the wind tunnel by two carefully aligned bearings. During accretion the tube is turned slowly in the icing cloud to form a uniform coating of ice on the split tube specimen. The two halves of the split tube are secured firmly by a longitudinal bolt to prevent relative motion between the two halves during ice accretion and handling. Tensile test strength results for a variety of icing conditions were obtained. Both glaze and rime ice conditions were investigated. In general, the tensile strength of impact ice was significantly less than refrigerator ice. Based on the limited data taken, the median strength of rime ice was less than glaze ice. However, the mean values were similar.

  17. Re-examination of the Present Stress State of the Atera Fault, Central Japan, Based on the Calibrated Crustal Stress Data of Hydraulic Fracturing Test by Measuring the Tensile Strength of Rocks

    NASA Astrophysics Data System (ADS)

    Yamashita, F.; Mizoguchi, K.; Fukuyama, E.; Omura, K.

    2008-12-01

    To infer the activity and physical state of intraplate faults in Japan, we re-examined the crustal stress with the hydraulic fracturing test by measuring the tensile strength of rocks. The tensile strength was measured by fracturing hollow cylindrical rock samples (inner and outer radius are 25.0-25.2 mm and 55.1-101.5 mm, respectively, length is 137.0-140.1 mm) which were obtained close to the in situ stress measurement locations by pressurizing the inner hole of the sample. Confining pressure is not applied to the samples in this test. To check the reliability and accuracy of this test, we conducted similar experiments with the standard rock sample (Inada granite) whose physical property is well known. Then, we measured the tensile strength of all available core samples including the Atera fault (at Ueno, Fukuoka, and Hatajiri), the Atotsugawa fault, and the Nojima fault (at Hirabayashi, Iwaya and Kabutoyama), in central Japan, which had been obtained by the National Research Institute for Earth Science and Disaster Prevention (NIED) by the stress measurement with the hydraulic fracturing method. The measured tensile strength data reveals that the in situ re- opening pressure, which is one of the parameters needed for the determination of the maximum in situ horizontal stress, was obviously biased. We re-estimated the re-opening pressure using the measured tensile strength and the in situ breakdown pressure, and re-calculated the in situ stress around the Atera fault. Although the past dislocation of the Atera fault has been considered to be left lateral from the geographical features around the fault, the re-estimated stress suggests that the present dislocation of the Atera fault is right lateral. And the shear stress decreases from the fault. The right lateral dislocation is also supported by the present-day horizontal crustal deformation observed by the triangular and GPS surveys by Geographical Survey Institute in Japan. Therefore, the dislocation direction of the Atera fault seems to change from left lateral to right lateral some time ago. The amount of accumulated right lateral dislocation estimated from the stress data with the dislocation model by Okada (1992) is 2.2-2.6 m. Because the current slip rate from the GPS survey is 2.1-2.3 mm/yr, the accumulation period of the dislocation becomes 960-1240 years if the slip rate is stable. This estimation suggests that during the last 1586 Tensho earthquake the Atera fault dislocated right laterally.

  18. Psychosis and autism as diametrical disorders of the social brain

    Microsoft Academic Search

    Bernard Crespi; Christopher Badcock

    2008-01-01

    Autistic-spectrum conditions and psychotic-spectrum conditions (mainly schizophrenia, bipolar disorder, and major depression) represent two major suites of disorders of human cognition, affect and behavior that involve altered development and function of the social brain. We describe evidence that a large set of phenotypic traits exhibit diametrically-opposite phenotypes in autistic-spectrum vs. psychotic-spectrum conditions, with a focus on schizophrenia. This suite of

  19. Tensile city

    E-print Network

    Chakkour, Mario Henri

    1987-01-01

    Tensile City is a story that provides the answer to the following question: II If we were to leap forward in time and visit a city of the future, what would learn about our contemporary city ? II The story unfolds when ...

  20. The theoretical strength of rubber: numerical simulations of polyisoprene networks at high tensile strains evidence the role of average chain tortuosity

    NASA Astrophysics Data System (ADS)

    Hanson, David E.; Barber, John L.

    2013-10-01

    The ultimate stress and strain of polyisoprene rubber were studied by numerical simulations of three-dimensional random networks, subjected to tensile strains high enough to cause chain rupture. Previously published molecular chain force extension models and a numerical network construction procedure were used to perform the simulations for network crosslink densities between 2 × 1019 and 1 × 1020 cm-3, corresponding to experimental dicumyl-peroxide concentrations of 1-5 parts per hundred. At tensile failure (defined as the point of maximum stress), we find that the fraction of network chains ruptured is between 0.1% and 1%, depending on the crosslink density. The fraction of network chains that are taut, i.e. their end-to-end distance is greater than their unstretched contour length, ranges between 10% and 15% at failure. Our model predicts that the theoretical (defect-free) failure stress should be about twice the highest experimental value reported. For extensions approaching failure, tensile stress is dominated by the network morphology and purely enthalpic bond distortion forces and, in this regime, the model has essentially no free parameters. The average initial chain tortuosity (?) appears to be an important statistical property of rubber networks; if the stress is scaled by ? and the tensile strain is scaled by ?-1, we obtain a master curve for stress versus strain, valid for all crosslink densities. We derive an analytic expression for the average tortuosity, which is in agreement with values calculated in the simulations.

  1. The determination of the mechanical strength of tablets of different shapes.

    PubMed

    Davies, Peter N; Worthington, Harry E C; Podczeck, Fridrun; Newton, J Michael

    2007-08-01

    The aim of the study was to investigate the influence of the platen design, on the evaluation of the mechanical strength of tablets of different shapes in terms of the potential of ensuring reproducible failure mechanisms and deriving their tensile strength. Tablets which were circular, square or hexagonal in shape were prepared at a range of formation pressures each from microcrystalline cellulose (Avicel PH102), a direct compression anhydrous beta-lactose (DCL 21) and dicalcium phosphate dihydrate (Emcompress) with a reciprocating single punch tablet machine. The mechanical strength of the tablets has been determined with a three-point bending test and by applying a diametral load across the edges of the tablets with platens of different designs. Many of the tablets tested in three-point bending did not fail in tension. However, with platens to which semi-circular rods of radius 3.0mm were attached and vertically aligned, a test procedure was provided with which a wide range of tablets tested failed in tension, i.e., split into two halves. Where this occurred it was possible to calculate the tensile strength from the breaking load. Although the value of the tensile strength obtained with such platens was generally lower than that obtained for circular tablets when flat platens were used, the ability to be able to use this new configuration for all the tablet shapes provided a practical system for a range of tablet shapes. The tablets of the three shapes tested here were found to have equivalent values for the tensile strength when formed at the same compaction pressure for the three materials tested. PMID:17329086

  2. THE TENSILE PROPERTIES OF NIOBIUM

    Microsoft Academic Search

    H. G. Vaughan; R. G. Rose

    1958-01-01

    The tensile properties of 1\\/8-in. thick annealed niobium sheet were ; measured over the temperature range 20 to 500 deg C. Strip. 0.04-in. thick, ; obtained by cold rolling 1\\/8-in. thick annealed niobium sheet, was tensile tested ; in the cold-worked and annealed conditions. Results show that niobium retains ; its strength up to 500 deg C, while the eloagation

  3. Surface properties and tensile bond strength of HVOF thermal spray coatings of WC-Co powder onto the surface of 420J2 steel and the bond coats of Ni, NiCr, and Ni\\/NiCr

    Microsoft Academic Search

    Tong Yul Cho; Jae Hong Yoon; Jae Young Cho; Yun Kon Joo; Jin Ho Kang; Shihong Zhang; Hui Gon Chun; Soon Young Hwang; Sik Chol Kwon

    2009-01-01

    Micron-sized WC-Co powder (powder) was coated onto an 420J2 steel substrate and the bond coats (BCs) of Ni, NiCr, and Ni\\/NiCr using high-velocity oxy-fuel thermal spraying to study the surface properties, friction behavior, and tensile bond strength of the WC-Co coating (WC-Co) on the 420J2 substrate (sub) and the BCs of Ni, NiCr, and Ni\\/NiCr. During the spray coating, a

  4. STRENGTH OF A C-SPHERE FLEXURE SPECIMEN

    SciTech Connect

    Wereszczak, Andrew A [ORNL; Wang, Wei [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville; Lance, Michael J [ORNL; Lin, Hua-Tay [ORNL

    2007-01-01

    A 'C-Sphere' flexure strength specimen geometry was conceived and developed to measure a relevant strength of bearing-grade Si{sub 3}N{sub 4} balls and to relate that to surface-located strength-limiting flaws and to ultimately link those flaw populations to rolling contact fatigue performance. A slot was machined into the balls to a set depth to produce the C-sphere geometry. C-sphere specimens were then diametrally compressed to produce a monotonically increasing flexure or hoop tensile stress at their surface that caused their fracture. The strength was determined using the combination of failure load, C-sphere geometry, and FEA, and the stress field was used to determine C-sphere effective areas and effective volumes as a function of Weibull modulus. A description of the specimen and the aforementioned analysis are provided and a comparison of C-sphere flexure strength distributions of two bearing grade Si{sub 3}N{sub 4} materials (NBD200 and SN101C) is given.

  5. Tensile testing of SiC whiskers

    SciTech Connect

    Petrovic, J.J.

    1984-01-01

    The room temperature tensile mechanical properties of SiC whiskers have been examined using a micro-tensile-test apparatus. SiC whiskers exhibit an average tensile strength of 8.4 GPa for a 5 mm tested length, and an average elastic modulus of 581 GPa. These results indicate that SiC whiskers possess significant potential as short-fiber reinforcement elements in ceramic matrix composites.

  6. Effects of Roller Speed, Die Temperature, Volumetric Flow Rate, and Multiple Extrusions on Mechanical Strength of Molten and Solidified LDPE under Tensile Deformation

    Microsoft Academic Search

    Wanlop Harnnarongchai; Naret Intawong; Narongrit Sombatsompop

    2011-01-01

    An experimental rig coupled with a high speed data-logging and recording system and a personal computer was specially designed and constructed for the real-time measurement of mechanical strength (in terms of drawdown force) as a function of volumetric flow rate and roller speed for virgin low-density polyethylene (LDPE) and reprocessed LDPE during a filament stretching process. The effect of the

  7. The Tensile and Tear Properties of a Biodegradable Polyester Film

    Microsoft Academic Search

    K. E. Nissen; B. H. Stuart; M. G. Stevens; A. T. Baker

    2008-01-01

    The tensile and tear properties of a biodegradable polymer, Biomax®, have been studied in order to assess this material in film applications. While the tensile strength of Biomax® was comparable to that of low-density polyethylene, the tear strength was found to be six times lower. A study of the load-displacement curves revealed a regular variation in load throughout the test,

  8. Microsample tensile testing of nanocrystalline metals

    Microsoft Academic Search

    M. Legros; B. R. Elliott; M. N. Rittner; J. R. Weertman; K. J. Hemker

    2000-01-01

    A novel non-contact strain measurement technique has been employed to measure the tensile properties of extremely small ‘microsamples’ of pure high-density ultrafine-grained Al (ufg-Al) nanocrystalline Cu (n-Cu) and nanocrystalline Ni (n-Ni). These microsample tests confirmed the absence of Young's modulus variations for metals with grain sizes approaching 25 nm. Significant strength enhancements were associated with the nanocrystalline specimens; the tensile

  9. Do Diametric Measurements Provide Sufficient and Reliable Tumor Assessment? An Evaluation of Diametric, Areametric, and Volumetric Variability of Lung Lesion Measurements on Computerized Tomography Scans

    PubMed Central

    Fogarty, Edward; Beal, James; Chaudhary, Vijay

    2015-01-01

    Diametric analysis is the standard approach utilized for tumor measurement on medical imaging. However, the availability of newer more sophisticated techniques may prove advantageous. An evaluation of diameter, area, and volume was performed on 64 different lung lesions by three trained users. These calculations were obtained using a free DICOM viewer and standardized measuring procedures. Measurement variability was then studied using relative standard deviation (RSD) and intraclass correlation. Volumetric measurements were shown to be more precise than diametric. With minimal RSD and variance between different users, volumetric analysis was demonstrated as a reliable measurement technique. Additionally, the diameters were used to calculate an estimated area and volume; thereafter the estimated area and volume were compared against the actual measured values. The results in this study showed independence of the estimated and actual values. Estimated area deviated an average of 43.5% from the actual measured, and volume deviated 88.03%. The range of this variance was widely scattered and without trend. These results suggest that diametric measurements cannot be reliably correlated to actual tumor size. Access to appropriate software capable of producing volume measurements has improved drastically and shows great potential in the clinical assessment of tumors. Its applicability merits further consideration.

  10. Tensile Properties of GRCop-84

    NASA Technical Reports Server (NTRS)

    Ellis, David L.; Loewenthal, William S.; Yun, Hee-Man

    2012-01-01

    This is a chapter in the final report on GRCop-84 for the Reusable Launch Vehicle (RLV) Second Generation/Project Constellation Program. It contains information on the tensile properties of GRCop-84. GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) was produced by extrusion and Hot Isostatic Pressing (HIPing). Some of the extrusions were rolled to plate and sheet while other extrusions were drawn into tubing. The material was further subjected to various heat treatments corresponding to annealing, anticipated typical brazing conditions, an end-of-life condition and various elevated temperature exposures to attempt to improve creep resistance. As anticipated, cold work increased strength while decreasing ductility. Annealing at 600 C (1112 F) and higher temperatures was effective. An exposure for 100 h at 500 C (932 F) resulted in an increase in strength rather than the anticipated decrease. High temperature simulated-braze cycles and thermal exposures lowered the strength of GRCop-84, but the deceases were small compared to precipitation strengthened copper alloys. It was observed that the excess Cr could form large precipitates that lower the reduction in area though it appears a minimum amount is required. Overall, GRCop-84 exhibits good stability of its tensile properties, which makes it an excellent candidate for rocket engine liners and many other high temperature applications.

  11. Tensile-property characterization of thermally aged cast stainless steels

    SciTech Connect

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K. [Argonne National Lab., IL (United States)

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  12. Tensile-property characterization of thermally aged cast stainless steels.

    SciTech Connect

    Michaud, W. F.; Toben, P. T.; Soppet, W. K.; Chopra, O. K.; Energy Technology

    1994-03-03

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  13. Tensile properties of nanoclay reinforced epoxy composites

    NASA Astrophysics Data System (ADS)

    Ku, H.; Trada, Mohan

    2013-08-01

    Kinetic epoxy resin was filled with nanoclay to increase tensile properties of the composite for civil and structural. This project manufactured samples with different percentages by weight of nanoclay in the composites in steps of 1 wt %, which were then post-cured in an oven. The samples were then subjected to tensile tests. The results showed that the composite with 3 wt % of nanoclay produced the highest yield and tensile strengths. However, the Young's modulus increased with increasing nanoparticulate loading. It is hoped that the discussion and results in this work would not only contribute towards the further development of nanoclay reinforced epoxy composites with enhanced material properties, but also provide useful information for the studies of fracture toughness, tensile properties and flexural properties of other composites.

  14. Utilization of a diametral fan in a closed cycle gas laser

    Microsoft Academic Search

    R. I. Soloukhin; Iu. A. Iakobi; E. I. Viazovich; S. P. Vagin

    1979-01-01

    It is shown experimentally that a diametral fan, used to generate subsonic flows in a gas laser, is superior to centrifugal and axial fans in that it generates a highly uniform flow in direction of its axis. In addition, the use of a rectilinear duct minimizes the hydraulic losses.

  15. Tensile testing of a single ultrafine polymeric fiber

    Microsoft Academic Search

    E. P. S. Tan; S. Y. Ng; C. T. Lim

    2005-01-01

    Due to the difficulty in handling micro and nanoscale fibers and measuring the small load required for deformation, mechanical properties of these fibers have not been widely characterized. In this study, tensile test of a single-strand polycaprolactone electrospun ultrafine fiber was performed using a nano tensile tester. The tested fiber exhibited the characteristic low strength and low modulus but high

  16. Shear and tensile bond testing for resin cement evaluation

    Microsoft Academic Search

    Yuichi Kitasako; Michael F. Burrow; Toru Nikaido; Naoko Harada; Shigehisa Inokoshi; Toshimoto Yamada; Toshio Takatsu

    1995-01-01

    Objectives. The aim of this study was to compare the tensile and shear bond strengths of one experimental and four commercially available resin cements following the ISO document TR 110405 for bond measurement.Methods. Tensile and shear bond tests were performed using bovine enamel and dentin as the tooth substrate with each of the resin cements. Resin composite rods were cemented

  17. Tensile testing of polysilicon

    Microsoft Academic Search

    W. N. Sharpe; K. T. Turner; R. L. Edwards

    1999-01-01

    Tensile specimens of polysilicon are deposited on a silicon wafer; one end remains affixed to the wafer and the other end has a relatively large paddle that can be gripped by an electrostatic probe. The overall length of the specimen is less than 2 mm, but the smooth tensile portion can be as small as 1.5×2m in cross section and

  18. Tensile Tests of Round-head, Flat-head, and Brazier-head Rivets

    NASA Technical Reports Server (NTRS)

    Schuette, Evan H; Bartone, Leonard M; Mandel, Merven W

    1944-01-01

    An investigation was conducted to determine the tensile strength of round-head (AN43C), flat-head(AN442), and brazier-head (AN4556) aluminum-alloy rivets because of the scarcity of information on the tensile strength of rivets. The results of the investigation are presented as curves that show the variation of the ratio of the tensile strength of the rivet to the tensile strength of the rivet crank with the ratio of the sheet thickness to the rivet diameter for the different types of rivet.

  19. Tensile Mechanical Properties of Swine Cortical Mandibular Bone

    PubMed Central

    Brosh, Tamar; Rozitsky, Doron; Geron, Silvia; Pilo, Raphael

    2014-01-01

    Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction. PMID:25463971

  20. Tensile mechanical properties of swine cortical mandibular bone.

    PubMed

    Brosh, Tamar; Rozitsky, Doron; Geron, Silvia; Pilo, Raphael

    2014-01-01

    Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction. PMID:25463971

  1. Instrumented tensile-impact tests of bone

    Microsoft Academic Search

    S. Saha; W. C. Hayes

    1974-01-01

    An instrumented pendulum-type impact tester was used to obtain tensile-impact properties for compact bone. Load-time histories\\u000a throughout impact were recorded. Impact tests on 50 longitudinally oriented fresh-beef-bone samples yielded a proportional\\u000a limit of 9.64.1 ksi (66.228.2 MPa), an ultimate stress of 17.65.3 ksi (121.336.5 MPa) and an energy-absorption capacity\\u000a of 14285 in. Ib\\/in.2 (2490014900 J\\/m2). A static tensile strength of

  2. Effect of Strain Rate on Tensile Properties of Carbon Fiber Epoxy-Impregnated Bundle Composite

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-03-01

    The tensile tests for high tensile strength polyacrylonitrile (PAN)-based (T1000GB) carbon fiber epoxy-impregnated bundle composite at various strain rates ranging from 3.33 × 10-5 to 6.0 × 102 s-1 (various crosshead speeds ranging from 8.33 × 10-7 to 1.5 × 101 m/s) were investigated. The statistical distributions of the tensile strength were also evaluated. The results clearly demonstrated that the tensile strength of bundle composite slightly increased with an increase in the strain rate (crosshead speed) and the Weibull modulus of tensile strength for the bundle composite decreased with an increase in the strain rate (crosshead speed), there is a linear relation between the Weibull modulus and the average tensile strength on log-log scale.

  3. 3-D Static Elastic Constants and Strength Properties of a Glass/Epoxy Unidirectional Laminate

    E-print Network

    elastic and strength properties for thick unidirectional glass fabric/epoxy laminate and for neat resin.6% shear strain. LAMINATE STRENGTH PROPERTIES STRESS DIRECTION STRENGTH (MPa) ULTIMATE STRAIN (%) Tension L Tensile Yield Stress (MPa) 41.0 Ultimate Tensile Strength (MPa) 76.3 Ultimate Tensile Strain (%) 4.20 0

  4. Approaches for Tensile Testing of Braided Composites

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Salem, Jonathan A.; Bail, Justin L.; Kohlman, Lee W.; Binienda, Wieslaw K.; Martin, Richard E.

    2011-01-01

    For angleply composites, lamina tension and compression strengths are commonly determined by applying classical lamination theory to test data obtained from testing of angleply composite specimens. For textile composites such as 2D triaxial braids, analysis is more complex and standard test methods do not always yield reliable strength measurements. This paper describes recent research focused on development of more reliable tensile test methods for braided composites and presents preliminary data for various approaches. The materials investigated in this work have 0deg+/-60 2D triaxial braid architecture with nearly equal fiber volume fraction in each of the three fiber directions. Flat composite panels are fabricated by resin transfer molding (RTM) using six layers of the braided preform aligned along the 0deg fiber direction. Various epoxy resins are used as matrix materials. Single layer panels are also fabricated in order to examine local variations in deformation related to the braid architecture. Specimens are cut from these panels in the shape of standard straight-sided coupons, an alternative bowtie geometry, and an alternative notched geometry. Axial tensile properties are measured using specimens loaded along the 0deg fiber direction. Transverse tensile properties are measured using specimens loaded perpendicular to the 0deg fibers. Composite tubes are also fabricated by RTM. These tubes are tested by internal pressurization using a soft rubbery material sealed between the inside diameter of the tube and the load fixtures. The ends of the tube are unconstrained, so the primary load is in the hoop direction. Tubes are fabricated with the 0deg fibers aligned along the tube axis by overbraiding the preform on a mandrel. Since the loading is in the hoop direction, testing of the overbraided tube provides a measure of transverse tensile strength. Previous work has indicated that straight-sided coupons yield a transverse tensile strength that is much lower than the expected material strength because of premature edge-initiated failure. Full-field strain measured during transverse tensile tests clearly showed accumulation of edge damage prior to failure. In the current work, high speed video and testing of single layer specimens are used to investigate potential failure mechanisms in more detail. High speed video clearly shows the edge initiation in six layer transverse tensile test coupons. Specimens with the bowtie geometry and the notched geometry minimize this edge effect and yield significantly higher transverse tensile strength values compared to the straight-sided coupons. However, bowtie and notched specimens geometries are not ideal because of the non-uniform stress and strain fields in the region of failure. Testing of tubes using internal pressurization eliminates edge-initiated failure and provides a more uniform state of stress and strain. Preliminary results indicate that bowtie, notched, and tube specimens yield comparable values for transverse tensile strength and that these values are much higher than the strength measured using a straight-sided coupon.

  5. Research on mechanical characteristics of conductive asphalt concrete by indirect tensile test

    NASA Astrophysics Data System (ADS)

    Wu, Shaopeng; Zhang, Yuan; Chen, Mingyu

    2010-03-01

    Conductive asphalt concrete is a functional composite that is composed of regular asphalt concrete and a certain amount of conductive components. In this paper, conductive asphalt concrete has been prepared by adding graphite and carbon fiber to regular asphalt concrete. The combination function of graphite and carbon fiber has obvious advantages in the conductivity improvement. Mechanical characteristics of conductive asphalt concrete have been specially studied by indirect tensile test, which includes indirect tensile strength (ITS), indirect tensile resilient modulus (ITRM) and indirect tensile fatigue (ITF) tests. The ITS test results indicate that conductive asphalt concrete shows higher values of indirect tensile strength than regular asphalt concrete, but lower values of indirect tensile strength ratio. Then, we conclude from ITRM test that the addition of conductive components increases indirect tensile resilient modulus of asphalt concrete. Furthermore, the results of ITF test show that fatigue life (load cycle times) of conductive asphalt concrete have been enhanced compared to regular asphalt concrete at higher stress levels.

  6. Research on mechanical characteristics of conductive asphalt concrete by indirect tensile test

    NASA Astrophysics Data System (ADS)

    Wu, Shaopeng; Zhang, Yuan; Chen, Mingyu

    2009-12-01

    Conductive asphalt concrete is a functional composite that is composed of regular asphalt concrete and a certain amount of conductive components. In this paper, conductive asphalt concrete has been prepared by adding graphite and carbon fiber to regular asphalt concrete. The combination function of graphite and carbon fiber has obvious advantages in the conductivity improvement. Mechanical characteristics of conductive asphalt concrete have been specially studied by indirect tensile test, which includes indirect tensile strength (ITS), indirect tensile resilient modulus (ITRM) and indirect tensile fatigue (ITF) tests. The ITS test results indicate that conductive asphalt concrete shows higher values of indirect tensile strength than regular asphalt concrete, but lower values of indirect tensile strength ratio. Then, we conclude from ITRM test that the addition of conductive components increases indirect tensile resilient modulus of asphalt concrete. Furthermore, the results of ITF test show that fatigue life (load cycle times) of conductive asphalt concrete have been enhanced compared to regular asphalt concrete at higher stress levels.

  7. Residual strength and pore structure of high-strength concrete and normal strength concrete after exposure to high temperatures

    Microsoft Academic Search

    Y. N. Chan; G. F. Peng; M. Anson

    1999-01-01

    Based on normal strength concrete (NSC) and high-strength concrete (HSC), with compressive strengths of 39, 76, and 94 MPa respectively, damage to concrete under high temperatures was identified. After exposure to temperatures up to 1200 °C, compressive strength and tensile splitting strength were determined. The pore structure in HSC and in NSC was also investigated. Results show that HSC lost

  8. Strength of Rewelded Inconel 718

    NASA Technical Reports Server (NTRS)

    Bayless, E.; Lovoy, C. V.; Mcllwain, M. C.; Munafo, P.

    1982-01-01

    Inconel 718, nickel-based alloy used extensively for high-temperature structural service, welded repeatedly without detriment to its strength. According to NASA report, tests show 12 repairs on same weld joint do not adversely affect ultimate tensile strenth, yield strength, fatigue strength, metallurgical grain structures, or ability of weld joint to respond to post weld heat treatments.

  9. Tensile Properties of Under-Matched Weld Joints for 950 MPa Steel.

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kouji; Arakawa, Toshiaki; Akazawa, Nobuki; Yamamoto, Kousei; Matsuo, Hiroki; Nakagara, Kiyoyuki; Suita, Yoshikazu

    In welding of 950 MPa-class high tensile strength steel, preheating is crucial in order to avoid cold cracks, which, however, eventually increases welding deformations. One way to decrease welding deformations is lowering preheating temperature by using under-matched weld metal. Toyota and others clarify that although breaking elongation can decrease due to plastic constraint effect under certain conditions, static tensile of under-matched weld joints is comparable to that of base metal. However, there has still been no report about joint static tensile of under-matched weld joints applied to 950 MPa-class high tensile strength steel. In this study, we aim to research tensile strength and fatigue strength of under-matched weld joints applied to 950 MPa-class high tensile steel.

  10. Effect of Electron Beam Irradiation on the Tensile Properties of Carbon Nanotubes Sheets and Yarns

    NASA Technical Reports Server (NTRS)

    Williams, Tiffany S.; Miller, Sandi G.; Baker, James S.; McCorkle, Linda S.; Meador, Michael A.

    2013-01-01

    Carbon nanotube sheets and yarns were irradiated using electron beam (e-beam) energy to determine the effect of irradiation dose on the tensile properties. Results showed that a slight change in tensile strength occurred after irradiating as-received CNT sheets for 20 minutes, and a slight decrease in tensile strength as the irradiation time approached 90 minutes. On the other hand, the addition of small molecules to the CNT sheet surface had a greater effect on the tensile properties of e-beam irradiated CNT sheets. Some functionalized CNT sheets displayed up to a 57% increase in tensile strength following 90 minutes of e-beam exposure. In addition, as-received CNT yarns showed a significant increase in tensile strength as the irradiation time increased.

  11. Development of Manila Hemp Fiber Epoxy Composite with High Tensile Properties Through Handpicking Fiber Fragments

    NASA Astrophysics Data System (ADS)

    Liu, Ke; Takagi, Hitoshi; Yang, Zhimao

    Manila hemp fibers are separated to several sequent fragments from single fiber. The tensile strength of each fiber fragments and their epoxy composite are measured, followed by scanning electronic microscopic (SEM) analysis. The results show that the tensile strength of fiber fragments is almost constant along fiber. For composite, the tensile strength first increases and then decreases at the position near to root. The Young's modulus presents increasing with location from root to top for fiber and composite. Microstructure analysis indicates that the difference of tensile properties between fiber fragments derive from the difference of fiber diameter.

  12. Effect of impact force on tensile properties and fiber splitting of splittable bicomponent hydroentangled fabrics

    Microsoft Academic Search

    Mbwana Suleiman Ndaro; Jin Xiangyu; Chen Ting; Chongwen Yu

    2007-01-01

    The effect of impact force when using inclined water jets on splittable bicomponents hydroentangled fabrics are investigated\\u000a focusing on changes in tensile properties and fiber splitting. The results indicated that with increase of impact force, the\\u000a tensile strength was increased in both machine direction (MD) and crosswise direction (CD). On changing of water jet inclination\\u000a angle, the tensile strength was

  13. Tensile properties of titanium electrolytically charged with hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1971-01-01

    Yield strength, ultimate tensile strength, and elongation were studied for annealed titanium electrolytically charged with hydrogen. The hydrogen was present as a surface hydride layer. These tensile properties were generally lower for uncharged titanium than for titanium with a continuous surface hydride; they were greater for uncharged titanium than for titanium with an assumed discontinuous surface hydride. We suggest that the interface between titanium and titanium hydride is weak. And the hydride does not necessarily impair strength and ductility of annealed titanium. The possibility that oxygen and/or nitrogen can embrittle titanium hydride is discussed.

  14. Tensile tests of ropes of very long aligned multiwall carbon nanotubes

    Microsoft Academic Search

    Z. W. Pan; S. S. Xie; L. Lu; B. H. Chang; L. F. Sun; W. Y. Zhou; G. Wang; D. L. Zhang

    1999-01-01

    We have directly measured the Young's modulus and tensile strength of multiwall carbon nanotubes by pulling very long (~2 mm) aligned nanotube ropes with a specially designed stress-strain puller. This puller can apply an axial force to the rope and simultaneously measure the corresponding rope elongation and the change in rope resistance. The average Young's modulus and tensile strength obtained

  15. Grips for Lightweight Tensile Specimens

    NASA Technical Reports Server (NTRS)

    Witte, William G., Jr.; Gibson, Walter D.

    1987-01-01

    Set of grips developed for tensile testing of lightweight composite materials. Double-wedge design substantially increases gripping force and reduces slippage. Specimen held by grips made of hardened wedges. Assembly screwed into load cell in tensile-testing machine.

  16. Treatment of High Temperature Tensile Data for Alloy 617 and Alloy 230

    SciTech Connect

    Sham, Sam [ORNL] [ORNL; Eno, Daniel R. [Lockheed Martin Corporation] [Lockheed Martin Corporation; Jensen, Krista P. [Lockheed Martin Corporation] [Lockheed Martin Corporation

    2008-01-01

    Yield strength and tensile strength at temperature are used to set time independent primary stress limits for structural materials in various high temperature design codes. For the Ni-based Alloy 617 and Alloy 230, the temperature trends for the yield strength and tensile strength change significantly above around 1100K and 1025K, respectively, from the lower temperature trends. It is shown that standard methods in obtaining design values for these parameters for Very High Temperature Reactor applications are not satisfactory. Improved methods for the treatment of tensile data are proposed, resulting in more consistent and quantifiable design margin over the full range of low to high temperatures.

  17. Effects of Coating and Diametric Load on Fiber Bragg Gratings as Cryogenic Temperature Sensors

    NASA Technical Reports Server (NTRS)

    Wu, meng-Chou; Pater, Ruth H.; DeHaven, Stanton L.

    2008-01-01

    Cryogenic temperature sensing was demonstrated using pressurized fiber Bragg gratings (PFBGs) with polymer coating of various thicknesses. The PFBG was obtained by applying a small diametric load to a regular fiber Bragg grating (FBG). The Bragg wavelengths of FBGs and PFBG were measured at temperatures from 295 K to 4.2 K. The temperature sensitivities of the FBGs were increased by the polymer coating. A physical model was developed to relate the Bragg wavelength shifts to the thermal expansion coefficients, Young's moduli, and thicknesses of the coating polymers. When a diametric load of no more than 15 N was applied to a FBG, a pressure-induced transition occurred at 200 K during the cooling cycle. The pressure induced transition yielded PFBG temperature sensitivities three times greater than conventional FBGs for temperatures ranging from 80 to 200 K, and ten times greater than conventional fibers for temperatures below 80 K. PFBGs were found to produce an increased Bragg wavelength shift of 2.2 nm compared to conventional FBGs over the temperature range of 4.2 to 300 K. This effect was independent of coating thickness and attributed to the change of the fiber thermo-optic coefficient.

  18. Tensile Properties of Single Desmin Intermediate Filaments

    PubMed Central

    Kreplak, Laurent; Herrmann, Harald; Aebi, Ueli

    2008-01-01

    Within muscle fibers, desmin intermediate filaments (IFs) are major constituents of the extrasarcomeric cytoskeleton. However, their contribution to the mechanical properties of myocytes has remained elusive. We present an experimental approach to measure the extensibility and the tensile strength of in vitro reconstituted desmin IFs adsorbed to a solid support. The tip of an atomic force microscope (AFM) was used to push on single filaments perpendicular to the filament axis. The torque of the AFM cantilever was monitored during the pushing events to yield an estimate of the lateral force necessary to bend and stretch the filaments. Desmin IFs were stretched up to 3.4-fold with a maximum force of ?3.5 nN. Fully stretched filaments exhibited a much smaller diameter than did native IFs, i.e., ?3.5 nm compared to 12.6 nm, both by AFM and electron microscopy. Moreover, we combined the morphological and lateral force data to compute an average stress-strain curve for a single desmin filament. The main features were a pronounced strain-hardening regime above 50% extension and a tensile strength of at least 240 MPa. Because of these nonlinear tensile properties, desmin IFs may dissipate mechanical energy and serve as a physical link between successive sarcomeres during large deformation. PMID:18178641

  19. Ceramic granule strength variability and compaction behavior

    SciTech Connect

    Glass, S.J.; Ewsuk, K.G.; Readey, M.J.

    1995-08-01

    Diametral compression strength distributions and the compaction behavior and of irregular shape 150--200 {mu}m ceramic granules and uniform-size 210 {mu}m glass spheres were measured to determine how granule strength variability relates to compaction behavior of granular assemblies. High variability in strength, represented by low Weibull modulus values (m<3) was observed for ceramic granules having a distribution of sizes and shapes, and for uniform-size glass spheres. Compaction pressure data were also analyzed using a Weibull distribution function, and the results were very similar to those obtained from the diametral compression strength tests for the same material. This similarity suggests that it may be possible to model granule compaction using a weakest link theory, whereby an assemblage of granules is viewed as the links of a chain, and failure of the weakest granule (i.e., the weakest link) leads to rearrangement and compaction. Additionally, with the use of Weibull statistics, it appears to be possible to infer the variability in strength of individual granules from a simple pressure compaction test, circumventing the tedious task of testing individual granules.

  20. Strength analysis of yttria-stabilized tetragonal zirconia polycrystals

    SciTech Connect

    Noguchi, K.; Matsuda, Y.; Oishi, M. (Toray Research Center, Inc., Otsu, Shiga 520 (JP)); Masaki, T.; Nakayama, S.; Mizushina, M. (Toray Industries, Inc., Otsu, Shiga 520 (JP))

    1990-09-01

    This paper reports the tensile strength of Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} polycrystals (Y-TZP) measured by a newly developed tensile testing method with a rectangular bar. The tensile strength of Y-TZP was lower than that of the three-point bend strength, and the shape of the tensile strength distribution was quite different from that of the three-point bend strength distribution. It was difficult to predict the distribution curve of the tensile strength using the data of the three-point bend strength by one-modal Weibull distribution. The distribution of the tensile strength was analyzed by two- or three-modal Weibull distribution coupled with an analysis of fracture origins. The distribution curve of the three-point bend strength which was estimated by multimodal Weibull distribution agreed favorably with that of the measured three-point bend strength values. A two-modal Weibull distribution function was formulated approximately from the distributions of the tensile and three-point bend strengths, and the estimated two-modal Weibull distribution function for the four-point bend strength agreed well with the measured four-point bend strength.

  1. Deformation behavior of human dentin in liquid nitrogen: a diametral compression test.

    PubMed

    Zaytsev, Dmitry; Panfilov, Peter

    2014-09-01

    Contribution of the collagen fibers into the plasticity of human dentin is considered. Mechanical testing of dentin at low temperature allows excluding the plastic response of its organic matrix. Therefore, deformation and fracture behavior of the dentin samples under diametral compression at room temperature and liquid nitrogen temperature are compared. At 77K dentin behaves like almost brittle material: it is deformed exclusively in the elastic regime and it fails due to growth of the sole crack. On the contrary, dentin demonstrates the ductile response at 300K. There are both elastic and plastic contributions in the deformation of dentin samples. Multiple cracking and crack tip blunting precede the failure of samples. Organic phase plays an important role in fracture of dentin: plasticity of the collagen fibers could inhibit the crack growth. PMID:25063091

  2. Tensile and Adhesion Properties of Metal Thin Films Deposited onto Polyester Film Substrate Prepared by a Conventional Vacuum Evaporator

    NASA Astrophysics Data System (ADS)

    Kita, Takuya; Saitoh, Shou; Iwamori, Satoru

    Four kinds of metal, such as aluminum, copper, indium and tin, thin films were deposited onto polyester (PET) substrate by a conventional vacuum evaporator and evaluated their tensile and adhesion properties. The tensile property was estimated by observations of micro-cracks of the thin films due to the tensile test at 150°C. The tensile property of the metal thin films seems to relate with Brinell hardness and thickness of the thin film. The adhesion property of these metal thin films was estimated by measuring the pull strength. Aluminum thin film showed highest pull strength of all the thin films, and the pull strength increased with increase of the thickness.

  3. Tensile strain rate effect in mechanical properties of dummy HTPB propellants

    Microsoft Academic Search

    H. L. Chung; K. Kawata; M. Itabashi

    1993-01-01

    The tensile strain rate effect in tensile strength and elongation at break for a series of filled dummy hydroxy-terminated polybutadiene (HTPB) propellant binders was studied. The data were obtained at various tensile strain rates from 10[sup [minus]4] to 10[sup [minus]1] s[sup [minus]1] on two types of specimens at room temperature. The high velocity ductility behavior, which is qualitatively similar to

  4. Tunable Tensile Ductility in Metallic Glasses

    PubMed Central

    Magagnosc, D. J.; Ehrbar, R.; Kumar, G.; He, M. R.; Schroers, J.; Gianola, D. S.

    2013-01-01

    Widespread adoption of metallic glasses (MGs) in applications motivated by high strength and elasticity combined with plastic-like processing has been stymied by their lack of tensile ductility. One emerging strategy to couple the attractive properties of MGs with resistance to failure by shear localization is to employ sub-micron sample or feature length scales, although conflicting results shroud an atomistic understanding of the responsible mechanisms in uncertainty. Here, we report in situ deformation experiments of directly moulded Pt57.5Cu14.7Ni5.3P22.5 MG nanowires, which show tunable tensile ductility. Initially brittle as-moulded nanowires can be coerced to a distinct glassy state upon irradiation with Ga+ ions, leading to tensile ductility and quasi-homogeneous plastic flow. This behaviour is reversible and the glass returns to a brittle state upon subsequent annealing. Our results suggest a novel mechanism for homogenous plastic flow in nano-scaled MGs and strategies for circumventing the poor damage tolerance that has long plagued MGs.

  5. Tensile and fatigue properties of Inconel 718 at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Malin, C. O.; Schmidt, E. H.

    1969-01-01

    Tests to determine the tensile and fatigue properties of Inconel 718 at cryogenic temperatures show that the alloy increases in strength at low temperatures, with very little change in toughness. The effect of surface finish and grain size on the fatigue properties was also determined.

  6. Tensile testing of nylon and Kevlar parachute materials under Federal specified temperature and relative humidity conditions

    SciTech Connect

    Botner, W.T.

    1980-01-01

    A small 10-ft x 12-ft temperature and relative humidity controlled room for tensile testing of parachute materials is presented. Tensile tests of nylon and Kevlar parachute materials indicate there is a negligible change in break strength of test samples soaked in the controlled environment vs samples soaked in ambient conditions.

  7. Electrothermal fracturing of tensile specimens

    NASA Technical Reports Server (NTRS)

    Blinn, H. O.; Hanks, J. G.; Perkins, H. P.

    1970-01-01

    Pulling device consisting of structural tube, connecting rod, spring-loaded nuts, loading rod, heating element, and three bulkheads fractures tensile specimens. Alternate heating and cooling increases tensile loading by increments until fracturing occurs. Load cell or strain gage, applied to pulling rod, determines forces applied.

  8. The Effect of Adhesion and Tensile Properties on the Formability of Laminated Steels

    Microsoft Academic Search

    Robert B. Ruokolainen; David R. Sigler

    2008-01-01

    Laminated steel has been implemented in vehicle structures by several automotive manufacturers to reduce in-cabin noise. This study provides an understanding of how the adhesion between the steel skin and the viscoelastic polymer core affects laminate formability. Material properties, including peel strength, shear strength, and tensile strength were determined. The presence of the viscoelastic core was found to slightly reduce

  9. Estimation of fibre and interfacial shear strength by using a single-fibre composite

    Microsoft Academic Search

    Masatoshi Shioya; Akira Takaku

    1995-01-01

    The fibre\\/matrix interfacial shear strength is often estimated from the fragmentation process of a fibre in a single-fibre composite loaded in tension. The interfacial shear strength is calculated from a knowledge of the critical length and the tensile strength of the fibre. Unfortunately, if the tensile strength of fibres distributes widely and increases with decreasing fibre length, then problems arise

  10. Tensile creep behavior of polycrystalline alumina fibers

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; Goldsby, J. C.

    1993-01-01

    Tensile creep studies were conducted on polycrystalline Nextel 610 and Fiber FP alumina fibers with grain sizes of 100 and 300 nm, respectively. Test conditions were temperatures from 800 to 1050 C and stresses from 60 to 1000 MPa. For both fibers, only a small primary creep portion occurred followed by steady-state creep. The stress exponents for steady-state creep of Nextel 610 and Fiber FP were found to be about 3 and 1, respectively. At lower temperatures, below 1000 C, the finer grained Nextel 610 had a much higher 0.2 percent creep strength for 100 hr than the Fiber FP; while at higher temperatures, Nextel 610 had a comparable creep strength to the Fiber FP. The stress and grain size dependencies suggest Nextel 610 and Fiber FP creep rates are due to grain boundary sliding controlled by interface reaction and Nabarro-Herring mechanisms, respectively.

  11. Towards an improved understanding of strength and anisotropy of cold compacted powder

    NASA Astrophysics Data System (ADS)

    Wang, Wenhai

    The strength of powder compacts after cold compaction is known to be anisotropic, which comes from the directionality of microstructure resulting from initial particle morphology and/or from particle deformation during compaction. Current work focuses on multi-scale numerical analysis of powder compaction with emphasis on the role of interparticle cohesion on post-compaction mechanical properties. At macroscopic level, we applied phenomenological model to describe the mechanical behavior of powder, in which the material is considered to be continuum medium. A user subroutine (VUMAT) was successfully developed for ABAQUS/Explicit analysis, in which one of the popular phenomenological models for powder compaction---Drucker Prager/Cap model---is implemented. By studying of pharmaceutical powder die compaction and subsequent diametrical compression test via finite element analysis, the capabilities and limitations of current constitutive models are evaluated on predicting such as density, stress and tool force evolution, as well as the strength and fracture tendency. Our results illustrate that current model has good predictive capability of powder densification (e.g. density evolution) but can not predict post-compaction strength well. The following studies focus on evaluating the physics and mechanics occurring at particle level. The compaction of granular media was explored by using MPFEM approach. In the new model, individual particles discretized with a finite element mesh allow for a full description of contact mechanics and local and global particle kinematics. The introduction of a layer of degrading material on the surface of each particle provides the means of introducing variable cohesion and its effect on the final strength of compacts. The simulations show that the unloading creates tensile stresses at the root of the contact necks, which may cause partial or full separation of contact interface when the cohesion developed during loading is not strong enough. These results, which are in agreement with recent strength anisotropy data for cold compaction, bring a new perspective on understanding the interparticle behavior and the origin of the strength and failure of cold compacts.

  12. Additional water use influencing strength and fluidity of recycled concrete

    Microsoft Academic Search

    Xue-bing Zhang; Zhi Fang; Shou-chang Deng; Ke Cheng; Yin-hui Qin

    2008-01-01

    Through adding different additional water use, the compressive strength, splitting tensile strength and fluidity of recycled\\u000a concrete of three aggregate combination forms were studied by experiment respectively. The experimental results show that\\u000a with the increase of adding additional water use, the compressive strength and splitting tensile strength of recycled coarse\\u000a aggregate concrete decrease, but that of recycled fine aggregate concrete

  13. Effects of neutron irradiation on tensile properties of oxide dispersion strengthened (ODS) steel claddings

    NASA Astrophysics Data System (ADS)

    Yano, Y.; Ogawa, R.; Yamashita, S.; Ohtsuka, S.; Kaito, T.; Akasaka, N.; Inoue, M.; Yoshitake, T.; Tanaka, K.

    2011-12-01

    The effects of fast neutron irradiation on ring tensile properties of oxide dispersion strengthened (ODS) steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the material irradiation rig at temperatures between 693 and 1108 K to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures. The experimental results showed that there was no significant change in tensile strengths after neutron irradiation below 923 K, but the tensile strengths at neutron irradiation above 1023 K up to 33 dpa were decreased by about 20%. On the other hand, uniform elongation after irradiation was more than 2% at all irradiation conditions. The ring tensile properties of these ODS claddings remained excellent within these irradiation conditions compared with conventional 11Cr ferritic/martensitic steel (PNC-FMS) claddings.

  14. Tensile Testing: A Simple Introduction

    ERIC Educational Resources Information Center

    Carr, Martin

    2006-01-01

    Tensile testing may be used to decide, say, which steel to use in various constructions. Analogous testing can be done simply in the classroom using plasticine and helps to introduce pupils to the various properties studied in materials science.

  15. Tensile testing: a simple introduction

    NASA Astrophysics Data System (ADS)

    Carr, Martin

    2006-01-01

    Tensile testing may be used to decide, say, which steel to use in various constructions. Analogous testing can be done simply in the classroom using plasticine and helps to introduce pupils to the various properties studied in materials science.

  16. Imparting strength and toughness to brittle composites

    NASA Technical Reports Server (NTRS)

    Atkins, A. G.

    1974-01-01

    Appropriate intermittent coatings of fibers can produce areas of low and high toughness in brittle composites. Experiments using silicon vacuum grease (SVG) and polyurethane varnish (PUV) coatings that achieve weakly and strongly bonded interfaces are described. Tensile strength and edge-crack fracture toughness for both SVG and PUV coatings were plotted against the percentage coating (C). Both coating materials maintain tensile strengths in the order of the rule of mixture strength values up to a large C. It is suggested that both materials produce similar coated interfacial shear strengths while producing different effects on toughness.

  17. The effect of structure on tensile properties of directionally solidified Zn-based alloys

    NASA Astrophysics Data System (ADS)

    Ares, A. E.; Schvezov, C. E.

    2011-03-01

    The main objective of this study was to measure thermal (cooling rates, temperature gradients and velocities of the liquidus and solidus isotherms), structural (grain size and primary and secondary dendritic arm spacings) and tensile parameters (maximum tensile strength (MTS), yield strength (YS) and ultimate tensile strength (UTS)) in zinc-aluminum (ZA) hypoeutectic (Zn-3 wt%Al) and hypereutectic (Zn-10 wt%Al, Zn-15 wt%Al, Zn-20 wt%Al, Zn-30 wt%Al, Zn-37 wt%Al and Zn-50 wt%Al) alloys directionally solidified, which present columnar, equiaxed and columnar-to-equiaxed transition (CET) structures. The different types of structures were analyzed with optical and Scanning Electron Microscopy (SEM). Correlations between temperature gradient, cooling rate, local solidification time, grain size and dendritic spacings and tensile tests parameters are presented and discussed. The results show the influence of concentration, microstructural arrangement and thermal conditions on the mechanical properties during the solidification process.

  18. Extreme strength observed in limpet teeth

    PubMed Central

    Barber, Asa H.; Lu, Dun; Pugno, Nicola M.

    2015-01-01

    The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GPa and was independent of sample size. These observations highlight an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres. This considerable tensile strength of limpet teeth is attributed to a high mineral volume fraction of reinforcing goethite nanofibres with diameters below a defect-controlled critical size, suggesting that natural design in limpet teeth is optimized towards theoretical strength limits. PMID:25694539

  19. Extreme strength observed in limpet teeth.

    PubMed

    Barber, Asa H; Lu, Dun; Pugno, Nicola M

    2015-04-01

    The teeth of limpets exploit distinctive composite nanostructures consisting of high volume fractions of reinforcing goethite nanofibres within a softer protein phase to provide mechanical integrity when rasping over rock surfaces during feeding. The tensile strength of discrete volumes of limpet tooth material measured using in situ atomic force microscopy was found to range from 3.0 to 6.5 GPa and was independent of sample size. These observations highlight an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres. This considerable tensile strength of limpet teeth is attributed to a high mineral volume fraction of reinforcing goethite nanofibres with diameters below a defect-controlled critical size, suggesting that natural design in limpet teeth is optimized towards theoretical strength limits. PMID:25694539

  20. Tensile strength of the brittle materials, probabilistic or deterministic approach?

    Microsoft Academic Search

    J. Jeong; H. Adib-Ramezani; G. Pluvinage

    2006-01-01

    For various loading rates we estimated the activated defect localization in Modified Brazilian Disk type glass specimens in\\u000a comparison with standard spherical glass specimens. Specimen geometry can considerably affect the mechanical response of material,\\u000a especially brittle ones, which are very sensitive to the distribution of defects. High and low loading rates of Modified Brazilian\\u000a Disk lead glass specimens have been

  1. BEHAVIOR OF CONCRETE BRIDGE DECKS REINFORCED WITH HIGH-STRENGTH AND HIGH CORROSION-RESISTANT STEEL

    E-print Network

    of bending of MMFX steel on its tensile strength consisted of two concrete blocks to anchor the two endsBEHAVIOR OF CONCRETE BRIDGE DECKS REINFORCED WITH HIGH- STRENGTH AND HIGH CORROSION-RESISTANT STEEL of bending of MMFX steel bars on its tensile strength. KEYWORDS Bridge decks, Concrete, Corrosion, High

  2. In situ EBSD during tensile test of aluminum AA3003 sheet.

    PubMed

    Kahl, Sören; Peng, Ru Lin; Calmunger, Mattias; Olsson, Björn; Johansson, Sten

    2014-03-01

    Miniature tensile-test specimens of soft-annealed, weakly textured AA3003 aluminum sheet in 0.9 mm thickness were deformed until fracture inside a scanning electron microscope. Tensile strength measured by the miniature tensile test stage agreed well with the tensile strength by regular tensile testing. Strain over the microscope field of view was determined from changes in positions of constituent particles. Slip lines were visible in secondary electron images already at 0.3% strain; activity from secondary slip systems became apparent at 2% strain. Orientation rotation behavior of the tensile load axis with respect to the crystallographic axes agreed well with previously reported trends for other aluminum alloys. Start of the fracture and tensile crack propagation were documented in secondary electron images. The region of fracture nucleation included and was surrounded by many grains that possessed high Schmid factors at zero strain. Crystal lattice rotation angles in the grains surrounding the initial fracture zone were higher than average while rotations inside the initial fracture zone were lower than average for strains from zero to 31%. The orientation rotation behavior of the tensile load axes of the grains around the fracture zone deviated from the average behavior in this material. PMID:24314927

  3. The effect of increased HIP temperatures on bifilms and tensile properties of A206-T71 aluminum castings

    Microsoft Academic Search

    James T. Staley; Murat Tiryakio?lu; John Campbell

    2007-01-01

    The effects of hot isostatic pressing (HIP) temperatures on bifilms and tensile properties of A206-T71 castings were investigated. Castings were: (i) non-HIPed, and HIPed at (ii) typical HIP temperature, (iii) solution heat-treat temperature and (iv) eutectic melting temperature. Tensile strength and elongation data were analyzed using Weibull statistics. In all cases, HIP was found to increase the threshold tensile properties.

  4. Determination of impact tensile properties of structural epoxy adhesive butt joints using a hat-shaped specimen

    NASA Astrophysics Data System (ADS)

    Yokoyama, T.; Nakai, K.

    2006-08-01

    The impact tensile properties of structural epoxy adhesive butt joints are determined with a modified version of the split Hopkinson pressure bar using a hat-shaped joint specimen. A typical two-component structural epoxy adhesive and two different adherend materials (Al alloy 7075-T6 and 99% pure titanium) are used in the adhesion tests. The impact joint tensile strength is evaluated from the applied tensile load history at failure. The corresponding static joint tensile strength is measured with an Instron testing machine using joint specimens of the same geometry as those used in the impact tests. It is demonstrated that the joint tensile strength increases definitely with increasing loading rate up to the order of 106 MPa/s, and decreases with increasing adhesive layer thickness up to nearly 180 ? m, depending on the adherend materials.

  5. Assessment of the tensile properties of coir, bamboo and jute fibre

    Microsoft Academic Search

    Nele Defoirdt; Subhankar Biswas; Linde De Vriese; Le Quan Ngoc Tran; Joris Van Acker; Qumrul Ahsan; Larissa Gorbatikh; Aart Van Vuure; Ignaas Verpoest

    2010-01-01

    Natural fibres are studied as alternatives for man-made fibres to reinforce composites while keeping the weight lower. The assessment of the value of some commonly available tropical fibres for the composite industry starts with the determination of the strength, E-modulus and strain to failure through single fibre tensile tests. The mean strength and standard deviation is calculated following the normal

  6. The Cryogenic Tensile Properties of an Extruded Aluminum-Beryllium Alloy

    NASA Technical Reports Server (NTRS)

    Gamwell, W. R.

    2002-01-01

    Basic mechanical properties; i.e., ultimate tensile strength, yield strength, percent elongation, and elastic modulus, were obtained for the aluminum-beryllium alloy, AlBeMet162, at cryogenic (-195.5 C (-320 F) and -252.8 C (-423 F)) temperatures. The material evaluated was purchased to the requirements of SAE-AMS7912, "Aluminum-Beryllium Alloy, Extrusions."

  7. Mechanical tensile testing of titanium 15-3-3-3 and Kevlar 49 at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    James, B. L.; Martinez, R. M.; Shirron, P.; Tuttle, J.; Galassi, N. M.; McGuinness, D. S.; Puckett, D.; Francis, J. J.; Flom, Y.

    2012-06-01

    Titanium 15-3-3-3 and Kevlar 49 are highly desired materials for structural components in cryogenic applications due to their low thermal conductivity at low temperatures. Previous tests have indicated that titanium 15-3-3-3 becomes increasingly brittle as the temperature decreases. Furthermore, little is known regarding the mechanical properties of Kevlar 49 at low temperatures, most specifically its Young's modulus. This testing investigates the mechanical properties of both materials at cryogenic temperatures through cryogenic mechanical tensile testing to failure. The elongation, ultimate tensile strength, yield strength, and break strength of both materials are provided and analyzed here.

  8. The tensile fatigue of wire rope: A new approach

    SciTech Connect

    Thorpe, T.W.; Rance, A.

    1983-05-01

    The fatigue behaviour in air and seawater of zinc coated steel wire taken from a 40 mm diameter wire rope has been studied. Seawater had little effect on short term tensile strength but it reduced fatigue life by an amount which increased with increasing mean stress and decreasing test frequency. The application of fretting during fatigue testing resulted in very low endurances, which were similar to those measured in fatigue tests on wire ropes.

  9. Studies on high-tensile proof tests of optical fibers

    Microsoft Academic Search

    Yoshiaki Miyajima

    1983-01-01

    By conducting high-tensile proof tests on optical fibers in order to eliminate weak points such as cracks or flaws, fiber strength is improved, but fiber length becomes shorter because of fiber breakage during proof tests. When the application is for submarine optical-fiber on cables, the upper limit of proof-test strain is determined based on theoretical and experimental studies on fiber

  10. Tensile behavior of unnotched and notched tungsten-copper laminar composites

    NASA Technical Reports Server (NTRS)

    Hoffman, C. A.

    1976-01-01

    Relations were studied between the tensile strengths of unnotched and of notched, and elastic moduli of unnotched laminar sheet or foil composites and the amounts of reinforcement. Tungsten was used as the reinforcement and copper as the matrix, and the tests were run at room temperature. Three thicknesses of tungsten (i.e., 0.00254, 0.0127, and 0.0254 cm (0.001, 0.005, and 0.010 in) were used and the nominal volume fraction of tungsten was varied from about 0.05 to 0.95. It was found that the tensile strength of the unnotched specimens could be related to the amount of reinforcement, as could the elastic moduli, and that these values could be predicted by use of the rule of mixtures. The tensile strengths of the notched laminar composites could be predicted by use of the rule of mixtures using strengths for notched constituents, provided notch effects did not predominate.

  11. Impact Strength of Glass and Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Bless, Stephan; Tolman, John

    2009-06-01

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning, Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression and the steady-state strength. For both glasses, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic---as opposed to intrinsic---property.

  12. Hybrid effects on tensile properties of hybrid short-glass-fiber-and short-carbon-fiber-reinforced polypropylene composites

    Microsoft Academic Search

    Shao-Yun Fu; Bernd Lauke; Edith Mäder; Chee-Yoon Yue; Xiao Hu; Yiu-Wing Mai

    2001-01-01

    Hybrid composites of polypropylene reinforced with short glass fibers and short carbon fibers were prepared using extrusion compounding and injection molding techniques. The tensile properties of these composites were investigated taking into account the effect of the hybridization by these two types of short fibers. It was noted that the tensile strength and modulus of the hybrid composites increase while

  13. Changes in boron fiber strength due to surface removal by chemical etching

    NASA Technical Reports Server (NTRS)

    Smith, R. J.

    1976-01-01

    The effects of chemical etching on the tensile strength of commercial boron/tungsten fibers were investigated. Fibers with as-received diameters of 203, 143, and 100 micrometers were etched to diameters as small as 43 micrometers. The etching generally resulted in increasing fiber tensile strength with decreasing fiber diameter. And for the 203 micrometer fibers there was an accompanying significant decrease in the coefficient of variation of the tensile strength for diameters down to 89 micrometers. Heat treating these fibers above 1,173 K in a vacuum caused a marked decrease in the average tensile strength of at least 80 percent. But after the fibers were etched, their strengths exceeded the as-received strengths. The tensile strength behavior is explained in terms of etching effects on surface flaws and the residual stress pattern of the as-received fibers.

  14. A Tensile Deformation Model for In-situ Dendrite/Metallic Glass Matrix Composites

    PubMed Central

    Qiao, J. W.; Zhang, T.; Yang, F. Q.; Liaw, P. K.; Pauly, S.; Xu, B. S.

    2013-01-01

    In-situ dendrite/metallic glass matrix composites (MGMCs) with a composition of Ti46Zr20V12Cu5Be17 exhibit ultimate tensile strength of 1510?MPa and fracture strain of about 7.6%. A tensile deformation model is established, based on the five-stage classification: (1) elastic-elastic, (2) elastic-plastic, (3) plastic-plastic (yield platform), (4) plastic-plastic (work hardening), and (5) plastic-plastic (softening) stages, analogous to the tensile behavior of common carbon steels. The constitutive relations strongly elucidate the tensile deformation mechanism. In parallel, the simulation results by a finite-element method (FEM) are in good agreement with the experimental findings and theoretical calculations. The present study gives a mathematical model to clarify the work-hardening behavior of dendrites and softening of the amorphous matrix. Furthermore, the model can be employed to simulate the tensile behavior of in-situ dendrite/MGMCs. PMID:24085187

  15. Effect of tungsten on tensile properties and flow behaviour of RAFM steel

    NASA Astrophysics Data System (ADS)

    Vanaja, J.; Laha, K.; Nandagopal, M.; Sam, Shiju; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2013-02-01

    Effect of tungsten in the range of 1-2 wt.% on tensile properties and flow behaviour of 9Cr-W-Ta-V Reduced Activation Ferritic-Martensitic (RAFM) steel has been investigated. The tungsten in the investigated range was found to have only minor effect on the tensile properties of the steel over the temperature range of 300-873 K and at a strain rate of 3 × 10-3 s-1. The tensile flow behaviour of the RAFM steels was adequately described by the Voce's constitutive equation. The tensile strength of the steels were predicted well from the parameters of the Voce's constitutive equation. The Voce's strain hardening parameter 'nv' was found to be quite sensitive to the tungsten content and predicted the onset of dislocation climbing process at relatively higher testing temperature with the increase in tungsten content. The equivalence between tensile and creep deformations and the influence of tungsten have been discussed.

  16. Specimen size effects on tensile properties of neutron-irradiated steels

    NASA Astrophysics Data System (ADS)

    Kohyama, A.; Hamada, K.; Matsui, H.

    1991-03-01

    In the research and development of miniaturized specimen technology, consideration of specimen size effect is the key issue. In this work, tensile tests were studied with variations of specimen size around the standard mini-tensile specimen in the Japanese fusion materials program. The materials used were JPCA (modified 316 SS) and JFMS (modified 10Cr-2Mo dual phase steel). Microstructure has been controlled to clarify the effect of grain size for the former and the effect of ferrite/martensite ratio for the latter. Neutron irradiations of post-irradiation deformation response, microstructure prior to and after deformation were examined by transmission electron microscopy. The effects of specimen thickness and aspect ratio (thickness/width) on tensile properties are studied. New scaling equations to evaluate valid yield strength and tensile strength from small specimens with thickness less than the critical thickness, tc, are proposed. The origins of specimen size effects from a microstructural viewpoint are also discussed.

  17. Tensile strain rate effect in mechanical properties of dummy HTPB propellants

    SciTech Connect

    Chung, H.L.; Kawata, K.; Itabashi, M. (Science Univ. of Tokyo, Chiba (Japan). Dept. of Materials Science and Technology)

    1993-10-05

    The tensile strain rate effect in tensile strength and elongation at break for a series of filled dummy hydroxy-terminated polybutadiene (HTPB) propellant binders was studied. The data were obtained at various tensile strain rates from 10[sup [minus]4] to 10[sup [minus]1] s[sup [minus]1] on two types of specimens at room temperature. The high velocity ductility behavior, which is qualitatively similar to those of unfilled elastomers, was revealed. This means that the breaking strain increases markedly at elevated strain rates. For Bukkon-type and rod-shaped specimens, test results are consistent with each other. The fact that the increased filled solids level leads to a decreased breaking elongation capability and an increased tensile strength was obviously found.

  18. Comparison of Elevated Temperature Tensile Properties and Fatigue Behavior of Two Variants of a Woven SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Sreeramesh, Kalluri

    2005-01-01

    Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength, and strain at failure) of two variants of a woven SiC/SiC composite, manufactured during two separate time periods (9/99 and 1/01), were determined at 1038 and 1204 C by conducting tensile tests on specimens machined from plates. Continuous cycling fatigue tests (R = 0.05) and 20 cpm) were also conducted at the same two temperatures on specimens from both composites. In this study, average tensile properties, 95% confidence intervals associated with the tensile properties, and geometric mean fatigue lives of both composite materials are compared. The observed similarities and differences in the tensile properties are highlighted and an attempt is made to understand the relationship, if any, between the tensile properties and the fatigue behaviors of the two woven composites.

  19. Tensile fracture behavior in CO 2 laser beam welds of 7075-T6 aluminum alloy

    Microsoft Academic Search

    Cheng Liu; D. O Northwood; S. D Bhole

    2004-01-01

    CO2 laser beam (LB) welding is conducted on 7075-T6 aluminum alloy sheets at two different welding speeds and compared with gas tungsten arc (GTA) welding. The mechanical and microstructural characteristics of the welds are evaluated using tensile tests, hardness tests, optical microscopy and energy dispersive X-ray spectroscopy (EDS). Results indicate that both the hardness and tensile strength of LB welds

  20. The strength of polycrystalline silicon at the micro- and nano-scales with applications to MEMS

    Microsoft Academic Search

    Ioannis Chasiotis

    2002-01-01

    A new method for tensile testing of thin films by means of an improved apparatus has been developed to measure the elastic properties (Young's modulus, tensile strength) of surface micromachined polycrystalline silicon specimens. The newly designed tensile tester makes use of an Ultraviolet (UV) light curable adhesive to clamp micron-sized specimens. The properties determination utilizes surface topologies of deforming specimens,

  1. High Temperature Tensile Testing of Modified 9Cr-1Mo after Irradiation with High Energy Protons

    SciTech Connect

    Toloczko, Mychailo B.; Hamilton, Margaret L.; Maloy, S A.

    2003-05-15

    This study examines the effect of tensile test temperatures ranging from 50 C to 600 C on the tensile properties of a modified 9Cr-1Mo ferritic steel after high energy proton irradiation at about 35 C-67 C to doses from 1 to 3 dpa and 9 dpa. For the specimens irradiated to doses between 1 and 3 dpa, it was observed that the yield strength and ultimate strength decreased monotonically as a function of tensile test temperature, whereas the uniform elongation remained at approximately 1% for tensile test temperatures up to 250 C and then increased for tensile test temperatures up to and including 500 C. At 600 C, the uniform elongation was observed to be less than the values at 400 C and 500 C. Uniform elongation of the irradiated material tensile tested at 400 C to 600 C was observed to be greater than the values for the unirradiated material at the same temperatures. Tensile tests on the 9 dpa specimens followed similar trends.

  2. Tensile softening of metallic-glass-matrix composites in the supercooled liquid region

    NASA Astrophysics Data System (ADS)

    Qiao, J. W.; Zhang, Y.; Jia, H. L.; Yang, H. J.; Liaw, P. K.; Xu, B. S.

    2012-03-01

    A Ti-based metallic-glass-matrix composite exhibits tensile softening (necking) in the supercooled liquid region, accompanied by a large tensile ductility and a fragmentation of dendrites. Subjected to high temperatures, concurrent crystallization does not occur, suggesting a good thermal stability of the glass matrix. The presence of high-volume-fractioned dendrites lowers the rheology of the viscous glass matrix at high temperatures, which results in an absence of super elongation as monolithic bulk metallic glasses (BMGs). A tensile strength of 970 MPa is higher than those of most BMGs under varying strain rates, ascribing to the retardation of softening by the dendrites.

  3. The Effect of Adhesion and Tensile Properties on the Formability of Laminated Steels

    Microsoft Academic Search

    Robert B. Ruokolainen; David R. Sigler

    2008-01-01

    Laminated steel has been implemented in vehicle structures by several automotive manufacturers to reduce in-cabin noise. \\u000a This study provides an understanding of how the adhesion between the steel skin and the viscoelastic polymer core affects\\u000a laminate formability. Material properties, including peel strength, shear strength, and tensile strength were determined.\\u000a The presence of the viscoelastic core was found to slightly reduce

  4. Tensile and fatigue properties of 17-4 PH stainless steel at high temperatures

    Microsoft Academic Search

    Jui-Hung Wu; Chih-Kuang Lin

    2002-01-01

    The tensile and high-cycle fatigue properties for 17-4 PH* stainless steels in three different conditions were investigated\\u000a at temperatures ranging from room temperature to 400 C. Results indicated that the yield strength and fatigue strength for\\u000a the three conditions at a given temperature took the following order: condition H900 > condition A> condition H1150. The yield\\u000a strength of each condition

  5. Strength and barrier properties of MFC films

    Microsoft Academic Search

    Kristin Syverud; Per Stenius

    2009-01-01

    The preparation of microfibrillar cellulose (MFC) films by filtration on a polyamide filter cloth, in a dynamic sheet former\\u000a and as a surface layer on base paper is described. Experimental evidence of the high tensile strength, density and elongation\\u000a of films formed by MFC is given. Typically, a MFC film with basis weight 35 g\\/m2 had tensile index 146 ± 18 Nm\\/g and elongation

  6. Probabilistic simulation of uncertainties in composite uniaxial strengths

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Stock, T. A.

    1990-01-01

    Probabilistic composite micromechanics methods are developed that simulate uncertainties in unidirectional fiber composite strengths. These methods are in the form of computational procedures using composite mechanics with Monte Carlo simulation. The variables for which uncertainties are accounted include constituent strengths and their respective scatter. A graphite/epoxy unidirectional composite (ply) is studied to illustrate the procedure and its effectiveness to formally estimate the probable scatter in the composite uniaxial strengths. The results show that ply longitudinal tensile and compressive, transverse compressive and intralaminar shear strengths are not sensitive to single fiber anomalies (breaks, intergacial disbonds, matrix microcracks); however, the ply transverse tensile strength is.

  7. Tensile fracture characteristics of nanostructured ferritic alloy 14YWT

    SciTech Connect

    Kim, Jeoung H [ORNL; Byun, Thak Sang [ORNL; Hoelzer, David T [ORNL

    2010-01-01

    High temperature tensile fracture behavior has been characterized for the ferritic alloy 14YWT (SM10 heat) with the composition of Fe-14Cr-3W-0.4Ti (in wt.%) and strengthened by dispersion of nanometer-sized oxygen, titanium, and yttrium rich clusters. Tensile tests were performed at various temperatures ranging from room temperature to 1000 C in a vacuum condition using a nominal strain rate of 10-3s-1. Comparing with the existing oxide dispersion strengthened (ODS) steels such as Eurofer 97 and PM2000, the nanostructured alloy showed much higher yield and tensile strength over the test temperature range, but with lower elongation. Microstructural characterization for fractured tensile specimens was focused on the details of fracture morphology and mechanism to provide a feedback for process improvement. Below 600 C, the fracture surfaces exhibited a quasi-ductile behavior presented by a mixture of dimples and cleavage facets. At or above 600 C, however, the fracture surfaces were fully covered with dimples. The spherical particles that seemed to be oxide or carbide particles were found inside of dimples. It was notable that numerous microcracks were observed on the side surface of broken specimens. Formation of these microcracks is believed to be the main origin of the poor ductility of 14YWT alloy. It is suggested that any grain boundary strengthening measure is essential to improve the fracture property of the alloy.

  8. Micro-tensile testing machine

    Microsoft Academic Search

    D M Marsh

    1961-01-01

    This paper describes a tensile testing machine for microscopic specimens. It can apply loads in the range from 1 mgf to 400 gf to specimens having cross-sectional areas down to 10-7 mm2. Specimen extensions from a few angström units to 15 mm can be measured and, at constant temperature, random errors in the extension measurement system are less than 5

  9. Elongation Transducer For Tensile Tests

    NASA Technical Reports Server (NTRS)

    Roberts, Paul W.; Stokes, Thomas R.

    1994-01-01

    Extensometer transducer measures elongation of tensile-test specimen with negligible distortion of test results. Used in stress-versus-strain tests of small specimens of composite materials. Clamping stress distributed more evenly. Specimen clamped gently between jaw and facing surface of housing. Friction force of load points on conical tips onto specimen depends on compression of spring, adjusted by turning cover on housing. Limp, light nylon-insulated electrical leads impose minimal extraneous loads on measuring elements.

  10. Tensile behavior of the L(1)2 compound Al67Ti25Cr8

    NASA Technical Reports Server (NTRS)

    Kumar, K. S.; Brown, S. A.

    1992-01-01

    Temperature-related variations in tensile yield strength and ductility were studied on cast, homogenized and isothermally forged Al67Ti25Cr8. Yield strength dropped discontinuously between 623 K and 773 K and then decreased gradually with increasing temperature. Below 623 K, fracture occurred prior to macroscopic yielding. Ductility decreased from 0.2 percent at 623 K to zero at 773 K, but increased again at higher temperatures. At 1073 K, an elongation of 19 percent was obtainable, and ultimate tensile strength and localized necking were observed. Fracture surfaces and deformed microstructures were examined. The 1073 K tensile specimen that exhibited 19 percent elongation showed grain boundary serrations and some evidence of recrystallization (likely dynamic) although fracture occurred predominantly via an intergranular mode.

  11. An Assessment of Variability in the Average Tensile Properties of a Melt-Infiltrated SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Calomino, Anthony M.

    2004-01-01

    Woven SiC/SiC Ceramic Matrix Composites (CMCs), manufactured by the slurry-cast, melt-infiltration process are under consideration as combustor liner materials in aircraft gas turbine engines. Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength and strain to failure) of the CMC, manufactured during two separate time periods (9/99 and 1/01) were determined at 816 and 1024 C by conducting tensile tests on specimens machined from the CMC plates. A total of 24 tensile tests were conducted for each temperature and CMC variant combination. In this study average tensile properties of the two cMC variants were statistically compared to evaluate significant differences, if any, within the CMC's properties.

  12. Tensile characteristics of ten commercial acrylic bone cements.

    PubMed

    Harper, E J; Bonfield, W

    2000-09-01

    The mechanical properties of acrylic bone cement, used in orthopedic surgery, are very influential in determining successful long-term stability of a prosthesis. A large number of commercial formulations are available, differing in chemical composition and physical properties of both powder and monomer constituents. In this study, the static and dynamic tensile characteristics of a number of the most commonly used bone cements (Palacos R, Simplex P, CMW 1 & 3, Sulfix-60, Zimmer Dough), along with some newer formulations (Endurance, Duracem 3, Osteobondtrade mark and Boneloc), have been investigated under the same testing regimes. Testing was performed in air at room temperature. Significant differences in both static and fatigue properties were found between the various bone cements. Tensile tests revealed that Palacos R, Sulfix-60, and Simplex P had the highest values of ultimate tensile strength, closely followed by CMW 3, while Zimmer Dough cement had the lowest strength. Fatigue testing was performed under stress control, using sinusoidal loading in tension-tension, with an upper stress level of 22MPa. The two outstanding cements when tested in these cyclic conditions were Simplex P and Palacos R, with the highest values of Weibull median cycles to failure. Boneloc bone cement demonstrated the lowest cycles to failure. While the testing regimes were not designed to replicate exact conditions experienced by the bone cement mantle in vivo, there was a correlation between these results and clinical outcome. PMID:10984711

  13. Tensile Hoop Behavior of Irradiated Zircaloy-4 Nuclear Fuel Cladding

    SciTech Connect

    Jaramillo, Roger A [ORNL; Hendrich, WILLIAM R [ORNL; Packan, Nicolas H [ORNL

    2007-03-01

    A method for evaluating the room temperature ductility behavior of irradiated Zircaloy-4 nuclear fuel cladding has been developed and applied to evaluate tensile hoop strength of material irradiated to different levels. The test utilizes a polyurethane plug fitted within a tubular cladding specimen. A cylindrical punch is used to compress the plug axially, which generates a radial displacement that acts upon the inner diameter of the specimen. Position sensors track the radial displacement of the specimen outer diameter as the compression proceeds. These measurements coupled with ram force data provide a load-displacement characterization of the cladding response to internal pressurization. The development of this simple, cost-effective, highly reproducible test for evaluating tensile hoop strain as a function of internal pressure for irradiated specimens represents a significant advance in the mechanical characterization of irradiated cladding. In this project, nuclear fuel rod assemblies using Zircaloy-4 cladding and two types of mixed uranium-plutonium oxide (MOX) fuel pellets were irradiated to varying levels of burnup. Fuel pellets were manufactured with and without thermally induced gallium removal (TIGR) processing. Fuel pellets manufactured by both methods were contained in fuel rod assemblies and irradiated to burnup levels of 9, 21, 30, 40, and 50 GWd/MT. These levels of fuel burnup correspond to fast (E > 1 MeV) fluences of 0.27, 0.68, 0.98, 1.4 and 1.7 1021 neutrons/cm2, respectively. Following irradiation, fuel rod assemblies were disassembled; fuel pellets were removed from the cladding; and the inner diameter of cladding was cleaned to remove residue materials. Tensile hoop strength of this cladding material was tested using the newly developed method. Unirradiated Zircaloy-4 cladding was also tested. With the goal of determining the effect of the two fuel types and different neutron fluences on clad ductility, tensile hoop strength tests were performed on cladding for these varying conditions. Experimental data revealed negligible performance differences for cladding containing TIGR vs non-TIGR processed fuel pellets. Irradiation hardening was observed in tensile hoop data as the strength of the cladding increased with increasing neutron dose and appeared to saturate for a fast fluence of 1.7 1021 neutrons/cm2.

  14. Tensile Properties and Fracture Behavior of Different Carbon Nanotube-Grafted Polyacrylonitrile-Based Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-11-01

    The tensile properties and fracture behavior of different carbon nanotube (CNT)-grafted polyacrylonitrile-based (T1000GB) single carbon fibers were investigated. Grafting of CNTs was achieved via chemical vapor deposition (CVD). When Fe(C5H5)2 (also applied via CVD) was used as the catalyst, the tensile strength and Weibull modulus of the carbon fibers were improved, possibly due to the growth of dense CNT networks on the carbon fibers, which may have led to a reduction in the number of strength-limiting defects. Separately, at lower concentrations of an Fe(NO3)3·9H2O catalyst in ethanol, which was applied via dipping, the tensile strength of CNT-grafted fibers was nearly identical to that of the as-received fibers, although the Weibull modulus was higher. For higher concentrations of the Fe(NO3)3·9H2O catalyst, however, the tensile strength and the Weibull modulus were lower than those for the as-received material. Although the density of the CNT network increased with the concentration of the Fe(NO3)3·9H2O catalyst in the ethanol solution, heating of the ethanolic Fe(NO3)3·9H2O catalyst solution generated nitric acid (HNO3) due to decomposition, which damaged the fiber surfaces, resulting in an increase in the number of flaws and consequently a reduction in the tensile strength. Therefore, the tensile strength and Weibull modulus of CNT-grafted carbon fibers vary due to the combination of these effects and as a function of the catalyst concentration.

  15. Evaluation of mechanical properties of high strength concrete for prestressed concrete bridge design

    E-print Network

    Chompreda, Praveen

    2001-01-01

    tensile strength, modulus of elasticity, and flexural strength (modulus of rupture) at 7, 28, and 56 days. Creep and shrinkage were also monitored. Statistical analyses were conducted to determine the probability distribution, bias factors...

  16. Tensile test of pressureless-sintered silicon nitride at elevated temperature

    NASA Technical Reports Server (NTRS)

    Matsusue, K.; Fujisawa, Y.; Takahara, K.

    1985-01-01

    Uniaxial tensile strength tests of pressureless sintered silicon nitride were carried out in air at temperatures ranging from room temperature up to 1600 C. Silicon nitrides containing Y2O3, Al2O3, Al2O3-MgO, or MgO-CeO2 additives were tested. The results show that the composition of the additive used influences the strength characteristics of the silicon nitride. The tensile strength rapidly decreased at temperatures above 1000 C for the materials containing MgO as the additive and above 1000 C for the material with Y2O3. When the temperature increased to as high as 1300 C, the strength decreased to about 10 percent of the room temperature strength in each case. Observations of the fracture origin and of the crack propagation on the fracture surfaces are discussed.

  17. Apple Strength Issues

    SciTech Connect

    Syn, C

    2009-12-22

    Strength of the apple parts has been noticed to decrease, especially those installed by the new induction heating system since the LEP campaign started. Fig. 1 shows the ultimate tensile strength (UTS), yield strength (YS), and elongation of the installed or installation-simulated apples on various systems. One can clearly see the mean values of UTS and YS of the post-LEP parts decreased by about 8 ksi and 6 ksi respectively from those of the pre-LEP parts. The slight increase in elongation seen in Fig.1 can be understood from the weak inverse relationship between the strength and elongation in metals. Fig.2 shows the weak correlation between the YS and elongation of the parts listed in Fig. 1. Strength data listed in Figure 1 were re-plotted as histograms in Figs. 3 and 4. Figs. 3a and 4a show histograms of all UTS and YS data. Figs. 3b and 4b shows histograms of pre-LEP data and Figs. 3c and 4c of post-LEP data. Data on statistical scatter of tensile strengths have been rarely published by material suppliers. Instead, only the minimum 'guaranteed' strength data are typically presented. An example of strength distribution of aluminum 7075-T6 sheet material, listed in Fig. 5, show that its scatter width of both UTS and YS for a single sheet can be about 6 ksi and for multi-lot scatter can be as large as 11 ksi even though the sheets have been produced through well-controlled manufacturing process. By approximating the histograms shown in Figs. 3 and 4 by a Gaussian or similar type of distribution curves, one can plausibly see the strength reductions in the later or more recent apples. The pre-LEP data in Figs. 3b and 4b show wider scatter than the post-LEP data in Figs. 3c and 4c and seem to follow the binomial distribution of strength indicating that the apples might have been made from two different lots of material, either from two different vendors or from two different melts of perhaps slightly different chemical composition by a single vendor. The post-LEP apples seem to have been from a single batch of material. The pre-LEP apples of the weak strength and the post-LEP apples with even weaker strength could have been made of the same batch of material, and the small strength differential might be due to the difference in the induction heating system. If the pre-LEP apples with the lower strength and the post LEP apples are made from the same batch of material, their combined scatter of strength data would be wider and can be understood as a result of the additional processing steps of stress relief and induction heating as discussed.

  18. Tensile properties of neutron-irradiated Nimonic PE16

    SciTech Connect

    Bajaj, R.; Shogan, R.P.; DeFlitch, C.; Fish, R.L.; Paxton, M.M.; Bleiberg, M.L.

    1981-01-01

    Tension specimens of Nimonic PE16 in the solution-treated and aged condition were irradiated in the experimental breeder reactor II to a maximum fluence of approximately 7 X 10/sup 22/ neutrons/cm/sup 2/ (E>0.1 MeV) over a temperature range of 450 to 735 degree C. Tension tests were conducted at 232 degree C (fuel handling temperature), temperature to simulate transient reactor events. The alloy exhibited high strength and adequate ductility at 232 degree C. At the irradiation temperature, the strength remained high; however, a loss in ductility occurred. No significant loss in grain boundary fracture stress was observed in the tests showing low ductility values. The loss in ductility can be explained by reduced differential between ultimate tensile strength and the yield stress.

  19. [Effect of fillers on the strength of silicone systems].

    PubMed

    Snejdrová, E; Zelenka, J; Rehula, M

    2002-07-01

    The present paper examines the strength behaviour of addition silicone systems composed of Lukopren A 6200 and three inorganic fillers (Skron SF 600, Cab-O-Sil LM 150, sodium chloride) in different concentrations and particle sizes. The tensile strength sigma (MPa) and the relative lengthening of samples on rupture epsilon (%) were measured. With increasing concentration of the filler in the system relative lengthening of matrices is decreased. This trend corresponds with the theoretical hypotheses and it is understandable also with regard to the fact that the filler, in comparison with silicone rubber, possesses very low ductility. An addition of Sikron increases tensile strength of samples. Dependence of tensile strength on the amount of Sikron in the system is linear. This behaviour is typical of fibrous composites and the composites with high adhesion between the filler and matrix. Concentrations of Cab-O-Sil up to 5% did not exert an effect on tensile strength. An important increase in strength was shown only by the systems containing 10% of Cab-O-Sil. Experimental dependence of tensile strength on the amount of Cab-O-Sil in the system can be described by the equation for composites with Hookean behaviour till destruction. The effect of sodium chloride on tensile strength is more complicated. In the systems with NaCl particles of 20 microns, strength is not practically changed up to a content of 40% of NaCl in the system. In larger size fractions, tensile strength is decreased, and with a change in particle size, shape is probably changed as well. PMID:12183909

  20. Determination of rock strength with a portable rock tester

    Microsoft Academic Search

    K. F. Unrug; Y. J. Zhang

    1991-01-01

    This paper reports on comprehensive and tensile strength that are the important parameters required in engineering characterization of rocks. They are being determined in uniaxial conditions using laboratory tests or through index tests performed in different conditions, i.e. field and in-situ. The uniaxial compressive and indirect tensile strength tests have been used widely for engineering calculations. Large scale in-situ tests

  1. INFUENCE OF SPECIMEN TYPE AND LOADING CONFIGURATION ON THE FRACTURE STRENGTH OF SiC LAYER IN COATED PARTICLE FUEL

    SciTech Connect

    Byun, Thak Sang [ORNL; Hong, Seong Gu [ORNL; Katoh, Yutai [ORNL; Snead, Lance Lewis [ORNL

    2006-01-01

    Internal pressurization and diametrical loading techniques were developed to measure the fracture strength of the chemical vapor deposition (CVD) silicon carbide (SiC) coatings in nuclear fuel particles. Miniature tubular and hemispherical shell specimens were used for both test methods. In the internal pressurization test an expansion load was applied to the inner surface of a specimen by use of a compressively loaded elastomeric insert (polyurethane). In the crush test a diametrical compressive load was applied to the outer surface(s) of a specimen. The test results revealed that the fracture strengths from four test methods obeyed Weibull's two-parameter distribution, and the measured values of the Weibull modulus were consistent for different test methods. The fracture strengths measured by crush test techniques were larger than those by internal pressurization tests. This is because the internal pressurization produces uniform stress distribution while the diametrical loading technique produces severely localized stress distribution. The test method dependence of fracture strength was explained by the size effect predicted by effective surface.

  2. Notched Strength Allowables and Inplane Shear Strength of AS4/VRM-34 Textile Laminates

    NASA Technical Reports Server (NTRS)

    Grenoble, Ray W.; Johnston, William M.

    2013-01-01

    Notched and unnotched strength allowables were developed for a textile composite to provide input data to analytical structural models based on the Pultruded Rod Stiffened Efficient Unitized Structure (PRSEUS) concept. Filled-hole tensile strength, filled-hole compressive strength, and inplane shear strength along stitch lines have been measured. The material system evaluated in this study is based on warp-knitted preforms of AS4 carbon fibers and VRM-34 epoxy resin, which have been processed via resin infusion and oven curing. All specimens were tested in as-fabricated (dry) condition. Filled-hole strengths were evaluated with and without through-thickness stitching. The effects of scaling on filled-hole tensile strength were evaluated by testing specimens in two widths, but with identical width / hole-diameter ratios. Inplane shear specimens were stitched in two configurations, and two specimen thicknesses were tested for each stitch configuration.

  3. Tensile Properties of Al-Cu 206 Cast Alloys with Various Iron Contents

    NASA Astrophysics Data System (ADS)

    Liu, K.; Cao, X.; Chen, X.-G.

    2014-05-01

    The Al-Cu 206 cast alloys with varying alloy compositions ( i.e., different levels of Fe, Mn, and Si) were investigated to evaluate the effect of the iron-rich intermetallics on the tensile properties. It is found that the tensile strength decreases with increasing iron content, but its overall loss is less than 10 pct over the range of 0.15 to 0.5 pct Fe at 0.3 pct Mn and 0.3 pct Si. At similar iron contents, the tensile properties of the alloys with dominant Chinese script iron-rich intermetallics are generally higher than those with the dominant platelet phase. In the solution and artificial overaging condition (T7), the tensile strength of the 206 cast alloys with more than 0.15 pct Fe is satisfactory, but the elongation does not sufficiently meet the minimum requirement of ductility (>7 pct) for critical automotive applications. However, it was found that both the required ductility and tensile strength can be reached at high Fe levels of 0.3 to 0.5 pct for the alloys with well-controlled alloy chemistry and microstructure in the solution and natural aging condition (T4), reinforcing the motivation for developing recyclable high-iron Al-Cu 206 cast alloys.

  4. A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

    2014-08-01

    The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 × 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

  5. Tensile and creep properties of reduced activation ferritic-martensitic steel for fusion energy application

    NASA Astrophysics Data System (ADS)

    Mathew, M. D.; Vanaja, J.; Laha, K.; Varaprasad Reddy, G.; Chandravathi, K. S.; Bhanu Sankara Rao, K.

    2011-10-01

    Tensile and creep properties of a reduced activation ferritic-martensitic (RAFM) steel for Indian Test Blanket Module (TBM) to be tested in ITER have been evaluated. The tensile strength was found to decrease with temperature; the rate of decrease being slower in the intermediate temperature range of 450-650 K. Tensile ductility of the steel decreased with increase in temperature up to 650 K, followed by a rapid increase beyond 650 K. Creep studies have been carried out at 773, 823 and 873 K over a stress range of 100-300 MPa. The variation of minimum creep rate with applied stress followed a power law, ? = A? n. The ' n' value decreased with increase in temperature. The creep rupture life was found to relate inversely with minimum creep rate through the Monkman-Grant relation, t r · ? = constant. The tensile and creep properties of the steel were comparable with those of Eurofer 97.

  6. Tensile Properties, Ferrite Contents, and Specimen Heating of Stainless Steels in Cryogenic Gas Tests

    NASA Astrophysics Data System (ADS)

    Ogata, T.; Yuri, T.; Ono, Y.

    2006-03-01

    We performed tensile tests at cryogenic temperatures below 77 K and in helium gas environment for SUS 304L and SUS 316L in order to obtain basic data of mechanical properties of the materials for liquid hydrogen tank service. We evaluate tensile curves, tensile properties, ferrite contents, mode of deformation and/or fracture, and specimen heating during the testing at 4 to 77 K. For both SUS 304L and 316L, tensile strength shows a small peak around 10 K, and specimen heating decreases above 30 K. The volume fraction of ?-phase increases continuously up to 70 % with plastic strain, at approximately 15 % plastic strain for 304L and up to 35 % for 316L. There was almost no clear influence of testing temperature on strain-induced martensitic transformation at the cryogenic temperatures.

  7. Revealing extraordinary intrinsic tensile plasticity in gradient nano-grained copper.

    PubMed

    Fang, T H; Li, W L; Tao, N R; Lu, K

    2011-03-25

    Nano-grained (NG) metals are believed to be strong but intrinsically brittle: Free-standing NG metals usually exhibit a tensile uniform elongation of a few percent. When a NG copper film is confined by a coarse-grained (CG) copper substrate with a gradient grain-size transition, tensile plasticity can be achieved in the NG film where strain localization is suppressed. The gradient NG film exhibits a 10 times higher yield strength and a tensile plasticity comparable to that of the CG substrate and can sustain a tensile true strain exceeding 100% without cracking. A mechanically driven grain boundary migration process with a substantial concomitant grain growth dominates plastic deformation of the gradient NG structure. The extraordinary intrinsic plasticity of gradient NG structures offers their potential for use as advanced coatings of bulk materials. PMID:21330487

  8. Strength Training

    MedlinePLUS

    Strength training is a vital part of a balanced exercise routine that includes aerobic activity and flexibility exercises. Regular ... sit-ups, or body weight squats) for strength training. Many people tend to lump all types of ...

  9. A Weibull characterization for tensile fracture of multicomponent brittle fibers

    NASA Technical Reports Server (NTRS)

    Barrows, R. G.

    1977-01-01

    Necessary to the development and understanding of brittle fiber reinforced composites is a means to statistically describe fiber strength and strain-to-failure behavior. A statistical characterization for multicomponent brittle fibers is presented. The method, which is an extension of usual Weibull distribution procedures, statistically considers the components making up a fiber (e.g., substrate, sheath, and surface) as separate entities and taken together as in a fiber. Tensile data for silicon carbide fiber and for an experimental carbon-boron alloy fiber are evaluated in terms of the proposed multicomponent Weibull characterization.

  10. EFFECTS OF THERMAL-MECHANICAL PROCESSING VARIABLES ON SHORT-TIME 3000 F TENSILE PROPERTIES OF TUNGSTEN + 0.6 PERCENT COLUMBIUM ALLOY

    Microsoft Academic Search

    V. DePierre; G. Saul

    1963-01-01

    The effects of thermal-mechanical processing variables on short-time ; 3000 deg F tensile properties of tungsten + 0.6 percent niobium alloy were ; determined by correlating both tensile properties and thermal-mechanical ; variables with microstructure and cold work condition of this alloy. From these ; correlations the spread in 3000 deg F tensile and yield strength values (22,000to ; 63,310

  11. Tensile properties of SiC/aluminum filamentary composites - Thermal degradation effects

    NASA Technical Reports Server (NTRS)

    Skinner, A.; Koczak, M. J.; Lawley, A.

    1982-01-01

    Aluminium metal matrix composites with a low cost fiber, e.g. SiC, provide for an attractive combination of high elastic modulus and longitudinal strengths coupled with a low density. SiC (volume fraction 0.55)-aluminum (6061) systems have been studied in order to optimize fiber composite strength and processing parameters. A comparison of two SiC/aluminum composites produced by AVCO and DWA is provided. Fiber properties are shown to alter composite tensile properties and fracture morphology. The room temperature tensile strengths appear to be insensitive to thermal exposures at 500 C up to 150 h. The elastic modulus of the composites also appears to be stable up to 400 C, however variations in the loss modulus are apparent. The fracture morphology reflects the quality of the interfacial bond, fiber strengths and fiber processing.

  12. Annealing and Test Temperature Dependence of Tensile Properties of UNS N04400 Alloy

    NASA Astrophysics Data System (ADS)

    Afzal, Naveed; Ahmad, R.; Akhtar, Tanveer; Ayub, R.; Ghauri, I. M.

    2013-07-01

    Effects of annealing and test temperatures on the tensile behavior of UNS N04400 alloy have been examined. The specimens were annealed at 800, 1000, and 1200 °C for 4 h under vacuum in a muffle furnace. Stress-strain curves of the specimens were obtained in the temperature range 25-300 °C using a universal testing machine fitted with a thermostatic chamber. The results indicate that the yield strength (YS), ultimate tensile strength (UTS), and percentage elongation of the specimens decrease with increase of annealing temperature. By increasing the test temperature, the YS and UTS decrease, whereas the percentage elongation initially decreases with increase of test temperature from 25 to 100 °C and then increases with further increasing the temperature up to 300 °C. The changes in the tensile properties of the alloy are associated with the post-annealing microstructure and modes of fracture.

  13. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G. (Lenexa, KS)

    2007-07-17

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  14. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G. (Lenexa, KS)

    2007-08-21

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  15. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2006-01-10

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  16. Measurement of the inherent strength of carbon atomic chains

    NASA Astrophysics Data System (ADS)

    Mikhailovskij, I. M.; Sadanov, E. V.; Kotrechko, S.; Ksenofontov, V. A.; Mazilova, T. I.

    2013-01-01

    The intrinsic strength of freestanding carbon atomic chains was measured by in situ high-field mechanical testing of carbon atomic chains carried out inside a field-ion microscope. The determined breaking field strength corresponds to a tensile strength of carbon atomic chains at 5 K equal to 245 GPa. Carbon atomic chains also show exceptionally high-evaporation stability in electric fields up to 259 V/nm. The tensile strength of linear carbon chains significantly exceeds the tensile strength of known two-dimensional and three-dimensional carbon materials, including carbon nanotubes and graphene. Our results can be considered as direct experimental evidence for Pauling's prediction of bond stiffening with reduced atomic bond order.

  17. Study on the Strength of GFRP/Stainless Steel Adhesive Joints Reinforced with Glass Mat

    NASA Astrophysics Data System (ADS)

    Iwasa, Masaaki

    The adhesive strengths of glass fiber reinforced plastics/metal adhesive joints reinforced with glass mat under tensile shear loads and tensile loads were investigated analytically and experimentally. First, the stress singularity parameters of the bonding edges were analyzed by FEM for various types of adhesive joints reinforced with glass mat. The shear stress and normal stress distributions near the bonding edge can be expressed by two stress singularity parameters. Second, tensile shear tests were performed on taper lap joint and taper lap joint reinforced with glass mat and tensile tests were performed on T-type adhesive joint and T-type adhesive joint reinforced with glass mat. The relationships between the loads and the crosshead displacements were measured. We concluded that reinforcing adhesive joints has a greater effect on strength under tensile load than under tensile shear load. The adhesive joints strength reinforced with glass mat can be evaluated by using stress singularity parameters.

  18. Tensile Deformation and Morphological Evolution of Precise Acid Copolymers

    NASA Astrophysics Data System (ADS)

    Middleton, Luri Robert; Szewczyk, Steve; Schwartz, Eric; Azoulay, Jason; Murtagh, Dustin; Cordaro, Joseph; Wagener, Kenneth; Winey, Karen

    2015-03-01

    Acid- and ion-containing polymers have specific interactions that produce complex and hierarchical morphologies that provide tunable mechanical properties. We report tensile testing and in situ x-ray scattering measurements of a homologous series of precise poly(ethylene-co-acrylic acid) copolymers (pxAA). Upon variation of the number of backbone carbons (x = 9, 15, 21) between pendant acrylic acid groups along the linear polyethylene chain, these materials exhibit pronounced changes in both their tensile properties as well as their morphological evolution during deformation. The hierarchical layered acid aggregate structure coincides with the onset of a strain hardening mechanism and was observed in both a semi-crystalline sample (p21AA) as well as an amorphous sample (p15AA). The polymer with the shortest spacing between acid groups (p9AA) maintains a liquid-like distribution of acid aggregates during deformation, exhibiting low tensile strength which we attribute to facile acid exchange between acid aggregates during deformation. Our results indicate that the formation of the hierarchical layered structure, which coincides with polymer strain-hardening regime, originates from the associating acid groups cooperatively preventing disentanglement. NSF-DMR-1103858.

  19. Tensile fracture characteristics of nanostructured ferritic alloy 14YWT

    NASA Astrophysics Data System (ADS)

    Kim, Jeoung Han; Byun, Thak Sang; Hoelzer, D. T.

    2010-12-01

    High temperature tensile fracture behavior has been characterized for the nanostructured ferritic alloy 14YWT (SM10 heat). Uniaxial tensile tests were performed at temperatures ranging from room temperature to 1000 °C in vacuum at a nominal strain rate of 10 -3 s -1. Comparing with the existing oxide dispersion strengthened (ODS) steels such as Eurofer 97 and PM2000, the nanostructured alloy showed much higher yield and tensile strength, but with lower elongation. Microstructural characterization for the tested specimens was focused on the details of fracture morphology and mechanism to provide a feedback for process improvement. Below 600 °C, the fracture surfaces exhibited a quasi-brittle behavior presented by a mixture of dimples and cleavage facets. At or above 600 °C, however, the fracture surfaces were fully covered with fine dimples. Above 700 °C dimple formation occurred by sliding and decohesion of grain boundaries. It was notable that numerous microcracks were observed on the side surface of broken specimens. Formation of these microcracks is believed to be the main origin of the poor ductility of 14YWT alloy. It is suggested that a grain boundary strengthening measure is essential to improve the fracture property of the alloy.

  20. Understanding the strength of hot-pressed nanostructured powder compacts

    SciTech Connect

    Rawers, J.C. [Dept. of Energy, Albany, OR (United States). Albany Research Center] [Dept. of Energy, Albany, OR (United States). Albany Research Center; Harlow, D.G. [Lehigh Univ., Bethlehem, PA (United States)] [Lehigh Univ., Bethlehem, PA (United States)

    1999-02-01

    Attrition-milled nanostructured powders were hot pressed, and macroscopic properties of density, hardness, grain size, and strength were measured. No correlation was found between processing conditions (temperature and time) used in this study and compact properties, nor was a correlation found between the tensile (or failure) stress and density, hardness, or grain size. Variations of compact properties of unmilled powder were similar to that of milled powders. Tensile data were not well fitted to a Gaussian distribution but were well fitted to a two-parameter Weibull distribution. Thus, although the milled powder compacts had an average tensile strength greater than the unmilled powder compacts, all sample compositions fit a distribution with zero as a possible minimal stress level. Weibull analysis suggests that the tensile and compression strength is controlled by the presence of fine cracks, which may limit future engineering applications. Efforts to eliminate these cracks during hot pressing were unsuccessful.

  1. Effect of heat treatments on tensile properties and microstructure of 2195 alloy

    Microsoft Academic Search

    Ziqiao Zheng; Biping Huang

    1998-01-01

    Effect of various aging treatments on the tensile properties and microstructure of 2195 alloy has been investigated. The experimental\\u000a results show that promising combination of strength and ductility is achievable under T8 temper. The lower aging temperature reduces T1 precipitation on the subgrain or grain boundaries and favors uniform dispersion of T1 phases in the matrix, resulting in better strength

  2. Investigation of the bond and tensile capacity of synthetic lightweight aggregates embedded in a cement matrix 

    E-print Network

    Nichols, Gisela Wagner

    1969-01-01

    gravity of the expanded material is lower than before heating . " The cooled light- 7 weight aggregate varies in structure and appearanoe, depending on the raw material used, the i'iring temperature, the rate of travel through the kiln and the rate... whereby either the aggregate- cement bond strength or the aggregate tensile strength could be measured; 2. to test the hypothesis that the particle with the greatest area exposed to shear stresses would form the strongest bond; 3. to compare the test...

  3. An end-effect model for the single-filament tensile test

    Microsoft Academic Search

    E. G. Stoner; D. D. Edie; S. D. Durham

    1994-01-01

    The effect of cross-sectional shape on tensile strength of pitch-based carbon fibres was investigated by extensive single-filament testing. For this study, round and trilobal pitch-based carbon fibres were produced at similar processing conditions. The application of a variety of distributions, including the simple Weibull distribution, to the strength data indicated two sources of failure, one source being the accentuation of

  4. Influence of texture on plastic tensile strain of rolled Zr1% Nb alloy

    Microsoft Academic Search

    M. G. Isaenkova; V. P. Konoplenko; V. V. Novikov; Yu. A. Perlovich; P. F. Prasolov

    1982-01-01

    the laws governing the formation of the properties of products. The anisotropy of plastic and strength properties of rolled zirconium alloys during tensile tests manifests itself in the different course taken by the process of deformation of specimens cut at various angles to the rolling direction. The action of plastic strain mechanisms is coupled with the regular reorientation of the

  5. JOURNAL OF MATERIALS SCIENCE 37 (2002) 1401 1406 Weibull analysis of the tensile behavior of fibers

    E-print Network

    Pan, Ning

    2002-01-01

    JOURNAL OF MATERIALS SCIENCE 37 (2002) 1401­ 1406 Weibull analysis of the tensile behavior the conventional Weibull/weakest-link model by incorporating the within-fiber diameter variation. This is necessary. The strength of wool fibers has been verified to follow this modified Weibull/weakest-link distribution

  6. Process Temperature–Dependent Mechanical Properties of Polysilicon Measured Using a Novel Tensile Test Structure

    Microsoft Academic Search

    Shoji Kamiya; Jan H. Kuypers; Achim Trautmann; Patrick Ruther; Oliver Paul

    2007-01-01

    A new test structure was developed to measure three major unknown mechanical parameters of deposited thin films, i.e., fracture strength, Young's modulus, and residual stress. The structure was designed to have plural specimens of a deposited thin film bridging the gap of the silicon substrate and enables the easy and efficient tensile testing of the film. It was used to

  7. A combined analytical-experimental tensile test technique for brittle materials

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Srivatsan, T. S.

    1992-01-01

    A semiconventional tensile test technique is developed for impact ices and other brittle materials. Accurate results have been obtained on ultimate strength and modulus of elasticity in a refrigerated ice test. It is noted that the technique can be used to determine the physical properties of impact ices accreted inside icing wind tunnels or other brittle materials.

  8. Tensile basic creep of early-age concrete under constant load

    Microsoft Academic Search

    Lennart Østergaard; David A. Lange; Salah A. Altoubat; Henrik Stang

    2001-01-01

    Viscoelastic behavior of early-age normal and high-strength concrete has been investigated. The study shows that concrete exhibits high tensile creep strain if loaded at an age less than or equal to 1 day. The investigations furthermore show that the creep strain is not proportional to the stress level in the specimen when loading occurs at 1 day. Creep experiments were

  9. The effect of martensite particle size on tensile fracture of surface-carburised AISI 8620 steel with dual phase core microstructure

    Microsoft Academic Search

    Mehmet Erdogan; Suleyman Tekeli

    2002-01-01

    In this study, the production of dual phase microstructure in the core of surface-carburised AISI 8620 cementation steel and the effect of martensite particle size at constant martensite volume fraction on tensile fracture have been investigated. The results showed that specimens with dual phase microstructure in the core exhibited slightly lower tensile and yield strength but superior ductility without sacrificing

  10. Impact Strength of Glass and Glass Ceramic

    NASA Astrophysics Data System (ADS)

    Bless, S.; Tolman, J.

    2009-12-01

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  11. IMPACT STRENGTH OF GLASS AND GLASS CERAMIC

    SciTech Connect

    Bless, S.; Tolman, J. [Institute for Advanced Technology, University of Texas at Austin, Austin, TX 78759 (United States)

    2009-12-28

    Strength of glass and glass ceramic was measured with a bar impact technique. High-speed movies show regions of tensile and compressive failure. The borosilicate glass had a compressive strength of at least 2.2 GPa, and the glass ceramic at least 4 GPa. However, the BSG was much stronger in tension than GC. In ballistic tests, the BSG was the superior armor.

  12. High-Hot-Strength Ceramic Fibers

    NASA Technical Reports Server (NTRS)

    Sayir, Ali; Matson, Lawrence E.

    1994-01-01

    Continuous fibers consisting of laminae of alumina and yttrium aluminum garnet offer exceptionally high strength, resistance to creep, and chemical stability at high temperatures. These fibers exceed tensile strength of sapphire fibers. Leading candidates for reinforcement of intermetallic-matrix composites in exhaust nozzles of developmental high-speed civil transport aircraft engines. Other applications are in aerospace, automotive, chemical-process, and power-generation industries.

  13. Tensile stress-strain behavior of boron/aluminum laminates

    NASA Technical Reports Server (NTRS)

    Sova, J. A.; Poe, C. C., Jr.

    1978-01-01

    The tensile stress-strain behavior of five types of boron/aluminum laminates was investigated. Longitudinal and transverse stress-strain curves were obtained for monotonic loading to failure and for three cycles of loading to successively higher load levels. The laminate strengths predicted by assuming that the zero deg plies failed first correlated well with the experimental results. The stress-strain curves for all the boron/aluminum laminates were nonlinear except at very small strains. Within the small linear regions, elastic constants calculated from laminate theory corresponded to those obtained experimentally to within 10 to 20 percent. A limited amount of cyclic loading did not affect the ultimate strength and strain for the boron/aluminum laminates. The laminates, however, exhibited a permanent strain on unloading. The Ramberg-Osgood equation was fitted to the stress-strain curves to obtain average curves for the various laminates.

  14. Tensile fracture dynamics and intrinsic plasticity of metallic glasses

    NASA Astrophysics Data System (ADS)

    Cui, J. W.; Calin, M.; Eckert, J.; Zhang, Z. F.

    2013-01-01

    Under tensile tests of metallic glasses (MGs) subjected to annealing below glass transition temperature Tg, ductile-to-brittle transition (DBT) occurs due to structural relaxation, which results in more ordered atomic packing and decrease of glass fraction ?. DBT is observed simultaneously with fracture mechanism transition: shear banding to cracking. All MG samples annealed under different temperature were also restricted to shear banding and cracking separately under small-aspect-ratio compression and compact tension avoiding DBT. Experimental results prove that as annealing temperature increases (or glass fraction ? decreases), strength for shear banding increases, while strength for cracking decreases; as ? becomes less than critical state ?DBT, MG samples tend to cracking instead of shear banding. So, ?DBT is proposed as an important parameter to characterize the intrinsic plasticity of various MGs and to conform to the previous factors soundly.

  15. Preparation and tensile properties of linear low density polyethylene/rambutan peels (Nephelium chryseum Blum.) flour blends

    NASA Astrophysics Data System (ADS)

    Nadhirah, A. Ainatun.; Sam, S. T.; Noriman, N. Z.; Voon, C. H.; Samera, S. S.

    2015-05-01

    The effect of rambutan peels flour (RPF) content on the tensile properties of linear low density polyethylene filled with rambutan peel flour was studied. RPF was melt blended with linear low-density polyethylene (LLDPE). LLDPE/RPF blends were prepared by using internal mixer (brabender) at 160 °C with the flour content ranged from 0 to 15 wt%. The tensile properties were tested by using a universal testing machine (UTM) according to ASTM D638. The highest tensile strength was observed for pure LLDPE while the tensile strength LLDPE/RPF decreased gradually with the addition of rambutan peels flour content from 0% to 15%. Young's modulus of 63 µm to 250 µm rambutan peels blends with LLDPE with the fiber loading of 0 - 15 wt% increased with increasing fiber loading.

  16. Influences of post-weld heat treatment on tensile properties of friction stir-welded AA6061 aluminum alloy joints

    SciTech Connect

    Elangovan, K. [Department of Mechanical and Production Engineering, Annamalai University, Annamalai Nagar - 608 002, Tamil Nadu (India); Balasubramanian, V. [Centre for Materials Joining Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar - 608 002, Tamil Nadu (India)], E-mail: visvabalu@yahoo.com

    2008-09-15

    This paper reports on studies of the influences of various post-weld heat treatment procedures on tensile properties of friction stir-welded AA6061 aluminum alloy joints. Rolled plates of 6-mm thick AA6061 aluminum alloy were used to fabricate the joints. Solution treatment, an artificial aging treatment and a combination of both were given to the welded joints. Tensile properties such as yield strength, tensile strength, elongation and joint efficiency were evaluated. Microstructures of the welded joints were analyzed using optical microscopy and transmission electron microscopy. A simple artificial aging treatment was found to be more beneficial than other treatment methods to enhance the tensile properties of the friction stir-welded AA6061 aluminum alloy joints.

  17. Effect of Thermal Exposure on the Tensile Properties of Aluminum Alloys for Elevated Temperature Service

    NASA Technical Reports Server (NTRS)

    Edahl, Robert A., Jr.; Domack, Marcia

    2004-01-01

    Tensile properties were evaluated for four aluminum alloys that are candidates for airframe applications on high speed transport aircraft. These alloys included the Al-Cu-Mg-Ag alloys C415 and C416 and the Al-Cu-Li-Mg-Ag alloys RX818 and ML377. The Al-Cu-Mg alloys CM001, which was used on the Concorde SST, and 1143, which was modified from the alloy used on the TU144 Russian supersonic aircraft, were tested for comparison. The alloys were subjected to thermal exposure at 200 F, 225 F and 275 F for times up to 30,000 hours. Tensile tests were performed on thermally-exposed and as-received material at -65 F, room temperature, 200 F, 225 F and 275 F. All four candidate alloys showed significant tensile property improvements over CM001 and 1143. Room temperature yield strengths of the candidate alloys were at least 20% greater than for CM001 and 1143, for both the as-received and thermally-exposed conditions. The strength levels of alloy RX818 were the highest of all materials investigated, and were 5-10% higher than for ML377, C415 and C416 for the as-received condition and after 5,000 hours thermal exposure. RX818 was removed from this study after 5,000 hours exposure due to poor fracture toughness performance observed in a parallel study. After 30,000 hours exposure at 200 F and 225 F, the alloys C415, C416 and ML377 showed minor decreases in yield strength, tensile strength and elongation when compared to the as-received properties. Reductions in tensile strength from the as-received values were up to 25% for alloys C415, C416 and ML377 after 15,000 hours exposure at 275 F.

  18. In situ tensile and creep testing of lithiated silicon nanowires

    SciTech Connect

    Boles, Steven T.; Kraft, Oliver [Institute for Applied Materials, KIT, 76344 Eggenstein-Leopoldshafen (Germany)] [Institute for Applied Materials, KIT, 76344 Eggenstein-Leopoldshafen (Germany); Thompson, Carl V. [Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts 02139 (United States)] [Department of Materials Science and Engineering, MIT, Cambridge, Massachusetts 02139 (United States); Mönig, Reiner [Institute for Applied Materials, KIT, 76344 Eggenstein-Leopoldshafen (Germany) [Institute for Applied Materials, KIT, 76344 Eggenstein-Leopoldshafen (Germany); Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), 89069 Ulm (Germany)

    2013-12-23

    We present experimental results for uniaxial tensile and creep testing of fully lithiated silicon nanowires. A reduction in the elastic modulus is observed when silicon nanowires are alloyed with lithium and plastic deformation becomes possible when the wires are saturated with lithium. Creep testing was performed at fixed force levels above and below the tensile strength of the material. A linear dependence of the strain-rate on the applied stress was evident below the yield stress of the alloy, indicating viscous deformation behavior. The observed inverse exponential relationship between wire radius and strain rate below the yield stress indicates that material transport was controlled by diffusion. At stress levels approaching the yield strength of fully lithiated silicon, power-law creep appears to govern the strain-rate dependence on stress. These results have direct implications on the cycling conditions, rate-capabilities, and charge capacity of silicon and should prove useful for the design and construction of future silicon-based electrodes.

  19. In situ tensile and creep testing of lithiated silicon nanowires

    NASA Astrophysics Data System (ADS)

    Boles, Steven T.; Thompson, Carl V.; Kraft, Oliver; Mönig, Reiner

    2013-12-01

    We present experimental results for uniaxial tensile and creep testing of fully lithiated silicon nanowires. A reduction in the elastic modulus is observed when silicon nanowires are alloyed with lithium and plastic deformation becomes possible when the wires are saturated with lithium. Creep testing was performed at fixed force levels above and below the tensile strength of the material. A linear dependence of the strain-rate on the applied stress was evident below the yield stress of the alloy, indicating viscous deformation behavior. The observed inverse exponential relationship between wire radius and strain rate below the yield stress indicates that material transport was controlled by diffusion. At stress levels approaching the yield strength of fully lithiated silicon, power-law creep appears to govern the strain-rate dependence on stress. These results have direct implications on the cycling conditions, rate-capabilities, and charge capacity of silicon and should prove useful for the design and construction of future silicon-based electrodes.

  20. Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements and Crazing

    E-print Network

    Ting Ge; Gary S. Grest; Mark O. Robbins

    2014-10-07

    Large-scale molecular simulations are performed to investigate tensile failure of polymer interfaces as a function of welding time $t$. Changes in the tensile stress, mode of failure and interfacial fracture energy $G_I$ are correlated to changes in the interfacial entanglements as determined from Primitive Path Analysis. Bulk polymers fail through craze formation, followed by craze breakdown through chain scission. At small $t$ welded interfaces are not strong enough to support craze formation and fail at small strains through chain pullout at the interface. Once chains have formed an average of about one entanglement across the interface, a stable craze is formed throughout the sample. The failure stress of the craze rises with welding time and the mode of craze breakdown changes from chain pullout to chain scission as the interface approaches bulk strength. The interfacial fracture energy $G_I$ is calculated by coupling the simulation results to a continuum fracture mechanics model. As in experiment, $G_I$ increases as $t^{1/2}$ before saturating at the average bulk fracture energy $G_b$. As in previous simulations of shear strength, saturation coincides with the recovery of the bulk entanglement density. Before saturation, $G_I$ is proportional to the areal density of interfacial entanglements. Immiscibiltiy limits interdiffusion and thus suppresses entanglements at the interface. Even small degrees of immisciblity reduce interfacial entanglements enough that failure occurs by chain pullout and $G_I \\ll G_b$.

  1. Tensile properties of Cr inserted amorphous Co 85Zr 9Nb 6 films deposited on polymer substrate

    Microsoft Academic Search

    F. Zeng; F. Lv; R. L. Zong; S. P. Wen; X. Y. Zhu; F. Pan

    2009-01-01

    Amorphous Co85Zr9Nb6 films with inserted Cr layer were deposited on polyethylene terephthalate (PET) substrate. After the Cr layers were inserted, tensile strengths calculated from stress–strain curves were found to be enhanced; the elastic regions were shortened, while the plastic regions were extended. Surface morphology examination after strain revealed cracks oriented at an angle of about 60° to the tensile direction

  2. The Effect of Thermomechanical Processing on the Tensile, Fatigue, and Creep Behavior of Magnesium Alloy AM60

    Microsoft Academic Search

    Zhe Chen; J. Huang; R. F. Decker; S. E. Lebeau; Larry R Walker; Odis Burl Cavin; Thomas R Watkins; C. J. Boehlert

    2011-01-01

    Tensile, fatigue, fracture toughness, and creep experiments were performed on a commercially available magnesium-aluminum\\u000a alloy (AM60) after three processing treatments: (1) as-THIXOMOLDED (as-molded), (2) THIXOMOLDED then thermomechanically processed\\u000a (TTMP), and (3) THIXOMOLDED then TTMP then annealed (annealed). The TTMP procedure resulted in a significantly reduced grain\\u000a size and a tensile yield strength greater than twice that of the as-molded material

  3. Diametral strain of fast reactor MOX fuel pins with austenitic stainless steel cladding irradiated to high burnup

    NASA Astrophysics Data System (ADS)

    Uwaba, Tomoyuki; Ito, Masahiro; Maeda, Koji

    2011-09-01

    The C3M irradiation test, which was conducted in the experimental fast reactor, "Joyo", demonstrated that mixed oxide (MOX) fuel pins with austenitic steel cladding could attain a peak pellet burnup of about 130 GWd/t safely. The test fuel assembly consisted of 61 fuel pins, whose design specifications were similar to those of driver fuel pins of a prototype fast breeder reactor, "Monju". The irradiated fuel pins exhibited diametral strain due to cladding void swelling and irradiation creep. The cladding irradiation creep strain were due to the pellet-cladding mechanical interaction (PCMI) as well as the internal gas pressure. From the fuel pin ceramographs and 137Cs gamma scanning, it was found that the PCMI was associated with the pellet swelling which was enhanced by the rim structure formation or by cesium uranate formation. The PCMI due to cesium uranate, which occurred near the top of the MOX fuel column, significantly affected cladding hoop stress and thermal creep, and the latter effect tended to increase the cumulative damage fraction (CDF) of the cladding though the CDF indicated that the cladding still had some margin to failure due to the creep damage.

  4. Increase vs. decrease in the strength of granitic rocks subjected to heat

    NASA Astrophysics Data System (ADS)

    Török, Anita; Török, Ákos

    2015-04-01

    Accidental fire generally causes catastrophic loss in granitic structures or tunnels excavated in granitic rocks. It is necessary to measure strength of materials at various degrees to understand the mechanical behaviour of such stone structures or tunnels. Our laboratory experiments were aimed to detect indirect tensile strength and uniaxial compressive strength of granitic rocks that were subjected to temperatures of up to 600°C. For control measurements ultrasonic pulse velocity was also recorded. The studied rocks included three granites: a Hungarian dark pink granite (Mórágy), an Austrian greyish granite (Mauthausen) and a common pinkish Spanish granite (Rosa Beta). Cylindrical tests specimens of the three granites were subjected to 300°C and 600°C, respectively. Compressive strength test and tensile strength test results were compared to strength values obtained at room temperature. Our test results show that two of the studied granites (Hungarian and the Spanish one) have higher strength at 300°C that at room temperature. To the contrary ultrasonic pulse velocity decreased for all the three granites from room temperature to 300°C. The tensile strength of the granites did not show such a clear trend, however Hungarian granite has a slightly increased tensile strength at 300°C than at room temperature. At 600°C the compressive strength, tensile strength and ultrasonic pulse velocity dropped but not at the same rate. Our experiments showed that a given and limited temperature increase can have a positive effect on strength of granites rather than an adverse effect on a short-term.

  5. Effect of Welding and Post-weld Heat Treatment on Tensile Properties of Nimonic 263 at Room and Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Jeon, Minwoo; Lee, Jae-Hyun; Woo, Ta Kwan; Kim, Sangshik

    2011-04-01

    Nimonic 263 has been developed for the improved ductility in welded assemblies and is a candidate material for gas turbine combustor and transition pieces along with its good weldability and mechanical properties at room and elevated temperatures. In this study, the tensile behavior of an as-welded Nimonic 263 specimen at room temperature and 1053 K (780 °C) was examined in conjunction with microstructural evolution during welding and postweld heat treatment (PWHT). With the welding and the PWHT, the yield strength (YS), ultimate tensile strength (UTS), and tensile elongation of Nimonic 263 varied in a complex manner. It was observed that the PWHT of resolutionization at 1423 K (1150 °C) for 2 hours gave the highest YS and UTS values, whereas the tensile elongation was the lowest, at both testing temperatures. With increasing resolutionization time, the YS and UTS tended to decrease along with the increase in tensile ductility. The tensile behaviors of as-welded Nimonic 263 specimens was affected by several factors, including grain size, residual stress, possible microsegregation of ?' forming elements, a tendency for interdendritic or intergranular fracture and a morphological change in both M23C6 and MC type carbides, depending on the testing temperature and the PWHT. The complex changes in tensile properties of Nimonic 263 with welding and PWHT at room temperature and 1053 K (780 °C) were discussed based on the micrographic and fractographic observations.

  6. Tensile and fatigue evaluation of Ti–15Al–33Nb (at.%) and Ti–21Al–29Nb (at.%) alloys for biomedical applications

    Microsoft Academic Search

    C. J. Boehlert; C. J. Cowen; C. R. Jaeger; M. Niinomi; T. Akahori

    2005-01-01

    In this work the fatigue and tensile behavior of Ti–15Al–33Nb (at.%) and Ti–21Al–29Nb (at.%) was evaluated and compared to that for other titanium-based biomedical implant alloys, in particular Ti–6Al–4V (wt.%). The mechanical properties of interest were fatigue strength, tensile strength, elastic modulus, and elongation-to-failure. Fatigue stress versus life curves were obtained for tests performed at room temperature in air as

  7. Influence of temperature, composition, and grain size on the tensile failure of water ice: Implications for erosion on Titan

    NASA Astrophysics Data System (ADS)

    Litwin, Kimberly L.; Zygielbaum, Beth R.; Polito, Peter J.; Sklar, Leonard S.; Collins, Geoffrey C.

    2012-08-01

    Ice resistance to tensile fracture influences surface morphodynamics on outer planetary satellites such as Titan, yet measurements of tensile strength and fracture toughness of polycrystalline water ice at temperatures below terrestrial conditions (<220 K) have not been previously reported. We investigated these parameters from 260 K to 110 K using a walk-in freezer, and chilling by dry ice and liquid nitrogen. We also investigated the influence of solid impurity concentration and the spread in crystal grain size distribution. Although fracture toughness showed no sensitivity to temperature, we find that tensile strength increases with decreasing temperature at 7 kPa K-1 for all ice types tested. For pure water ice, samples made from uniform-sized seed crystals were stronger than mixed-grain-size ice, suggesting that strength is limited by the coarse tail of the size distribution. Samples tested submerged in liquid ethanol were 0.45 MPa weaker than in air; increasing porosity reduced tensile strength. Tensile strength increased linearly with concentration of urea, basalt and ammonium sulfate. These results suggest that on Titan and other icy satellites, the tensile strength of fine-grained polycrystalline water ice containing solid impurities may be several times greater than the 1 MPa value commonly used in modeling. For low strain rate processes where fracture propagation rather than fracture initiation limits strength, a temperature invariant fracture toughness of 0.15 MPa m1/2 is appropriate. Understanding ice diagenesis on Titan, and the resulting composition, grain size distribution, and porosity, is needed to accurately model surface processes that are limited by ice resistance to fracture.

  8. The intrinsic tensile behavior of the matrix of bovine articular cartilage and its variation with age.

    PubMed

    Roth, V; Mow, V C

    1980-10-01

    To study the age dependence of the uniaxial tensile behavior of bovine articular cartilage, 216 specimens of articular cartilage from the patellofemoral joint were grouped into two age categories: those from joints with growth plates present (open physes) and those from joints without growth plates (no physes). We prepared standard, dumbbell-shaped test specimens from the three ultrastructural zones of the tissue: the superficial tangential zone, the middle zone, and the deep zone. As was done in the early works of Kempson et al. and of Woo et all., we prepared specimens whose long axes were either parallel or perpendicular to the axis of the local split line on the joint surface. In these tensile tests we observed a profound difference between the two age groups in terms of the variations in the tensile properties related to the depth below the surface. With increasing distance from the articular surface, the tensile strength and stiffness increased in the open-physis group and decreased in the no-physis group. Directional dependence of the tensile response was manifested by increased stiffness and strength of the samples oriented parallel to the split-line axis when compared with the samples oriented perpendicular to it. Distortion of the initially flat, straight-sided portion of the gauge section was observed in most of the 216 specimens immediately after the application of tensile strains. This effect casts serious doubts on all previous measurements of cross-sectional dimensional changes. At present, we believe that this distortion occurs because articular cartilage is an inhomogeneous, layered material. We also observed that cartilage exudes substantial amounts of its interstitial fluid when the applied tensile strain becomes large. These two effects create serious problems in assessing the true volumetric changes and the material properties of cartilage specimens during uniaxial tension experiments. PMID:7430196

  9. Determination of the relationship between strength and test method for glass fibre epoxy composite coupons using Weibull analysis

    Microsoft Academic Search

    M. K. Cattell; K. A. Kibble

    2001-01-01

    Glass fibre epoxy composite test coupons exhibit variability in their tensile strength data dependent on the test method used. The three common test standards are for tensile, three-point flexure and four-point flexure and it is accepted that flexure tests yield higher strengths than tensile tests. Tests were carried out on coupons of a woven E-glass epoxy composite for each type

  10. Origins of shear strength of polymers and reinforced polymers

    Microsoft Academic Search

    Karen Ka Yan Liu

    1997-01-01

    In tests on neat polymers, it was shown that for most of the polymers, the tensile strength was approximately the same as the shear strength measured by the punch test. Classical shear sliding off failure appeared to be rare, and instead most of the polymers seemed to be failing in tension. The polymers giving anomalous results were brittle ones with

  11. Morphy et al. BENT EFFECT ON STRENGTH OF CFRP STIRRUPS

    E-print Network

    . The variables considered were the type of material, bar diameter, stirrup anchorage and embedment length are typically oriented with an angle with respect to the stirrups and consequently their tensile strength the material, bar diameter, stirrup anchorage and embedment length, the strength of CFRP stirrups is proposed

  12. Strength of welded copper joints

    SciTech Connect

    Kuzyukova, A.N.; Fedorenko, M.I.; Kovalenko, N.I.; Zelik, E.I.

    1983-07-01

    A coefficient of the strength of welded joints in structures of copper and its alloys made by manual arc welding are known. At the Severedonetsk Branch of the Institute of Chemical Engineering the strength coefficients were determined for welded joints made of MZR (phosphorous-deoxydized) copper produced by manual argonarc welding. Optimum welding regimes were selected, and specimens of strips tested for tensile strength. Metallographic investigations showed significant grain growth in the zone of thermal influence. The results of mechanical tests are given. The results are verified by the fabrication of nine models. All the models ruptured in the zone of thermal influence, confirming results that the zone of thermal influence was the weak point in the welded joints in copper.

  13. Effect of Pre-Loading with Tensile Stress on Laboratory UCS of a Synthetic Rock

    NASA Astrophysics Data System (ADS)

    Singh, Mahendra; Lakshmi, Vijaya; Yudhbir; Srivastava, L. P.

    2015-01-01

    Amongst various index properties used by rock engineers, the uniaxial compressive strength (UCS) is probably the most widely used property of intact rocks. In the field, in situ stresses are always present, and, when samples are extracted from such rocks, the stresses are released. These specimens, when tested in the laboratory, may give low strength values in comparison to what would have been obtained without stress removal. It is difficult to exactly follow the stress path of coring of rock in a natural stress environment; an indirect way of simulating effect of stress removal has been adopted in this study. Specimens of a synthetic rock have been subjected to pre-loading with tensile stress, and qualitative assessment of the reduction in the laboratory UCS of the rock has been made. To induce tensile stresses, conventional Brazilian test apparatus was modified. The results indicate that if pre-loading tensile stress exceeds about half of the Brazilian tensile strength, stress removal has substantial effect on the UCS and conservative results may be expected from laboratory tests on rock specimens.

  14. Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-09-01

    The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

  15. Elevated-temperature tensile and creep properties of several ferritic stainless steels

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1977-01-01

    The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.

  16. Rheological behaviour of commercial cooked meat products evaluated by tensile test and texture profile analysis (TPA).

    PubMed

    Romero de Ávila, M Dolores; Isabel Cambero, M; Ordóñez, Juan A; de la Hoz, Lorenzo; Herrero, Ana M

    2014-10-01

    The breaking strength (BS) and energy to fracture (EF) of commercial cooked meat products (CMP) manufactured from different entire pieces were determined by tensile test. BS and EF were related to texture profile analysis (TPA) and physico-chemical data. Two textural profiles were characterized mainly by BS, springiness adhesiveness and fat content. Multivariate regression analysis confirms that TPA parameters could be used to construct models to predict BS and EF. Therefore, just one TPA analysis will allow to obtain both TPA and tensile parameters, providing valuable information about mechanical behaviour to improve product handling at industrial level especially in sliced CMP. PMID:24880977

  17. Multi-scale investigation of tensile creep of ultra-high performance concrete for bridge applications

    NASA Astrophysics Data System (ADS)

    Garas Yanni, Victor Youssef

    Ultra-high performance concrete (UHPC) is relatively a new generation of concretes optimized at the nano and micro-scales to provide superior mechanical and durability properties compared to conventional and high performance concretes. Improvements in UHPC are achieved through: limiting the water-to-cementitious materials ratio (i.e., w/cm ? 0.20), optimizing particle packing, eliminating coarse aggregate, using specialized materials, and implementing high temperature and high pressure curing regimes. In addition, and randomly dispersed and short fibers are typically added to enhance the material's tensile and flexural strength, ductility, and toughness. There is a specific interest in using UHPC for precast prestressed bridge girders because it has the potential to reduce maintenance costs associated with steel and conventional concrete girders, replace functionally obsolete or structurally deficient steel girders without increasing the weight or the depth of the girder, and increase bridge durability to between 75 and 100 years. UHPC girder construction differs from that of conventional reinforced concrete in that UHPC may not need transverse reinforcement due to the high tensile and shear strengths of the material. Before bridge designers specify such girders without using shear reinforcement, the long-term tensile performance of the material must be characterized. This multi-scale study provided new data and understanding of the long-term tensile performance of UHPC by assessing the effect of thermal treatment, fiber content, and stress level on the tensile creep in a large-scale study, and by characterizing the fiber-cementitious matrix interface at different curing regimes through nanoindentation and scanning electron microscopy (SEM) in a nano/micro-scale study. Tensile creep of UHPC was more sensitive to investigated parameters than tensile strength. Thermal treatment decreased tensile creep by about 60% after 1 year. Results suggested the possibility of achieving satisfactory microstructural refinement at the same temperature input despite the maximum temperature applied. For the first time, the presence of a 10 microm (394 micro inch) wide porous fiber-cementitious matrix interface was demonstrated by nanoindentation and SEM for non-thermally treated UHPC only. Tensile creep at 90 days increased by 64% and 46% upon eliminating fibers for thermally and non-thermally treated UHPC, respectively. Increases in creep upon reducing the fiber content suggested that fibers carry part of the sustained load and thus reduce creep. Tensile creep strain was proportional to the stress applied up to 60% of the ultimate strength. No tensile creep failure occurred for a period of 1 year for pre-cracked UHPC under stress level of 40%. Also, no tensile creep failure occurred for a period of 90 days under stress level of 60%. Tensile creep failure occurred at stress levels of 70% and 80%. This study showed that fibers cannot be accounted for as shear reinforcement in lieu of stirrups unless micro-defect-free fiber-matrix interface is achieved.

  18. Transverse and longitudinal tensile properties at 760 C of several oxide dispersion strenghened nickel-base alloys

    NASA Technical Reports Server (NTRS)

    Anglin, A. E., Jr.

    1979-01-01

    The transverse and longitudinal tensile properties of the oxide dispersion strengthened nickel base alloys MA-793, MA-754, MA-755E, and MA-6000E were determined at 760 C. Transverse tensile strengths were comparable to longitudinal strengths. Transverse ductility levels generally were less than two percent elongation. Both tensile and yield strengths increased with increasing strain rate over the range 0.001 to 0.05 per second. Ductility was not strain rate sensitive, but related to grain size and grain aspect ratio. The fracture mode of most alloys changed from transgranular for longitudinally oriented specimens to intergranular for transverse specimens. Transverse properties of DM MAR M-200 + Hf were also determined for comparison.

  19. Transverse and longitudinal tensile properties at 760 C of several oxide dispersion strengthened nickel-base alloys

    NASA Technical Reports Server (NTRS)

    Anglin, A. E., Jr.

    1979-01-01

    The transverse and longitudinal tensile properties of the oxide dispersion strengthened nickel-base alloys were determined at 760 C. The alloys with small amounts of gamma prime have strength levels suitable for turbine vane applications, while other highly alloyed, gamma prime strengthened superalloys have strengths typical of turbine blade materials. These alloys were produced by mechanical alloying and extrusion and the turbine blade alloys were also directionally recrystallized. Resultant grain aspect ratios varied from 1:1 to over 20:1. Longitudinal tensile strengths ranged from 285 to 1175 MPa, while longitudinal elongations were in excess of 4 percent for all alloys. Transverse tensile strengths were comparable to longitudinal strengths, but transverse ductility levels were generally less than 2 percent elongation. Tensile and yield strengths increased with increasing strain rate over the range 0.001 to 0.05 per second. Ductility in both orientations was not strain rate sensitive but could be related to grain size and grain aspect ratio.

  20. High temperature tensile testing of ceramic composites

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Hemann, John H.

    1988-01-01

    The various components of a high temperature tensile testing system are evaluated. The objective is the high temperature tensile testing of SiC fiber reinforced reaction bonded Si3N4 specimens at test temperatures up to 1650 C (3000 F). Testing is to be conducted in inert gases and air. Gripping fixtures, specimen configurations, furnaces, optical strain measuring systems, and temperature measurement techniques are reviewed. Advantages and disadvantages of the various techniques are also noted.

  1. Tensile bond testing of concrete repairs

    Microsoft Academic Search

    Simon Austin; Peter Robins; Youguang Pan

    1995-01-01

    The development and maintenance of a sound band is an essential requirement of a concrete patch repair. Tensile bond tests\\u000a are increasing in popularity as a means of measuring this adhesive property, both on site for quality control and in the laboratory\\u000a for materials evaluation. This paper discusses the main issues relevant to tensile bond testing, namely material properties,\\u000a surface

  2. Modified ring stretch tensile testing of Zr-1Nb cladding.

    SciTech Connect

    Billone, M. C.; Chung, H. M.; Cohen, A. B.; Majumdar, S.; Neimark, L. A.; Ruther, W. E.

    1997-12-05

    In a round robin effort between the US Nuclear Regulatory Commission, Institut de Protection et de Surete Nucleaire in France, and the Russian Research Centre-Kurchatov Institute, Argonne National Laboratory conducted 16 modified ring stretch tensile tests on unirradiated samples of Zr-1Nb cladding, which is used in Russian VVER reactors. Tests were conducted at two temperatures (25 and 400 C) and two strain rates (0.001 and 1 s{sup {minus}1}). At 25 C and 0.001 s{sup {minus}1}, the yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE), and total elongation (TE) were 201 MPa, 331 MPa, 18.2%, and 57.6%, respectively. At 400 C and 0.001 s{sup {minus}1}, the YS, UTS, UE, and TE were 109 MPa, 185 MPa, 15.4%, and 67.7%, respectively. Finally, at 400 C and 1 s{sup {minus}1}, the YS, UTS, UE, and TE were 134 MPa, 189 MPa, 18.9%, and 53.4%, respectively. The high strain rate tests at room temperature were not successful. Test results proved to be very sensitive to the amount of lubrication used on the inserts; because of the large contact area between the inserts and specimen, too little lubrication leads to significantly higher strengths and lower elongations being reported. It is also important to note that only 70 to 80% of the elongation takes place in the gauge section, depending on specimen geomeq. The appropriate percentage can be estimated from a simple model or can be calculated from finite-element analysis.

  3. Fatigue Strength Evaluation of the Clinched Lap Joints of a Cold Rolled Mild Steel Sheet

    NASA Astrophysics Data System (ADS)

    Kim, Ho-Kyung

    2013-01-01

    Static tensile and fatigue tests were conducted using tensile-shear specimens to evaluate the fatigue strength of clinched lap joints of a cold rolled mild steel sheet. The maximum tensile force (= holding force) of the specimen produced at the optimal punching force was 70 kN. The fatigue endurance limit (= 760 N) approached 43% of the maximum tensile load (= 1750 N) at a load ratio of 0.1, suggesting that the fatigue limit is approximately half of the value of the maximum tensile force. The FEM analysis showed that at the fatigue endurance limit, the maximum von Mises stress of 373 MPa is very close to the ultimate tensile strength of the cold rolled mild steel sheet (= 382 MPa).

  4. Strength scaling in fiber composites

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Morton, John

    1991-01-01

    A research program was initiated to study and isolate the factors responsible for scale effects in the tensile strength of graphite/epoxy composite laminates. Four layups were chosen with appropriate stacking sequences so as to highlight individual and interacting failure modes. Four scale sizes were selected for investigation including full scale size, 3/4, 2/4, and 1/4, with n = to 4, 3, 2, and 1, respectively. The full scale specimen sizes was 32 piles thick as compared to 24, 16, and 8 piles for the 3/4, 2/4, and 1/4 specimen sizes respectively. Results were obtained in the form of tensile strength, stress-strain curves and damage development. Problems associated with strength degradation with increasing specimen sizes are isolated and discussed. Inconsistencies associated with strain measurements were also identified. Enchanced X-ray radiography was employed for damage evaluation, following step loading. It was shown that fiber dominated layups were less sensitive to scaling effects compared to the matrix dominated layups.

  5. Strength Scaling in Fiber Composites

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Morton, John

    1990-01-01

    A research program was initiated to study and isolate the factors responsible for scale effects in the tensile strength of graphite/epoxy composite laminates. Four layups were chosen with appropriate stacking sequences so as to highlight individual and interacting failure modes. Four scale sizes were selected for investigation including full scale size, 3/4, 2/4, and 1/4, with n = to 4, 3, 2, and 1, respectively. The full scale specimen sizes was 32 piles thick as compared to 24, 16, and 8 piles for the 3/4, 2/4, and 1/4 specimen sizes respectively. Results were obtained in the form of tensile strength, stress-strain curves and damage development. Problems associated with strength degradation with increasing specimen sizes are isolated and discussed. Inconsistencies associated with strain measurements were also identified. Enhanced x ray radiography was employed for damage evaluation, following step loading. It was shown that fiber dominated layups were less sensitive to scaling effects compared to the matrix dominated layups.

  6. Tensile and Tensile-Mode Fatigue Testing of Microscale Specimens in Constant Humidity Environment

    Microsoft Academic Search

    T. Tsuchiya; Y. Yamaji; K. Sugano; O. Tabata

    2010-01-01

    A tensile and tensile-mode-fatigue tester has been developed for testing microscale specimens in high humidity environments\\u000a in order to investigate the fracture mechanisms of microelectromechanical materials. A humidity control system was installed\\u000a on a tensile-mode fatigue tester equipped with an electrostatic force grip. A specimen and a griping device were inserted\\u000a into a small chamber and the humidity was controlled

  7. Superior Tensile Ductility in Bulk Metallic Glass with Gradient Amorphous Structure

    PubMed Central

    Wang, Q.; Yang, Y.; Jiang, H.; Liu, C. T.; Ruan, H. H.; Lu, J.

    2014-01-01

    Over centuries, structural glasses have been deemed as a strong yet inherently ‘brittle’ material due to their lack of tensile ductility. However, here we report bulk metallic glasses exhibiting both a high strength of ~2?GPa and an unprecedented tensile elongation of 2–4% at room temperature. Our experiments have demonstrated that intense structural evolution can be triggered in theses glasses by the carefully controlled surface mechanical attrition treatment, leading to the formation of gradient amorphous microstructures across the sample thickness. As a result, the engineered amorphous microstructures effectively promote multiple shear banding while delay cavitation in the bulk metallic glass, thus resulting in superior tensile ductility. The outcome of our research uncovers an unusual work-hardening mechanism in monolithic bulk metallic glasses and demonstrates a promising yet low-cost strategy suitable for producing large-sized, ultra-strong and stretchable structural glasses. PMID:24755683

  8. Superior Tensile Ductility in Bulk Metallic Glass with Gradient Amorphous Structure

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Yang, Y.; Jiang, H.; Liu, C. T.; Ruan, H. H.; Lu, J.

    2014-04-01

    Over centuries, structural glasses have been deemed as a strong yet inherently `brittle' material due to their lack of tensile ductility. However, here we report bulk metallic glasses exhibiting both a high strength of ~2 GPa and an unprecedented tensile elongation of 2-4% at room temperature. Our experiments have demonstrated that intense structural evolution can be triggered in theses glasses by the carefully controlled surface mechanical attrition treatment, leading to the formation of gradient amorphous microstructures across the sample thickness. As a result, the engineered amorphous microstructures effectively promote multiple shear banding while delay cavitation in the bulk metallic glass, thus resulting in superior tensile ductility. The outcome of our research uncovers an unusual work-hardening mechanism in monolithic bulk metallic glasses and demonstrates a promising yet low-cost strategy suitable for producing large-sized, ultra-strong and stretchable structural glasses.

  9. Properties of cold-rolled high-strength steel sheets

    Microsoft Academic Search

    K. Toda; H. Gondoh; H. Takechi; H. Masui

    1976-01-01

    For high-strength steel sheets, a new concept has become necessary,viz, the relation between strength and formability. When the relation between tensile strength and elongation is appraised for\\u000a ranking in terms of the strengthening mechanism, it is found that the substitutional solid-solution hardening type is excellent\\u000a and the precipitation hardening type is inferior. In batch annealing, the phosphorus-added aluminum-killed steel sheets

  10. Apparent strength scaling in continuous fiber composite laminates

    Microsoft Academic Search

    J. Andre Lavoie; Costas Soutis; John Morton

    2000-01-01

    The tensile strength of the 0° plies within different cross-ply and quasi-isotropic laminates of varying size and stacking sequence has been investigated. For those lay-ups having failure confined to the gauge section, no size effect was observed in the strength of 0° plies. In laminates exhibiting a size versus strength relationship, failures were found to occur in the gauge section

  11. Some strength properties of graphite-zirconium carbide composite materials

    Microsoft Academic Search

    V. S. Dergunova; A. N. Shurshakov; G. D. Posos'eva; L. N. Lutsenko

    1972-01-01

    1.Some factors influencing the strength of composite materials were examined.2.A study was made of the strength properties of graphite-zirconium carbide and graphite-zirconium carbide-zirconium composite materials having varying structures and compositions. It was found that, at 2500‡C, the tensile strength of TsG-25 type composite material is 30% higher than that of dense VPP constructional graphite.3.It was established that, by varying the

  12. Strength properties of nylon- and polypropylene-fiber-reinforced concretes

    Microsoft Academic Search

    P. S. Song; S. Hwang; B. C. Sheu

    2005-01-01

    The strength potential of nylon-fiber-reinforced concrete was investigated versus that of the polypropylene-fiber-reinforced concrete, at a fiber content of 0.6 kg\\/m3. The compressive and splitting tensile strengths and modulus of rupture (MOR) of the nylon fiber concrete improved by 6.3%, 6.7%, and 4.3%, respectively, over those of the polypropylene fiber concrete. On the impact resistance, the first-crack and failure strengths

  13. Dry Bag Isostatic Pressing for Improved Green Strength of Nuclear Fuel Pellets

    SciTech Connect

    G. W. Egeland; L. D. Zuck; W. R. Cannon; P. A. Lessing; P. G. Medvedev

    2010-11-01

    Dry bag isostatic pressing is proposed for mass production of nuclear fuel pellets. Dry bag isostatically pressed rods of a fuel surrogate (95% CeO2-5% HfO2) 200 mm long by 8 mm diameter were cut into pellets using a wire saw. Four different binder and two different CeO2 powder sources were investigated. The strength of the isostatically pressed pellets for all binder systems measured by diametral compression was about 50% higher than pellets produced by uniaxial dry pressing at the same pressure. It was proposed that the less uniform density of uniaxially pressed pellets accounted for the lower strength. The strength of pellets containing CeO2 powder with significantly higher moisture content was five times higher than pellets containing CeO2 powder with a low moisture content. Capillary pressure of the moisture was thought to supply the added binding strength.

  14. Influence of thermo-mechanical treatment on the tensile properties of a modified 14Cr-15Ni stainless steel

    NASA Astrophysics Data System (ADS)

    Vijayanand, V. D.; Laha, K.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.

    2014-10-01

    The titanium modified 14Cr-15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 × 10-4 s-1 over a temperature range of 298-1073 K. The yield stress and the ultimate tensile strength of the steel increased with increase in solution treatment temperature and this has been attributed to the fine and higher density of Ti(C,N) precipitate. Tensile flow behaviour of the steel has been analysed using Ludwigson and Voce constitutive equations. The steel heat treated at higher solution temperature exhibited earlier onset of cross slip during tensile deformation. The rate of recovery at higher test temperatures was also influenced by variations in solution heat treatment temperature. In addition, dynamic recrystallization during tensile deformation at higher temperatures was profound for steel solution heat-treated at lower temperature. The differences in flow behaviour and softening mechanisms during tensile testing of the steel after different heat treated conditions have been attributed to the nature of Ti(C,N) precipitation.

  15. Tensile fracture mechanisms of ferritic/martensitic structural materials

    NASA Astrophysics Data System (ADS)

    Pan, Xiao

    Radiation-induced defect structures are known to elevate material yield strength and reduce material ductility so that small strains induce plastic instability. This process is commonly known as flow localization. Recent research indicates that the flow localization in face-centered cubic (FCC) materials is controlled by critical stress, the true stress of onset of necking. Critical stress dose not change with irradiation dose but has strong temperature dependence. Because critical stress acts as a material intrinsic property similar to yield strength, it is important to understand the controlling mechanism and the temperature dependence of critical stress. It is believed that critical stress is associated with critical interfacial strength between particle and matrix, which determines the void nucleation. Void nucleation has received extensive attention motivated by the need to enhance damage tolerance and avoid fracture in structural materials. Several initiation models have been built to predict critical interfacial strength of void nucleation. However, all of these models are limited because they were derived from post-deformation (static) micro-structural characterization, which contains no information about the dynamic processes involved in the evolution of failure. This dissertation project aims to examine the controlling mechanism of critical stress, and the effects of temperature and particle characters by investigating the void nucleation through in-situ tensile tests with high energy X-ray diffraction and small angle X-ray scattering. By combining stress and void evolution from X-ray experiments, the critical interfacial strength right at the beginning of void nucleation is directly measured for four types of Fe-Cr-C model alloys: Fe-9%Cr-0.1%C, Fe-9%Cr-0.5%C, Fe-12%Cr-0.2%C, and Fe-12%Cr-0.5%C, which are promising candidates for high-temperature advanced nuclear system applications. The effects of temperature, particle size, particle volume fraction, particle crystal orientation, and chemical composition on critical interfacial strength have been inspected thoroughly. Results from this study demonstrate that critical stress is strongly linearly correlated with critical interfacial strength. The effects of temperature and particle size on critical stress are correspondingly determined by how temperature and particle size influence critical interfacial strength. In addition, a new Micro-Structural Model (MSM) is developed to predict critical interfacial strength using macro tensile testing parameters. This MSM model is consistent with experimental measurements under all testing conditions. Pre-existing dislocation models are also evaluated by the X-ray measurements. Results show that the MSM model can provide better prediction than dislocation models. X-ray measurements and analysis not only support the hypothesis of the association between critical stress and critical interfacial strength, but also offer a new method to determine the true strain/stress behavior during deformation. This method is called the Universal Micro-structural Geometry-corrected Model (UMGM) in this dissertation. Due to the development of tri-axial stress and severe distortion of grain structure in the necking region, it is a challenge to determine the true strain/stress curve, a critical input in finite element modeling (FEM) analysis. Previous scholars have developed several analytical methods to characterize true strain/stress behavior after necking merely based on geometry correction or direct linear extrapolation. Grounded with experimental data, the UMGM provides empirical validation for these existing methods.

  16. High temperature tensile deformation behavior of Grade 92 steel

    NASA Astrophysics Data System (ADS)

    Alsagabi, Sultan; Shrestha, Triratna; Charit, Indrajit

    2014-10-01

    Candidate structural materials for advanced reactors need to have superior high temperature strength and creep-rupture properties among other characteristics. The ferritic-martensitic Grade 92 steel (Fe-9Cr-2W-0.5Mo, wt.%) is considered such a candidate structural material. Tensile tests were performed at temperatures of 600, 650 and 700 °C in the strain rate range of 10-5-10-3 s-1. After analyzing the tensile results using the Bird-Mukherjee-Dorn (BMD) equation, a stress exponent of about 9.5 and an activation energy of about 646 kJ/mol were obtained. In the light of high values of the stress exponent and activation energy, the threshold stress concept was used to elucidate the operating high temperature deformation mechanism. As a result of this modification, the true activation energy and stress exponent of the high temperature deformation in Grade 92 steel were found to be about 245 kJ/mol and 5, respectively. Thus, the dominant high temperature deformation mechanism was identified as the high temperature climb of edge dislocations and the appropriate constitutive equation was developed.

  17. Tensile fracture criterion of metallic glass

    NASA Astrophysics Data System (ADS)

    Qu, R. T.; Eckert, J.; Zhang, Z. F.

    2011-04-01

    The fracture criterion of metallic glass (MG) is still under debate so far. On the issue of describing the normal stress effect on the tensile fracture behaviors of MGs, there are two fracture criteria: the Mohr-Coulomb (M-C) criterion and the Ellipse criterion. In this study, the normal stress acting on the tensile fracture planes was controlled and varied in a wide range by introducing inclined notches with different inclination angles to a series of Zr-based MG specimens. Based on the experimental results, both the Ellipse criterion and the M-C criterion are compared and analyzed. The experimental results reveal that the Ellipse criterion gives a better prediction than the M-C criterion for the tensile fracture behavior of the investigated Zr-based MG in a wide normal stress range. Moreover, the pressure and normal stress effects were separately considered and some other criteria were further discussed. It is found that under tensile loading, the pressure effect is weak while the normal stress effect is strong. Combined with previously reported results for a variety of MGs, the Ellipse criterion is found to have the capability to describe all the different contributions of the normal stress effect and thus may be suitable as a unified tensile fracture criterion for all MGs with different fracture behaviors.

  18. Numerical modeling of the compressive and tensile response of brittle materials under high pressure dynamic loading

    NASA Astrophysics Data System (ADS)

    Clegg, Richard A.; Hayhurst, Colin J.

    2000-04-01

    Ceramic materials are commonly used as ballistic protection materials. The response of a ceramic to impact, perforation and penetration is complex and only limited physical instrumentation can be used in experiments. This paper demonstrates how a hydrocode, such as AUTODYN, can be used to aid in the understanding of the response of brittle materials to high pressure impact loading. While the penetration process is dominated by the material compressive thermodynamic and deviatoric response, the final damaged state of the material can be significantly influenced by the tensile behavior. Modelling of the final damage state is important since this is often the only physical experimental information available. In this paper we present a unique implementation, in a hydrocode, of a tensile crack softening model for improved modeling of brittle materials in the tensile regime. Tensile failure initiation is based on principal stress while the post-failure tensile strength of the material is controlled through a damaging Rankine plasticity failure surface. The performance of the model is demonstrated with the relatively new meshless SPH technique; simulations of steel ball impacts onto alumina ceramic are presented and compared with experiments.

  19. Mechanical Testing of TR-55 Rubber Thermally Aged Under Tensile Strain

    SciTech Connect

    Small IV, W; Alviso, C T; Wilson, T S; Chinn, S C; Maxwell, R S

    2009-03-10

    TR-55 rubber specimens were previously subjected to an aging process consisting of the application of a tensile strain of approximately 67%, 100%, 133%, or 167% elongation for 4, 8, 12, or 16 h at either 250 C or room temperature. Control specimens at the same temperatures/durations were not subjected to tensile strain. The specimens were allowed to recover at room temperature without external stimuli for over 100 days before tensile testing. A single dog bone was cut from each specimen and a stress-strain curve was obtained. The elastic modulus of each specimen was calculated. Specimens aged under tensile strain exhibited rubber-like behavior dependent on the aging elongation and duration. This behavior was not evident in the unstrained controls. For the unstrained controls, exposure to 250 C resulted in an increase in modulus relative to the unheated material independent of the heating duration. The tensile strain applied during the aging process caused a reduction in modulus relative to the controls; lower moduli were observed for the shorter aging durations. Slippage of the specimens in the grips prevented determination of ultimate strength, as all specimens either slipped completely out of the grip before failure or failed at the original grip edge after slipping.

  20. Spaghetti Strength

    NSDL National Science Digital Library

    2013-07-08

    In this activity on page 7 of the PDF, learners explore how engineers characterize building materials. Learners test the strength of spaghetti and determine how the number of spaghetti strands affects the strength of a bundle of spaghetti. Use this activity to chemical bonds, mechanical testing, and engineering. Note: The pasta strands can be dipped in water and stuck together to more closely mimic the layers within a piece of plywood. More information about this can be found at the top of page 7, directly underneath the cartoon image. Safety note: Do not eat or drink any of the materials in this activity.

  1. Hot strength of creep resistant ferritic steels and relationship to creep rupture data

    E-print Network

    Cambridge, University of

    Hot strength of creep resistant ferritic steels and relationship to creep rupture data R. C relationship between the temperature dependence of hot tensile strength and creep rupture stress. Keywords: Hot in which the hot strength of austenite has been modelled, primarily as an aid to the simulation of the hot

  2. Effects of Sample Geometry and Loading Rate onTensile Ductility of TRIP800 Steel

    SciTech Connect

    Sun, Xin; Soulami, Ayoub; Choi, Kyoo Sil; Guzman, O.; Chen, Weinong W.

    2012-04-15

    The effects of sample geometry and loading rate on the tensile ductility of a commercial grade Transformation Induced Plasticity (TRIP) steel are examined in this paper. Quasistatic tensile tests were performed for the 1.2mm gauge TRIP800 steel sheets with two geometries: sub-sized ASTM E-8 and a custom designed miniature tensile sample. Sample geometry effects on post-uniform elongation are discussed together with other experimental data reported in the open literature. Further discussions on the effects of sample geometry are cast in the context of mesh-size dependent ductility in finite element-based engineering simulations. The quasi-static tensile curve for the miniature sample is then compared with the split Hopkinson bar results at the loading rates of 1700-S-1 and 2650-S-1 with the same sample design. In contrary to the typical strain rate sensitivity results for mild steel where the dynamic strength increase at high strain rate usually occurs at the price of ductility reduction, our results show that the TRIP800 under examination has positive strain rate sensitivity on both strength and ductility. Images of the deformation process captured by high speed camera together with scanning electron microscopy (SEM) near the fracture zone are also used to elucidate the different deformation modes at different loading rates.

  3. Tensile behavior of tungsten and tungsten-alloy wires from 1300 to 1600 K

    SciTech Connect

    Yun, Hee Mann.

    1988-01-01

    The tensile behavior of 200-{mu}m-diameter tungsten lamp (218CS-W), tungsten + 1.0 atomic percent (a/o) thoria (ST300-W), and tungsten + 0.4 a/o hafnium carbide (WHfC) wires was determined over the temperature range 1300 to 1600 K at strain rates of 3.3 x 10{sup -2} to 3.3 x 10{sup -5} sec{sup -1}. Although most tests were conducted on as-drawn materials, one series of tests was undertaken on ST300-W wires in four different conditions: as-drawn and vacuum annealed at 1535 K for 1 hr, with and without electropolishing. Whereas heat treatment had no effect on tensile properties, electropolishing significantly increased both the proportional limit and ductility, but not the ultimate tensile strength. Comparison of the behavior of the three alloys indicates that the HfC-dispersed material possesses superior tensile properties. Theoretical calculations indicate that the strength/ductility advantage of WHfC is due to the resistance to recrystallization imparted by the dispersoid. 19 refs., 9 figs., 4 tabs.

  4. Homogeneous cavitation in microfluidics: a record high dynamic tensile threshold

    NASA Astrophysics Data System (ADS)

    Ando, Keita; Liu, Ai-Qun; Ohl, Claus-Dieter

    2011-11-01

    An experimental technique is presented which allows one to measure the rupture strength of water using a microfluidic approach. A transparent microfluidic channel is filled with clean water, partially leaving an air-water interface. A focused infrared laser pulse within the liquid creates a spherical shock wave near the interface. The shock reflects, due to acoustic impedance mismatch, as a strong tension wave with high negative pressures. The liquid becomes stretched and at the homogeneous cavitation threshold ruptures with the nucleation of vapor bubbles. These bubbles are captured using an optical delay and very short exposure times. Reproducible observations of the bubble nucleation are obtained, supporting our claim of homogeneous bubble nucleation. Multicomponent Euler flow simulation estimates a tensile stress threshold of -60 MPa, which is the largest reported tension for dynamic measurements.

  5. Effect of Cyclic Oxidation Exposure on Tensile Properties of a Pt-Aluminide Bond-Coated Ni-Base Superalloy

    NASA Astrophysics Data System (ADS)

    Zafir Alam, Md.; Hazari, N.; Varma, Vijay K.; Das, Dipak K.

    2011-12-01

    The tensile behavior of a directionally solidified (DS) Ni-base superalloy, namely, CM-247LC, was evaluated in the presence of a Pt-aluminide bond coat. The effect of the thermal cycling exposure of the coated alloy at 1373 K (1100 °C) on its tensile properties was examined. The tensile properties were evaluated at a temperature of 1143 K (870 °C). The presence of the bond coating caused an approximately 8 pct drop in the strength of the alloy in the as-coated condition. However, the coating did not appreciably affect the tensile ductility of the substrate alloy. The bond coat prevented oxidation-related surface damage to the superalloy during thermal cycling exposure in air at 1373 K (1100 °C). Such cyclic oxidation exposure (up to 750 hours) did not cause any further reduction in yield strength (YS) of the coated alloy. There was a marginal decrease in the ultimate tensile strength (UTS) with increased exposure duration. Because of the oxidation protection provided by the bond coat, the drastic loss in ductility of the alloy, which would have happened in the absence of the coating, was prevented.

  6. A new tensile stage for in situ electron microscopy examination of the mechanical properties of 'superelastic' specimens

    SciTech Connect

    Dragnevski, Kalin I.; Fairhead, Trevor W.; Balsod, Rik; Donald, Athene M. [Department of Physics, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

    2008-12-15

    We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of ''superelastic'' materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch (''roll on'') any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.

  7. A new tensile stage for in situ electron microscopy examination of the mechanical properties of ``superelastic'' specimens

    NASA Astrophysics Data System (ADS)

    Dragnevski, Kalin I.; Fairhead, Trevor W.; Balsod, Rik; Donald, Athene M.

    2008-12-01

    We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of "superelastic" materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch ("roll on") any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.

  8. Evaluation of Tensile Deformation Properties of Friction Stir Processed Pure Copper: Effect of Processing Parameters and Pass Number

    NASA Astrophysics Data System (ADS)

    Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Jafari, Jalal

    2014-01-01

    In this work, the tensile behavior of pure copper including ultimate tensile stress, yield stress, and elongation in the specimens friction stir processed under different processing parameters and pass adding was investigated in detail. The effect of strain hardening, grain refinement, and heat input on the tensile properties of these specimens was explained as well. It was observed that, regarding the aforementioned factors, the processing parameters and pass number could have considerable effects on the tensile deformation properties of the pure copper such as 300 and 47% enhancements in elongation and ultimate strength, respectively. It was demonstrated that higher passes resulted in the development of ultrafine grains (up to 700-800 nm) in the specimens. The fracture surface morphology was also used to further support the elongation results.

  9. Factors which affect fatigue strength of fasteners

    SciTech Connect

    Skochko, G.W.; Herrmann, T.P.

    1992-11-01

    Axial load cycling fatigue tests of threaded fasteners are useful in determining fastener fatigue failure or design properties. By using appropriate design factors between the failure and design fatigue strengths, such tests are used to establish fatigue failure and design parameters of fasteners for axial and bending cyclic load conditions. This paper reviews the factors which influence the fatigue strength of low Alloy steel threaded fasteners, identifies those most significant to fatigue strength, and provides design guidelines based on the direct evaluation of fatigue tests of threaded fasteners. Influences on fatigue strength of thread manufacturing process (machining and rolling of threads), effect of fastener membrane and bending stresses, thread root radii, fastener sizes, fastener tensile strength, stress relaxation, mean stress, and test temperature are discussed.

  10. Strength loss in kraft pulping

    NASA Astrophysics Data System (ADS)

    Iribarne, Jose

    Unbleached kraft pulps from two U.S. mills were 21% and 26% weaker than comparable laboratory pulps from the same chip sources, when assessed as the tear index at a tensile index of 70 kN.m/kg. The phenomena involved were clarified by characterizing the differences between the mill and laboratory pulps in terms of fundamental fiber properties. All of the strength loss could be explained by a reduction in intrinsic fiber strength of 9% to 11%, as estimated from wet zero-span tensile tests and fiber length distributions. Most of the effects of different fiber shape and length were isolated by PFI mill refining and decrilling, respectively. The higher fiber coarseness of mill pulps was a factor in their maximum density and bond strength, but changes in these variables were analogous to those of laboratory pups due to similar swelling. Specific bond strength, determined from a wet pressing experiment, was similar in mill and laboratory pulps. Neither carbohydrate composition nor crystalline structure, assessed through x-ray diffraction analysis, were significant factors in the observed fiber strength differences. The mill pulps were not more heterogeneous than the laboratory pulps, within the resolution of a fractionation experiment. The number of weak points in each pulp was assessed through analysis of the amount of fiber cutting during PFI mill refining and treatments with potassium superoxide or cellulase. The results suggested that the chemistry of kraft pulping preferentially weaken short, slender fibers, while mechanical stresses during the hot discharge of batch digesters mainly affect long, thick fibers. The greater number of weak points in the long-fiber fractions of mill pulps is probably associated with their lower wet zero-span tensile indices. Automated optical detection of major singularities with a prototype instrument suggested that only the weak points induced by mechanical stress could be detected by local variations in birefringence. In contrast, chemically damaged short, slender fibers were not optically active. Strong chemical attack during superoxide treatment appeared to affect all fibers, but the effect of fiber cutting was partially offset by a preferential dissolution of short fibers and fines. A simple model of weak point formation by combinations of mechanical stress and localized chemical attack was sufficient to explain all the experimental results.

  11. In Situ Radiography During Tensile Tests

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Bhatt, Ramakrishna T.

    1994-01-01

    Laboratory system for testing specimens of metal-, ceramic-, and intermetallic-matrix composite materials incorporates both electromechanical tensile-testing subsystem and either of two imaging subsystems that take x-ray photographs of specimens before, during, and after tensile tests. Used to test specimens of reaction-bonded silicon nitride reinforced with silicon carbide fibers (SiC/RBSN) considered for high-temperature service in advanced aircraft turbine engines. Provides data on effects of preexisting flaws (e.g., high-density impurities and local variations of density) on fracture behavior. Accumulated internal damage monitored during loading. X-ray source illuminates specimen in load frame while specimen is pulled. X-ray images on film correlated with stress-vs.-strain data from tensile test.

  12. Tensile-strained germanium microdisk electroluminescence.

    PubMed

    Prost, M; El Kurdi, M; Ghrib, A; Sauvage, S; Checoury, X; Zerounian, N; Aniel, F; Beaudoin, G; Sagnes, I; Boeuf, F; Boucaud, P

    2015-03-01

    We report room temperature electroluminescence of tensile-strained germanium microdisks. The strain is transferred into the microdisks using silicon nitride stressors. Carrier injection is achieved with Schottky contacts on n-type doped germanium. We show that a biaxial tensile-strain up to 0.72% can be transferred by optimizing the carrier injection profile. The transferred strain is measured by the electroluminescence spectral red-shift and compared to finite element modeling. We discuss the impact of this strain level to achieve population inversion in germanium. PMID:25836888

  13. Geometrically controlled tensile response of braided sutures.

    PubMed

    Rawal, Amit; Sibal, Apurv; Saraswat, Harshvardhan; Kumar, Vijay

    2015-03-01

    Sutures are the materials used for wound closure that are caused by surgery or trauma. The main pre-requisite to the success of the suture is to obtain ultimate level of tensile properties with defined geometrical constraints. In this communication, the model for tensile properties of braided sutures has been proposed by elucidating the most important geometrical and material parameters. The model has accounted for the kinematical changes occurring in the braid and constituent strand geometries under defined level of strain. A comparison has been made between the theoretical and experimental results of stress-strain characteristics of braided sutures. PMID:25579946

  14. Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

    NASA Astrophysics Data System (ADS)

    Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

    2014-09-01

    Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

  15. Tensile and compressive behavior of tungsten, molybdenum, tantalum and niobium at the nanoscale

    E-print Network

    Greer, Julia R.

    ­15,25]. While FIB-fabricated bcc Mo nanopillars also show size effects in the flow stress [20,21,27], the under to investigate the tensile and compressive behavior of h0 0 1i-oriented body-centered cubic (bcc) metals W, Mo depen- dence. The compressive size effect in Nb, as evaluated by the log­log slope of strength vs

  16. Cryogenic tensile, fatigue, and fracture parameters for a solution-annealed 18 percent nickel maraging steel

    Microsoft Academic Search

    R. L. Tobler; R. P. Reed; R. E. Schramm

    1978-01-01

    The mechanical properties of an eighteen percent nickel, solution-annealed 300-grade maraging steel were measured to assist in the evaluation of this material for low-temperature structural applications. Tensile, fatigue-crack growth rate, and fracture toughness tests were performed in ambient air (295 K), liquid nitrogen (76 K), and liquid helium (4 K), with the following results: the yield strength of this material

  17. A review on the tensile properties of natural fiber reinforced polymer composites

    Microsoft Academic Search

    H. Ku; H. Wang; N. Pattarachaiyakoop; M. Trada

    2011-01-01

    This paper is a review on the tensile properties of natural fiber reinforced polymer composites. Natural fibers have recently become attractive to researchers, engineers and scientists as an alternative reinforcement for fiber reinforced polymer (FRP) composites. Due to their low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics, they are exploited as a replacement for

  18. Micro-tensile bond testing of resin cements to dentin and an indirect resin composite

    Microsoft Academic Search

    Yiu-Fai Mak; Shirley C. N Lai; Gary S. P Cheung; Alex W. K Chan; Franklin R Tay; David H Pashley

    2002-01-01

    Objectives: Micro-tensile bond strength (?TBS) evaluation and fractographic analysis were used to compare four resin cement systems (AC: All-Bond 2\\/Choice; RX: Single Bond\\/RelyX ARC; SB: Super-Bond C&B; and PF: Panavia F) in indirect composite\\/dentin adhesive joints.Methods: Flat dentin surfaces were created on extracted human third molars. The resin cements were used according to the manufacturers' instructions for bonding silanized composite

  19. The elevated temperature tensile properties of S-200E commercially pure beryllium

    SciTech Connect

    Henshall, G.A.; Torres, S.G.; Hanafee, J.E.

    1995-03-01

    Experiments were performed at 300-100 C in longitudinal and transverse orientations at quasi-static strain rate 5.5 {times} 10{sup {minus}4}s{sup {minus}1}. Results show that the stress-strain curve is smooth, without yield points or serrations. Yield stress and ultimate tensile stress decrease monotonically with temperature. Similar strengths were measured for both orientations. Failure elongation vs temperature is complex.

  20. Mechanical performance of thin-walled tubular composite elements under uniaxial loading part 1: tensile behavior

    Microsoft Academic Search

    H. Levi; O. Ishai; E. Altus; I. Sheinman

    1995-01-01

    Filament wound thin-wall CFRP and GFRP composite tubes were tested under uniaxial (longitudinal) tensile loading up to failure. Elastic and strength properties as well as failure mechanisms were evaluated as related to the wall lay-up configuration. Angle-ply lay-ups of different (± ?)n orientations were compared with tubes having the same thickness but where internal and external ? plies were replaced

  1. Experimental determination of probabilistic edge-delamination strength of a graphite–fiber\\/epoxy composite

    Microsoft Academic Search

    Xiang-Fa Wu; Yuris A. Dzenis

    2005-01-01

    Probabilistic edge-delamination strength of a thermosetting polymer composite was studied experimentally in this work. During the procedure, by means of edge-delamination tensile test, the graphite–fiber\\/epoxy laminate made of unidirectional Toray P7051S-20Q-1000 prepregs with an optimized lay-up of [122\\/–122\\/02]S was used for examining its probabilistic distributions of the edge-delamination onset stress and the ultimate tensile strength. Acoustic emission (AE) equipment and

  2. Tensile testing of bone over a wide range of strain rates: effects of strain rate, microstructure and density

    Microsoft Academic Search

    T. M. Wrightt; W. C. Hayes

    1976-01-01

    Uniaxial tensile tests were performed on standardised longitudinal specimens of bovine compact bone at strain rates from 5·3×10?4 to 237 s?1. After testing, the microstructure and dry density of each specimen was determined. The test results demonstrated highly\\u000a significant (P<0·01) positive correlations between ultimate strength and strain rate, and between ultimate strength and density.\\u000a A highly significant negative correlation between

  3. Development of AFM tensile test technique for evaluating mechanical properties of sub-micron thick DLC films

    Microsoft Academic Search

    Yoshitada Isono; Takahiro Namazu; Nobuyuki Terayama

    2006-01-01

    This paper describes mechanical properties of submicron thick diamond-like carbon (DLC) films used for surface modification in MEMS devices. A new compact tensile tester operating under an atomic force microscope (AFM) is developed to measure Young's modulus, Poisson's ratio and fracture strength of single crystal silicon (SCS) and DLC coated SCS (DLC\\/SCS) specimens. DLC films with a thickness ranging from

  4. Opposite risk patterns for autism and schizophrenia are associated with normal variation in birth size: phenotypic support for hypothesized diametric gene-dosage effects.

    PubMed

    Byars, Sean G; Stearns, Stephen C; Boomsma, Jacobus J

    2014-11-01

    Opposite phenotypic and behavioural traits associated with copy number variation and disruptions to imprinted genes with parent-of-origin effects have led to the hypothesis that autism and schizophrenia share molecular risk factors and pathogenic mechanisms, but a direct phenotypic comparison of how their risks covary has not been attempted. Here, we use health registry data collected on Denmark's roughly 5 million residents between 1978 and 2009 to detect opposing risks of autism and schizophrenia depending on normal variation (mean ± 1 s.d.) in adjusted birth size, which we use as a proxy for diametric gene-dosage variation in utero. Above-average-sized babies (weight, 3691-4090 g; length, 52.8-54.3 cm) had significantly higher risk for autism spectrum (AS) and significantly lower risk for schizophrenia spectrum (SS) disorders. By contrast, below-average-sized babies (2891-3290 g; 49.7-51.2 cm) had significantly lower risk for AS and significantly higher risk for SS disorders. This is the first study directly comparing autism and schizophrenia risks in the same population, and provides the first large-scale empirical support for the hypothesis that diametric gene-dosage effects contribute to these disorders. Only the kinship theory of genomic imprinting predicts the opposing risk patterns that we discovered, suggesting that molecular research on mental disease risk would benefit from considering evolutionary theory. PMID:25232142

  5. Dynamic-Tensile-Extrusion of Polyurea

    NASA Astrophysics Data System (ADS)

    Furmanski, Jevan; Cady, Carl; Rae, Philip; Trujillo, Carl; Gray, G. T., III; Brown, Eric

    2011-06-01

    Polyurea was investigated under Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) loading where spherical projectiles were propelled at 440-509 m/s through an extrusion die with an area reduction of 87%. Momentum of the leading edge imposes a rapid tensile deformation on the extruding material. Polyurea is an elastomer with outstanding high-rate tensile performance of interest in the shock regime. Previous Dyn-Ten-Ext work on semi-crystalline polymers (PTFE, PCTFE) resulted in small-scale fragmentation of the polymer, and did not provide clear information on the evolution of tensile damage in those materials. The polyurea behaved very differently; the polymer first extruded a jet of apparently intact material, which then broke down via void formation and coalescence, followed by fibrillation and tearing of the material. Most of the material in the jet elastically retracted back into the die, and only a few fragments of torn material were liberated from the sample. The surface texture of all failed surfaces was rough indicating a considerable amount of energy was absorbed by sub-critical failure mechanisms. It is interesting to note that while damage nucleation appeared pervasive in the extruded jet, the samples were nevertheless recovered largely intact, with limited fragmentation.

  6. Anisotropic parameter identification using inhomogeneous tensile test

    Microsoft Academic Search

    A. Khalfallah; H. Bel Hadj Salah; A. Dogui

    2002-01-01

    In this contribution, an inverse identification strategy of constitutive laws for elastoplastic behaviour is presented. The proposed inverse algorithm is composed on an appropriate finite element calculation combined with an optimisation procedure. It is applied to identify material anisotropic coefficients using a set up of easy performed laboratory tests. The used experimental data are the plane tensile test and the

  7. Ensuring the strength of rolled metal

    SciTech Connect

    Belen`kii, D.M.; Beskopyl`nyi, A.N. [State Academy of Construction, Rostov-on-Don (Russian Federation)

    1995-02-01

    A new approach to ensuring the strength of a material is considered. Strength is considered as the unity of the stress-strain state resulting from external factors and the material resistance to this state. The material resistance is characterized by the random vector of mechanical properties determined by tensile impact toughness, fatigue, crack resistance, etc. testings. The method of impact indentation of a conical indenter in the material and recording of the parameters of the impact indentation curve is proposed to determine this vector. This principle is used to develop equipment allowing the determination of the mechanical properties of steels.

  8. Tensile Properties, Collagen Content, and Crosslinks in Connective Tissues of the Immature Knee Joint

    PubMed Central

    Athanasiou, Kyriacos A.

    2011-01-01

    Background The major connective tissues of the knee joint act in concert during locomotion to provide joint stability, smooth articulation, shock absorption, and distribution of mechanical stresses. These functions are largely conferred by the intrinsic material properties of the tissues, which are in turn determined by biochemical composition. A thorough understanding of the structure-function relationships of the connective tissues of the knee joint is needed to provide design parameters for efforts in tissue engineering. Methodology/Principal Findings The objective of this study was to perform a comprehensive characterization of the tensile properties, collagen content, and pyridinoline crosslink abundance of condylar cartilage, patellar cartilage, medial and lateral menisci, cranial and caudal cruciate ligaments (analogous to anterior and posterior cruciate ligaments in humans, respectively), medial and lateral collateral ligaments, and patellar ligament from immature bovine calves. Tensile stiffness and strength were greatest in the menisci and patellar ligament, and lowest in the hyaline cartilages and cruciate ligaments; these tensile results reflected trends in collagen content. Pyridinoline crosslinks were found in every tissue despite the relative immaturity of the joints, and significant differences were observed among tissues. Notably, for the cruciate ligaments and patellar ligament, crosslink density appeared more important in determining tensile stiffness than collagen content. Conclusions/Significance To our knowledge, this study is the first to examine tensile properties, collagen content, and pyridinoline crosslink abundance in a direct head-to-head comparison among all of the major connective tissues of the knee. This is also the first study to report results for pyridinoline crosslink density that suggest its preferential role over collagen in determining tensile stiffness for certain tissues. PMID:22022553

  9. Quantitative fractographic analysis of variability in the tensile ductility of high-pressure die-cast AE44 Mg-alloy

    Microsoft Academic Search

    S. G. Lee; G. R. Patel; A. M. Gokhale; A. Sreeranganathan; M. F. Horstemeyer

    2006-01-01

    Cast magnesium alloys often exhibit large variability in fracture related mechanical properties such as ductility and strength. In this contribution, the variability in the tensile ductility of individually cast tensile test specimens of high-pressure die-cast AE44 Mg-alloy is examined at room temperature and at 394K. Significant specimen-to-specimen variations in the ductility are observed at both temperatures. The variability in the

  10. Acoustic emission monitoring of tensile testing of corroded and un-corroded clad aluminum 2024-T3 and characterization of effects of corrosion on AE source events and material tensile properties

    NASA Astrophysics Data System (ADS)

    Okafor, A. Chukwujekwu; Natarajan, Shridhar

    2014-02-01

    Corrosion damage affects structural integrity and deteriorates material properties of aluminum alloys in aircraft structures. Acoustic Emission (AE) is an effective nondestructive evaluation (NDE) technique for monitoring such damages and predicting failure in large structures of an aircraft. For successful interpretation of data from AE monitoring, sources of AE and factors affecting it need to be identified. This paper presents results of AE monitoring of tensile testing of corroded and un-corroded clad Aluminum 2024-T3 test specimens, and characterization of the effects of strain-rate and corrosion damage on material tensile properties and AE source events. Effect of corrosion was studied by inducing corrosion in the test specimens by accelerated corrosion testing in a Q-Fog accelerated corrosion chamber for 12 weeks. Eight (8) masked dog-bone shaped specimens were placed in the accelerated corrosion chamber at the beginning of the test. Two (2) dog-bone shaped specimens were removed from the corrosion chamber after exposure time of 3, 6, 9, and 12 weeks respectively, and subjected to tension testing till specimen failure along with AE monitoring, as well as two (2) reference samples not exposed to corrosion. Material tensile properties (yield strength, ultimate tensile strength, toughness, and elongation) obtained from tension test and AE parameters obtained from AE monitoring were analyzed and characterized. AE parameters increase with increase in exposure period of the specimens in the corrosive environment. Aluminum 2024-T3 is an acoustically silent material during tensile deformation without any damage. Acoustic emission events increase with increase of corrosion damage and with increase in strain rate above a certain value. Thus AE is suitable for structural health monitoring of corrosion damage. Ultimate tensile strength, toughness and elongation values decrease with increase of exposure period in corrosion chamber.

  11. Bounds on the Strength Distribution of Unidirectional Fiber Composites

    SciTech Connect

    Mahesh, S.; Beyerlein, I.J.; Phoenix, S.L.

    1999-06-13

    Failure mechanisms under tensile loading of unidirectional fiber composites comprising of Weibull fibers embedded in a matrix are studied using Monte-Carlo simulations. Two fundamental mechanisms of failure are recognized--stress concentration driven failure and strength driven failure. It is shown that the cumulative distribution function for composite strength predicted by the stressconcentration-driven failure and strength-driven failure form apparent upper and lower bounds respectively and also that failure mechanism switches from one to the other as fiber strength variability changes.

  12. Designing tensile ductility in metallic glasses

    PubMed Central

    Sarac, Baran; Schroers, Jan

    2013-01-01

    Effectiveness of a second phase in metallic glass heterostructures to improve mechanical properties varies widely. Unfortunately, methods to fabricate such heterostructures like foams and composites do not allow controlled variation of structural features. Here we report a novel strategy, which allows us to vary heterostructural features independently, thereby enabling a systematic and quantitative study. Our approach reveals the optimal microstructural architecture for metallic glass heterostructures to achieve tensile ductility. Critical design aspect is a soft second phase, which is most effective when spacing between the second phase assumes the critical crack length of the metallic glass. This spacing should coincide with the second phase’s size, and beyond, the specific second phase morphology of the heterostructure is crucial. These toughening strategies are only effective in samples that are large compared with the spacing of the second phase. The identified design aspects provide guidance in designing tensile ductility into metallic glasses. PMID:23863967

  13. Improving wet and dry strength properties of recycled old corrugated carton (OCC) pulp using various polymers.

    PubMed

    Hamzeh, Yahya; Sabbaghi, Sanaz; Ashori, Alireza; Abdulkhani, Ali; Soltani, Farshid

    2013-04-15

    In this study, the application of different dosages of low and high molecular weights (MW) of chitosan (Ch), cationic starch (CS) and poly vinyl alcohol (PVA) were systematically investigated using old corrugated carton (OCC) furnishes. Various sequences of above-mentioned polymeric additives were also examined to find out the optimal combination for improving both wet and dry tensile strength. For each treatment, 4 handsheets, each having basis weight of 100 g/m(2), were made. In general, the tensile strength of handsheets was significantly affected by the addition of polymeric agents. The enhancing effect of additives on dry tensile property was much higher than wet condition. The results also showed that the tensile strength of the samples made from OCC furnishes were improved upon the addition of high molecular weight chitosan (ChI) compared to the untreated ones (control). The low MW chitosan did not change the properties of handsheets dramatically. Application of polymeric agents moderately decreased the stretch to rupture, however with increasing dosage the stretch was improved. Sequential addition of used polymers showed that triple application of polymers was beneficial to both dry and wet tensile strength, although the effect was larger for dry. The best results in wet and dry tensile strengths were achieved using sequential of PVA-ChI-CS. Sequential addition of oppositely charged polymers forms a macromolecular layered structure of polyelectrolytes. PMID:23544577

  14. Tensile properties of commercially pure vanadium from room temperature to 1200{degree}C

    SciTech Connect

    Henshall, G.A.; Torres, S.G.

    1993-12-01

    The tensile properties of vanadium are sensitive to interstitial impurity content, on grain size and strain rate. Thus, it is problematic to use published tensile data for materials potentially varying in these quantities. This investigation was undertaken to fully characterize the tensile properties of the commercially pure vanadium used at Lawrence Livermore. Both sheet and rod stock were tested in vacuum from ambient temperature to 1200C at strain rates 6.67 {times} 10{sup {minus}5} to 6.67 {times} 10{sup {minus}2} s{sup {minus}1}. The results of these experiments show that vanadium behaves in a manner typical of many bcc metals containing interstitial impurities. Local peaks in yield stress and ultimate tensile stress vs temperature curves are observed at intermediate temperatures. Serrated yielding also is observed in some temperature ranges. Changes in strain rate within the quasi-static regime have a relatively small, predictable effect. The rod and sheet stock have similar properties, except that the lower yield stress of the rod is less than that of the sheet over most of the temperature range studied. No plateau in yield strength vs temperature curve was observed for the rod. In both forms, and for all temperatures, vanadium is ductile. The elongation to failure reaches a minimum of approximately 35% at a temperature of 500C and a maximum of approximately 140% at 1200C.

  15. Strength evaluation test of pressureless-sintered silicon nitride at room temperature

    NASA Technical Reports Server (NTRS)

    Matsusue, K.; Takahara, K.; Hashimoto, R.

    1984-01-01

    In order to study strength characteristics at room temperature and the strength evaluating method of ceramic materials, the following tests were conducted on pressureless sintered silicon nitride specimens: bending tests, the three tensile tests of rectangular plates, holed plates, and notched plates, and spin tests of centrally holed disks. The relationship between the mean strength of specimens and the effective volume of specimens are examined using Weibull's theory. The effect of surface grinding on the strength of specimens is discussed.

  16. Effect of fiber-matrix interfacial shear strength on reliability of composite materials

    Microsoft Academic Search

    ZHANJUN GAO

    1993-01-01

    An analytical methodology is presented to study the effects of fiber-matrix interfacial bonding strength on global failure and the reliability of graphite\\/epoxy composite laminates under general multidirectional loadings. It utilizes strength data of laminae, and a micromechanical model of unidirectional tensile strength which is verified by data in the literature on graphite\\/epoxy laminae with different interfacial strengths (AU-4\\/828, AS-4\\/828, and

  17. Tensile superplasticity in a nanocrystalline nickel aluminide

    Microsoft Academic Search

    R. S. Mishra; R. Z. Valiev; S. X. McFadden; A. K. Mukherjee

    1998-01-01

    Tensile superplasticity has been demonstrated in a nanocrystalline nickel aluminide processed by severe plastic deformation at 650–725°C and a strain rate of 1×10?3 s?1. The flow curves exhibit an unusually large strain hardening stage and very high flow stresses as compared to the flow stress of microcrystalline Ni3Al alloy of the same composition at typical superplastic strain rate and temperature.

  18. Hydration dependent viscoelastic tensile behavior of cornea.

    PubMed

    Hatami-Marbini, Hamed

    2014-08-01

    The cornea is a protective transparent connective tissue covering the front of the eye. The standard uniaxial tensile experiments are among the most popular techniques for investigating biomechanical properties of the cornea. This experimental method characterizes the stress-strain response of corneal strips immersed in a bathing solution. In the present study, the important roles of corneal hydration on tensile viscoelastic properties were investigated. The thickness was used as a surrogate for hydration and uniaxial tensile experiments were performed on bovine corneal samples with four different average thickness (hydration), i.e., 1100 ?m (4.87 mg water/mg dry tissue), 900 ?m (4.13 mg water/mg dry tissue), 700 ?m (3.20 mg water/mg dry tissue), and 500 ?m (1.95 mg water/mg dry tissue). The samples were immersed in mineral oil in order to prevent their swelling during the experiments. A quasilinear viscoelastic (QLV) model was used to analyze the experimental measurements and determine viscoelastic material constants. It was observed that both maximum and equilibrium (relaxed) stresses were exponentially increased with decreasing tissue thickness (hydration). Furthermore, the QLV model successfully captured the corneal viscoelastic response with an average R (2) value greater than 0.99. Additional experiments were conducted in OBSS in order to confirm that these significant changes in viscoelastic properties were because of corneal hydration and not the bathing solution. The findings of this study suggest that extra care must be taken in interpreting the results of earlier uniaxial tensile testings and their correspondence to the corneal biomechanical properties. PMID:24668183

  19. Technique for tensile creep testing of ceramics

    Microsoft Academic Search

    Daniel F. Carroll; S. M. Wiederhom; D. E. Roberts

    1989-01-01

    An experimental technique for measuring tensile creep deformation in ceramic materials to temperatures of 1500°C is described. The technique uses simple flat dog-bone-shaped specimens and a hot-grip design for the loading fixture, which provide good alignment at minimum cost. Creep deformation is measured using laser extensometry to monitor the relative displacement of flags that are attached to the gauge section

  20. Dynamic-tensile-extrusion of polyurea

    NASA Astrophysics Data System (ADS)

    Furmanski, Jevan; Cady, Carl; Rae, Philip; Trujillo, Carl P.; Gray, George Thompson, III; Brown, Eric

    2012-03-01

    Polyurea was investigated under Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) loading where spherical projectiles were propelled at 440 to 509 ms-1 through a conical extrusion die with an area reduction of 87%. Momentum of the leading edge imposes a rapid tensile deformation on the extruded jet of material. Polyurea is an elastomer with outstanding high-rate tensile performance of interest in the shock regime. Previous Dyn-Ten-Ext work on semi-crystalline fluoropolymers (PTFE, PCTFE) elucidated irregular deformation and profuse stochastic-based damage and failure mechanisms, but with limited insight into damage inception or progression in those polymers. The polyurea behaved very differently; the polymer first extruded a jet of apparently intact material, which then broke down via void coalescence, followed by fibrillation and tearing of the material. Most of the material in the jet elastically retracted back into the die, and only a few unique fragments were formed. The surface texture of all failed surfaces was found to be tortuous and covered with drawn hair-like filaments, implying a considerable amount of energy was absorbed during damage progression.

  1. Tensile Stress-Strain Results for 304L and 316L Stainless-Steel Plate at Temperature

    SciTech Connect

    R. K. Blandford; D. K. Morton; S. D. Snow; T. E. Rahl

    2007-07-01

    The Idaho National Laboratory (INL) is conducting moderate strain rate (10 to 200 per second) research on stainless steel materials in support of the Department of Energy’s (DOE) National Spent Nuclear Fuel Program (NSNFP). For this research, strain rate effects are characterized by comparison to quasi-static tensile test results. Considerable tensile testing has been conducted resulting in the generation of a large amount of basic material data expressed as engineering and true stress-strain curves. The purpose of this paper is to present the results of quasi-static tensile testing of 304/304L and 316/316L stainless steels in order to add to the existing data pool for these materials and make the data more readily available to other researchers, engineers, and interested parties. Standard tensile testing of round specimens in accordance with ASTM procedure A 370-03a were conducted on 304L and 316L stainless-steel plate materials at temperatures ranging from -20 °F to 600 °F. Two plate thicknesses, eight material heats, and both base and weld metal were tested. Material yield strength, Young’s modulus, ultimate strength, ultimate strain, failure strength and failure strain were determined, engineering and true stress-strain curves to failure were developed, and comparisons to ASME Code minimums were made. The procedures used during testing and the typical results obtained are described in this paper.

  2. New tungsten alloy has high strength at elevated temperatures

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Tungsten-hafnium-carbon alloy has tensile strengths of 88,200 psi at 3000 deg F and 62,500 psi at 3500 deg F. Possible industrial applications for this alloy would include electrical components such as switches and spark plugs, die materials for die casting steels, and heating elements.

  3. Residual stress modification by post-weld treatment and its beneficial effect on fatigue strength of welded structures

    Microsoft Academic Search

    Xiaohua Cheng; John W. Fisher; Henry J. Prask; Thomas Gnäupel-Herold; Ben T. Yen; Sougata Roy

    2003-01-01

    High tensile weld residual stress is one important factor contributing to fatigue crack development even under reversal or compressive cyclic loadings. A compressive stress induced by post-weld treatment is beneficial by eliminating the tensile residual stresses and generating compressive residual stresses, which improves fatigue strength of welded structures. A study is underway to characterize the magnitude and subsurface distribution of

  4. Tensile and impact properties of candidate alloys for high-temperature gas-cooled reactor applications

    SciTech Connect

    Bruch, U.; te Heesen, E.; Ennis, F.J.; Schuhmacher, D.

    1984-08-01

    The tensile properties of solution-treated Incoloy alloy 800H, Hastelloy-X, Nimonic-86, and Inconel-617 have been determined in the temperature range 20 to 1000/sup 0/C. The strength parameters at temperatures above 700/sup 0/C showed a strong dependence on the strain rate; at low strain rates the deformation was dominated by creep effects, the strain rate and maximum stress being related by the Norton creep equation. The tensile and impact properties of the alloys were also determined after exposure at 700 to 1000/sup 0/C for up to 30 000 h. For Incoloy-800H, the results showed good retention of ductility and impact strength. The nickel-base alloys, in contrast, were found to have low room-temperature impact resistance after long time exposure at 700 to 900/sup 0/C, typical values being 10 to 20 J x cm/sup -2/. In impact tests at the exposure temperature, impact strengths were generally above 50 J x cm/sup -2/. At room temperature, allowances in design must be made for the low impact strength of the nickel-base alloys to ensure against brittle fracture. For example, excessive stresses during cooling of components following shutdown should be avoided.

  5. Considerations about the theoretically expected crushing strength of tablets from binary powder mixtures: double layer tablets versus arithmetic additivity rule.

    PubMed

    Belda, Petra M; Mielck, Jobst B

    2006-11-01

    The theoretically expected breaking strength of tablets from powder mixtures is often calculated by the weighted arithmetic mean from the breaking strength of the single components, which corresponds to a linear interpolation. The validity of this additivity of fracture strength shall be evaluated by the underlying model of parallel couplings. It assumes the components linked in parallel with respect to the direction of loading during diametrical strength testing. Parallel couplings were experimentally realised by the preparation of double layer tablets from crystalline and spray-dried lactose on the one hand and from maltitol and metamizol-sodium on the other. Constant total true volumes of the single substances and of layered powders in varying ratios of true volume were compressed on an eccentric tabletting machine to constant geometric mean punch force. Simulated crushing profiles of parallel couplings were derived from force-displacement profiles measured during diametrical compression of the one-component tablets. At given finely graded deformation levels, the forces exerted by the components during loading were added in the proportion of the true volume fractions of the components in the coupling. The results from the experiments and from the simulations are in good accordance. They demonstrate that a linear change of the crushing strength in dependence on the true volume fraction of the components can only be assumed if the single components deform to the same extent up to the point of fracture. This behaviour was approximately found with the parallel lactose system. In all other cases it must be expected that the crushing strength of parallel systems will be lowered beneath the weighted arithmetic mean values or even below the crushing strength of the single components. The latter was observed with the maltitol-metamizol combinations. Thus, if tablets from binary powder mixtures exhibit a crushing strength depression, this is not necessarily an indication of weak bonding between the components or of structural defects. PMID:16914296

  6. Effect of temperature on the shear strength of aluminium single lap bonded joints for high temperature applications

    Microsoft Academic Search

    M. D. Banea; L. F. M. da Silva; R. D. S. G. Campilho

    2012-01-01

    An experimental and numerical investigation into the shear strength behaviour of adhesive single lap joints (SLJs) was carried out in order to understand the effect of temperature on the joint strength. The adherend material used for the experimental tests was an aluminium alloy in the form of thin sheets, and the adhesive used was a high-strength high temperature epoxy. Tensile

  7. Fatigue strength of transverse butt welded joints under random loading. Application of Miner's rule in ?max = ?y tests

    Microsoft Academic Search

    A. Ota; Y. Maeda; N. Suzuki

    1997-01-01

    The fatigue strength of transverse butt welded joints is obtained in tests involving the maximum stress ?max being kept the same as the yield strength of the material ?y while the minimum stress ?min is randomly varied. The tests involve modification of the stress conditions of actual welded structures containing high tensile residual stress up to the yield strength. The

  8. Strength loss in MA-MOX green pellets from radiation damage to binders

    NASA Astrophysics Data System (ADS)

    Lessing, Paul A.; Cannon, W. Roger; Egeland, Gerald W.; Zuck, Larry D.; Jewell, James K.; Akers, Douglas W.; Groenewold, Gary S.

    2013-06-01

    The fracture strength of green Minor Actinides (MA)-MOX pellets containing 75 wt.% DUO2, 20 wt.% PuO2, 3 wt.% AmO2 and 2 wt.% NpO2 was studied as a function of storage time, after mixing with the binder and before sintering, to test the effect of radiation damage on binders. Fracture strength degraded continuously over the 10 days of the study for all three binders studied: PEG binder (Carbowax 8000), microcrystalline wax (Mobilcer X) and styrene-acrylic copolymer (Duramax B1022) but the fracture strength of Duramax B1022 degraded the least. For instance, for several hours after mixing Carbowax 8000 with MA-MOX, the fracture strength of a pellet was reasonably high and pellets were easily handled without breaking but the pellets were too weak to handle after 10 days. Strength measured using diametral compression test showed that strength degradation was more rapid in pellets containing 1.0 wt.% Carbowax PEG 8000 compared to those containing only 0.2 wt.%, suggesting that irradiation not only left the binder less effective but also reduced the pellet strength. In contrast the strength of pellets containing Duramax B1022 degraded very little over the 10 days period. It was suggested that the styrene portion present in the Duramax B1022 copolymer provided the radiation resistance.

  9. Effect of plastic anisotropy on the creep strength of single crystals of a nickel-based superalloy

    SciTech Connect

    Kakehi, Koji

    2000-02-01

    The effect of plastic anisotropy, which is caused by the arrangement of slip systems, on the creep strength of notched specimens of Ni-based superalloy single crystals, is described. It was revealed that the creep strength of the notched specimens was affected by the crystallographic orientation, not only in the tensile direction, but also in the thickness direction. The creep strength was superior in the notched specimen with the [011] tensile and [01{bar 1}] plate-normal orientation, whereas the notched specimen with [011] tensile and [100] plate-normal orientation exhibited extremely poor creep strength. In the case of specimens whose tensile orientation was [011], results of the creep-rupture tests at 973 K were in agreement with the assumption of the operation of {l{underscore}brace}111{r{underscore}brace}{l{underscore}angle}112{r{underscore}angle} slip systems. The creep strength in the notched specimen with [001] tensile and [100] plate-normal orientations was superior to that in the notched specimen with [001] tensile and [011] plate-normal orientations. When the tensile orientation was [001], the results of the creep-rupture tests were in agreement with the assumption of the operation of {l{underscore}brace}111{r{underscore}brace}{l{underscore}angle}112{r{underscore}angle} slip systems during primary creep region and {l{underscore}brace}111{r{underscore}brace}{l{underscore}angle}101{r{underscore}angle} slip systems during secondary creep region.

  10. Effect of formation and state of interface on joint strength in friction stir spot welding for advanced high strength steel sheets

    NASA Astrophysics Data System (ADS)

    Taniguchi, Koichi; Matsushita, Muneo; Ikeda, Rinsei; Oi, Kenji

    2014-08-01

    The tensile shear strength and cross tension strength of friction stir spot welded joints were evaluated in the cases of lap joints of 270 N/mm2 grade and 980 N/mm2 grade cold rolled steel sheets with respect to the stir zone area, hardness distribution, and interface condition between the sheets. The results suggested that both the tensile shear strength and cross tension strength were based on the stir zone area and its hardness in both grades of steel. The "hook" shape of the interface also affected the joint strength. However, the joining that occurred across the interfaces had a significant influence on the value of the joint strength in the case of the 270 N/mm2 grade steel.

  11. Dynamic tensile response of a carbon-fiber-reinforced LCP composite and its temperature sensitivity

    NASA Astrophysics Data System (ADS)

    Shim, Victor P. W.; Yuan, J.; Lim, C. T.

    2001-06-01

    The tensile mechanical behavior of a short carbon fiber filled liquid crystalline polymer (LCP) composite, Vectra A230, was examined under static extension and dynamic loading at three temperatures. Dynamic tension was applied using a pendulum-type tensile spilt Hopkinson bar device. Specimens fabricated according to both the mould flow and transverse directions were tested. The stress-strain curves at various strain rates and temperatures were determined and found to be sensitive to strain rate as well as temperature for both types of specimens. With reference to the properties of pure LCP, mechanical anisotropy and fiber reinforcement effects were characterized and are discussed. Failed specimens were observed suing an optical microscope. Deformation and failure mechanisms in the microstructure of the LCP composite were studied to understand the effects of strain rate and temperature on material strength and failure strain.

  12. Dynamic tensile fracture of mortar at ultra-high strain-rates

    SciTech Connect

    Erzar, B., E-mail: benjamin.erzar@cea.fr; Buzaud, E.; Chanal, P.-Y. [CEA, DAM, GRAMAT, F-46500 Gramat (France)

    2013-12-28

    During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 10{sup 4} to 4 × 10{sup 4}?s{sup ?1}. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of this cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.

  13. Dynamic tensile fracture of mortar at ultra-high strain-rates

    NASA Astrophysics Data System (ADS)

    Erzar, B.; Buzaud, E.; Chanal, P.-Y.

    2013-12-01

    During the lifetime of a structure, concrete and mortar may be exposed to highly dynamic loadings, such as impact or explosion. The dynamic fracture at high loading rates needs to be well understood to allow an accurate modeling of this kind of event. In this work, a pulsed-power generator has been employed to conduct spalling tests on mortar samples at strain-rates ranging from 2 × 104 to 4 × 104 s-1. The ramp loading allowed identifying the strain-rate anytime during the test. A power law has been proposed to fit properly the rate-sensitivity of tensile strength of this cementitious material over a wide range of strain-rate. Moreover, a specimen has been recovered damaged but unbroken. Micro-computed tomography has been employed to study the characteristics of the damage pattern provoked by the dynamic tensile loading.

  14. Effect of surface nanostructure on tensile and low cycle fatigue behavior of Al 2014 alloy

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, K.; Pandey, V.; Srinivas, N. C. S.; Singh, V.

    2014-08-01

    Aluminium alloy 2014 is an important age hardening alloy for aerospace industries. Effect of ultrasonic shot peening (USSP) in peak aged condition of this alloy was studied on its surface microstructure, tensile properties and low cycle fatigue behavior. The structure of the USSP treated specimens, close to surface was characterized by X-ray diffraction and transmission electron microscopy. The top surface region was found to contain nanosize grains of ~30 nm. Both yield as well as tensile strength was found to increase progressively with increasing duration of shot peening for 10, 15 and 20 minutes. LCF behavior was studied following ultrasonic shot peening for 10 minutes, at three total strain amplitudes (??t/2) of ±0.4%, ±0.5% and ±0.6%.

  15. Effect of Chemical Treatments on Flax Fibre Reinforced Polypropylene Composites on Tensile and Dome Forming Behaviour

    PubMed Central

    Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

    2015-01-01

    Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

  16. Effect of chemical treatments on flax fibre reinforced polypropylene composites on tensile and dome forming behaviour.

    PubMed

    Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

    2015-01-01

    Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

  17. Tensile Properties of 17-7 PH and 12 MoV Stainless-Steel Sheet under Rapid-Heating and Constant-Temperature Conditions

    NASA Technical Reports Server (NTRS)

    Manning, Charles R., Jr.; Price, Howard L.

    1961-01-01

    Results are presented of rapid-heating tests of 17-7 PH and 12 MoV stainless-steel sheet heated to failure at temperature rates from about 1 F to 170 F per second under constant-load conditions. Yield and rupture strengths obtained from rapid-heating tests are compared with yield and tensile strengths obtained from short-time elevated-temperature tensile tests (30-minute exposure). A rate-temperature parameter was used to construct master curves from which yield and rupture stresses or temperatures can be predicted. A method for measuring strain by optical means is described.

  18. Application of Strength Diagnosis.

    ERIC Educational Resources Information Center

    Newton, Robert U.; Dugan, Eric

    2002-01-01

    Discusses the various strength qualities (maximum strength, high- and low-load speed strength, reactive strength, rate of force development, and skill performance), noting why a training program design based on strength diagnosis can lead to greater efficacy and better performance gains for the athlete. Examples of tests used to assess strength

  19. Effects of La addition on the microstructure and tensile properties of Al-Si-Cu-Mg casting alloys

    NASA Astrophysics Data System (ADS)

    Lu, Tao; Pan, Ye; Wu, Ji-li; Tao, Shi-wen; Chen, Yu

    2015-04-01

    The effects of La addition on the microstructure and tensile properties of B-refined and Sr-modified Al-11Si-1.5Cu-0.3Mg casting alloys were investigated. With a trace addition of La (0.05wt%-0.1wt%), the mutual poisoning effect between B and Sr can be neutralized by the formation of LaB6 rather than SrB6. By employing a La/B weight ratio of 2:1, uniform microstructures, which are characterized by well refined ?-Al grains and adequately modified eutectic Si particles as well as the incorporation of precipitated strengthening intermetallics, are obtained and lead to appreciable tensile properties with an ultimate tensile strength of 270 MPa and elongation of 5.8%.

  20. Stress-rupture life and strength retention of an aramid fiber\\/epoxy composite under accelerating conditions

    Microsoft Academic Search

    L. Penn; R. J. Sherry

    1977-01-01

    The long-term tensile strength retention of Kevlar 49 (aramid fiber)\\/epoxy composite under sustained loading at 56.4 percent of the ultimate fiber tensile strength (3400 MPa) was studied to evaluate the lifetime to failure of the composite under the same load level. To obtain data in a conveniently short time, elevated temperature was used according to an acceleration relation (Arrhenius type)

  1. EVALUATIONS OF EFFECT OF UOâ ON THE CORE STRENGTH OF STAINLESS STEEL FUEL ELEMENTS (TASK 7306)

    Microsoft Academic Search

    Funston

    1952-01-01

    A test procedure was established for evaluating the core strength of ; stainless steel fuel elements at temperatures to 1800 deg F. This evaluation, ; known as a transverse rupture test, measures the short time tensile stress ; required to rupture a specimen in a plane parallel to the surface of the sheet. ; The strength of commercial 309 stainless

  2. Concrete breakout strength of single anchors in tension using neural networks

    Microsoft Academic Search

    A. F. Ashour; M. A. Alqedra

    2005-01-01

    A feed forward neural network model for evaluating the concrete breakout strength of single cast-in and post-installed mechanical anchors in tension is presented. The nodes of the neural network input layer represent the embedment depth, anchor head diameter, concrete strength and anchor installation system, and the neural network output is the tensile capacity of anchors as governed by the concrete

  3. The determination of the mechanical strength of tablets of different shapes

    Microsoft Academic Search

    Peter N. Davies; Harry E. C. Worthington; Fridrun Podczeck; J. Michael Newton

    2007-01-01

    The aim of the study was to investigate the influence of the platen design, on the evaluation of the mechanical strength of tablets of different shapes in terms of the potential of ensuring reproducible failure mechanisms and deriving their tensile strength. Tablets which were circular, square or hexagonal in shape were prepared at a range of formation pressures each from

  4. Resistance of steel strength wires used in small fiber-optic cables to seawater corrosion

    Microsoft Academic Search

    Colin J. Sandwith; Robert L. Ruedisueli; Allan L. James; Gerald A. Gotthardt

    1996-01-01

    The corrosion rates of single strands of strength wire and the same wires assembled in small, fiber-optic cables with jacket damage that exposes the wire have been measured and used to predict the loss in wire and cable strength with time. The wires consisted of galvanized and ungalvanized extra improved plow steel. The results of laboratory measurements and of tensile

  5. Maintained ship hull xcgirxcder ultimate strength reliability considering corrosion and fatigue

    Microsoft Academic Search

    Yong Hu; Weicheng Cui; Preben Terndrup Pedersen

    2004-01-01

    The purpose of this paper is to propose a methodology to assess the time-variant ultimate strength of ship hull girder under the degradations of corrosion and fatigue. The effects of fatigue cracks on the tensile and compressive residual ultimate strength of stiffened panels and unstiffened plates are analyzed by an FE method. Based on FE analysis results, some empirical formulae

  6. Increasing strengths of boron fiber and graphite fiber plastic composites. Final report May--Dec 1971

    Microsoft Academic Search

    G. J. Mills; W. M. Wochos; G. G. Brown

    1971-01-01

    Prestressing of boron\\/epoxy prepreg tape material yields composites with substantial improvements in both average tensile strength and standard deviation over that obtained with conventional prepreg to laminate processing. The process has a fundamental effect on the prepreg fiber strength properties by prebreaking the fibers at their weak sites, and these induced changes are then carried into the composite as a

  7. Hydraulically Driven Grips For Hot Tensile Specimens

    NASA Technical Reports Server (NTRS)

    Bird, R. Keith; Johnson, George W.

    1994-01-01

    Pair of grips for tensile and compressive test specimens operate at temperatures up to 1,500 degrees F. Grips include wedges holding specimen inside furnace, where heated to uniform temperature. Hydraulic pistons drive wedges, causing them to exert clamping force. Hydraulic pistons and hydraulic fluid remain outside furnace, at room temperature. Cooling water flows through parts of grips to reduce heat transferred to external components. Advantages over older devices for gripping specimens in high-temperature tests; no need to drill holes in specimens, maintains constant gripping force on specimens, and heated to same temperature as that of specimen without risk of heating hydraulic fluid and acuator components.

  8. Actuator Exerts Tensile Or Compressive Axial Load

    NASA Technical Reports Server (NTRS)

    Nozzi, John; Richards, Cuyler H.

    1994-01-01

    Compact, manually operated mechanical actuator applies controlled, limited tensile or compressive axial force. Designed to apply loads to bearings during wear tests in clean room. Intended to replace hydraulic actuator. Actuator rests on stand and imparts axial force to part attached to clevis inside or below stand. Technician turns control screw at one end of lever. Depending on direction of rotation of control screw, its end of lever driven downward (for compression) or upward (for tension). Lever pivots about clevis pin at end opposite of control screw; motion drives downward or upward link attached via shearpin at middle of lever. Link drives coupling and, through it, clevis attached to part loaded.

  9. Influence of corrosion on brazed joints' strength.

    PubMed

    Angelini, E; Pezzoli, M; Rosalbino, F; Zucchi, F

    1991-02-01

    The influence of corrosion on the bond strength of different brazed joints commonly used in dentistry has been investigated by means of accelerated immersion tests in artificial saliva buffered at pH 2, and in Ringer's solution, both kept at 37 degrees C. Two Co-Cr base metal alloys were brazed with a gold and a non-precious alloy. After 60 days' immersion the tensile strength of the samples brazed with the gold alloy was dramatically reduced because of galvanic corrosion phenomena. The bond strength of the specimens brazed with the non-precious alloy was largely unaffected. Corrosion products rich in nickel were detected. The electrochemical characterization of the base metal alloys and brazing materials was performed by means of polarization curves in the two media investigated. High short circuit currents were only produced with the gold brazing materials. PMID:1673131

  10. Locking mechanism strength of absorbable ligating devices.

    PubMed

    Hay, D L; von Fraunhofer, J A; Chegini, N; Masterson, B J

    1988-03-01

    The locking mechanism strengths of the absorbable Absolok and Lactomer ligating clips and the absorbable Lactomer staple have been determined following implantation in an animal model. Three sizes of each type of clip and the single size of staple were enclosed in open mesh nylon pouches and implanted subcutaneously in rabbits for periods of 4, 7, 14, 21, and 28 days before tensile testing of the lock mechanisms. No change in the lock mechanism strength was detected for the Absolok clips before 21 days. The Lactomer clips and staples, however, showed significant decrease in lock mechanism strength within 7 days of implantation, this loss increasing with longer implantation times. A proportion of all the devices were found to have dissolved to an extent that precluded testing at 21 and 28 days. The findings indicate that the lock mechanisms of absorbable ligating clips differ significantly in their short-term (30 days) durability. PMID:3360813

  11. Shear strength properties of wet granular materials.

    PubMed

    Richefeu, Vincent; El Youssoufi, Moulay Saïd; Radjaï, Farhang

    2006-05-01

    We investigate shear strength properties of wet granular materials in the pendular state (i.e., the state where the liquid phase is discontinuous) as a function of water content. Sand and glass beads were wetted and tested in a direct shear cell and under various confining pressures. In parallel, we carried out three-dimensional molecular dynamics simulations by using an explicit equation expressing capillary force as a function of interparticle distance, water bridge volume, and surface tension. We show that, due to the peculiar features of capillary interactions, the major influence of water content over the shear strength stems from the distribution of liquid bonds. This property results in shear strength saturation as a function of water content. We arrive at the same conclusion by a microscopic analysis of the shear strength. We propose a model that accounts for the capillary force, the granular texture, and particle size polydispersity. We find fairly good agreement of the theoretical estimate of the shear strength with both experimental data and simulations. From numerical data, we analyze the connectivity and anisotropy of different classes of liquid bonds according to the sign and level of the normal force as well as the bond direction. We find that weak compressive bonds are almost isotropically distributed whereas strong compressive and tensile bonds have a pronounced anisotropy. The probability distribution function of normal forces is exponentially decreasing for strong compressive bonds, a decreasing power-law function over nearly one decade for weak compressive bonds, and an increasing linear function in the range of tensile bonds. These features suggest that different bond classes do not play the same role with respect to the shear strength. PMID:16802930

  12. TENSILE TESTING OF CARBON STEEL IN HIGH PRESSURE HYDROGEN

    SciTech Connect

    Duncan, A; Thad Adams, T; Ps Lam, P

    2007-05-02

    An infrastructure of new and existing pipelines and systems will be required to carry and to deliver hydrogen as an alternative energy source under the hydrogen economy. Carbon and low alloy steels of moderate strength are currently used in hydrogen delivery systems as well as in the existing natural gas systems. It is critical to understand the material response of these standard pipeline materials when they are subjected to pressurized hydrogen environments. The methods and results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. Tensile properties of one type of steel (A106 Grade B) in base metal, welded and heat affected zone conditions were tested at room temperature in air and high pressure (10.34 MPa or 1500 psig) hydrogen. A general reduction in the materials ability to plastically deform was noted in this material when specimens were tested in hydrogen. Furthermore, the primary mode of fracture was changed from ductile rupture in air to cleavage with secondary tearing in hydrogen. The mechanical test results will be applied in future analyses to evaluate service life of the pipelines. The results are also envisioned to be part of the bases for construction codes and structural integrity demonstrations for hydrogen service pipeline and vessels.

  13. Tensile Characterization of Porcine Temporomandibular Joint Disc Attachments

    PubMed Central

    Murphy, M.K.; Arzi, B.; Hu, J.C.; Athanasiou, K.A.

    2013-01-01

    The frequency and impact of temporomandibular joint (TMJ) disorders necessitate research in characterizing the joint’s function. The 6 discal attachments have not yet been systematically characterized under tension. Understanding their role in joint function may guide our study of TMJ pathologies, including disc displacement. In the present study, a porcine model was used to characterize the attachments in tension anteroposteriorly and mediolaterally, based on previously identified similarities in the porcine and human masticatory behaviors and discal properties. Tensile stiffness, strength, toughness, and maximum strain were quantified. Collagen alignment was characterized via polarized light and scanning electron microscopy. Anisotropy was demonstrated in all attachments, with the exception of the anterior inferior attachment. Anteroposteriorly, the lateral attachment was stiffest (8.3 MPa) and the anterior superior was least stiff (1.4 MPa). Mediolaterally, the posterior superior attachment was stiffest (16.3 MPa) and the medial was least stiff (1.4 MPa). The greatest strain was observed in the lateral attachment in the mediolateral direction and the posterior superior attachment in the anteroposterior direction. With greatest strains in the most commonly observed directions of disc displacement, it is suggested that compromise in the posterior and lateral attachments contributes to partial lateral and anterior disc displacement. PMID:23783320

  14. Finite element analysis of steel fiber-reinforced concrete (SFRC): validation of experimental tensile capacity of dog-bone specimens

    NASA Astrophysics Data System (ADS)

    Islam, Md. Mashfiqul; Chowdhury, Md. Arman; Sayeed, Md. Abu; Hossain, Elsha Al; Ahmed, Sheikh Saleh; Siddique, Ashfia

    2014-09-01

    Finite element analyses are conducted to model the tensile capacity of steel fiber-reinforced concrete (SFRC). For this purpose dog-bone specimens are casted and tested under direct and uniaxial tension. Two types of aggregates (brick and stone) are used to cast the SFRC and plain concrete. The fiber volume ratio is maintained 1.5 %. Total 8 numbers of dog-bone specimens are made and tested in a 1000-kN capacity digital universal testing machine (UTM). The strain data are gathered employing digital image correlation technique from high-definition images and high-speed video clips. Then, the strain data are synthesized with the load data obtained from the load cell of the UTM. The tensile capacity enhancement is found 182-253 % compared to control specimen to brick SFRC and in case of stone SFRC the enhancement is 157-268 %. Fibers are found to enhance the tensile capacity as well as ductile properties of concrete that ensures to prevent sudden brittle failure. The dog-bone specimens are modeled in the ANSYS 10.0 finite element platform and analyzed to model the tensile capacity of brick and stone SFRC. The SOLID65 element is used to model the SFRC as well as plain concretes by optimizing the Poisson's ratio, modulus of elasticity, tensile strength and stress-strain relationships and also failure pattern as well as failure locations. This research provides information of the tensile capacity enhancement of SFRC made of both brick and stone which will be helpful for the construction industry of Bangladesh to introduce this engineering material in earthquake design. Last of all, the finite element outputs are found to hold good agreement with the experimental tensile capacity which validates the FE modeling.

  15. Influence of strain rate and temperature on tensile properties and flow behaviour of a reduced activation ferritic-martensitic steel

    NASA Astrophysics Data System (ADS)

    Vanaja, J.; Laha, K.; Sam, Shiju; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

    2012-05-01

    Tensile strength and flow behaviour of a Reduced Activation Ferritic-Martensitic (RAFM) steel (9Cr-1W-0.06Ta-0.22V-0.08C) have been investigated over a temperature range of 300-873 K at different strain rates. Tensile strength of the steel decreased with temperature and increased with strain rate except at intermediate temperatures. Negative strain rate sensitivity of flow stress of the steel at intermediate temperatures revealed the occurrence of dynamic strain ageing in the steel, even though no serrated flow was observed. The tensile flow behaviour of the material was well represented by the Voce strain hardening equation for all the test conditions. Temperature and strain rate dependence of the various parameters of Voce equation were interpreted with the possible deformation mechanisms. The equivalence between the saturation stress at a given strain rate in tensile test and steady state deformation rate at a given stress in creep test was found to be satisfied by the RAFM steel.

  16. Statistical analysis of the strength and lifetime under tension of crystalline polymeric solids

    NASA Astrophysics Data System (ADS)

    Li, C. Y.; Nitta, K. H.

    2015-06-01

    The ductile fracture behavior under uniaxial tension of melt-crystallized isotactic polypropylene specimens at room temperature was investigated from a statistical point of view. Each tensile test was performed more than one hundred times and statistical data for the breaking point were obtained under each tensile condition. The probability distribution curves of the fracture time and strength approximately followed Gaussian statistics at lower tensile speeds, but changed to a Weibull function at higher-speed tests. Additionally, with increasing tensile speed the mean and standard deviation of the fracture time decreased linearly. The toughness, which is the total area under the stress-strain curves, was found to be independent of the tensile conditions, indicating that fracture toughness is a criterion for fracture under tension.

  17. Development of the Z Specimen for Tensile-Tensile, Tensile-Compression, Compression-Compression Wire Testing

    NASA Astrophysics Data System (ADS)

    Pike, K.; Berg, B.; Adler, P.

    2011-07-01

    A new wire test specimen was developed as part of the Safe Technology consortium project to produce a nitinol algorithm for the fe-safe™ fatigue postprocessor. The requirements for the design were permit tensile and compressive loading, accommodate data collection of strains from ±0.1 to 6% at high-frequency cycling. The requirements for the wire were inexpensive, stable, consistent, and commercially available. The requirements for the processing were incorporate deformation and multiple anneal cycles to simulate manufacturing methods associated with vascular stent production. The final design was 0.508 mm (0.020 in.) diameter wire formed in a two-stage process to produce a Z-shaped specimen. The final part met all requirements for testing. Subsequently, a second specimen, Z3, and a straight wire specimen were produced to supply additional data to the consortium.

  18. Thermal degradation of the tensile properties of undirectionally reinforced FP-AI203/EZ 33 magnesium composites

    NASA Technical Reports Server (NTRS)

    Bhatt, R. T.; Grimes, H. H.

    1982-01-01

    The effects of isothermal and cyclic exposure on the room temperature axial and transverse tensile strength and dynamic flexural modulus of 35 volume percent and 55 volume percent FP-Al2O3/EZ 33 magnesium composites were studied. The composite specimens were continuously heated in a sand bath maintained at 350 C for up to 150 hours or thermally cycled between 50 and 250 C or 50 and 350 C for up to 3000 cycles. Each thermal cycle lasted for a total of six minutes with a hold time of two minutes at the maximum temperature. Results indicate to significant loss in the room temperature axial tensile strength and dynamic flexural modulus of composites thermally cycled between 50 and 250 C or of composites isothermally heated at 350 C for up to 150 hours from the strength and modulus data for the untreated, as fabricated composites. In contrast, thermal cycling between 50 and 350 C caused considerable loss in both room temperature strength and modulus. Fractographic analysis and measurement of composite transverse strength and matrix hardness of thermally cycled and isothermally heated composites indicated matrix softening and fiber/matrix debonding due to void growth at the interface and matrix cracking as the likely causes of the strength and modulus loss behavior.

  19. Thermal degradation of the tensile properties of undirectionally reinforced FP-Al2O3/EZ 33 magnesium composites

    NASA Technical Reports Server (NTRS)

    Bhatt, R.T.; Grimes, H. H.

    1983-01-01

    The effects of isothermal and cyclic exposure on the room temperature axial and transverse tensile strength and dynamic flexural modulus of 35 volume percent and 55 volume percent FP-Al203/EZ 33 magnesium composites were studied. The composite specimens were continuously heated in a sand bath maintained at 350 C for up to 150 hours or thermally cycled between 50 and 250 C or 50 and 350 C for up to 3000 cycles. Each thermal cycle lasted for a total of six minutes with a hold time of two minutes at the maximum temperature. Results indicate no significant loss in the room temperature axial tensile strength and dynamic flexural modulus of composites thermally cycled between 50 and 250 C or of composites isothermally heated at 350 C for up to 150 hours from the strength and modulus data for the untreated, as-fabricated composites. In contrast, thermal cycling between 50 and 350 C caused considerable loss in both room temperature strength and modulus. Fractographic analysis and measurement of composite transverse strength and matrix hardness of thermally cycled and isothermally heated composites indicated matrix softening and fiber/matrix debonding due to void growth at the interface and matrix cracking as the likely causes of the strength and modulus loss behavior. Previously announced in STAR as N82-21260

  20. Nanocrystalline Metal Enabled Conductors for Enhanced Strength-to-Weight Aerospace Electrical Wiring

    NASA Astrophysics Data System (ADS)

    Winfield, Ian

    High strength-to-weight nanocrystalline alloy enabled conductor (NEC) prototypes were successfully developed by reinforcing an oxygen-free copper core material with electrodeposited cobalt phosphorus (CoP) coatings. A rule of mixtures approach was utilized to design the NEC prototypes to meet materials performance indices. Three unique NEC prototypes were produced with CoP coatings composed of alternating nanocrystalline (11 nm) and coarse-grained layers. The tensile properties were dependant on the coating microstructures, with tensile strengths of 1000 MPa, 970 MPa, and 900 MPa, respectively, and corresponding tensile elongations of 4.6%, 6.1%, and 10%, respectively. The electrical conductivity of the NEC prototypes was 58 %IACS (resistivity of ˜ 2.96 muO-cm). The rule of mixtures approach effectively predicted the tensile strength and conductivity. The NEC samples were significantly stronger than the incumbent high-strength aerospace conductor material, Be-Cu alloy CS95, which exhibits a tensile strength of only 655 MPa and conductivity of 63 %IACS.

  1. The ideal strength of iron in tension and shear

    SciTech Connect

    Clatterbuck, D.M.; Chrzan, D.C.; Morris, Jr., J.W.

    2002-12-01

    The ideal strength of a material is the stress at which the lattice itself becomes unstable and, hence, sets a firm upper bound on the mechanical strength the material can have. The present paper includes an ab-initio calculation of the ideal shear strength of Fe. It is, to our knowledge, the first such computation for any ferromagnetic material. The paper also elaborates on our earlier calculation of the ideal tensile strength of Fe by studying the effects of strains which break the tetragonal symmetry. The strengths were calculated using the Projector Augmented Wave Method within the framework of density functional theory and the generalized gradient approximation. In <001> tension the ideal strength is determined by an elastic instability of the ferromagnetic phase along the ''Bain'' strain path from bcc to fcc. An <001> tensile strain also leads to instability with respect to transformation into a face centered orthorhombic structure, and to various magnetic instabilities. However, these are encountered at larger strains and, thus, do not affect the ideal strength. We also investigated the ideal shear strength of bcc iron in two prominent shear systems, <111>{l_brace}112{r_brace} and <111>{l_brace}110{r_brace}. In both shear systems the ideal strength is determined by the body centered tetragonal structure that defines a nearby saddle point on the energy surface. The ideal shear strengths are thus very similar, though they are not identical since the two shears follow slightly different strain paths from bcc to bct. We investigated the magnetic instabilities encountered during <111>{l_brace}112{r_brace} shear. These instabilities do not appear until the strain is significantly greater than the instability strain of the ferromagnetic crystal. Hence while Fe exhibits some novel effects due to magnetism, they do not affect the ideal strength, which is determined by the same elastic instabilities that determine the strengths of most other bcc metals.

  2. Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.

    1974-01-01

    An investigation was conducted to determine the effects of mechanical working on the 1093 C (2000 F) tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C (2000 F). The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C (2000 F). Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C (2000 F). The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C (2000 F) ultimate tensile strength of the composites.

  3. Revision of the tensile database for V-Ti and V-Cr-Ti alloys tested at ANL.

    SciTech Connect

    Billone, M. C.

    1998-01-13

    The published database for the tensile properties of unirradiated and irradiated vanadium-based alloys tested at Argonne National Laboratory (ANL) has been reviewed. The alloys tested are in the ranges of V-(0-18)wt.%Ti and V-(4-15)wt.%Cr-(3-15)wt.%Ti. A consistent methodology, based on ASTM terminology and standards, has been used to re-analyze the unpublished load vs. displacement curves for 162 unirradiated samples and 91 irradiated samples to determine revised values for yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE) and total elongation (TE). The revised data set contains lower values for UE ({minus}5{+-}2% strain) and TE ({minus}4{+-}2% strain) than previously reported. Revised values for YS and UTS are consistent with the previously-published values in that they are within the scatter usually associated with these properties.

  4. Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes

    SciTech Connect

    Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Rasid, Rozaidi [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Yahya, S. Y. [Institute of Sciences, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

    2009-06-01

    This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180 deg. C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

  5. Mechanical strength of PET fibers treated in cold plasma and thermal exposed

    Microsoft Academic Search

    M. O. H. Cioffi; H. J. C. Voorwald; V. Ambrogi; T. Monetta; F. Bellucci; L. Nicolais

    2003-01-01

    As a followup to previous work, experiments with argon and oxygen Radio Frequency plasma treated polyethylene terepthalate\\u000a (PET) exposed to 100 ?C after cold plasma treatment were performed. Tensile tests results in monofilaments treated in oxygen\\u000a and argon plasma for 5 s, 20 s, 30 s, and 100 s showed a decrease in the average tensile strength compared with the

  6. Crystal growth vs. conventional acid etching: a comparative evaluation of etch patterns, penetration depths, and bond strengths.

    PubMed

    Devanna, Raghu; Keluskar, K M

    2008-01-01

    The present study was undertaken to investigate the effect on enamel surface, penetration depth, and bond strength produced by 37% phosphoric acid and 20% sulfated polyacrylic acid as etching agents for direct bonding. Eighty teeth were used to study the efficacy of the etching agents on the enamel surface, penetration depth, and tensile bond strength. It was determined from the present study that a 30 sec application of 20% sulfated polyacrylic acid produced comparable etching topography with that of 37% phosphoric acid applied for 30 sec. The 37% phosphoric acid dissolves enamel to a greater extent than does the 20% sulfated polyacrylic acid. Instron Universal testing machine was used to evaluate the bond strengths of the two etching agents. Twenty percent sulfated polyacrylic acid provided adequate tensile bond strength. It was ascertained that crystal growth can be an alternative to conventional phosphoric acid etching as it dissolves lesser enamel and provides adequate tensile bond strength. PMID:19075433

  7. Dynamic tensile characterization of pig skin

    NASA Astrophysics Data System (ADS)

    Khatam, H.; Liu, Q.; Ravi-Chandar, K.

    2014-04-01

    The strain-rate dependent response of porcine skin oriented in the fiber direction is explored under tensile loading. Quasi-static response was obtained at strain rates in the range of 10-3 s-1 to 25 s-1. Characterization of the response at even greater strain rates is accomplished by measuring the spatio-temporal evolution of the particle velocity and strain in a thin strip subjected to high speed impact loading that generates uniaxial stress conditions. These experiments indicate the formation of shock waves; the shock Hugoniot that relates particle velocity to the shock velocity and the dynamic stress to dynamic strain is obtained directly through experimental measurements, without any assumptions regarding the constitutive properties of the material. [Figure not available: see fulltext.

  8. Formability Characterization of a New Generation High Strength Steels

    SciTech Connect

    Sriram Sadagopan; Dennis Urban; Chris Wong; Mai Huang; Benda Yan

    2003-05-16

    Advanced high strength steels (AHSS) are being progressively explored by the automotive industry all around the world for cost-effective solutions to accomplish vehicle lightweighting, improve fuel economy, and consequently reduce greenhouse emissions. Because of their inherent high strength, attractive crash energy management properties, and good formability, the effective use of AHSS such as Duel Phase and TRIP (Transformation Induced Plasticity) steels, will significantly contribute to vehicle lightweighting and fuel economy. To further the application of these steels in automotive body and structural parts, a good knowledge and experience base must be developed regarding the press formability of these materials. This project provides data on relevant intrinsic mechanical behavior, splitting limits, and springback behavior of several lots of mild steel, conventional high strength steel (HSS), advanced high strength steel (AHSS) and ultra-high strength steel (UHSS), supplied by the member companies of the Automotive Applications Committee (AAC) of the American Iron and Steel Institute (AISI). Two lots of TRIP600, which were supplied by ThyssenKrupp Stahl, were also included in the study. Since sheet metal forming encompasses a very diverse range of forming processes and deformation modes, a number of simulative tests were used to characterize the forming behavior of these steel grades. In general, it was found that formability, as determined by the different tests, decreased with increased tensile strength. Consistant with previous findings, the formability of TRIP600 was found to be exceptionally good for its tensile strength.

  9. Effects of strontium and titanium on the microstructure, tensile properties and creep behavior of AM50 alloys

    Microsoft Academic Search

    Peng Zhao; Qudong Wang; Chunquan Zhai; Yanping Zhu

    2007-01-01

    The microstructure, tensile properties and creep behavior of Mg–5Al based alloys with strontium and titanium additions were investigated. Small additions of strontium mainly dissolved into Mg17Al12 particles and increased the thermal stability and creep strength, since they did not cause the formation of any new phase in the microstructure. Small additions of strontium could refine the as-cast microstructure and improve

  10. Effect of microstructure on the room temperature tensile and creep deformation mechanisms of alpha-beta titanium alloys

    Microsoft Academic Search

    Allan Wayne Jaworski Jr.

    2005-01-01

    Two-phase alpha-beta titanium alloys are used in many applications because of their high specific strength, corrosion resistance, processability, and biocompatibility. The room temperature tensile and creep deformation mechanisms of alpha-beta alloys must be understood in order to design alloys with desired properties and improved creep resistance. There is a lack of understanding in this regard. The aim of this investigation

  11. In-situ scanning electron microscopy (sem) observations of the tensile and tensile-creep deformation of Titanium-8Aluminum-1mo-1v (wt.%) alloy

    NASA Astrophysics Data System (ADS)

    Ghosh Dastidar, Indraroop

    Titanium (Ti) and titanium alloys (Ti alloys) are attractive for structural applications, such as in the aerospace and automotive industries due to their high specific strength, excellent corrosion resistance and good ability to withstand elevated temperatures. To develop Ti alloys with better mechanical properties, it is necessary to comprehend the deformation behavior of available Ti alloys. Previous studies performed by another graduate student, Dr. Hongmei Li, involved investigation of the deformation behavior of commercially pure (CP) Ti, Ti-5Al-2.5Sn (wt.%), Ti-3Al-2.5V (wt.%) and Ti-6Al-4V (wt.%) alloys. The current thesis focused on investigating the deformation behavior of Ti-8Al-1Mo-1V (wt.%). In-situ tensile and tensile-creep experiments were performed at temperatures ranging from room temperature (RT) to 650OC inside a scanning electron microscope (SEM), which allowed for the observation of the surface deformation evolution. Electron Back Scattered Diffraction (EBSD) was used to identify the distribution of the active deformation systems. In this thesis efforts were made to characterize the various deformation modes of the Ti-8Al-1Mo-1V (wt.%) alloy as a function of the testing conditions (stress and temperature). It was observed that prismatic slip made up the majority of the observed slip systems during the RT tensile deformation, while basal and prismatic slip were almost equally active during the 455OC tensile deformation. Grain boundary ledges were observed during the elevated temperature tensile-creep deformation and from this observation it was suggested that grain boundary sliding was an active deformation mode. This work also involved estimating the Critical Resolved Shear Stress (CRSS) ratios of the alpha-phase deformation modes. The CRSS ratios were compared with the CRSS ratios of CP Ti and other Ti alloys. Overall, this work was intended to add more data to the scientific literature of Ti alloys in order to better comprehend their deformation modes, so as to design and develop higher performance Ti alloys.

  12. Fabrication of a high-strength hydrogel with an interpenetrating network structure

    Microsoft Academic Search

    Qunwei Tang; Xiaoming Sun; Qinghua Li; Jihuai Wu; Jianming Lin

    2009-01-01

    Hydrogels have potential applications in many fields, but the poor mechanical strength has limited their further development. In this article, we designed a high-strength hydrogel with an interpenetrating network (IPN) structure from polyacrylamide (PAM) and poly(vinyl alcohol) (PVA). Synthesis parameters, such as PVA\\/AM mass ratio, crosslinker dosage and elongation time were carried out for high tensile strength and elongation. The

  13. Effect of adherend's rigidity on the shear strength of single lap adhesive joints

    Microsoft Academic Search

    P. N. B. Reis; J. A. M. Ferreira; F. Antunes

    2011-01-01

    The present paper compares the tensile shear strength of single-lap joints with different adherends. Three materials were combined in the single lap joints: a carbon\\/epoxy laminated composite, a high elastic limit steel and the 6082-T6 aluminium alloy. The shear strength of joints was influenced by the adherend stiffness and the highest shear strengths were obtained using high stiffness adherend materials.

  14. The Effect of Environmental-Loading History on the Transverse Strength of GRP Laminate

    Microsoft Academic Search

    Ori Ishai; A. Mazor

    1975-01-01

    Loaded transverse GRP specimens and epoxy references were exposed to different environmental conditions. Tensile strength measurements conducted under exposure and after a drying period yielded the following main conclusions:Current and residual transverse strength was not affected much by cold-water and hot dry air during a short exposure period.Under hot-water exposure, transverse strength showed a significant drop with time, especially beyond

  15. Effect of compatibilizer on the strength of ABS/PMMA blends

    NASA Astrophysics Data System (ADS)

    Zhou, J. C.; Gao, J.; Wang, S. H.; Lin, S. X.; Huang, J.; Xu, L. L.

    2014-08-01

    To explore the influence of different compatibilizers on the strength of ABS/PMMA, two groups of tests were performed. Polymers were mixed by melt blending, and then the ternary blends were tested. SMA makes the tensile strength and impact strength of ABS/PMMA blends decrease obviously, while SBS improves the two properties except the addition of 2wt%. The results of different compatibilizers on ABS/PMMA blends were unlike.

  16. Improving Joint Properties of Friction Welded Joint of High Tensile Steel

    NASA Astrophysics Data System (ADS)

    Kimura, Masaaki; Kusaka, Masahiro; Seo, Kenji; Fuji, Akiyoshi

    This report describes the improvements in the joint properties of friction welded joint of 780MPa class high tensile steel. Welded joint made by a continuous drive friction welding machine, the conventional method, had not obtained 100% joint efficiency despite applying forge pressure. This was due to the softening of the welded interface zone for heat input during braking times. Therefore, we developed a continuous drive friction welding machine with an electromagnetic clutch to prevent heat input during braking time. We proposed the process as “The Low Heat Input Friction Welding Method (the LHI method).” In this case, the joint had the same tensile strength as the base metal at friction time when the friction torque reached the initial peak torque. That is, the welded joint obtained 100% joint efficiency by using only the friction stage up to the initial peak torque without the forge (upsetting) stage, despite the existence of a slightly softened region adjacent to the welded interface. Furthermore, the softened region was hardly generated when this joint was made by applying forge pressure at the initial peak torque. In conclusion, a welded joint of high tensile steel made by only the friction stage of the LHI method had excellent joint properties. The LHI method has a lot of advantages for joining such materials as super fine grain steel with which conventional fusion welding processes have difficulty.

  17. Why Strength Training?

    MedlinePLUS

    ... Physical Activity Physical Activity Share Compartir Why strength training? Research has shown that strengthening exercises are both ... person's mental and emotional health. Benefits of Strength Training There are numerous benefits to strength training regularly, ...

  18. Laboratory simulations of tensile (hydro) fracture via cyclical fluid pressurisation

    NASA Astrophysics Data System (ADS)

    Benson, P. M.; Heap, M. J.; Lavallee, Y.; Flaws, A.; Hess, K.; Selvadurai, A. P.; Dingwell, D. B.

    2011-12-01

    During magma ascent, cracking and faulting of the host rock provide conduits for the movement of magmatic fluids. The spatial and temporal formation of such conduits, driven largely by pressurized magmas in the form of dykes, is of key importance in the volcano-tectonic system. In particular, it is known that both a fracture mechanical (brittle) mechanism (due to the propagating dyke tip) as well as a petrological mechanism (due to the elevated pressure-temperature environment), play roles in dyke propagation. As the use of elevated temperatures in the laboratory is technically challenging, early work has tended to concentrate either on analogue setups using gelatine and other materials that are fractured by injection of coloured water or - for simulation of representative pressures - a simplified experimental setup at modest (room) temperatures. Here, we overcome these difficulties by simulating magma intrusion in the laboratory through an experimental protocol that compresses a 'conduit' of magma encapsulated inside a hollow cylindrical shell. A well-controlled stress is then imposed onto the conduit which has the effect of transmitting this force onto the inner wall of the surrounding shell. Although we present our work with a view to investigating fluid driven tensile fracture applicable to high temperature processes, this general protocol may be used to analyse a wide range of processes whereby direct fluid pressure is used to fracture a host medium. To analyse the system, we make use of a number of well-known fracture mechanics methods allied to independently measured rheological parameters for the inner conduit to develop a model to explain (a) the stress relaxations, and (b) the peak stress measured at failure, as well as the observed interactions between the ductile inner conduit and brittle outer shell, interpreted as analogous to dykes driving though a volcanic edifice. We show that (a), the coupling of stress, strain and seismic data through time can be used to infer the stability of volcanic conduits and/or the state of the magma during periods of unrest by calculating the viscoelastic relaxation parameters and hence the modulus or viscosity of the melt, (b), that dyke propagation is initiated when the tensile strength of the country rock is overcome of between 7-11 MPa, in the case of basalt from Etna Volcano, and that the initial tensile failure is energetic enough to melt, and to produce shock waves in it, (c), that the fracture of silicate melt is strain rate dependent and the presence of cracks in the core rhyolite melt provides evidence that the fracture of the outer shell is sufficient to trigger the fracture of a magma conduit and potentially, episodes of explosive activity, and (d), that the material fracture parameters are largely temperature independent. We anticipate that these data will provide a starting point for more detailed models incorporating the full thermal-hydraulic-mechanical process, with applications ranging from deep ore-forming processes to geothermal energy extraction and improved hazard mitigation strategies.

  19. Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Zimmerman, Richard S.; Adams, Donald F.

    1989-01-01

    Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber; Nippon Carbon, Ltd., (Dow Corning) nicalon NLM-102 silicon carbide fiber; and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 C to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

  20. Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Zimmerman, Richard S.; Adams, Donald F.

    1988-01-01

    Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber, Nippon Carbon, Ltd., (Dow Corning) Nicalon NLM-102 silicon carbide fiber, and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

  1. Fracture of glass in tensile and bending tests

    Microsoft Academic Search

    Orestes E. Alarcón; Ricardo E. Medrano; Pcter P. Gillis

    1994-01-01

    To fully characterize the mechanical behavior of ceramics, it is useful to study their response to both tensile and bending tests. In this investigation, a quantitative comparison is made between tensile and bending results from (circularly) cylindrical glass rods of borosilicate glass and of fused silica. These experimental results show that in each material, the Weibull exponent m is approximately

  2. Polystyrene cryostat facilitates testing tensile specimens under liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Shogan, R. P.; Skalka, R. J.

    1967-01-01

    Lightweight cryostat made of expanded polystyrene reduces eccentricity in a tensile system being tested under liquid nitrogen. The cryostat is attached directly to the tensile system by a special seal, reducing misalignment effects due to cryostat weight, and facilitates viewing and loading of the specimens.

  3. Tensile Properties of Contractile and Synthetic Vascular Smooth Muscle Cells

    Microsoft Academic Search

    Hiroshi Miyazaki; Yoshitaka Hasegawa; Kozaburo Hayashi

    2002-01-01

    Tensile properties of vascular smooth muscle cells (VSMCs) of synthetic and contractile phenotypes were determined using a newly developed tensile test system. Synthetic and contractile VSMCs were isolated from the rabbit thoracic aorta with an explant and an enzymatic digestion method, respectively. Each cell floated in Hanks' balanced salt solution of 37°C was attached to the fine tips of a

  4. Comparative evaluation of the effectiveness of steels under hydrogen absorption conditions based on the results of short term tensile tests

    SciTech Connect

    Nikolaev, A.F.; Chernykh, E.M.; Frolov, V.V.

    1983-03-01

    Because stress-rupture tests of the reduction of strength of metal hydrogen absorption require large expenditures, a simple parameter, t /SUB f/ (the time until failure in short term quasistatic tests of samples in a uniaxial tension with a constant strain rate), is suggested. Tests were made of ST-3 steel electrolytically impregnated with hydrogen. The relations of tensile strength, time until failure, failure stress, and ductility to time of hydrogen absorption are obtained. The results indicate that the time-until-failure parameter, applied with the same rule of loading, is the most effective.

  5. Temperature-dependent tensile and shear response of graphite/aluminum

    NASA Technical Reports Server (NTRS)

    Fujita, T.; Pindera, M. J.; Herakovich, C. T.

    1987-01-01

    The thermo-mechanical response of unidirectional P100 graphite fiber/6061 aluminum matrix composites was investigated at four temperatures:-150, +75, +250, and +500 F. Two types of tests, off-axis tension and losipescu shear, were used to obtain the desired properties. Good experimental-theoretical correlation was obtained for Exx, vxy, and G12. It is shown that E11 is temperature independent, but E22, v12, and G12 generally decrease with increasing temperature. Compared with rather high longitudinal strength, very low transverse strength was obtained for the graphite/aluminum. The poor transverse strength is believed to be due to the low interfacial bond strength in this material. The strength decrease significantly with increasing temperature. The tensile response at various temperatures is greatly affected by the residual stresses caused by the mismatch in the coefficients of thermal expansion of fibers and matrix. The degradation of the aluminum matrix properties at higher temperatures has a deleterious effect on composite properties. The composite has a very low coefficient of thermal expansion in the fiber direction.

  6. Temperature-dependent tensile and shear response of graphite/aluminum

    SciTech Connect

    Fujita, T.; Pindera, M.J.; Herakovich, C.T.

    1987-05-01

    The thermo-mechanical response of unidirectional P100 graphite fiber/6061 aluminum matrix composites was investigated at four temperatures:-150, +75, +250, and +500 F. Two types of tests, off-axis tension and losipescu shear, were used to obtain the desired properties. Good experimental-theoretical correlation was obtained for Exx, vxy, and G12. It is shown that E11 is temperature independent, but E22, v12, and G12 generally decrease with increasing temperature. Compared with rather high longitudinal strength, very low transverse strength was obtained for the graphite/aluminum. The poor transverse strength is believed to be due to the low interfacial bond strength in this material. The strength decrease significantly with increasing temperature. The tensile response at various temperatures is greatly affected by the residual stresses caused by the mismatch in the coefficients of thermal expansion of fibers and matrix. The degradation of the aluminum matrix properties at higher temperatures has a deleterious effect on composite properties. The composite has a very low coefficient of thermal expansion in the fiber direction.

  7. Properties of aluminum alloys: Tensile, creep, and fatigue data at high and low temperatures

    SciTech Connect

    Kaufman, J.G. (ed.)

    1999-01-01

    Based on work by Alcoa Laboratories over several years, this book compiles more than 300 tables listing typical average properties of a wide range of aluminum alloys. Contents include: Typical Mechanical Properties of Wrought and Cast Aluminum Alloys at Various Temperatures--tensile properties at subzero temperatures at temperature after various holding times at the test temperature, and at room temperature after exposure at various temperatures for various holding times; creep rupture strengths for various times at various temperatures; stresses required to generate various amounts of creep in various lengths of time; rotating-beam fatigue strengths; modulus of elasticity as a function of temperature; Fatigue Data--fatigue strength of wrought aluminum alloys, axial stress fatigue strength of wrought aluminum alloys (at various stress ratios, smooth and notched specimens), average fatigue strength for aluminum and aluminum alloy flat sheet specimens (under complete reversed flexure), cantilever-beam fatigue test results of aluminum alloys at elevated temperatures and following stabilization at the test temperature. The properties in this book are typical values--expected average values for representative lots produced using commercial processes and that meet industry standards, whose room temperature properties correspond to published typical values for the alloys.

  8. Role of cladding in the notched tensile properties of a titanium matrix composite

    SciTech Connect

    Ramamurty, U.; Zok, F.W.; Leckie, F.A. [Univ. of California, Santa Barbara, CA (United States)

    1997-12-01

    The utility of Ti cladding in alleviating the notch sensitivity of both the monotonic and cyclic tensile properties of Ti matrix composites (TMC) has been examined. Experiments have been conducted on panels with two different clad thicknesses as well as on the TMC alone. Crack bridging models have been used to describe the composite behavior, incorporating explicitly the effects of the cladding. It is demonstrated that the notched strength can be raised up to the level corresponding to the unnotched TMC alone, with a critical clad thickness that depends on the fracture properties of the TMC and the notch size. The fatigue threshold can be elevated also, though it cannot reach the threshold of the un-notched TMC. The bridging models have been used to calculate the trends in the strength and the fatigue threshold with the clad thickness.

  9. Tensile Behavior of Long-term Aged Nickel-base Superalloy

    NASA Astrophysics Data System (ADS)

    Xia, P. C.; Chen, F. W.; Xie, K.; Yu, J. J.

    2015-07-01

    The microstructural change of directionally solidified nickel-base superalloy which was aged at 900 °C for 1500 hours and tensile behavior at different temperatures were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). ?' phase of the alloy coarsens and rafts in the course of aged treatment. The driving force of rafting is the decrease of interface energy and elastic strain energy. The stress of aged alloy increases slightly with the testing temperature. This arises from a few dislocations shearing the ?' precipitates. There is a peak stress value at 760 °C, which is attributed to the high strength of the ?' phase, the homogeneous deformation structure, and dislocation-?' precipitate and dislocation-dislocation interactions. The stress then decreases rapidly with increased temperature. The low stress of the ?' phase and ?' rafting at high temperature contribute to the drop of alloy strength. The change of elongation is inverse to that of the stress.

  10. High Temperature Tensile Properties of Unidirectional Hi-Nicalon/Celsian Composites In Air

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Bansal, Narottam P.

    2000-01-01

    High temperature tensile properties of unidirectional BN/SiC-coated Hi-Nicalon SiC fiber reinforced celsian matrix composites have been measured from room temperature to 1200 C (2190 F) in air. Young's modulus, the first matrix cracking stress, and the ultimate strength decreased from room temperature to 1200 C (2190 F). The applicability of various micromechanical models, in predicting room temperature values of various mechanical properties for this CMC, has also been investigated. The simple rule of mixtures produced an accurate estimate of the primary composite modulus. The first matrix cracking stress estimated from ACK theory was in good agreement with the experimental value. The modified fiber bundle failure theory of Evans gave a good estimate of the ultimate strength.

  11. Interrelationship between matrix microhardness and ultimate tensile strength of discontinuous particulate-reinforced aluminum alloy composites

    Microsoft Academic Search

    M Gupta; T. S Srivatsan

    2001-01-01

    In this study, silicon carbide particulate (SiCp)-reinforced aluminum alloy-based composites were synthesized using the technique of disintegrated melt deposition (DMD). Microstructural characterization of the disintegration melt deposition-processed and extruded composite samples revealed minimal porosity, a near uniform distribution of the reinforcing silicon carbide particulates and good interfacial integrity between the reinforcement phase and the aluminum alloy matrix. Vickers microhardness measurements

  12. Wound tensile strength and contraction rate are not affected by laparotomy or pneumoperitoneum

    Microsoft Academic Search

    J. C. Wickens; R. L. Whelan; J. D. F. Allendorf; J. Donahue; E. Buxton; A. McKee; K. Panageas; N. Gleason; S.-H. Lee; M. Bessler

    1998-01-01

    Background: Many cellular elements responsible for wound healing are affected by laparotomy. The aim of this study was to evaluate the effects of laparotomy and CO2 pneumoperitoneum on wound healing. Methods: Male Sprague Dawley rats were randomly assigned to one of three experimental groups. Anesthesia control rats underwent no procedure. Pneumoperitoneum group rats were insufflated with CO2 gas. Laparotomy group

  13. A comparison of direct and indirect methods of determining tensile strength of concrete 

    E-print Network

    Brown, James Timon

    1957-01-01

    the ends of each specimen. This would eliminate any adverse effect which might have resulted from the momentary loss of load when spalling oocurrcd Stress influence at the end of the grips did not seemingly affect the location of the failure... t meat eemtemt Ql 4. 55 t ga per catt yard Volume of C, A, (coarse aggregate) per unit volume m 0, 61e Weight of C. A. (2 1 cu ft )(0, 61)(l(g 8 lbs. /cu, ft ~ ) gg 134 ~ 3 lbs, Approximate entrapped air 2+ Solid volume of cement gg ( bascu, 2. 1 c...

  14. Adhesive strength and tensile fracture of Ni particle enhanced Sn–Ag composite solder joints

    Microsoft Academic Search

    H. T. Lee; Y. H. Lee

    2006-01-01

    This study forms composite solders by adding 0.5–3wt% of Ni particles in situ to Sn–3.5wt%Ag lead-free solder. Cu\\/solder\\/Cu specimens are prepared by dipping two Cu rods into a solder bath to produce a solder joint. Some of the joint specimens are retained in the as-soldered condition, while the others are aged at 150°C for 100, 200, 400, or 500h, respectively.

  15. Tensile strength of preceramic solder joints formed using an infrared heat source.

    PubMed

    Louly, A C; Mora, A F; Moore, B K; Andres, C J; Goodacre, C J

    1991-01-01

    Infrared soldering was compared to gas-oxygen torch soldering by testing specimens made from each of the following four classes of metal ceramic alloys: gold-platinum-palladium, gold-palladium, palladium-silver, and nickel-chromium-beryllium. There was no significant difference between infrared and torch soldering for the gold-palladium, palladium-silver, and base metal alloy specimens. However, infrared soldering of the gold-platinum-palladium alloy samples produced significantly weaker joints than those produced by torch soldering. PMID:1687435

  16. Determination of Rock Fracture Toughness K IIC and its Relationship with Tensile Strength

    Microsoft Academic Search

    Yan JinJianbo; Jianbo Yuan; Mian Chen; K. P. Chen; Yunhu Lu; Huaiying Wang

    2011-01-01

    Hydraulic fracture propagation is greatly influenced by mode-II fracture toughness since this is one of the factors which\\u000a determine whether a fracture diverts. Direct measurement of rock fracture toughness is constrained by high cost, limited number\\u000a of available cores and long turn around time. Therefore, to overcome these constrains, it is necessary to develop an effective\\u000a mode-II fracture toughness test

  17. Tensile strength of a surgeon’s or a square knot

    E-print Network

    Muffly, Tyler M.; Boyce, Jamie; Kieweg, Sarah L.; Bonham, Aaron J.

    2014-09-19

    these criteria. The use of a more permanent suture, such as polypropylene, was proposed for sacral colpopexy.[7–8] Permanent suture is not ideal, as chronic pain, vaginal discharge, or erosion can be caused. In the setting of sacral colpopexy, recently published...

  18. (Finite) statistical size effects on compressive strength.

    PubMed

    Weiss, Jérôme; Girard, Lucas; Gimbert, Florent; Amitrano, David; Vandembroucq, Damien

    2014-04-29

    The larger structures are, the lower their mechanical strength. Already discussed by Leonardo da Vinci and Edmé Mariotte several centuries ago, size effects on strength remain of crucial importance in modern engineering for the elaboration of safety regulations in structural design or the extrapolation of laboratory results to geophysical field scales. Under tensile loading, statistical size effects are traditionally modeled with a weakest-link approach. One of its prominent results is a prediction of vanishing strength at large scales that can be quantified in the framework of extreme value statistics. Despite a frequent use outside its range of validity, this approach remains the dominant tool in the field of statistical size effects. Here we focus on compressive failure, which concerns a wide range of geophysical and geotechnical situations. We show on historical and recent experimental data that weakest-link predictions are not obeyed. In particular, the mechanical strength saturates at a nonzero value toward large scales. Accounting explicitly for the elastic interactions between defects during the damage process, we build a formal analogy of compressive failure with the depinning transition of an elastic manifold. This critical transition interpretation naturally entails finite-size scaling laws for the mean strength and its associated variability. Theoretical predictions are in remarkable agreement with measurements reported for various materials such as rocks, ice, coal, or concrete. This formalism, which can also be extended to the flowing instability of granular media under multiaxial compression, has important practical consequences for future design rules. PMID:24733930

  19. Strength of Polysilicon for MEMS Devices

    SciTech Connect

    Buchheit, Thomas E.; LaVan, David A.

    1999-07-20

    The safe, secure and reliable application of Microelectromechanical Systems (MEMS) devices requires knowledge about the distribution in material and mechanical properties of the small-scale structures. A new testing program at Sandia is quantifying the strength distribution using polysilicon samples that reflect the dimensions of critical MEMS components. The strength of polysilicon fabricated at Sandia's Microelectronic Development Laboratory was successfully measured using samples 2.5 microns thick, 1.7 microns wide with lengths between 15 and 25 microns. These tensile specimens have a freely moving hub on one end that anchors the sample to the silicon die and allows free rotation. Each sample is loaded in uniaxial tension by pulling laterally with a flat tipped diamond in a computer-controlled Nanoindenter. The stress-strain curve is calculated using the specimen cross section and gage length dimensions verified by measuring against a standard in the SEM.

  20. Use of Spherical Instrumented Indentation to Evaluate the Tensile Properties of 3D Combined Structures

    NASA Astrophysics Data System (ADS)

    Song, Won-Seok; Kim, Seung-Gyu; Kim, Young-Cheon; Kwon, Dongil

    2015-03-01

    In this paper we propose a novel method, spherical indentation, for evaluation of the plastic properties of combined structures. Three-dimensional (3D) printed products, for example gradient metal alloys consisting of different kinds of material, contain interfaces that can act as weak points and threaten the mechanical reliability of products. Combined structures containing an interface between Cu alloy and Ag were prepared for testing. Samples were heat-treated at 100°C and 200°C for 3 h to optimize processing conditions. The indentation tensile properties of the samples were estimated by analyzing multiple loading-unloading curves obtained by use of the representative stress and strain method. A continuous increase in both yield strength and tensile strength was observed for the Cu alloy and the Cu/Ag interface after heat treatment at up to 200°C, because of precipitation hardening. These experimental results show that mechanical characterization of combined structures by spherical indentation is highly useful on the nano and micro scales.