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1

Tensile properties of short fiber composites with fiber strength distribution  

Microsoft Academic Search

The influence of fiber rupture, fiber pull-out and fiber tensile strength distribution on the post-cracking behavior of short-randomly-distributed fiber reinforced brittle-matrix composites has been analyzed using an approach based on the Weibull weakest-link statistics. The analysis led to the development of a predicting model for the composite bridging stress-crack opening displacement (sc - d) law—a fundamental material property necessary for

M. Maalej

2001-01-01

2

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

NASA Technical Reports Server (NTRS)

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.

Miyoshi, K.; Buckley, D. H.

1982-01-01

3

Comparison of the Tensile, Creep, and Rupture Strength Properties of Stoichiometric SiC Fibers  

NASA Technical Reports Server (NTRS)

Tensile strength, creep strength, and rupture strength properties were measured for the following types of polymer-derived stoichiometric SiC fibers: Hi-Nicalon Type S from Nippon Carbon, Tyranno SA from Ube, and Sylramic from Dow Corning. Also included in this study were an earlier version of the SA fiber plus two recent developmental versions of the Sylramic fiber. The tensile strength measurements were made at room temperature on as-received fibers and on fibers after high-temperature inert exposure. The creep-rupture property data were obtained at 1400 deg C in air as well as, argon. Some fiber types showed strong effects of environment on their strength properties. These results are compared and discussed in terms of underlying mechanisms and implications for ceramic composites.

Yun, H. M.; DiCarlo, J. A.

1999-01-01

4

Tensile properties of an ultrahigh-strength graphite fiber in an epoxy matrix  

NASA Technical Reports Server (NTRS)

The fiber performance and reinforcement potential for fiber composites of a special PAN-based graphite fiber were evaluated by testing the fiber's tensile properties in an epoxy matrix. Representative strand samples were taken from 30 spools of single-end, 1500-filament fiber to make over 5000 fiber/epoxy strand specimens using the filament-winding process. Characteristics studied were fiber uniformity, strength and modulus distributions at room and liquid-nitrogen temperatures, stress-strain behavior, the effect of strain rate on fiber strength, and acoustic emission during tensile loading to failure. The fiber was found to have a 3570-MPa failure stress, a 1.7% failure strain, a 206-GPa modulus, and a density of 1.77 Mg/cu m at 23 C. Liquid-nitrogen temperature and various strain rates had no significant effect on fiber tensile properties.

Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.

1974-01-01

5

Hydrate adhesive and tensile strengths  

NASA Astrophysics Data System (ADS)

The physical properties of hydrate-bearing sediments depend on the interaction between hydrates and minerals. In particular, hydrates prefer to nucleate on mineral surfaces, therefore, the hydrate-mineral adhesive strength and the tensile strength of the hydrate mass itself affect the mechanical response of hydrate-bearing sediments. In this study, ice and hydrates made with various guest molecules (CO2, CH4, and THF) are formed between mica and calcite substrates. Adhesive and tensile strengths are measured by applying an external pull-out force. Results show that tensile failure occurs in CO2 and CH4 hydrates when calcite is the substrate, while ice and all hydrates exhibit adhesive failure on mica. The debonding strength is higher when calcite substrates are involved rather than mica substrates. A nominal pull-out strength of 0.15 ± 0.03 MPa can be adopted for mechanical analyses of hydrate-bearing sediments.

Jung, J. W.; Santamarina, J. Carlos

2011-08-01

6

Tensile strength of hybrid composites  

Microsoft Academic Search

This paper presents an approximate, statistical analysis for the tensile strength of unidirectional hybrid composite materials consisting of two-dimensional arrays of alternating low elongation and high elongation fibres in a common matrix. Expressions for ineffective length and fibre strain concentration factor in hybrid composites are developed. The analysis identifies a number of important material properties that affect the failure process

Carl Zweben; E. L du Pont de Nemours

1977-01-01

7

Determination of tensile strength of paraffin waxes  

Microsoft Academic Search

The tensile strength of paraffin wax is considered to be one of the important property indices that are used to characterize the service properties of this material. Methods used to determine the tensile strength of waxes are based on the use of Perkins and Tinius-Olsen testers [1]. Essentially, these methods consist of determinations of the force required to break a

O. G. Asadchii; B. Z. Votlokhin; N. F. Bogdanov; V. P. Gladyshev

1979-01-01

8

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

NASA Technical Reports Server (NTRS)

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.

Miyoshi, K.; Buckley, D. H.

1981-01-01

9

Evaluation of Tensile Strength Testing.  

National Technical Information Service (NTIS)

The report contains a summary of the activities related to the development, application and use of the splitting tensile test and of the flexure beam test to estimate the tensile strength of portland cement concrete pavement. Information related to the de...

A. H. Meyer D. W. Fowler L. M. Melis

1985-01-01

10

7 CFR 29.3061 - Strength (tensile).  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Strength (tensile). 29.3061 Section 29...Foreign Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important...

2009-01-01

11

7 CFR 29.3061 - Strength (tensile).  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Strength (tensile). 29.3061 Section 29...Foreign Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important...

2010-01-01

12

Relationship of Tensile and Tear Strengths of Fabrics to Component Yarn Properties.  

National Technical Information Service (NTIS)

The investigation was conducted on six selected fabrics to determine the relationship of breaking load, elongation and tear strength of fabrics to the properties of the component yarns. A system for expressing fabric properties as ratios of the contributi...

C. J. Pope, V. K. Devarakonda

1970-01-01

13

Making High-Tensile-Strength Amalgam Components  

NASA Technical Reports Server (NTRS)

Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams, ternary additions to liquid or solid components should be considered as means to impart desired properties to amalgams.

Grugel, Richard

2008-01-01

14

Silphenylene elastomers have high thermal stability and tensile strength  

NASA Technical Reports Server (NTRS)

Two polymeric silphenylene ethers, when cured by reactions with ethyl silicates and metal salts at room temperature, form elastomers having excellent thermal stability and tensile properties. The highest tensile strength obtained in a reinforced elastomer was 2800 psi.

1969-01-01

15

Tensile strength testing of Topopah Spring tuff.  

National Technical Information Service (NTIS)

Laboratory experiments were conducted to compare two techniques for determining the tensile strength of nonlithophysal, welded tuff of the Topopah Spring Member and determine which technique should be used for site characterization. Tensile strengths were...

L. W. Teufel M. J. McNamee

1991-01-01

16

An Interlaminar Tensile Strength Specimen  

NASA Technical Reports Server (NTRS)

This paper describes a technique to determine interlaminar tensile strength, sigma(sub 3c), of a fiber reinforced composite material using a curved beam. The specimen was a unidirectional curved beam, bent 90 deg, with straight arms. Attached to each arm was a hinged loading mechanism that was held by the grips of a tension testing machine. Geometry effects of the specimen, including the effects of loading arm length, inner radius, thickness, and width, were studied. The data sets fell into two categories: low strength corresponding to a macroscopic flaw related failure and high strength corresponding to a microscopic flaw related failure. From the data available, the specimen width and loading arm length had little effect on sigma(sub 3c). The inner radius was not expected to have a significant effect on sigma(sub 3c), but this conclusion could not be confirmed because of differences in laminate quality for each curve geometry. The thicker specimens had the lowest value of sigma(sub 3c) because of poor laminate quality.

Martin, Roderick H.; Jackson, Wade C.

1993-01-01

17

Study on longitudinal tensile properties of SiC f\\/Ti–6Al–4V composites with different interfacial shear strength  

Microsoft Academic Search

Effect of interfacial shear strength on longitudinal tensile properties for SiCf\\/Ti–6Al–4V composites is investigated by Monte Carlo finite element method. A two-parameter Weibull function is employed to describe random distribution of fiber strength. Fiber breakage, matrix cracking and interfacial debonding are simulated by killing the element when stress applied to element exceeds corresponding strength and releasing coupled nodes when shear

J. H. Lou; Y. Q. Yang; Q. Sun; J. Li; X. Luo

2011-01-01

18

Method and apparatus for determining tensile strength  

DOEpatents

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.

Ratigan, J.L.

1982-05-28

19

Method and apparatus for determining tensile strength  

DOEpatents

A method and apparatus 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.

Ratigan, Joe L. (Rapid City, SD)

1984-01-01

20

Tear Strength and Tensile Strength of Model Filled Elastomers.  

National Technical Information Service (NTIS)

Measurements have been made of the tear strength, tensile strength, and energy dissipated during stretching for model filled elastomers consisting of polybutadiene with glass beads incorporated. The glass beads were pretreated with various silanes, some o...

P. Dreyfuss A. N. Gent J. R. Williams

1980-01-01

21

Tensile Strength of Notched Composites  

Microsoft Academic Search

Two postulates on the strength of notched laminated composites are compared to experimental data. The first concerns the use of the fracture strength of angle ply composites to estimate the fracture strength of lami nates of several angle plys. The second concerns a macromechanics ex planation of the notch size effect on static strength for circular notches. The results of

Thomas A. Cruse

1973-01-01

22

Polypropylene-elastomer (TPO) nanocomposites: 2. Room temperature Izod impact strength and tensile properties  

Microsoft Academic Search

Room temperature Izod impact strength was determined for polypropylene (PP)\\/ethylene-co-octene elastomer (EOR) blends and nanocomposites, containing organoclays based on montmorillonite (MMT), at fixed elastomer content of 30 wt% and 0–7 wt% MMT. A ratio of maleated polypropylene, PP-g-MA to organoclay of unity was used as a compatibilizer in the nanocomposites. The organoclay serves to reduce the size of the EOR

Rajkiran R. Tiwari; D. R. Paul

2011-01-01

23

Tensile strength of wet granula materials  

Microsoft Academic Search

The dimensionless tensile strength ?d\\/? of wet granular materials with saturation levels in the plateau region of the pendular state was correlated with the void fraction of the agglomerate. The correlation fitted well with experimental measurements carried out on glass beads of diameter 93 ?m and with literature data, and was an improvement over the traditional Rumpf model. The tensile

Patrice Pierrat; Hugo S. Caram

1997-01-01

24

Effect of Fiber Strength on the Room Temperature Tensile Properties of Sic/Ti-24Al-11Nb  

NASA Technical Reports Server (NTRS)

SCA-6 SiC fibers of known strength were incorporated into SiC/Ti-24Al-11Nb (at. percent) composites and the effect of fiber strength variability on room temperature composite strength was investigated. Fiber was etched out of a composite fabricated by the powder cloth technique and the effect of the fabrication process on fiber strength was assessed. The strength of the composite was directly correlated with the strength of the as-received fiber. The strength of composite plates containing mixed fiber strengths was dominated by the lower strength fiber. Fabrication by the powder cloth technique resulted in only a slight degradation of fiber strength. The strength of the composite was found to be overestimated by the rule of mixtures strength calculation. Examination of failed tensile specimens revealed periodic fiber cracks and the failure mode was concluded to be cumulative. With the variation in fiber strength eliminated, the composite UTS was found to have a positive correlation with volume fraction of fiber.

Draper, S. L.; Brindley, P. K.; Nathal, M. V.

1991-01-01

25

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

Microsoft Academic Search

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

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

2003-01-01

26

Numerical simulation of microstructural damage and tensile strength of snow  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

27

Dynamic tensile strength of lunar rock types  

NASA Technical Reports Server (NTRS)

The dynamic tensile strength of four rocks are determined. A flat plate impact experiment is employed to generate approximately one-microsecond-duration tensile stress pulses in rock samples by superposing rarefaction waves to induce fracture. It is noted that the effect of chemical weathering and other factors has not been explicitly studied. The given tensile strengths are based on a series of experiments on each rock where determination of incipient spallation is made by terminal microscopic examination. The data are generally consistent with previous determinations, at least one of which was for a significantly chemically altered but physically coherent rock.

Cohn, S. N.; Ahrens, T. J.

1981-01-01

28

Dynamic tensile strength of lunar rock types  

NASA Astrophysics Data System (ADS)

The dynamic tensile strength of four rocks are determined. A flat plate impact experiment is employed to generate approximately one-microsecond-duration tensile stress pulses in rock samples by superposing rarefaction waves to induce fracture. It is noted that the effect of chemical weathering and other factors has not been explicitly studied. The given tensile strengths are based on a series of experiments on each rock where determination of incipient spallation is made by terminal microscopic examination. The data are generally consistent with previous determinations, at least one of which was for a significantly chemically altered but physically coherent rock.

Cohn, S. N.; Ahrens, T. J.

1981-03-01

29

Strength properties of glued laminated timber made from edge-glued laminae II: bending, tensile, and compressive strength of glued laminated timber  

Microsoft Academic Search

The purpose of this study was to investigate the strength properties of glued laminated timber composed of edge-glued laminae\\u000a and to investigate the influence of edge gluing on the strength properties. Glued laminated timber composed of multiple-grade\\u000a laminae (symmetrical composition, strength grade E95-F270, 10 laminations) was produced from karamatsu (Larix kaempferi) edge-glued laminae according to the Japanese Agricultural Standard. The

Yasushi Hiramatsu; Kiyohiko Fujimoto; Atsushi Miyatake; Kenta Shindo; Hirofumi Nagao; Hideo Kato; Hirofumi Ido

2011-01-01

30

Ultrasonic Spot Welding of Aluminum to High-Strength Low-Alloy Steel: Microstructure, Tensile and Fatigue Properties  

NASA Astrophysics Data System (ADS)

The structural applications of lightweight aluminum alloys inevitably involve dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change, lap shear tensile load, and fatigue resistance of dissimilar ultrasonic spot-welded joints of aluminum-to-galvanized high-strength low-alloy (HSLA) steel. Two non-uniform layers were identified in between Al and HSLA steel via SEM/EDS and XRD. One was an Al-Zn eutectic layer and the other was a thin (<2 ?m) layer of intermetallic compound (IMC) of Al and Fe in the nugget zone. The lap shear tensile testing gave a maximum load of 3.7 kN and the sample failed initially in between the Al-Zn eutectic film and Al-Fe IMC, and afterward from the region containing Al on both matching fracture surfaces. The fatigue test results showed a fatigue limit of about 0.5 kN (at 1 × 107 cycles). The maximum cyclic stress at which transition of the fatigue fracture from transverse through-thickness crack growth mode to the interfacial failure mode occurs increases with increasing energy input.

Patel, V. K.; Bhole, S. D.; Chen, D. L.

2014-04-01

31

Tensile properties of textile composites  

NASA Technical Reports Server (NTRS)

The importance of textile composite materials in aerospace structural applications has been gaining momentum in recent years. With a view to better understand the suitability of these materials in aerospace applications, an experimental program was undertaken to assess the mechanical properties of these materials. Specifically, the braided textile preforms were infiltrated with suitable polymeric matrices leading to the fabrication of composite test coupons. Evaluation of the tensile properties and the analyses of the results in the form of strength moduli, Poisson's ratio, etc., for the braided composites are presented. Based on our past experience with the textile coupons, the fabrication techniques have been modified (by incorporating glass microballoons in the matrix and/or by stabilizing the braid angle along the length of the specimen with axial fibers) to achieve enhanced mechanical properties of the textile composites. This paper outlines the preliminary experimental results obtained from testing these composites.

Avva, V. Sarma; Sadler, Robert L.; Lyon, Malcolm

1992-01-01

32

49 CFR 230.26 - Tensile strength of shell plates.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Tensile strength of shell plates. 230.26 Section... Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of steel or wrought-iron shell...

2013-10-01

33

49 CFR 230.26 - Tensile strength of shell plates.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Tensile strength of shell plates. 230.26 Section... Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of steel or wrought-iron shell...

2009-10-01

34

49 CFR 230.26 - Tensile strength of shell plates.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Tensile strength of shell plates. 230.26 Section... Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of steel or wrought-iron shell...

2010-10-01

35

Improved molding process ensures plastic parts of higher tensile strength  

NASA Technical Reports Server (NTRS)

Single molding process ensures that plastic parts /of a given mechanical design/ produced from a conventional thermosetting molding compound will have a maximum tensile strength. The process can also be used for other thermosetting compounds to produce parts with improved physical properties.

Heier, W. C.

1968-01-01

36

Tensile strength of dried gelcast green bodies  

SciTech Connect

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.

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

1994-04-01

37

Inherent tensile strength of molybdenum nanocrystals  

NASA Astrophysics Data System (ADS)

The strength of Mo nanorods was measured under uniaxial tension. Tensile tests of lang 110rang-oriented single-crystalline molybdenum rod-shaped specimens with diameters from 25 to 90 nm at the apex were conducted inside a field-ion microscope (FIM). The nanocrystals were free from dislocations, planar defects and microcracks, and exhibited the plastic mode of failure under uniaxial tension with the formation of a chisel-edge tip by multiple gliding in the (11\\bar{2})[111] and (112)[11\\bar{1}] deformation systems. The experimental values of tensile strength vary between 6.3 and 19.8 GPa and show a decrease with increasing nanorod diameter. A molecular dynamic simulation of Mo nanorod tension also suggests that the strength decreases from 28.8 to 21.0 GPa when the rod diameter increases from 3.1 to 15.7 nm. The maximum values of experimental strength are thought to correspond to the inherent strength of Mo nanocrystals under uniaxial tension (19.8 GPa, or 7.5% of Young's modulus).

Shpak, Anatoly P.; Kotrechko, Sergiy O.; Mazilova, Tatjana I.; Mikhailovskij, Igor M.

2009-08-01

38

Tensile properties of impact ices  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

39

Tensile and shear strength of adhesives  

NASA Technical Reports Server (NTRS)

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.

Stibolt, Kenneth A.

1990-01-01

40

Tensile properties of nanoclay reinforced epoxy composites  

NASA Astrophysics Data System (ADS)

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.

Ku, H.; Trada, Mohan

2013-08-01

41

Collagen cross-linking and ultimate tensile strength in dentin.  

PubMed

Several studies have indicated differences in bond strength of dental materials to crown and root dentin. To investigate the potential differences in matrix properties between these locations, we analyzed upper root and crown dentin in human third molars for ultimate tensile strength and collagen biochemistry. In both locations, tensile strength tested perpendicular to the direction of dentinal tubules (undemineralized crown = 140.4 +/- 48.6/root = 95.9 +/- 26.1; demineralized crown = 16.6 +/- 6.3/root = 29.0 +/- 12.4) was greater than that tested parallel to the tubular direction (undemineralized crown = 73.1 +/- 21.2/root = 63.2 +/- 22.6; demineralized crown = 9.0 +/- 3.9/root = 16.2 +/- 8.0). The demineralized specimens showed significantly greater tensile strength in root than in crown. Although the collagen content was comparable in both locations, two major collagen cross-links, dehydrodihydroxylysinonorleucine/its ketoamine and pyridinoline, were significantly higher in the root (by ~ 30 and ~ 55%, respectively) when compared with those in the crown. These results indicate that the profile of collagen cross-linking varies as a function of anatomical location in dentin and that the difference may partly explain the site-specific tensile strength. PMID:15381724

Miguez, P A; Pereira, P N R; Atsawasuwan, P; Yamauchi, M

2004-10-01

42

Stochastic models for the tensile strength, fatigue  

NASA Technical Reports Server (NTRS)

The time-to-failure of a single fiber is modeled as a functional of the fiber load history and reasonable forms for this functional are proposed. Earlier models by Daniels and Coleman are shown to be special cases of the proposed model and apparent disparities in their behavior are discussed. Techniques are presented for determining analytically the asymptotic distributions of the tensile strength and time-to-failure for bundles of a large number of fibers. For smaller bundles, exact results are far too cumbersome to be of use so that efficient Monte Carlo simulation procedures are proposed.

Phoenix, S. L.

1976-01-01

43

Strength and modulus of carbon nanotubes under a tensile load  

NASA Astrophysics Data System (ADS)

Carbon nanotubes (CNTs) were fabricated using low-pressure chemical vapor deposition and then embedded in epoxy polymer at several weight ratios, 0, 0.75, 1.5, and 3 wt%, for tensile testing and Young's modulus determination using an Instron machine. The tensile strength and Young's modulus of the epoxy resin were increased with the addition of CNTs to a certain extent, and then decreased with the increase in the weight fraction of CNTs. The best properties occurred at 1.5 wt% of CNTs. Scanning electron microscopy was used to reveal the dispersion status of CNTs in the nanocomposites.

Alnefaie, Khaled A.

2014-05-01

44

Measuring the Tensile Strength of B/AL Composites  

NASA Technical Reports Server (NTRS)

Proposed nondestructive technique correlates damping measurements with material strength. Increasing axial damping and decreasing axial tensile strength are observed after 1-hour treatment of B/AL composites containing about 50 percent fiber. Damping was measured in vacuum at frequencies near 2,000 Hz, and tensile strength was normalized by maximum strength observed before thermally induced degradation.

Dicarlo, J. A.

1983-01-01

45

The tensile strength of liquid helium four  

SciTech Connect

In this study, a piezoelectric transducer in the form of a hemispherical shell was used to focus high-intensity ultrasound into a small volume of {sup 4}He. The transducer was gated at its resonant frequency of 566 kHz with gate widths of less than 1 msec in order to minimize the effects of transducer heating and acoustic streaming. The onset of the nucleation was detected from the absorption of acoustic energy and the scattering of laser light from microscopic bubbles. A new theory for the diffraction of light from the focal zone of a spherical converging sound wave was developed to confirm calculations of the acoustic pressure amplitude at the focus of the piezoelectric transducer, calculations which were based on the acoustic power radiated into the liquid and the nonlinear absorption of sound. The experimental results were in agreement with homogeneous nucleation theory for a nucleation rate of approximately 10{sup 15} critical size bubbles/sec-cm{sup 3}. This is only the third liquid for which the theoretical tensile strength has been reached and it confirms homogeneous nucleation theory over a range three times greater than any other experiment. A noticeable decrease in the magnitude of the tensile strength was noted at temperatures near the lambda transition and a hypothesis that bubbles are being nucleated heterogeneously on quantitized vortices is presented.

Nissen, J.A.

1988-01-01

46

The relationship between tensile strength and flexure strength in fiber-reinforced composites  

Microsoft Academic Search

Tensile data on unidirectional composites generated from a flexure test usually yield a higher strength than observed from a standard tensile coupon. According to a statistical-strength theory based on a Weibull distribution, the presence of a stress gradient in the flexure-test results in an apparent increase in tensile strength as compared to the tensile test under uniform stress. In the

J. M. Whitney; M. Knight

1980-01-01

47

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

SciTech Connect

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.

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

2003-07-29

48

Tensile bond strength of maxillofacial adhesives.  

PubMed

A common technique for fixation of facial prostheses is the use of skin adhesives. The present study compared the tensile bond strength of five RTV-silicone elastomers used with four different skin adhesives to human skin. The elastomers were: Silskin II, MDX4-4210, Cosmesil, Cosmesil HC2, and RS 330 T-RTV. The adhesives were: Dow Corning 355 medical adhesive, PSA 1, Daro, and 9874 3M double-coated medical tape. The RTV silicones were cured as described by the manufacturer, fixed in circular metal holders, and glued to the skin (inner aspect of forearm) with the various adhesives. The specimens were pulled off 20 seconds after fixation by use of a universal testing machine with a crosshead speed of 1 mm/minute. Eight specimens of each silicone and adhesive combination were tested, and a mean bond strength was calculated for each combination and compared by Duncan's multiple range test on a personal computer. Significant differences were observed among the various combinations of silicones and adhesives. Dow Corning 355 adhesive showed the highest bond strength with all materials, and the medical tape had the lowest. Differences between the RTV silicones were also significant. The strongest bond with all adhesives was MDX4-4210 elastomer and the weakest for RS 330 T-RTV elastomer. PMID:8463965

Polyzois, G L; Oilo, G; Dahl, J E

1993-04-01

49

Neutron irradiated beryllium: tensile strength and swelling  

NASA Astrophysics Data System (ADS)

Four different species of beryllium: S-200F (vacuum hot pressed, 1.2 wt% BeO), S-200FH (hot isostatic pressed, 0.9 wt% BeO); S-65 (vacuum hot pressed, 0.6 wt% BeO) and S-65H (hot isostatic pressed, 0.5 wt% BeO) are fabricated by Brush Wellman. Three batches of the berylliums are investigated, a neutron irradiated batch, a thermal control batch and a reference batch. Neutron irradiation is performed at nominal temperature conditions of 200, 400 and 600°C up to a fluence of 1.5 × 10 25 n m -2 ( En ? 1 MeV). Based on the tensile tests results, the S-65 VHP and the S-200 HIP show slightly higher elongation and strength after irradiation. Based on the swelling determination, S-200 swells less than S-65. In conclusion, the S-200 HIP might tentatively be selected.

Moons, Frans; Sannen, Leo; Rahn, August; Van De Velde, José

1996-10-01

50

Tensile properties of irradiated surveillance coupons  

SciTech Connect

Tensile testing of austenitic steel and superalloy samples irradiated in the HMO 13 assembly was performed in support of the Fast Flux Test Facility (FFTF) Surveillance Program. Postirradiation yield stress, ultimate tensile stress, uniform elongation, total elongation, and reduction in area of 304 stainless steel (SS), 308 SS weld, 316 SS, A286, In718, and In718 weld were determined. Results showed the strength of austenitic steels increased while the ductility decreased as a result of irradiation. Low irradiation exposure produced little property change in In718. Overall, the tensile properties of HMO 13 surveillance coupons showed a lower magnitude of irradiation-induced property change than was expected based on earlier studies. Results from these tests gave no indications of unexpectedly severe irradiation damage to FFTF components.

Huang, F.H.; Blackburn, L.D.

1994-06-01

51

Experimental Study on Tensile Strength of Composite Repair  

NASA Astrophysics Data System (ADS)

In this research, CFRP scarf repair panels were tested to evaluate the tensile mechanical properties and impact characteristics. CFRP scarf repair panels were prepared to simulate the assumed three different situations. These situations consist of two different scarf repair methods and impact damage case which are autoclave repair, heat blanket repair, and impact damage case. As the result, these strengths are not recovered in all situations, however, stiffness was recovered in all situations. Moreover, the strength of heat blanket repair and impact damage case were reduced compared with autoclave repair.

Hoshi, Hikaru; Iwahori, Yutaka; Yajima, Hiroshi

52

[Tensile strength of short-fiber-reinforced temporary plastics].  

PubMed

Glass fibers added to temporary crown and bridge material (Proviso-Blend, Blendax) by 5% to the weight increased the tensile strength of the acrylic resin by 38%. The increase was even greater when carbon fibers were added (50%), but the resin discoloured to a greyish shade. The results were less spectacular with Dentalon Plus (Kulzer), and the experiment did not work with Protemp (Espe). The amount of improvement in tensile strength depended on the type and geometry of the fiber and of the fiber concentration. Neither the properties of the polished surface of a fiber-reinforced acrylic nor adverse effects of such fibers possibly swallowed by the patient are investigated as yet. PMID:2772590

Setz, J; Lin, W

1989-01-01

53

THE DYNAMIC TENSILE STRENGTH OF ICE AND ICE-SILICATE MIXTURES  

Microsoft Academic Search

We determined the dynamic tensile of fracturing and fragmentation properties of icy strength of ice and ice silicate mixtures at substances. Our goal in previous studies has been strain rates of 104 s -1. At these strain rates, to establish some data and scaling laws related to ice has a tensile strength of ~17 MPa, and impact crater formation and

Manfred A. Lange; Thomas J. Ahrens

1983-01-01

54

Elevated temperature tensile properties of borated 304 stainless steel: Effect of boride dispersion on strength and ductility  

SciTech Connect

This paper has documented the increase in strain to fracture and yield strength obtained with Grade A versions of types 304B5 and 304B7 relative to their respective Grade B, counterparts. The apparent microstructural reason for these property increases is the finer dispersion of boride in the Grade A material, obtained by means of a Powder Metallurgy process, relative to the conventional Grade B material which is produced using an Ingot Metallurgy process. The area size distribution of borides can be well approximated using a log-normal distribution, with the largest boride particles in the Grade B material having areas in the range of 450--600 {mu}m{sup 2}. By comparison, the largest boride particles in the Grade A material have areas nearly an order of magnitude smaller than the largest particles in their Grade B counterparts. A Section III ASME B&PV code case inquiry has been initiated for non-welded versions of 304B4A, 3045A and 3046A ,material.

Stephens, J.J.; Sorenson, K.B.; McConnell, P.

1991-12-31

55

Study of the theoretical tensile strength of Fe by a first-principles computational tensile test  

NASA Astrophysics Data System (ADS)

This paper employs a first-principles total-energy method to investigate the theoretical tensile strengths of bcc and fcc Fe systemically. It indicates that the theoretical tensile strengths are shown to be 12.4, 32.7, 27.5 GPa for bcc Fe, and 48.1, 34.6, 51.2 GPa for fcc Fe in the [001], [110] and [111] directions, respectively. For bcc Fe, the [001] direction is shown to be the weakest direction due to the occurrence of a phase transition from ferromagnetic bcc Fe to high spin ferromagnetic fcc Fe. For fcc Fe, the [110] direction is the weakest direction due to the formation of an instable saddle-point 'bct structure' in the tensile process. Furthermore, it demonstrates that a magnetic instability will occur under a tensile strain of 14%, characterized by the transition of ferromagnetic bcc Fe to paramagnetic fcc Fe. The results provide a good reference to understand the intrinsic mechanical properties of Fe as a potential structural material in the nuclear fusion Tokamak.

Liu, Yue-Lin; Zhang, Ying; Hong, Rong-Jie; Lu, Guang-Hong

2009-05-01

56

The relationship between tensile strength and shear strength in composite materials subjected to high strain rates  

Microsoft Academic Search

The dynamic behavior of a woven carbon\\/epoxy composite subjected to tensile and shear impact loading in the orthogonal direction (using the tensile and torsional split-Hopkinson bars, respectively) is studied. The influences of the equivalent strain rates on the tensile and shear yield stress and strength are found. The yield stress ratio and strength ratio between tensile and shear loading on

Chi-Yuen Chiem; Zeng-Gang Liu

1988-01-01

57

Aluminum/steel wire composite plates exhibit high tensile strength  

NASA Technical Reports Server (NTRS)

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.

1966-01-01

58

An experimental evaluation of the tensile strength of impact ice  

NASA Technical Reports Server (NTRS)

The evaluation of the tensile strength of impact built-up ice on structural components has been prompted by such problems as electrical transmission line losses and catastrophic failures in Arctic regions, deicing problems with fixed-wing and rotary-wing aircraft, etc. It is demonstrated that the conventional tensile-testing technique furnishes adequate data on artificially refrigerated ice, and helps establish the influence of extrinsic factors on ice tensile strength.

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

1989-01-01

59

Tensile Properties of GRCop-84.  

National Technical Information Service (NTIS)

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 extru...

D. L. Ellis H. M. Yun W. S. Loewenthal

2012-01-01

60

Effects of Rolling and Cooling Conditions on Microstructure and Tensile and Charpy Impact Properties of Ultra-Low-Carbon High-Strength Bainitic Steels  

NASA Astrophysics Data System (ADS)

Six ultra-low-carbon high-strength bainitic steel plates were fabricated by controlling rolling and cooling conditions, and effects of bainitic microstructure on tensile and Charpy impact properties were investigated. The microstructural evolution was more critically affected by start cooling temperature and cooling rate than by finish rolling temperature. Bainitic microstructures such as granular bainites (GBs) and bainitic ferrites (BFs) were well developed as the start cooling temperature decreased or the cooling rate increased. When the steels cooled from 973 K or 873 K (700 °C or 600 °C) were compared under the same cooling rate of 10 K/s (10 °C/s), the steels cooled from 973 K (700 °C) consisted mainly of coarse GBs, while the steels cooled from 873 K (600 °C) contained a considerable amount of BFs having high strength, thereby resulting in the higher strength but the lower ductility and upper shelf energy (USE). When the steels cooled from 673 K (400 °C) at a cooling rate of 10 K/s (10 °C/s) or 0.1 K/s (0.1 °C/s) were compared under the same start cooling temperature of 873 K (600 °C), the fast cooled specimens were composed mainly of coarse GBs or BFs, while the slowly cooled specimens were composed mainly of acicular ferrites (AFs). Since AFs had small effective grain size and contained secondary phases finely distributed at grain boundaries, the slowly cooled specimens had a good combination of strength, ductility, and USE, together with very low energy transition temperature (ETT).

Sung, Hyo Kyung; Shin, Sang Yong; Hwang, Byoungchul; Lee, Chang Gil; Kim, Nack J.; Lee, Sunghak

2011-07-01

61

The microstructure, hardness and tensile properties of a new super high strength aluminum alloy with Zr addition  

Microsoft Academic Search

This research is based on the addition of zirconium to a new super high strength Al–12.24Zn–3.25Mg–2.46Cu alloy. The results showed that Zr addition decreases average grain size (approximately 20%), forms rosette-like microstructure and introduces proper distribution of the second phases. In addition, due to the presence of Al3Zr particles in Zr-refined specimen, the area fraction of recrystallized regions decreased by

S. H. Seyed Ebrahimi; M. Emamy; N. Pourkia; H. R. Lashgari

2010-01-01

62

The Hen's egg: Variation in tensile strength of shell material and its relationship with shearing strength  

Microsoft Academic Search

The tensile strength of egg?shell material is believed to play an important role in determining whether or not a shell will crack when exposed to an environmental insult. Experiments are described in which shell tensile strength was measured. It is concluded that: i. the force required to produce tensile failure did not vary linearly with the width of the piece

T. C. Carter

1971-01-01

63

Tensile properties of stainless steel sandwich sheets with fibrous cores  

Microsoft Academic Search

The unnotched and notched tensile properties of flocked and brazed stainless steel sandwiches with fibrous cores were examined. The tensile stress-strain responses show that the fibres do not carry any load in the flocked sheets and that the load transfer is better facilitated in the brazed sandwich sheets. Notched strength results show that the flocked sheets are notch-insensitive whereas the

M. A. Azeem; C. Shortall; U. Ramamurty

2007-01-01

64

Effects of Porosity on Weld-Joint Tensile Strength of Aluminum Alloys.  

National Technical Information Service (NTIS)

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 ...

C. V. Lovoy

1974-01-01

65

Residual Stress Distribution of 600MPa Grade High Tensile Strength Steel Pipe Using Welding fe Simulation  

NASA Astrophysics Data System (ADS)

This paper aims to determine the residual stress distribution of 600MPa grade high tensile strength steel pipe (STKT590) by girth welding. Welding FE simulation is achieved considering temperature dependent physical constants and mechanical properties, obtained by the temperature elevated tensile tests. Comparative analyses clarify the characteristics of residual stress profile near weld joint of STKT590 pipe.

Chang, Kyong-Ho; Jang, Gab-Chul

2011-06-01

66

Enhanced tensile strength for electrodeposited nickel-copper multilayer composites  

NASA Astrophysics Data System (ADS)

The tensile strength of electrodeposited layered composites of the nominal overall composition 90 pct Ni-10 pct Cu is shown to increase sharply to the 1300 MPa range as the thickness of the Cu layers is decreased below ~0.4 ?m. This tensile strength value is almost a factor of three greater than that measured for Ni itself, and more than a factor of two greater than the handbook value for Monel 400.

Tench, Dennis; White, John

1984-11-01

67

Effects of temperature on the tensile strength of pharmaceutical powders.  

PubMed

Measurements have been made of the tensile strengths of fatty acids, lactose and of an oxtetracycline and a paracetamol tablet formulation at temperatures between -20 and +90 degrees. The measurements were made on compressed tablets and on consolidated beds of powders, using a diametral compression tester and a split plate tensile tester which had been designed to operate over this range of temperature. The tensile strengths of all the materials increase with temperature and values are given for the activation energies of bonding between particles. PMID:31427

Britten, J R; Pilpel, N

1978-11-01

68

Correlation of Yield Strength and Tensile Strength with Hardness for Steels  

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

69

Hoop Tensile Strength Testing of Small Diameter Ceramic Particles  

SciTech Connect

A method to measure hoop tensile strength of 1-mm-diameter brittle ceramic spheres was demonstrated through the use of a "C-sphere" flexure strength specimen. This innovative specimen geometry was chosen because a simple, monotonically increasing uniaxial compressive force produces a hoop tensile stress at the C-sphere's outer surface that ultimately initiates fracture. This enables strength quantification and strength-limiting flaw identification of the sphere itself. Such strength information is relevant to design optimization and durability assessments of ceramic fuel particles and breeder/multiplier pebbles for fusion whose surfaces are subjected to tensile stresses caused by thermal gradients, thermal transients, swelling, etc., during their manufacturing or service.

Wereszczak, Andrew A [ORNL; Jadaan, Osama M. [University of Wisconsin, Platteville; Lin, Hua-Tay [ORNL; Champoux, Gregory J [ORNL; Ryan, David P [ORNL

2007-01-01

70

The tensile strength and ductility of continuous fibre composites  

Microsoft Academic Search

The plastic instability approach has been applied to the tensile behaviour of a continuous fibre composite. It is shown that the combination of two components with different strengths and degrees of work-hardening produces a new material with a new degree of work-hardening, which may be determined by the present analysis. Expressions for the elongation at rupture and the strength of

S. T. Mileiko

1969-01-01

71

Experimental and Numerical Studies on Determination of Indirect Tensile Strength of Rocks  

NASA Astrophysics Data System (ADS)

Indirect tension tests using Brisbane tuff Brazilian disc specimens under standard Brazilian jaws and various loading arcs were performed. The standard Brazilian indirect tensile tests caused catastrophic, crushing failure of the disc specimens, rather than the expected tensile splitting failure initiated by a central crack. This led to an investigation of the fracturing of Brazilian disc specimens and the existing indirect tensile Brazilian test using steel loading arcs with different angles. The results showed that the ultimate failure load increased with increasing loading arc angles. With no international standard for determining indirect tensile strength of rocks under diametral load, numerical modelling and analytical solutions were undertaken. Numerical simulations using RFPA2D software were conducted with a heterogeneous material model. The results predicted tensile stress in the discs and visually reproduced the progressive fracture process. It was concluded that standard Brazilian jaws cause catastrophic, crushing failure of the disc specimens instead of producing a central splitting crack. The experimental and numerical results showed that 20° and 30° loading arcs result in diametral splitting fractures starting at the disc centre. Moreover, intrinsic material properties (e.g. fracture toughness) may be used to propose the best loading configuration to determine the indirect tensile strength of rocks. Here, by using numerical outcomes and empirical relationships between fracture toughness and tensile strength, the best loading geometry to obtain the most accurate indirect tensile strength of rocks was the 2? = 30° loading arc.

Erarslan, Nazife; Liang, Zheng Zhao; Williams, David John

2012-09-01

72

On the dynamic tensile strength of Zirconium  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

73

Silicon nitride having a high tensile strength  

DOEpatents

A silicon nitride ceramic is disclosed comprising: (a) inclusions no greater than 25 microns in length, (b) agglomerates no greater than 20 microns in diameter, and (c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa. 4 figs.

Pujari, V.K.; Tracey, D.M.; Foley, M.R.; Paille, N.I.; Pelletier, P.J.; Sales, L.C.; Willkens, C.A.; Yeckley, R.L.

1996-11-05

74

Silicon nitride having a high tensile strength  

DOEpatents

A silicon nitride ceramic comprising: a) inclusions no greater than 25 microns in length, b) agglomerates no greater than 20 microns in diameter, and c) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa.

Pujari, Vimal K. (Northboro, MA); Tracey, Dennis M. (Medfield, MA); Foley, Michael R. (Oxford, MA); Paille, Norman I. (Oxford, MA); Pelletier, Paul J. (Millbury, MA); Sales, Lenny C. (Grafton, MA); Willkens, Craig A. (Sterling, MA); Yeckley, Russell L. (Oakham, MA)

1996-01-01

75

Tensile properties of titanium electrolytically charged with hydrogen  

NASA Technical Reports Server (NTRS)

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.

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

1971-01-01

76

Tensile and fatigue properties of Inconel 718 at cryogenic temperatures  

NASA Technical Reports Server (NTRS)

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.

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

1969-01-01

77

On the Tensile Strength of a Solid Nanowire  

Microsoft Academic Search

The present paper is concerned with the mechanical characterization of the measured tensile strength of a solid nanowire.\\u000a As miniaturization is a general trend in nanotechnology, a variety of nanowires have been successfully fabricated\\/synthesized,\\u000a including but not limited to Si, C, polymer DNA, MoSe, Au, Cu, TiC, Fe, Mo, NiAl and W. Mechanical strength is essential to\\u000a maintaining the structural

Tze-jer Chuang

78

An investigation into geometry and microstructural effects upon the ultimate tensile strengths of butt welds  

NASA Technical Reports Server (NTRS)

A mathematical theory was evaluated empirically. This theory predicts weld ultimate tensile strength based on material properties and fusion line angles, mismatch, peaking, and weld widths. Welds were made on 1/4 and 1/2 in. aluminum 2219-T87, their geometries were measured, they were tensile tested, and these results were compared to theoretical predictions. Statistical analysis of results was performed to evaluate correlation of theory to results for many different categories of weld geometries.

Gordon, Stephen S.

1992-01-01

79

Measurement of the tensile strength of brittle materials  

Microsoft Academic Search

Three alternative methods for measuring the tensile strengths of brittle materials are investigated and compared with the conventional pull method. These are a bending test, an indentation test and a test in which disks are compressed diametrally. Experiments on plaster of Paris, coal and cement show that, apart from the bending test, the methods give results in reasonable agreement. The

R. Berenbaum; I. Brodie

1959-01-01

80

Through-the-Thickness Tensile Strength of Textile Composites.  

National Technical Information Service (NTIS)

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-t...

W. C. Jackson P. G. Ifju

1994-01-01

81

Importance of Tensile Strength on the Shear Behavior of Discontinuities  

NASA Astrophysics Data System (ADS)

In this study, the shear behavior of discontinuities possessing two different rock wall types with distinct separate compressive strengths was investigated. The designed profiles consisted of regular artificial joints molded by five types of plaster mortars, each representing a distinct uniaxial compressive strength. The compressive strengths of plaster specimens ranged from 5.9 to 19.5 MPa. These specimens were molded considering a regular triangular asperity profile and were designed so as to achieve joint walls with different strength material combinations. The results showed that the shear behavior of discontinuities possessing different joint wall compressive strengths (DDJCS) tested under constant normal load (CNL) conditions is the same as those possessing identical joint wall strengths, but the shear strength of DDJCS is governed by minor joint wall compressive strength. In addition, it was measured that the predicted values obtained by Barton's empirical criterion are greater than the experimental results. The finding indicates that there is a correlation between the joint roughness coefficient (JRC), normal stress, and mechanical strength. It was observed that the mode of failure of asperities is either pure tensile, pure shear, or a combination of both. Therefore, Barton's strength criterion, which considers the compressive strength of joint walls, was modified by substituting the compressive strength with the tensile strength. The validity of the modified criterion was examined by the comparison of the predicted shear values with the laboratory shear test results reported by Grasselli (Ph.D. thesis n.2404, Civil Engineering Department, EPFL, Lausanne, Switzerland, 2001). These comparisons infer that the modified criterion can predict the shear strength of joints more precisely.

Ghazvinian, A. H.; Azinfar, M. J.; Geranmayeh Vaneghi, R.

2012-05-01

82

Tensile Properties of Polycarbonate\\/Polymethyl Methacrylate Blend Coated Natural Fabric Hildegardia Populifolia  

Microsoft Academic Search

The uniaxial natural fabric Hildegardia populifolia was coated with polycarbonate\\/polymethyl methacrylate blend and its tensile strength, modulus and percentage of elongation at break were determined. The effect of alkali treatment on the tensile properties of the fabric was also studied. The tensile properties were enhanced by alkali treatment. The morphology of the fabric before and after coating was studied by

D. Jagadeesh; A. Varada Rajulu; B. R. Guduri

2010-01-01

83

The theoretical tensile strength of fcc crystals predicted from shear strength calculations.  

PubMed

This work presents a simple way of estimating uniaxial tensile strength on the basis of theoretical shear strength calculations, taking into account its dependence on a superimposed normal stress. The presented procedure enables us to avoid complicated and time-consuming analyses of elastic stability of crystals under tensile loading. The atomistic simulations of coupled shear and tensile deformations in cubic crystals are performed using first principles computational code based on pseudo-potentials and the plane wave basis set. Six fcc crystals are subjected to shear deformations in convenient slip systems and a special relaxation procedure controls the stress tensor. The obtained dependence of the ideal shear strength on the normal tensile stress seems to be almost linearly decreasing for all investigated crystals. Taking these results into account, the uniaxial tensile strength values in three crystallographic directions were evaluated by assuming a collapse of the weakest shear system. Calculated strengths for [Formula: see text] and [Formula: see text] loading were found to be mostly lower than previously calculated stresses related to tensile instability but rather close to those obtained by means of the shear instability analysis. On the other hand, the strengths for [Formula: see text] loading almost match the stresses related to tensile instability. PMID:21825337

Cerný, M; Pokluda, J

2009-04-01

84

Tensile Strength of Natural Fiber Reinforced Polyester Composite  

NASA Astrophysics Data System (ADS)

Nowadays, increasing awareness of replacing synthetic fiber such as glass fiber has emerged due to environmental problems and pollutions. Automotive manufacturers also seek new material especially biodegradable material to be non-load bearing application parts. This present work discussed on the effect of silane treatment on coir fiber reinforced composites. From the results of tensile tests, fibers treated with silane have attained maximum material stiffness. However, to achieve maximum ultimate tensile strength and strain at failure performances, untreated fibers work very well through fiber bridging and internal friction between fiber and polymeric matrix. Scanning electron microscope (SEM) observations have coincided with these results.

Ismail, Al Emran; Awang, Muhd. Khairudin; Sa'At, Mohd Hisham

2007-05-01

85

Tensile Properties of Self-Healing Epoxy  

Microsoft Academic Search

This project investigates the effect of microcapsule concentration on tensile properties of self-healing epoxy. The self-healing material under investigation is an epoxy matrix composite, which incorporates microencapsulated healing agent that is released by crack intrusion. Polymerization of the healing agent is triggered by contact with an embedded catalyst. Uniaxial tensile tests were performed on standard dogbone samples to measure Young's

Alyssa A. Rzeszutko

86

Tensile Properties of Resin-infiltrated Demineralized Human Dentin  

Microsoft Academic Search

The ability of adhesive resins to restore the physical properties of demineralized dentin has not been well-documented. The unfilled resins that are used for adhesion have relatively low moduli of elasticity and limited ability to increase dentin stiffness, although they may increase the ultimate tensile strength of dentin. This study tested the hypothesis that resin infiltration of demineralized dentin can

H. Sano; T. Takatsu; B. Ciucchi; C. M. Russell; D. H. Pashley

1995-01-01

87

The tensile strength of bilayered tablets made from different grades of microcrystalline cellulose  

Microsoft Academic Search

The aim of this work was to determine the tensile strength of bilayered tablets made from different grades of microcrystalline cellulose. While these grades are chemically identical, they differ significantly in their particle size distribution and in their mechanical properties such as Young's modulus of elasticity. Tablets were produced in the shape of beams of similar dimensions using uniaxial compression,

Fridrun Podczeck; Emad Al-Muti

2010-01-01

88

Morphogenesis of Plasmodium zoites is uncoupled from tensile strength  

PubMed Central

A shared feature of the motile stages (zoites) of malaria parasites is a cortical cytoskeletal structure termed subpellicular network (SPN), thought to define and maintain cell shape. Plasmodium alveolins comprise structural components of the SPN, and alveolin gene knockout causes morphological abnormalities that coincide with markedly reduced tensile strength of the affected zoites, indicating the alveolins are prime cell shape determinants. Here, we characterize a novel SPN protein of Plasmodium berghei ookinetes and sporozoites named G2 (glycine at position 2), which is structurally unrelated to alveolins. G2 knockout abolishes parasite transmission and causes zoite malformations and motility defects similar to those observed in alveolin null mutants. Unlike alveolins, however, G2 contributes little to tensile strength, arguing against a cause-effect relationship between tensile strength and cell shape. We also show that G2 null mutant sporozoites display an abnormal arrangement of their subpellicular microtubules. These results provide important new understanding of the factors that determine zoite morphogenesis, as well as the potential roles of the cortical cytoskeleton in gliding motility.

Tremp, Annie Z; Carter, Victoria; Saeed, Sadia; Dessens, Johannes T

2013-01-01

89

Distribution of tensile property and microstructure in friction stir weld of 6063 aluminum  

Microsoft Academic Search

Dominant microstructural factors governing the global tensile properties of a friction-stir-welded joint of 6063 aluminum\\u000a were examined by estimating distribution of local tensile properties corresponding to local microstructure and hardness. Yield\\u000a and ultimate tensile strengths of the as-welded weld were significantly lower than those of the base material. Postweld aging\\u000a and postweld solution heat-treatment and aging (SHTA) restored the strengths

Yutaka S. Sato; Hiroyuki Kokawa

2001-01-01

90

Tensile strength of bilayered ceramics and corresponding glass veneers  

PubMed Central

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.

Champirat, Tharee; Jirajariyavej, Bundhit

2014-01-01

91

Scale effects on the transverse tensile strength of graphite epoxy composites  

NASA Technical Reports Server (NTRS)

The influence of material volume on the transverse tensile strength of AS4/3501-6 graphite epoxy composites was investigated. Tensile tests of 90 degree laminates with 3 different widths and 5 different thicknesses were conducted. A finite element analysis was performed to determine the influence of the grip on the stress distribution in the coupons and explain the tendency for the distribution of failure locations to be skewed toward the grip. Specimens were instrumented with strain gages and extensometers to insure good alignment and to measure failure strains. Data indicated that matrix dominated strength properties varied with the volume of material that was stressed, with the strength decreasing as volume increased. Transverse strength data were used in a volumetric scaling law based on Weibull statistics to predict the strength of 90 degree laminates loaded in three point bending. Comparisons were also made between transverse strength measurements and out-of-plane interlaminar tensile strength measurements from curved beam bending tests. The significance of observed scale effects on the use of tests for material screening, quality assurance, and design allowables is discussed.

Obrien, T. Kevin; Salpekar, Satish A.

1992-01-01

92

[The compressive strength, tensile strength, flexural strength and micro-hardness of Plat-II Castable Ceramics].  

PubMed

In preparation for the clinical use of Plat-II Castable Ceramics (PCC-II), we tested its compressive strength, tensile strength, flexural strength and microhardness. The flexural strength was tested by the three-point bending test. The result showed that the compressive strength was 541.7 MPa; the tensile strength 42.5 MPa; the flexural strength 142.0 MPa; the modulus of elasticity 61.4 GPa; and the micro-hardness 499.6 kg/mm3. The strength anol micro-hardness of PCC-II materials were better than those of human enamel. So PCC-II is applicable to restorations in dentistry. PMID:10683943

Wang, H; Zhao, Y; Fan, Y; Chen, Y

1997-12-01

93

Through-the-thickness tensile strength of textile composites  

NASA Technical Reports Server (NTRS)

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.

Jackson, Wade C.; Ifju, Peter G.

1994-01-01

94

Predicting Tensile Strengths of Boron/Aluminum Composites  

NASA Technical Reports Server (NTRS)

To develop predictive theory to account for time/temperature effect of B/A1 composites, series of deformation and fracture studies was performed on commercial boron fibers over wide ranges of stress, stress application time, and temperature. By combining these single fiber results with fracture theory for metal matrix composites, design formulas were derived that describe B/A1 composite tensile and stress rupture strengths as function of time and temperature. Using derived formulas, calculated and experimental results agree to within 3 percent.

Decarlo, J. A.

1982-01-01

95

Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study.  

PubMed

The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks. PMID:23858281

Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

2012-06-01

96

Dynamic yield and tensile strengths of spark plasma sintered alumina  

NASA Astrophysics Data System (ADS)

Fully dense alumina samples with 0.6 ?m grain size were produced from alumina powder using Spark Plasma Sintering and tested in two types of VISAR-instrumented planar impact tests. In the tests of the first type the samples of 0.28 to 6-mm thickness were loaded by 1-mm tungsten impactors accelerated up to a velocity of about 1 km/s. These tests were aimed to study the Hugoniot elastic limit (HEL) of the SPS-processed alumina and the decay of the elastic precursor wave with propagation distance. In the second type of test the samples of ~3-mm thickness were loaded by 1-mm copper impactors accelerated up to velocities 100-1000 m/s. These tests were aimed to study the dynamic tensile (spall) strength of the alumina. The data on tensile fracture of the alumina demonstrate a monotonic decline of the spall strength with the amplitude of the loading stress pulse. The data on the decay of the elastic precursor wave allows for determining the rates of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of shock-induced inelastic deformation and, thus, to derive some conclusions concerning the mechanisms responsible of the deformation.

Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M.; Frage, N.

2014-05-01

97

High Tensile Strength Amalgams for In-Space Repair and Fabrication  

NASA Technical Reports Server (NTRS)

Amalgams are defined as an alloy of mercury with one or more other metals. These, along with those based on gallium (also liquid at near room temperature), are widely used in dental practice as a tooth filling material. Amalgams have a number of useful attributes that indude room temperature compounding. corrosion resistance, dimensional stability, and good compressive strength. These properties well serve dental needs but, unfortunately, amalgams have extremely poor tensile strength, a feature that severely limits their applications. The work presented here demonstrates how, by modifying particle geometry, the tensile strength of amalgams can be increased and thus extending the range of potential applications. This is relevant to, for example, the freeform fabrication of replacement parts that might be necessary during an extended space mission. Advantages, i.e. Figures-of-Merit. include the ability to produce complex parts, minimum crew interaction, high yield - minimum wasted material, reduced gravity compatibility, minimum final finishing, safety, and minimum power consumption.

Grugel, R. N.

2005-01-01

98

Experimental and numerical investigation on the dynamic tensile strength of concrete  

Microsoft Academic Search

A new experimental method for testing the dynamic tensile behavior of concrete at high strain rates was designed and established. By using this method, the dynamic tensile strength of concrete and its dependence on strain rates were measured and investigated. The experimental results indicate that the dynamic tensile strength of concrete is rate sensitive. The numerical simulation results have a

Haijun Wu; Qingming Zhang; Fenglei Huang; Qiankun Jin

2005-01-01

99

Some investigations about the tensile strength and the desiccation process of unsaturated clay  

NASA Astrophysics Data System (ADS)

The current paper presents an investigation on the tensile strength of unsaturated clay, and a discussion about the significant differences between the behaviours of compacted soils and those of the completely remoulded soils. The adapted experimental device based on the shear box for the measurement of the tensile strength is also presented. In the tensile tests, stress-strain characteristics are measured using high precision transducers and electronic data acquisition. The equipment is capable of measuring tensile strengths of soil (about 10 MPa). Moreover, a new model to predict cracks is presented in 3D. This analytical model for the prediction of tensile strength, as a function of suction and porosity, is given.

Trabelsi, H.; Jamei, M.; Guiras, H.; Hatem, Z.; Romero, E.; Sebastia, O.

2010-06-01

100

Tensile strength of single-walled carbon nanotubes directly measured from their macroscopic ropes  

Microsoft Academic Search

20 mm long ropes consisting of soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements. The average tensile strength of SWNT rope composites is as high as 3.6+\\/-0.4 GPa, similar to that of carbon fibers. The tensile strength of SWNT bundles was extrapolated from the strength of the

F. Li; H. M. Cheng; S. Bai; G. Su; M. S. Dresselhaus

2000-01-01

101

Enhancement of hydrophobicity and tensile strength of muga silk fiber by radiofrequency Ar plasma discharge  

NASA Astrophysics Data System (ADS)

The hydrophobicity and tensile strength of muga silk fiber are investigated using radiofrequency (RF) Ar plasma treatment at various RF powers (10-30 W) and treatment times (5-20 min). The Ar plasma is characterized using self-compensated Langmuir and emissive probe. The ion energy is observed to play an important role in determining the tensile strength and hydrophobicity of the plasma treated fibers. The chemical compositions of the fibers are observed to be affected by the increase in RF power rather than treatment time. XPS study reveals that the ions that are impinging on the substrates are mainly responsible for the cleavage of peptide bond and side chain of amino acid groups at the surface of the fibers. The observed properties (tensile strength and hydrophobicity) of the treated fibers are found to be dependent on their variation in atomic concentration and functional composition at the surfaces. All the treated muga fibers exhibit almost similar thermal behavior as compared to the virgin one. At RF power of 10 W and treatment time range of 5-20 min, the treated fibers exhibit properties similar to that of the virgin one. Higher RF power (30 W) and the increase in treatment time deteriorate the properties of the fibers due to incorporation of more surface roughness caused by sufficiently high energetic ion bombardment. The properties of the plasma treated fibers are attempted to correlate with the XPS analysis and their surface morphologies.

Gogoi, D.; Choudhury, A. J.; Chutia, J.; Pal, A. R.; Dass, N. N.; Devi, D.; Patil, D. S.

2011-10-01

102

Tensile Properties of Irradiated Tzm and Tungsten.  

National Technical Information Service (NTIS)

The effect of neutron irradiation on the elevated temperature tensile properties of TZM and tungsten has been experimentally determined. Specimens were irradiated at a temperature of approximately 720 exp 0 F to fluences of 0.4 and 0.9 x 10 exp 22 n/cm ex...

J. M. Steichen

1975-01-01

103

Prediction of Uniaxial Compressive Strength, Tensile Strength and Porosity of Sedimentary Rocks Using Sound Level Produced During Rotary Drilling  

NASA Astrophysics Data System (ADS)

The main purpose of the study is to develop a general prediction model and to investigate the relationships between sound level produced during drilling and physical properties such as uniaxial compressive strength, tensile strength and percentage porosity of sedimentary rocks. The results were evaluated using the multiple regression analysis taking into account the interaction effects of various predictor variables. Predictor variables selected for the multiple regression model are drill bit diameter, drill bit speed, penetration rate and equivalent sound level produced during rotary drilling ( L eq). The constructed models were checked using various prediction performance indices. Consequently, it is possible to say that the constructed models can be used for practical purposes.

Rajesh Kumar, B.; Vardhan, Harsha; Govindaraj, M.

2011-09-01

104

Tensile properties of amorphous diamond films  

SciTech Connect

The strength and modulus of amorphous diamond, a new material for surface micromachined MEMS and sensors, was tested in uniaxial tension by pulling laterally with a flat tipped diamond in a nanoindenter. Several sample designs were attempted. Of those, only the single layer specimen with a 1 by 2 {micro}m gage cross section and a fixed end rigidly attached to the substrate was successful. Tensile load was calculated by resolving the measured lateral and normal forces into the applied tensile force and frictional losses. Displacement was corrected for machine compliance using the differential stiffness method. Post-mortem examination of the samples was performed to document the failure mode. The load-displacement data from those samples that failed in the gage section was converted to stress-strain curves using carefully measured gage cross section dimensions. Mean fracture strength was found to be 8.5 {+-} 1.4 GPa and the modulus was 831 {+-} 94 GPa. Tensile results are compared to hardness and modulus measurements made using a nanoindenter.

Lavan, D.A.; Hohlfelder, R.J.; Sullivan, J.P.; Friedmann, T.A.; Mitchell, M.A.; Ashby, C.I.

1999-12-02

105

Predicting yield strength and tensile strength after forming for automotive integral body structural rail type parts  

SciTech Connect

Samples of cold rolled and hot dip galvanized mild steel, microalloyed high strength steel, and dual phase steel were prestrained by bending and straightening, bending and straightening with superimposed tensile strain in a die, and cold rolling (dual phase steels only). In all three cases, the strain state was approximately plane strain. Stress-strain behavior was evaluated by conventional tensile testing of as-received and prestrained samples. For the mild and the high strength microalloyed steels, it is shown that the use of effective prestrain calculated assuming isotropy coupled with simple parabolic work hardening provides reasonable engineering estimates of the yield and tensile strength after prestraining if K and n are taken from as-received tensile tests oriented coaxially to the restrain direction. It was also found that in bending and straightening, only the absolute average value of the bending strain should be used in calculating the effective prestrain. For steels with dual phase microstructures, this approach to predicting cold work strengthening does not provide useful engineering estimates.

Levy, B.S.

1984-01-01

106

Prediction of residual tensile strength of transversely impacted composite laminates  

NASA Technical Reports Server (NTRS)

The response to low velocity impact of graphite-epoxy T300/5208 composite laminates is discussed. Steel balls of 3/8 inch, 5/8 inch, and 1 inch diameter were the projectiles. Impact energy was limited to 1.2 joules. Impacted specimens were ultrasonically C scanned to determine the impact damaged region. The threshold value of impact energy for impact damage was found to be approximately 0.3 joules. A model was developed to predict the tensile residual strength of impact damaged specimens from fracture mechanics concepts. Impacted specimens were tested in tension to provide a fracture data base. The experimental results agreed well with the predictions from fracture mechanics. In this study, the maximum impact velocity used to simulate the low velocity transverse impact from common objects like tool drops was 10 m/s.

Lal, K. M.

1982-01-01

107

Tensile Strength and the Mining of Black Holes  

NASA Astrophysics Data System (ADS)

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.

Brown, Adam R.

2013-11-01

108

Casting behavior and tensile strength of cast BaTiO sub 3 tape  

SciTech Connect

The casting behavior and properties of thin, unsintered BaTiO{sub 3} tapes were studied by measuring viscosity of the slip, green density, ultimate tensile stress, and strain to failure. It was found that increasing the binder to plasticizer ratio increased slip viscosity and strength as expected but also increased strain to failure, and that increasing the poly(ethylene glycol) to benzyl butyl phthalate ratio improved tape release and tape strength, but a small amount of benzyl butyl phthalate improved strain to failure. In addition, increasing the powder to organics ratio increased slip viscosity and green density but strength passed through a maximum and strain to failure decreased. Both slip viscosity and green density were optimized at a particular dispersant concentration but strength decreased monotonically with increased dispersant addition. Finally, an optimum cyclohexanone addition led to a maximum density and strength.

Karas, A.; Kumagai, Toshiya; Cannon, W.R. (Rutgers, The State Univ. of New Jersey, Piscataway (USA))

1988-07-01

109

Quantifying the tensile strength of microbial mats grown over noncohesive sediments.  

PubMed

Biofilms in marine and fluvial environments can comprise strong bacterial and diatom mats covering large areas of the bed and act to bind sediments. In this case the bed material becomes highly resistant to shear stresses applied by the overlying fluid motion and detachment, when it does occur, is manifest in patches of biofilm of the order cm(2) being entrained into the flow. This article is the first to report tensile test data specific to the centimeter scale using moist biofilm/sediment composite materials; the strain (?)-stress (?) relationships permit quantification of the elasticity (Young's modulus, E) and cohesive strength of each specimen. Specifically, we compare the mechanical strength of cyanobacterial biofilm-only samples to that of biofilm cultured over sediment samples (glass beads or natural sands of d ~ 1 mm) for up to 8 weeks. The range of tensile strength (1,288-3,283 Pa) for composite materials was up to three times higher than previous tensile tests conducted at smaller scale on mixed culture biofilm [Ohashi et al. (1999) Water Sci Technol 39:261-268], yet of similar range to cohesive strength values recorded on return activated sludge flocs [RAS; Poppele and Hozalski (2003) J Microbiol Methods 55:607-615]. Composite materials were 3-6 times weaker than biofilm-only samples, indicating that adhesion to sediment grains is weaker than cohesion within the biofilm. Furthermore, in order to relate the tensile test results to the more common in-situ failure of bio-mats due to shear flow, controlled erosion experiments were conducted in a hydraulic flume with live fluid flow. Here, the fluid shear stress causing erosion was 3 orders of magnitude lower than tensile stress; this highlights both the problem of interpreting material properties measured ex-situ and the need for a better mechanistic model of bio-mat detachment. PMID:22170239

Vignaga, E; Haynes, H; Sloan, W T

2012-05-01

110

The relation between the tensile strength and the hardness of metals  

NASA Technical Reports Server (NTRS)

This report presents methods determining the hardness and tensile strength of metals by showing the effect and dependence of the hardness numbers on the strain-hardening. Relations between the hardness numbers and the ordinary stress-strain diagrams and tensile strength are given. Procedures for finding the Brinell strength are also presented.

Schwarz, O

1930-01-01

111

Tensile Properties of Unirradiated PCA (Prime Candidate Alloy) from Room Temperature to 700 exp 0 C.  

National Technical Information Service (NTIS)

The tensile properties of Prime Candidate Alloy (PCA) austenitic stainless steel after three different thermomechanical treatments were determined from room temperature to 700 exp 0 C. The solution-annealed PCA had the lowest strength and highest ductilit...

D. N. Braski P. J. Maziasz

1983-01-01

112

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

NASA Technical Reports Server (NTRS)

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.

Lovoy, C. V.

1974-01-01

113

ZERODUR: bending strength data for tensile stress loaded support structures  

NASA Astrophysics Data System (ADS)

In the past ZERODUR® was mainly used for mirror and substrate applications, where mechanical loads were given by its own weight. Nowadays substrates become more sophisticated and subject to higher stresses as consequences of high operational accelerations or vibrations. The integrity of structures such as reticle and wafer stages e.g. must be guaranteed with low failure probability over their full intended life time. Their design requires statistically relevant strength data and information. The usual way determining the design strength employs statistical Weibull distributions obtained from a set of experimental data extrapolating the results to low acceptable failure probability values. However, in many cases this led to allowable stress values too low for the intended application. Moreover, the experimental basis has been found to be too small for reliable calculations. For these reasons measurement series on the strength of ZERODUR® have been performed with different surface conditions employing a standardized ring-on-ring test setup. The numbers of specimens per sample have been extended from about 20 to 100 or even much more. The results for surfaces ground with different diamond grain sizes D151, D64 and D25 as well as for etched surfaces are presented in this paper. Glass ceramics like all glassy materials exhibit some strength reduction when being exposed to loads above a tensile stress threshold over long time periods. The strength change of ZERODUR® with time will be discussed on the basis of known and newly determined stress corrosion data. The results for samples with large numbers of specimens contribute new aspects to the common practice of extrapolation to low failure probability, since they provide evidence for the existence of minimum strength values depending on the structures surface conditions. For ground surfaces the evidence for minimum strength values is quite obvious. For etched surfaces minimum values are to be expected also. However, here closer observation is still needed. The systematic deviations from Weibull distributions lie below about 5 % failure probability and thus could not be seen in small samples as they were common in the past.

Bizjak, Tanja; Hartmann, Peter; Westerhoff, Thomas

2012-03-01

114

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

PubMed

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

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

2010-05-01

115

Fast tablet tensile strength prediction based on non-invasive analytics.  

PubMed

In this paper, linkages between tablet surface roughness, tablet compression forces, material properties, and the tensile strength of tablets were studied. Pure sodium halides (NaF, NaBr, NaCl, and NaI) were chosen as model substances because of their simple and similar structure. Based on the data available in the literature and our own measurements, various models were made to predict the tensile strength of the tablets. It appeared that only three parameters-surface roughness, upper punch force, and the true density of material-were needed to predict the tensile strength of a tablet. Rather surprising was that the surface roughness alone was capable in the prediction. The used new 3D imaging method (Flash sizer) was roughly a thousand times quicker in determining tablet surface roughness than traditionally used laser profilometer. Both methods gave practically analogous results. It is finally suggested that the rapid 3D imaging can be a potential in-line PAT tool to predict mechanical properties of tablets in production. PMID:24638870

Halenius, Anna; Lakio, Satu; Antikainen, Osmo; Hatara, Juha; Yliruusi, Jouko

2014-06-01

116

High Tensile Strength Amalgams for In-Space Fabrication and Repair  

NASA Technical Reports Server (NTRS)

Amalgams are well known for their use in dental practice as a tooth filling material. They have a number of useful attributes that include room temperature fabrication, corrosion resistance, dimensional stability, and very good compressive strength. These properties well serve dental needs but, unfortunately, amalgams have extremely poor tensile strength, a feature that severely limits other potential applications. Improved material properties (strength and temperature) of amalgams may have application to the freeform fabrication of repairs or parts that might be necessary during an extended space mission. Advantages would include, but are not limited to: the ability to produce complex parts, a minimum number of processing steps, minimum crew interaction, high yield - minimum wasted material, reduced gravity compatibility, minimum final finishing, safety, and minimum power consumption. The work presented here shows how the properties of amalgams can be improved by changing particle geometries in conjunction with novel engineering metals.

Grugel, Richard N.

2006-01-01

117

Evaluation of tensile strength of surgical synthetic absorbable suture materials: an in vitro study  

PubMed Central

Purpose The purpose of this study was to evaluate the tensile strength of surgical synthetic absorbable sutures over a period of 14 days under simulated oral conditions. Methods Three suture materials (polyglycolic acid [PGA], polyglactin [PG] 910, and poly (glycolide-co-?-caprolactone) [PGC]) were used in 4-0 and 5-0 gauges. 210 suture samples (35 of each material and gauge) were used. All of the samples were tested preimmersion and 1 hour and 1, 3, 7, 10, and 14 days postimmersion. The tensile strength of each suture material and gauge was assessed. The point of breakage and the resorption pattern of the sutures were also assessed. Results During the first 24 hours of immersion, all 4-0 and 5-0 samples of PGA, PG 910, and PGC maintained their initial tensile strength. At baseline (preimmersion), there was a statistically significant (P<0.001) difference in the tensile strengths between the 4-0 and 5-0 gauge of PGA, PG 910, and PGC. PGA 4-0 showed the highest tensile strength until day 10. At 7 days, all the 4-0 sutures of the three materials had maintained their tensile strength with PGA 4-0 having significantly greater (P=0.003) tensile strength compared to PG. Conclusions 4-0 sutures are stronger and have greater tensile strength than 5-0 sutures. The PGA 4-0 suture showed the highest tensile strength at the end of day 10.

Ranganath, V.; Nichani, Ashish Sham

2013-01-01

118

Tensile Properties of Hydrogels and of Snake Skin  

NASA Technical Reports Server (NTRS)

Stimulus-responsive or 'smart' gels are of potential interest as sensors and actuators, in industrial separations, and as permeable delivery systems. In most applications, a certain degree of mechanical strength and toughness will be required, yet the large-strain behavior of gels has not been widely reported. Some exceptions include work on gelatin and other food gels, some characterization of soft gels applicable for in-vitro cell growth studies, and toughness determinations on commercial contact lens materials. In general, it can be anticipated that the gel stiffness will increase with increasing degree of crosslinking, but the tensile strength may go through a maximum. Gel properties can be tailored by varying not only the degree of crosslinking, but also the polymer concentration and the nature of the polymer backbone (e.g. its stiffness or solubility). Polypeptides provide an especially interesting case, where secondary structure affects trends in moduli and conformational transitions may accompany phase changes. A few papers on the tensile properties of responsive gels have begun to appear. The responsive hydrogel chosen for the present study, crosslinked hydroxypropylcellulose, shrinks over a rather narrow temperature range near 44 C. Some vertebrate skin is also subject to substantial strain. Among reptiles, the morphologies of the skin and scales show wide variations. Bauer et al. described the mechanical properties and histology of gecko skin; longitudinal tensile properties of snake skin were examined by Jayne with reference to locomotion. The present measurements focus on adaptations related to feeding, including the response of the skin to circumferential tension. Tensile properties will be related to interspecific and regional variation in skin structure and folding.

Hinkley, Jeffrey A.; Savitzky, Alan H.; Rivera, Gabriel; Gehrke, Stevin H.

2002-01-01

119

Effects of acid-etching on the tensile properties of demineralized dentin matrix  

Microsoft Academic Search

Objectives. Little research has been done to evaluate the effects of acids commonly used in adhesive dentistry, on the tensile properties of the demineralized dentin matrix. The purpose of this study was to evaluate the effects of a number of acidic conditioners on the ultimate tensile strength (UTS) and modulus of elasticity (E) of human coronal dentin matrix.Methods. Small hour-glass

Yi Zhang; Kelli Agee; Jacques Nör; Ricardo Carvalho; Bhupinder Sachar; Carl Russell; David Pashley

1998-01-01

120

A second study of tensile fatigue properties of human articular cartilage.  

PubMed Central

The tensile fatigue properties of the collagen fibre meshwork in normal human articular cartilage were measured by subjecting isolated specimens of post-mortem femoral head cartilage to cyclic tensile stress. The results of the study showed (1) that the collagen fibre meshwork is fatigue prone and (2) that its fatigue strength decreases rapidly with age. Extrapolation of the data to physiologically possible stress levels suggests that tensile fatigue failure of the collagen meshwork could occur in life.

Weightman, B; Chappell, D J; Jenkins, E A

1978-01-01

121

Tensile property of low carbon steel with gridding units  

NASA Astrophysics Data System (ADS)

Although much effort has been devoted to the mechanical properties of biomimetic coupled laser remelting (BCLR) processed steels, our understanding to the strengthening and toughening mechanisms of it has still remained unclear. To address it, here we studied the roles played by the gridding units of BCLR steels. Tensile tests show that the gridding units have a significant influence on the tensile properties. Interestingly, such an influence is essentially decided by the unit distance of gridding units. The strength increases with the unit distance narrowing while the ductility first increases with it up to a maximum then decreases. The mechanism behind these changes is attributed to the combined effects of the microstructure changes in the units and the stress transition throughout the BCLR samples.

Wang, Chuanwei; Zhou, Hong; Zhang, Zhihui; Jing, Zhengjun; Cong, Dalong; Meng, Chao; Ren, Luquan

2013-05-01

122

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

PubMed

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

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

2014-01-01

123

Tensile and flexural strength of non-graphitic superhybrid composites: Predictions and comparisons  

NASA Technical Reports Server (NTRS)

Equations are presented and described which can be used to predict bounds on the tensile and flexural strengths of nongraphitic superhybrid (NGSH) composites. These equations are derived by taking into account the measured stress-strain behavior, the lamination residual stresses and the sequence of events leading to fracture. The required input for using these equations includes constituents, properties (elastic and strength), NGSH elastic properties, cure temperature, and ply stress influence coefficients. Results predicted by these equations are in reasonably good agreement with measured data for strength and for the apparent knees in the nonlinear stress-strain curve. The lower bound values are conservative compared to measured data. These equations are relatively simple and are suitable for use in the preliminary design and initial sizing of structural components made from NGSH composites.

Chamis, C. C.; Sinclair, J. H.; Lark, R. F.

1979-01-01

124

Tensile and flexural strength of nongraphitic superhybrid composites - Predictions and comparisons  

NASA Technical Reports Server (NTRS)

Equations are presented and described which can be used to predict bounds on the tensile and flexural strengths of nongraphitic superhybrid (NGSH) composites. These equations are derived by taking into account the measured stress-strain behavior, the lamination residual stresses and the sequence of events leading to fracture. The required input for using these equations includes constituent composites, elastic and strength properties, NGSH elastic properties, cure temperature, and ply stress influence coefficients. Results predicted by these equations are in reasonably good agreement with measured data for strength and for the apparent 'knees' in the nonlinear stress-strain curve. The lower bound values are conservative compared to measured data. These equations are relatively simple and should be suitable for use in the preliminary design and initial sizing of structural components made from NGSH composites.

Chamis, C. C.; Sinclair, J. H.; Lark, R. F.

1979-01-01

125

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

PubMed Central

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.

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

2014-01-01

126

Gigacycle fatigue behaviors of two SNCM439 steels with different tensile strengths  

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

127

Tensile strength of fiber reinforced plastics at 77K irradiated by various radiation sources  

SciTech Connect

The influence of radiation damage on the mechanical properties of fiber reinforced plastics (FRPs), which are considered as candidate materials for the insulation of superconducting magnets for nuclear fusion reactors, has been investigated. Different types of FRPs (epoxies, bismaleimides; two- and three-dimensional reinforcement structures with E-, S-, or T-glass fibers) has been included in the test program. Three aspects of our present results will be discussed in detail. The first is related to an assessment of the tensile strength and its radiation dependence under the influence of strongly varying radiation conditions. The second aspect refers to low temperature ({approx}5 K) reactor irradiation of selected materials. In this case, identical sets of tensile test samples were transferred into the tensile testing machine, one without warming-up to room temperature and the other after an annealing cycle to room temperature. Finally, a comparison between the radiation response of different materials is made. It turns out that the three-dimensionally reinforced bismaleimide shows the smallest degradation of its tensile properties under all irradiation conditions.

Humer, K.; Weber, H.W. [Atominstitut der Oesterreichischen Universitaeten, Vienna (Austria); Tschegg, E.K. [Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik; Egusa, S. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Birtcher, R.C. [Argonne National Lab., IL (United States); Gerstenberg, H. [Technische Univ. Muenchen, Garching (Germany). Physikdepartment

1993-08-01

128

Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys  

NASA Technical Reports Server (NTRS)

Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

Gray, H. R.

1975-01-01

129

Strength and Breaking Mechanism of Multiwalled Carbon Nanotubes Under Tensile Load  

Microsoft Academic Search

The tensile strengths of individual multiwalled carbon nanotubes (MWCNTs) were measured with a ``nanostressing stage'' located within a scanning electron microscope. The tensile-loading experiment was prepared and observed entirely within the microscope and was recorded on video. The MWCNTs broke in the outermost layer (``sword-in-sheath'' failure), and the tensile strength of this layer ranged from 11 to 63 gigapascals for

Min-Feng Yu; Oleg Lourie; Mark J. Dyer; Katerina Moloni; Thomas F. Kelly; Rodney S. Ruoff

2000-01-01

130

Degradation of tensile and shear properties of composites exposed to fire or high temperature  

NASA Technical Reports Server (NTRS)

The decrease in ultimate tensile strength, shear strength, tensile modulus, and shear modulus of fiber reinforced composites exposed to fire or to high temperature was investigated. A simple model was developed for calculating the mass loss of the material and the thickness of the char layer. The mass loss as well as the degradation in tensile and shear properties of Fiberite T300/1034 and Hercules AS/3501-6 graphite epoxy composites exposed to fire were measured. A correlation between the degradation in properties and the calculated mass loss and the char layer thickness was developed. A technique was proposed for predicting material damage through the use of such correlations.

Pering, G. A.; Farrell, P. V.; Springer, G. S.

1980-01-01

131

Effect of heat treatment on microstructures and tensile properties of Ni-base superalloy M963  

Microsoft Academic Search

The effect of solution treatment (ST) on tensile properties of M963 Ni-base superalloy tested at 800°C has been investigated. The detailed microstructures, fracture surfaces and dislocation structures are examined through energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). With increasing solution treated temperature, the yield strength (YS) and ultimate tensile strength (UTS) increase, however,

L. Z. He; Q. Zheng; X. F. Sun; H. R. Guan; Z. Q. Hu; A. K. Tieu; C. Lu; H. T. Zhu

2005-01-01

132

The postirradiation tensile properties and microstructure of several vanadium alloys  

SciTech Connect

Tensile specimens of V-15Cr-5Ti, Vanstar-7, V-3Ti-1si, and V-20Ti were irradiated at 420)degrees)C in FFTF-MOTA to a damage level of 82 dpa. Helium was preimplanted to levels up to 480 appm in selected specimens using a modified tritium trick. Irradiation hardening was the dominant effect influencing the postirradiation tensile properties, and it markedly increased the yield strength and reduced the total elogation. The V-15Cr-5Ti alloy was very sensitive to helium embrittlement, but Vanstar-7 and V-3Ti-1Si were only slightly affected. Without helium, negligible swelling (<1%) were measured in V-3Ti-1Si and V-20Ti. Preimplanted helium increased swelling in V-3Ti-1Si by increasing cavity nucleation. 11 refs., 11 figs., 3 tabs.

Braski, D.N.

1988-01-01

133

The dynamic tensile strength of ice and ice-silicate mixtures  

NASA Technical Reports Server (NTRS)

The dynamic tensile strength of icy media is measured at strain rates on the order of 10,000/sec to aid in the understanding of impact and cratering phenomena. Compressed samples consisting of ice and ice-silicate mixtures with 5 and 30 wt % sand were impacted at temperatures between 230 and 250 K by projectile plexiglas plates imparting the required strain rates in less than 0.75 microsec. Taking the tensile stress corresponding to the transition from intact to spalled or fragmented samples as the dynamic tensile strength, strengths of 17, 20 and 22 MPa were obtained for the pure ice, 5 wt % sand, and 30 wt % sand specimens, respectively. The values lie considerably above those observed in static testing. A continuum fracturing model is used to obtain relations between tensile strength and stress rate as well as to derive stress and damage histories during tensile loading and the size distribution of icy fragments as a function of strain rate.

Lange, M. A.; Ahrens, T. J.

1983-01-01

134

Diametral tensile strength and water sorption of glass-ionomer cements used in Atraumatic Restorative Treatment.  

PubMed

The purposes of this study were to evaluate the diametral tensile strength and the water sorption of restorative (Fuji IX and Ketac Molar) and resin-modified glass-ionomer luting cements (ProTec Cem, Fuji Plus and Vitremer) mixed at both manufacturer and increased powder: liquid ratio, for their use in the Atraumatic Restorative Treatment. A conventional restorative glass-ionomer (Ketac Fil) was used as control. Specimens (6.0 mm in diameter x 3.0 mm in height) were prepared and stored (1 hour, 1 day and 1 week) for a diametral tensile strength test. Data were subjected to two-way ANOVA and Tukey tests (p<0.05). For the water sorption test, specimens of 15.0 mm in diameter x 0.5 mm in height were prepared and transfered to desiccators until a constant mass was obtained. Then the specimens were immersed in deionized water for 7 days, weighed and reconditioned to a constant mass in desiccators. Data were subjected to one-way ANOVA and Tukey tests (p<0.05). Five specimens of each studied material and consistency were prepared for each test. The resin-modified glass-ionomer cements showed significantly higher strength than the conventional materials. Except for ProTec Cem, the diametral tensile strength of the resin-modified materials significantly increased from luting to restorative consistency. Except for ProTec Cem, the water sorption of the resin-modified glass ionomers was higher than the others. The water sorption of resin-modified materials at restorative consistency was significantly lower than at luting consistency. Resin-modified glass-ionomer luting cements mixed at increased powder: liquid ratio showed better properties than at luting consistency. PMID:21409320

Cefaly, Daniela Francisca Gigo; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Francisconi, Paulo Afonso Silveira; Navarro, Maria Fidela de Lima

2003-06-01

135

Tensile Properties of Boronized N80 Steel Tube Cooled by Different Methods  

NASA Astrophysics Data System (ADS)

The microstructures and tensile properties of boronized N80 steel pipes by pack boriding under four different cooling conditions were investigated. The boride layer was composed of FeB and Fe2B phases with a hardness range of 1200-1600 HV. Fan cooling and fan cooling with a graphite bar in the center of the boriding agent were employed to improve the tensile properties. As cooling velocity was increased, the thickness of boride layer and grain size of the steel substrate were consequently reduced, whereas the pearlite volume in steel substrate was increased, resulting in improvement of tensile properties. Boronized N80 steel pipe which was fan cooled with a graphite bar inside possessed the highest ultimate tensile strength and yield strength, in accordance with the mechanical properties required by API SPEC 5L. Fracture surface analysis revealed that the boronized N80 steel showed ductile fracture at room temperature.

Tian, X.; Yang, Y. L.; Sun, S. J.; An, J.; Lu, Y.; Wang, Z. G.

2009-03-01

136

Increased tensile strength of carbon nanotube yarns and sheets through chemical modification and electron beam irradiation.  

PubMed

The inherent strength of individual carbon nanotubes (CNTs) offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of CNT forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated into that of sheets and yarns, where the bulk material strength is limited by intertube electrostatic attractions and slippage. The focus of this work was to assess postprocessing of CNT sheets and yarns to improve the macro-scale strength of these material forms. Both small-molecule functionalization and electron-beam irradiation were evaluated as means to enhance the tensile strength and Young's modulus of the bulk CNT materials. Mechanical testing revealed a 57% increase in tensile strength of CNT sheets upon functionalization compared with unfunctionalized sheets, while an additional 48% increase in tensile strength was observed when functionalized sheets were irradiated. Similarly, small-molecule functionalization increased tensile strength of yarn by up to 25%, whereas irradiation of the functionalized yarns pushed the tensile strength to 88% beyond that of the baseline yarn. PMID:24720450

Miller, Sandi G; Williams, Tiffany S; Baker, James S; Solá, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S; Wilmoth, Nathan G; Gaier, James; Chen, Michelle; Meador, Michael A

2014-05-14

137

The Cryogenic Tensile Properties of an Extruded Aluminum-Beryllium Alloy  

NASA Technical Reports Server (NTRS)

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."

Gamwell, W. R.

2002-01-01

138

Tensile, Compressive, and Shear Properties of a 96 kg cubic meter Polyurethane Foam at Low Temperatures.  

National Technical Information Service (NTIS)

Polyurethane foam, having a density of 96 kg/cu m, was tested at 295, 111, 76, and 4 K. The material properties reported are Young's modulus, proportional limit, yield strength (at 0.2% offset), tensile, shear, and compressive strengths, and elongation (e...

J. M. Arvidson R. S. Bell L. L. Sparks C. Guobang

1983-01-01

139

Relationships between tensile strength, morphology and crystallinity of treated kenaf bast fibers  

NASA Astrophysics Data System (ADS)

Surface treatments on kenaf bast fibers were carried out with steam, alkali and a combination of steam-alkali. To verify and gain an understanding of their inter-relationship, tensile strength, surface morphology and crystallinity of treated and raw fibers were characterized. Tensile strength of fibers was measured with a universal tensile machine (UTM), crystallinity was estimated using X-ray diffraction (XRD) and Fourier transformation infrared (FTIR) spectroscopy, and surface morphology was examined by scanning electron microscopy (SEM). Tensile strength of the treated fibers was higher than that of the raw fiber. Tensile strength increased after steam treatment and was further improved by alkali treatment, but slightly reduced after steam treatment followed by alkalization. Increase of concentration of alkali tended to increase tensile strength. Differences in tensile strength of the treated fibers are discussed in relation to the changes in surface morphology and crystallinity. Understanding of these relationships may provide direction towards the goal of producing better performance of natural fiber composites.

Sosiati, H.; Rohim, Ar; Ma`arif; Triyana, K.; Harsojo

2013-09-01

140

An Experimental Study of the Rate Dependence of Tensile Strength Softening of Longyou Sandstone  

NASA Astrophysics Data System (ADS)

It is well-known that the strengths of sandstones measured under fully saturated conditions are smaller than those measured under nominally dry conditions. This strength softening phenomenon has profound implications to rock engineering. In this work we investigate the tensile strength softening of Longyou sandstone from China. Defining the strength softening factor as the ratio of the strength under nominally dry conditions over that under saturated conditions, the static compressive strength softening factor of Longyou sandstone is close to 2 and the static tensile strength softening factor is about 7.9. To further address the applications, where the load may be dynamic, we examine the rate dependence of the tensile strength softening of this sandstone. The dynamic tensile strength is measured using the split Hopkinson pressure bar system in combination with the Brazilian disc sample geometry. The results show that the tensile strength softening factor decreases with the loading rate. Because the saturated sample shows stronger loading rate sensitivity than the dry sample, the softening factor decreases with the loading rate.

Huang, Sheng; Xia, Kaiwen; Yan, Fei; Feng, Xiating

2010-11-01

141

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

Microsoft Academic Search

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

Toshiyuki Tsuchiya; Osamu Tabata; Jiro Sakata; Yasunori Taga

1998-01-01

142

Tensile strength of thermomechanically processed Cu-9Ni-6Sn alloys  

SciTech Connect

The tensile properties of Cu-9Ni-6Sn alloys with different swaging amounts of 64, 77, and 95 pct, either solutionized and aged (S/A), were examined as a function of aging time. It was found that the aging response of Cu-9Ni-6Sn alloys varied greatly depending on the prior solution heat treatment before aging and/or different swaging amounts. The swaged S/A Cu-9Ni-6Sn alloys showed a multistage increase in tensile strength with respect to aging time, probably due to the sequential occurrence of spinodal decomposition, formation of metastable {gamma}{center{underscore}dot} precipitates, and recrystallization. The effect of different swaging amounts, ranging from 64 to 95 pct, was minimal on the aging response of S/A specimens. The prior cold working, however, appeared to favor the spinodal strengthening, comparing unswaged and swaged S/A Cu-9Ni-6Sn alloys. In 95 pct swaged D/A Cu-9Ni-6Sn alloys, the level of hardening was much less sensitive to aging time. A complex interaction between the reduction in dislocation density, the formation of equilibrium precipitates, and the reduction of Sn content in the Sn-rich segregates during an aging process is believed to be responsible for such a lean sensitivity. The increases in tensile strength of 64 and 77 pct swaged D/A Cu-9Ni-6Sn alloys were found to be much steeper than that in the 95 pct counterparts in the early and intermediate stages of aging, which is believed to be related to the relative contribution from work hardening and precipitation hardening to the strength level of D/A specimens.

Rhu, J.C.; Kim, S.S.; Jung, Y.C.; Han, S.Z.; Kim, C.J.

1999-10-01

143

Semicircular bend testing with split Hopkinson pressure bar for measuring dynamic tensile strength of brittle solids  

Microsoft Academic Search

We propose and validate an indirect tensile testing method to measure the dynamic tensile strength of rocks and other brittle solids: semicircular bend (SCB) testing with a modified split Hopkinson pressure bar (SHPB) system. A strain gauge is mounted near the failure spot on the specimen to determine the rupture time. The momentum trap technique is utilized to ensure single

F. Dai; K. Xia; S. N. Luo

2008-01-01

144

Tensile-strength apparatus applies high strain-rate loading with minimum shock  

NASA Technical Reports Server (NTRS)

Tensile-strength testing apparatus employs a capillary bundle through which a noncompressible fluid is extruded and a quick-release valve system. This apparatus applies the test loads at relatively constant very high strain rates with minimal shock and vibration to the tensile specimen and apparatus.

Cotrill, H. E., Jr.; Mac Glashan, W. F., Jr.

1966-01-01

145

Correlation between ultimate tensile strength and solidification microstructure for the sand cast A357 aluminium alloy  

Microsoft Academic Search

Many studies have demonstrated a relationship between secondary dendrite arm spacing (SDAS) and the mechanical behaviour of cast aluminium–silicon alloys, both for tensile and fatigue strength. SDAS is related to the solidification time and can be predicted, with a good approximation, by finite-element simulation. However, other microstructural features can affect the tensile behaviour of cast aluminium alloys such as size

L. Ceschini; Alessandro Morri; Andrea Morri; A. Gamberini; S. Messieri

2009-01-01

146

Unbinding force of chemical bonds and tensile strength in strong crystals  

Microsoft Academic Search

A model of covalent and ionic bond strength is proposed in terms of the tensile unbinding force by introducing the concept of the effectively bonded valence electron (EBVE) number of a chemical bond. Bond strength proves to be exclusively dependent on two microscopic parameters: bond length and EBVE number. This model allows us to determine bond strength for a variety

Xiaoju Guo; Li-Min Wang; Bo Xu; Zhongyuan Liu; Dongli Yu; Julong He; Hui-Tian Wang; Yongjun Tian

2009-01-01

147

Micro-cantilever method for measuring the tensile strength of biofilms and microbial flocs  

Microsoft Academic Search

Cohesive strength is an important factor in determining the structure and function of biofilm systems, and cohesive strength plays a key role in our ability to remove or control biofilms in engineered systems. A micro-mechanical device has been developed to directly measure the tensile strength of biofilms and other microbial aggregates. An important feature of this method is the combination

Eric H Poppele; Raymond M Hozalski

2003-01-01

148

Experimental and Numerical Study on Tensile Strength of Concrete under Different Strain Rates  

PubMed Central

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.

Min, Fanlu; Yao, Zhanhu; Jiang, Teng

2014-01-01

149

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

PubMed

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

Min, Fanlu; Yao, Zhanhu; Jiang, Teng

2014-01-01

150

Effect of Steam Oxidation on the Tensile Strength of HTGR Structural Graphites.  

National Technical Information Service (NTIS)

The core support system of the General Atomic Company design High Temperature Gas-Cooled Reactor (HTGR) contains type PGX graphite as core support blocks. The change in ultimate tensile strength of PGX graphite specimens with oxidation (burnoff) has been ...

A. J. Romano J. G. Y. Chow

1977-01-01

151

Effects of Strain Rate and Moisture on the Tensile Strength of Heterogeneous Materials.  

National Technical Information Service (NTIS)

Strain rate effects on tensile strength of concrete and mortar were investigated using three different size specimens, two different sized split Hopkinson pressure bars (SHPB) and a standard material test machine. All combinations of data show the same tr...

C. A. Ross

1998-01-01

152

Influence of Gold Plating of Stainless Steel Pins on the Tensile Strength of Dental Amalgam  

Microsoft Academic Search

Neither gold plating of stainless steel pins nor mercury wetting of gold-plated stainless steel pins caused an increase in tensile strength of amalgam that was significantly higher than that caused by plain stainless steel pins in amalgam.

M. S. Bapna; A. A. Lugassy

1971-01-01

153

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

NASA Astrophysics Data System (ADS)

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.

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

2011-03-01

154

High-temperature tensile properties of fiber reinforced reaction bonded silicon nitride  

NASA Technical Reports Server (NTRS)

Measurements of tensile properties of unidirectional silicon carbide fiber-reinforced reaction-bonded silicon nitride (SiC/RBSN) composite specimens were carried out in air at 25, 1300, and 1500 C, using a new testing technique and a specially designed gripping system that minimizes bending moment and assures that failure always occurred in the gage section. The material was found to display metallike stress-strain behavior at all temperatures tested, and a noncatastrophic failure beyond the matrix fracture. The tensile properties were found to be temperature dependent, with the values of the ultimate tensile strength decreasing with temperature, from 543 MPa at 25 C to 169 at 1500 C.

Jablonski, David A.; Bhatt, Ramakrishna T.

1990-01-01

155

Enhancement of hydrophobicity and tensile strength of muga silk fiber by radiofrequency Ar plasma discharge  

Microsoft Academic Search

The hydrophobicity and tensile strength of muga silk fiber are investigated using radiofrequency (RF) Ar plasma treatment at various RF powers (10–30W) and treatment times (5–20min). The Ar plasma is characterized using self-compensated Langmuir and emissive probe. The ion energy is observed to play an important role in determining the tensile strength and hydrophobicity of the plasma treated fibers. The

D. Gogoi; A. J. Choudhury; J. Chutia; A. R. Pal; N. N. Dass; D. Devi; D. S. Patil

2011-01-01

156

An Experimental Method to Determine the Tensile Strength of Concrete at High Rates of Strain  

Microsoft Academic Search

In the present work, dynamic tensile strength of concrete is experimentally investigated by means of spalling tests. Based\\u000a on extensive numerical simulations, the paper presents several advances to improve the processing of spalling tests. The striker\\u000a is designed to get a more uniform tensile stress field in the specimen. Three methods proposed in the literature to deduce\\u000a the dynamic strength

B. Erzar; P. Forquin

2010-01-01

157

Strength and Related Properties of a Randomly Selected Sample of Second-Growth Redwood.  

National Technical Information Service (NTIS)

Most mechanical properties were found to be 20 to 25 percent lower than those of virgin material. Exceptions to this were maximum shearing strength parallel to grain and maximum tensile strength parallel to grain. The mechanical properties were generally ...

B. A. Bendtsen

1966-01-01

158

The Effects of Silanized Ultrafine Silica on the Curing Characteristics, Tensile Properties, and Morphological Study of Natural Rubber Compounds  

Microsoft Academic Search

The curing characteristics, tensile properties, and morphological of untreated and silanized ultrafine silica filled natural rubber with bis[(3-triethoxysilylpropyl)tetra sulfide] (Si-69) were studied. The results show the scorch time and cure time of silanized silica was shorter as compared to untreated silica at the same filler loading. On tensile properties, the presence of Si-69 had improved the tensile strength, elongation at

Suhaida S. Idrus; H. Ismail; Samayamutthirian Palaniandy

2011-01-01

159

Cuticle damage and the tensile properties of human hair  

Microsoft Academic Search

Synopsis Oxidation of hair fibers with diperisophthalic acid can produce extensive damage throughout several cuticle layers that is readily observed microscopically. At the same time, no detectable changes in the tensile properties (wet or dry) are detectable. These results are consistent with the hypothesis that the tensile properties of human hair are due primarily to the cortex, with little or

C. R. ROBBINS; R. J. CRAWFORD; Colgate Palmolive

160

Effects of Test Temperature, Strain Rate, and Thermal Exposure on the Tensile Properties of Alloy 600.  

National Technical Information Service (NTIS)

The tensile properties of annealed and thermally exposed Alloy 600 have been characterized for test and exposure temperatures to 760 exp 0 C (1400 exp 0 F) and strain rates to 1.0 sec exp -1 . Results indicate strength properties and ductility of annealed...

J. M. Steichen, A. L. Ward

1976-01-01

161

Morphological, thermal and tensile properties of halloysite nanotubes filled ethylene propylene diene monomer (EPDM) nanocomposites  

Microsoft Academic Search

A novel ethylene propylene diene monomer\\/halloysite nanotubes (EPDM\\/HNT) nanocomposite was prepared by mixing 0–100 parts per hundred rubber (phr) of HNTs with EPDM on a two-roll mill. The results obtained show that the tensile strength, elongation at break, tensile modulus at 100% elongation (M100) and crosslink density were tremendously increased with increase of HNT loading. The thermal and flammability properties

H. Ismail; Pooria Pasbakhsh; M. N. Ahmad Fauzi; A. Abu Bakar

2008-01-01

162

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

NASA Astrophysics Data System (ADS)

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.

Balzer, Brian B.

163

Numerical investigations on the role of micro-cracks in determining the compressive and tensile strength of rocks  

NASA Astrophysics Data System (ADS)

Bonded particle models implemented using the Discrete Element Method (DEM [1]) have proven a useful numerical laboratory to investigate the interplay between geological structure and mechanical response of rock specimens [4]. However, it is well-known that such bonded particle models fail to reproduce the ratios of compressive:tensile strength of rocks (typically ranging between 10:1 and 50:1). Since this strength ratio is a critical geotechnical engineering design parameter, it is important to resolve this discrepancy between rock and their DEM analogues. To date, the largest compressive:tensile strength ratio achieved in DEM rock analogue models ranges between 10:1 and 12:1 [3]. In said studies, the compressive:tensile strength ratio was found to depend on the number of particle bonds removed from the specimen prior to testing; a modelling analogy for changing the micro-crack density within the specimen. These results are consistent with the popular conjecture that the compressive and tensile strengths of rock are impacted by the opening (or closure) of micro-cracks oriented parallel (or perpendicular) to the loading direction. The current research consists of a rigorous analysis of the role of micro-cracks in governing the compressive:tensile strength ratio of DEM rock specimens. Micro-cracks are geometrically represented as planar surfaces of variable size and orientation. Spherical particles are packed around each planar micro-crack forming a surface that is flat on scales larger than the particle scale. This geometrical approach permits prescription of the sizes and orientations of micro-cracks, as well as the crack density. A series of cylindrical DEM rock specimens are prepared with varying micro-crack densities and orientations. Specimens with either or both micro-cracks sub-parallel to, or sub-perpendicular to the cylinder axis are consided. Each DEM rock specimen is subjected to both a numerical uniaxial compression test and a numerical direct tension test. From these tests, four macroscopic material properties are measured for each specimen: Young's modulus, Poisson's ratio, uniaxial compressive strength and unixial tensile strength. Fracture mechanisms are also examined. Preliminary results indicate that both micro-crack density and micro-crack orientation significantly impact the macroscopic mechanical properties of DEM rock specimens. Quantitative results will be presented at the meeting. The software employed for these experiments is ESyS-Particle [2], an Open Source DEM simulation package for multi-core PCs or supercomputers.

Weatherley, D.; Ayton, T.

2012-04-01

164

Further Studies of the Partial Gasification of Coke in Relation to the Coke Tensile Strength.  

National Technical Information Service (NTIS)

Previous reports have described studies of the partial gasification of coke and its influence on the coke tensile strength and of the quantification of the changes in the coke structure and strength brought about by reaction with carbon dioxide at 1000 Sq...

1980-01-01

165

Effect of abrasive wear on the tensile strength of steel wire rope  

Microsoft Academic Search

Known amounts of external abrasive wear were introduced into a new 6-strand steel wire rope and the effects of this wear on the tensile strength of the rope examined against the rope discard criteria for wear stated in ISO 4309: 1990 and other selected international standards. The variations of strength with degree of wear in the test rope were compared

A. R. T. de Silva; Long Woon Fong

2002-01-01

166

An experimental study on the tensile strength of steel fiber reinforced concrete  

Microsoft Academic Search

This paper deals with steel fiber reinforced concrete mechanical static behaviour and with its classification with respect to fibers content and mix-design variations. A number of experimental tests were conducted to investigate uniaxial compressive strength and tensile strength. Different mixtures were prepared varying both mix-design and fiber length. Fibers content in volume was of 1% and 2%. Mechanical characterization was

R. S. Olivito; F. A. Zuccarello

2010-01-01

167

Shear vs. Tensile Bond Strength of Resin Composite Bonded to Ceramic  

Microsoft Academic Search

Since the mode of failure of resin composites bonded to ceramics has frequently been reported to be cohesive fracture of either ceramic or resin composite rather than separation at the adhesive interface, this study was designed to question the validity of shear bond strength tests. The reasons for such a failure mode are identified and an alternative tensile bond strength

A. Della Bona; R. van Noort

1995-01-01

168

Tensile strength and creep resistance in nanocrystalline Cu, Pd and Ag.  

National Technical Information Service (NTIS)

Measurements of tensile strength and creep resistance have been made on bulk samples of nanocrystalline Cu, Pd and Ag consolidated from powders by cold compaction. Samples of Cu-Cu(sub 2)O have also been tested. Yield strength for samples with mean grains...

G. W. Nieman J. R. Weertman R. W. Siegel

1990-01-01

169

Ideal tensile and shear strength of a gum metal approximant: Ab initio density functional calculations  

NASA Astrophysics Data System (ADS)

The ideal tensile and shear strengths of binary ?-phase Ti3Nb alloys have been investigated using ab initio density functional calculations. The binary alloy is considered as an approximant to the multifunctional Ti-Nb-Ta-Zr-O alloy known as “gum metal,” which displays high strength, low elastic modulus, high yield strain, and very good ductility. This alloy has been reported to deform elastically until the stress approaches the ideal tensile strength. Our calculations have been performed for an optimized chemical decoration of the body-centered cubic (bcc) structure of the ? phase. Previous work has demonstrated that this model yields elastic constants in very good agreement with those measured for gum metal specimens and leads to a reasonably accurate description of the martensitic transformations between the bcc ?, the orthorhombic ?'' and the hexagonal ? phases [Lazar , Phys. Rev. BPLRBAQ0556-280510.1103/PhysRevB.84.054202 84, 054202 (2011)]. The simulations of the response to tensile and shear loading have been performed for large supercells which account also for the different orientations of the -Nb-Nb- chains characteristic for the ?-phase structure relative to the direction of the applied load. The energy-strain and stress-strain curves are found to be very different from those reported for all bcc metals. Under uniaxial <100> loading we find an ideal tensile strength of 2.4 GPa, the upper limit to the tensile stress arising from a shear instability of the structure. Under uniaxial <110> load we calculate an ideal tensile strength of 2.2 or 2.8 GPa, depending on the orientation of the -Nb-Nb- chains relative to the loading direction. For a realistic multidomain structure the ideal strength is expected to correspond to the average of these values. An ideal strength of 2.6 GPa under <110> loading is roughly the same as under <100> load, despite a considerable anisotropy of the tensile moduli. For {211}<111> shear we calculate an ideal shear strength of 1.6 GPa, again as an average over different possible shearing directions relative to the Nb-Nb bonds. For the {110}<110> shear system we find a lower strength of 0.9 GPa. The structures reached at the stress maximum under <100> uniaxial tension and {211}<111> shear are identical, and since the maximal shear stress is much lower than the tensile stress, the alloy will fail by shear even under strictly uniaxial tension. The values of the ideal tensile and shear strengths are significantly low, even in comparison with those calculated for bcc V and Nb with very small shear moduli and approach the values reported for gum metal alloys.

Nagasako, Naoyuki; Asahi, Ryoji; Hafner, Jürgen

2012-01-01

170

Comparison of tensile and knot security properties of surgical sutures.  

PubMed

Sutures are classified into non-absorbable and absorbable, and mechanical properties of these materials vary by the composition. Knotting induces decrease in mechanical properties. The objective of this study was to measure the tensile and knot security properties depending on the type and caliber of sutures. Changes in properties after tensile loading were measured with absorbable sutures. Tensile properties such as maximum tensile load, elongation rate, stiffness and energy absorbed before breakage of seven kinds of surgical sutures were measured. Absorbable sutures were immersed in 37 degrees C Hank's balanced salt solution up to 14 days under the tensile load of 100 g/thread, and properties were measured again. Knot was formed with surgeon's knot method, and tensile properties were measured. Five specimens were tested for each condition. Values were analyzed with one- or two-way analysis of variance (alpha = 0.05). Maximum tensile load of seven sutures (caliber = 4-0) ranged from 10.0 N to 14.3 N. In non-absorbable sutures, the type of suture material influenced the tensile properties (P < 0.05). In absorbable sutures, the maximum tensile load after tensile loading decreased, which was significant in chromic catgut (CC). Knot security of seven sutures (caliber = 4-0) ranged from 8.7 N to 11.9 N. Type of non-absorbable suture influenced knot security (P < 0.05), and the synthetic monofilament materials showed a tendency to be untied easily. Since no single suture material possesses all of the requirements, proper type and caliber suture should be selected based on this study. PMID:17569012

Kim, Jin-Cheol; Lee, Yong-Keun; Lim, Bum-Soon; Rhee, Sang-Hoon; Yang, Hyeong-Cheol

2007-12-01

171

Functional loading augments the initial tensile strength and energy absorption capacity of regenerating rabbit Achilles tendons.  

PubMed

The biomechanical effect of functional loading was studied in surgically tenotomized, repaired and immobilized right Achilles tendons of 34 rabbits. Beginning from the 5th day after surgery, loading was initiated by removing the immobilization casts of the animals to permit unrestricted weight-bearing to tolerance. At each of 12, 18 and 21 days after surgery, functionally loaded tendons and their corresponding nonloaded controls were excised and compared for differences in tensile strength, tensile stress and energy absorption capacity. Functional loading induced a twofold increase in the tensile strength (P less than 0.05) and energy absorption capacity (P less than 0.05) of the tendons, at both 12 and 18 days after surgery. No statistically significant differences were observed in the tensile strength and energy absorption capacity of the tendons at 21 days after surgery. Statistically significant differences in tensile stress were not observed at any time period throughout the study. These findings demonstrate that functional loading augments the tensile strength and energy absorption capacity of experimentally tenotomized tendons without promoting re-rupture, but only during the very early stages of healing. Even though the healing process of rabbit tendons may differ from healing of human tendons, these results suggest that similar beneficial effects may be attained if repaired human Achilles tendon ruptures are carefully loaded during the very early rather than later stages of healing. PMID:1739442

Enwemeka, C S

1992-02-01

172

Quantitative fracture strength and plasticity measurements of lithiated silicon nanowires by in situ TEM tensile experiments.  

PubMed

We report in situ tensile strength measurement of fully lithiated Si (Li-Si alloy) nanowires inside a transmission electron microscope. A specially designed dual probe with an atomic force microscopy cantilever and a scanning tunneling microscopy electrode was used to conduct lithiation of Si nanowires and then perform in situ tension of the lithiated nanowires. The axial tensile strength decreased from the initial value of 3.6 GPa for the pristine unlithiated Si nanowires to 0.72 GPa for the lithiated Li-Si alloy. We observed large fracture strain ranging from 8% to 16% for Li-Si alloy, 70% of which remained permanent after fracture. This indicates a certain degree of tensile plasticity in the lithiated silicon before fracture, important for constitutive modeling of the lithium-ion battery cyclability. We also compare the ab initio computed ideal strengths with our measured strengths and attribute the differences to the morphology and flaws in the lithiated nanowires. PMID:23025575

Kushima, Akihiro; Huang, Jian Yu; Li, Ju

2012-11-27

173

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

SciTech Connect

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.

P.E. Klingsporn

2011-08-01

174

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

175

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

176

Some Tensile Properties of Metal-Metallic Glass Laminates.  

National Technical Information Service (NTIS)

The tensile properties of brass (Cu-30% Zn)-nickel base metallic glass (MBF-35 Metglas) laminates have been investigated. Laminates were prepared by soldering these constituents together with a Pb-Sn alloy. The metallic glass exhibited an enhanced tensile...

Y. Leng T. H. Courtney

1989-01-01

177

A modified Johnson–Cook model for tensile behaviors of typical high-strength alloy steel  

Microsoft Academic Search

The uniaxial tensile tests were conducted with the initial strain rates range of (0.0001–0.01)s?1 and the temperature range of (1123–1373)K for typical high-strength alloy steel. Based on the experimental results, the modified Johnson–Cook model, which considers the coupled effects of strain, strain rate and deformation temperature, was proposed to describe the tensile behaviors of the studied alloy steel. Results show

Y. C. Lin; Xiao-Min Chen; Ge Liu

2010-01-01

178

Age-related changes in the density and tensile strength of human femoral cortical bone  

Microsoft Academic Search

Summary  In order to ascertain whether the intrinsic strength of human bone changes with age or not, we have determined the ultimate\\u000a tensile strength and density of strips of femoral cortical bone. These femora were collected from cadavers varying in age\\u000a from 13 to 97 years. The results show that both density and intrinsic strength of bone increase up to about

J. C. Wall; S. K. Chatterji; J. W. Jeffery

1979-01-01

179

Change in Tensile Properties of Neoprene and Nitrile Gloves After Repeated Exposures to Acetone and Thermal Decontamination  

Microsoft Academic Search

This study investigated the change in tensile properties of neoprene and nitrile gloves after repeated cycles of exposure to acetone, followed by thermal decontamination. The glove was exposed to acetone (outer surface in contact with chemical), subjected to thermal decontamination, and tested for the tensile strength and the ultimate elongation. Thermal decontamination was carried out inside an oven for 16

Pengfei Gao; Beth Tomasovic

2005-01-01

180

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

Microsoft Academic Search

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

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

2001-01-01

181

Tensile Strength of Welded Steel Tubes : First Series of Experiments  

NASA Technical Reports Server (NTRS)

The purpose of the experiments was to determine the difference in the strength of steel tubes welded by different methods, as compared with one another and also with unwelded, unannealed tubes, including; moreover, a comparison of the results obtained by experienced and inexperienced welders.

Rechtlich, A

1928-01-01

182

Effects of strain rate on tensile properties of TZM and Mo-5%Re  

NASA Astrophysics Data System (ADS)

In the present work, we have studied the strain rate sensitivity of tensile properties of TZM and Mo-5%Re alloys. Tests were performed at room temperature and around the transition temperature of each alloy, at strain rates varying over five decades. Ductility appeared insensitive to strain rate, whereas the strength is found to be strain rate dependent. Both proof stress and ultimate tensile strength are affected by strain rate and the Mo-5%Re alloy is more sensitive than TZM. As expected, the hardening decreases with temperature; in TZM alloy the strain rate sensitivity was apparent only at room temperature.

Filacchioni, G.; Casagrande, E.; De Angelis, U.; De Santis, G.; Ferrara, D.

2002-12-01

183

Tensile strength of laser welded cobalt-chromium alloy with and without an argon atmosphere.  

PubMed

The tensile strength and depth of weld of two cobalt chromium alloys before and after laser welding with and without an argon gas atmosphere were investigated. Using two cobalt chromium alloys, rod shaped specimens (5 cm x 1.5 mm) were cast. Specimens were sand blasted, sectioned and welded with a pulsed Nd: YAG laser welding machine and tested in tension using an Instron universal testing machine. A statistically significant difference in tensile strength was observed between the two alloys. The tensile strength of specimens following laser welding was significantly less than the unwelded controls. Scanning electron microscopy showed that the micro-structure of the cast alloy was altered in the region of the weld. No statistically significant difference was found between specimens welded with or without an argon atmosphere. PMID:20698419

Tartari, Anna; Clark, Robert K F; Juszczyk, Andrzej S; Radford, David R

2010-06-01

184

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

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

185

Relationship between Fracture Toughness and Tensile Properties of A357 Cast Aluminum Alloy  

NASA Astrophysics Data System (ADS)

The fracture-related mechanical properties of the A357 cast aluminum alloy, namely, elongation to fracture, tensile strain energy density (tensile toughness), strain-hardening exponent, and plane strain fracture toughness were investigated. Correlations between these properties have been established for 25 different artificial aging heat-treatment conditions and for five minor variations in chemical composition. Empirical relationships between the strain energy density and both the tensile elongation to fracture and the strain-hardening exponent have been developed. Analysis of the fracture surfaces indicated that the fracture mechanism of the investigated specimens varies according to the artificial aging conditions. Moreover, empirical relationships between the fracture toughness and strain energy density and between fracture toughness and strain-hardening exponent have been developed; these can be used to estimate the plane strain fracture toughness of A357 as a function of yield strength and tensile toughness.

Alexopoulos, N. D.; Tiryakio?lu, M.

2009-03-01

186

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

NASA Astrophysics Data System (ADS)

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.

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

2006-03-01

187

Development of a silicon carbide fibre with high tensile strength  

Microsoft Academic Search

MUCH work has been done on preparing heat-resistant silicon carbide materials in fibrous form, since plastics or metals can be reinforced with them to obtain very heat-resistant material of great mechanical strength. SiC whiskers1 are, however, impractical because of their shortness (several mm), their non-uniform diameter and high cost of production. SiC-on-W (ref. 2) and SiC-on-C (ref. 3) filaments have

S. Yajima; J. Hayashi; M. Omori; K. Okamura

1976-01-01

188

Effects of strain rate on tensile properties of TZM and Mo–5%Re  

Microsoft Academic Search

In the present work, we have studied the strain rate sensitivity of tensile properties of TZM and Mo–5%Re alloys. Tests were performed at room temperature and around the transition temperature of each alloy, at strain rates varying over five decades. Ductility appeared insensitive to strain rate, whereas the strength is found to be strain rate dependent. Both proof stress and

G. Filacchioni; E. Casagrande; U. De Angelis; G. De Santis; D. Ferrara

2002-01-01

189

The Addition of Carbon Nanotube on the Tensile Properties of Carbon Fiber-Reinforced PEEK Composites  

Microsoft Academic Search

The main objective of this paper is to develop high strength resistance carbon fiber-reinforced polyether ether ketone (PEEK) composites with the addition of multiwall carbon nanotubes (MWCNT). These compounds were well mixed in a Haake batch mixer, and compounded polymers were fabricated into sheets of known thickness by compression moulding. Samples were tested for tensile properties with respect to different

J. Li; L. Q. Zhang

2009-01-01

190

Establishing a Mathematical Model to Predict the Tensile Strength of Friction Stir Welded Pure Copper Joints  

NASA Astrophysics Data System (ADS)

This investigation was undertaken to predict the tensile strength of friction stir welded pure copper. Response surface methodology based on a central composite rotatable design with four welding parameters, five levels, and 31 runs was used to conduct the experiments and to develop the mathematical regression model by means of Design-Expert software. Four welding parameters considered were tool profile design, rotational speed, welding speed, and axial force. Analysis of variance was applied to validate the predicted model. Confirmation experiments including microstructural characterization and conducted tensile tests showed that developed models are reasonably accurate. The results showed that the joints welded using the square and triangular tools had higher tensile strength compared to the joints welded using other tools. The increase in tool rotational speed, welding speed, and axial force resulted in increasing the tensile strength of the joints up to a maximum value. Also, the developed model showed that the optimum parameters to get a maximum of tensile strength were rotational speed, welding speed, and axial force of 942 rpm, 84 mm/min, and 1.62 kN, respectively.

Heidarzadeh, A.; Saeid, T.; Khodaverdizadeh, H.; Mahmoudi, A.; Nazari, E.

2013-02-01

191

First-principles Calculations of Ideal Tensile and Shear Strengths for Gum-Metal Approximants  

NASA Astrophysics Data System (ADS)

A newly developed bcc-type Ti-23Nb-0.7Ta-2Zr-O (mol%) alloy named Gum-Metal showed unusual properties including ultralow elastic modulus, ultrahigh strength, super-elastic-like behavior, and super-plastic-like behavior, in particular, accompanied by dislocation-free plastic deformation. [1]. As proposed in first-principles calculations, one of the requirements for the Gum-Metal is dramatic softening of the elastic shear modulus C'=(C11-C12)/2 ˜ 0, which happens at a valence electron concentration around 4.24. We also study ideal tensile and shear strengths for Gum-Metal approximants to understand microscopic origin of such unique mechanical properties. The most stable Gum-metal approximant among all the possible 1820 atomic configurations of Ti12Nb4 has been determined, and showed good agreement with the experimental elastic constants of Gum-Metal.[4pt] [1] T. Saito et al., Science 300, 464 (2003).

Nagasako, Naoyuki; Jahnatek, Michal; Asahi, Ryoji; Hafner, Jürgen

2010-03-01

192

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

193

Density and Tensile Properties Changed by Aging Plutonium.  

National Technical Information Service (NTIS)

We present volume, density, and tensile property change observed from both naturally and accelerated aged plutonium alloys. Accelerated alloys are plutonium alloys with a fraction of Pu-238 to accelerate the aging process by approximately 18 times the rat...

2005-01-01

194

The effect of temperature on the tensile strength and disintegration of paracetamol and oxytetracycline tablets.  

PubMed

The tensile strengths and disintegration times of paracetamol and oxytetracycline tablets at room temperature are higher when they have been prepared at high temperatures, e.g. 85 degrees, than at room temperature or below, e.g.--20 degrees. The activation energies of the two materials, 3 and 1 k cal mol-1 (13 and 4kJmol-1) respectively, were derived from plots of log tensile strength and log disintegration time versus the reciprocal of the absolute temperature. The results have been explained in terms of sintering theory and the formation of welded bonds between particles. PMID:19574

Pilpel, N; Esezobo, S

1977-07-01

195

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

NASA Technical Reports Server (NTRS)

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.

Nettles, A. T.

1990-01-01

196

Factors which influence tensile strength of a SiC/Ti-24Al-11Nb (at. pct) composite  

NASA Technical Reports Server (NTRS)

Tensile and fiber pullout tests were used in conjunction with SEM to investigate structural and processing effects on SiC fiber, a neat Ti-24Al-11Nb matrix alloy, and a composite fabricated from the two. The effects of oxygen content, fiber spacing, fiber volume fraction, fiber-matrix reaction thickness, Teflon content, and matrix powder size, appear to be smaller than the effects of variability in fiber strength. Fiber spacing did not influence radial crack formation, interfacial bond shear strength, or stress-strain behavior in the composite. The temperature dependence of composite properties was investigated over the 23-815 C range.

Brindley, P. K.; Draper, S. L.; Nathal, M. V.; Eldridge, J. I.

1990-01-01

197

The tensile properties of polyimide film at cryogenic temperatures and radiation effects on polyimide films  

SciTech Connect

Polyimide films has been used as insulating component in superconducting machinery. A full understanding of the property at low temperatures and the radiation effect is very important for stabilization of superconducting coils. The tensile properties of polyimide films have been measured at 4.2 K {approximately} 473 K. Stress-Strain curve profiles vary as a function of temperature. At cryogenic temperature, the elongation is much lower but the tensile strength is higher than that at room temperature. Also, polyimide film degradation performances after exposure of to an electron beam at very high dose level are examined. The test device for irradiation has a cooling system for preventing polyimide film from heating by electron absorption. The tests are performed at room temperature in He gas. After 80 MGy absorption, the elongation maintains about 60% level of the non irradiated film, and the tensile strength maintains about 85%.

Tanaka, T. [Dupont - Toray Co., Tokai Aichi (Japan); Hosoyama, K.; Hara, K. [National Lab. for High Energy Physics, Tsukuba Ibaragi (Japan)] [and others

1997-06-01

198

Tensile and Impact Properties of Thermoplastic Natural Rubber (TPNR) Filled with Carbon Nanotubes (MWNTs)  

NASA Astrophysics Data System (ADS)

This paper discusses the effect of multi-walled carbon nanotubes (MWNT) on the tensile and impact properties of thermoplastic natural rubber (TPNR) nanocomposite. The nanocomposite was prepared using melt blending method. MWNT were added to improve the mechanical properties of MWNTs/TPNR composites at different compositions which is 1, 3, 5, and 7 wt.%. The result of tensile test showed that tensile strength and Young's modulus increase in the presence of nanotubes and maximum value are obtained with 3 wt.% of MWNTs. On other hand, higher MWNTs concentration has caused the formation of aggregates. The elongation at break considerably decreased with increasing the percentage of MWNTs. The maximum impact strength is recorded with 5 wt.% of MWNTs. SEM micrograph has confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which is improved mechanical significantly.

Tarawneh, Mou'ad. A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi; Hock, Yew Chin; Halim, Hazwani Binti

2010-07-01

199

Tensile properties of palladium-silver alloys with absorbed hydrogen  

NASA Technical Reports Server (NTRS)

The alloys 90Pd-10Ag, 80Pd-20Ag, 70Pd-30Ag, 60Pd-40Ag, and 50Pd-50Ag containing absorbed hydrogen were tested in tension. The results show the tensile properties to be independent of the phase transition. Also, hydrogen in the lattice does not necessarily cause embrittlement or poor elongation. The changes in the tensile properties appear dependent on the electron to atom site ratio.

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

1975-01-01

200

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

201

Mechanical properties of high-strength steel fiber-reinforced concrete  

Microsoft Academic Search

The marked brittleness with low tensile strength and strain capacities of high-strength concrete (HSC) can be overcome by the addition of steel fibers. This paper investigated the mechanical properties of high-strength steel fiber-reinforced concrete. The properties included compressive and splitting tensile strengths, modulus of rupture, and toughness index. The steel fibers were added at the volume fractions of 0.5%, 1.0%,

P. S Song; S Hwang

2004-01-01

202

Comparison of polymer-based temporary crown and fixed partial denture materials by diametral tensile strength  

PubMed Central

PURPOSE The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (ø 4 mm × 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (? = 0.05). RESULTS Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.

Ha, Seung-Ryong; Yang, Jae-Ho; Lee, Jai-Bong; Han, Jung-Suk

2010-01-01

203

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

204

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

NASA Astrophysics Data System (ADS)

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 tensile properties of the laminate compared to the skin sheet. Forming limit diagrams were also determined. These indicated that the viscoelastic core properties can significantly affect formability of laminated steel compared to that of solid steel sheet. In general, the formability of laminated steel was found to be similar to or less than that of the much thinner skin sheet material, which indicates that its formability should be less than that of solid steel of the same gauge.

Ruokolainen, Robert B.; Sigler, David R.

2008-06-01

205

Effect of particle size and volume fraction on tensile properties of fly ash/polyurea composites  

NASA Astrophysics Data System (ADS)

Fly ash, which consists of hollow particles with porous shells, was introduced into polyurea elastomer. A one-step method was chosen to fabricate pure polyurea and the polyurea matrix for the composites based on Isonate® 2143L (diisocyanate) and Versalink® P-1000 (diamine). Scanning electron microscopy was used to observe the fracture surfaces of the composites. Particle size and volume fraction were varied to study their effects on the tensile properties of the composites. The tensile properties of the pure polyurea and fly ash/polyurea (FA/PU) composites were tested using an Instron load frame with a 1 kN Interface model 1500ASK-200 load cell. Results showed that fly ash particles were distributed homogeneously in the polyurea matrix, and all of the composites displayed rubber-like tensile behavior similar to that of pure polyurea. The tensile strength of the composites was influenced by both the fly ash size and the volume fraction. Compared to the largest particle size or the highest volume fraction, an increase in tensile strength was achieved by reducing particle size and/or volume fraction. The strain at break of the composites also increased by using fine particles. In addition, the composites filled with 20% fly ash became softer. These samples showed lower plateau strength and larger strain at break than the other composites.

Qiao, Jing; Schaaf, Kristin; Amirkhizi, Alireza V.; Nemat-Nasser, Siavouche

2010-03-01

206

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

207

Tensile properties of as-cast iron-aluminide alloys  

SciTech Connect

Room-temperature tensile properties of as-cast Fe{sub 3}Al-based FA-129 alloy were investigated. Tensile properties were obtained in the as-cast condition in air, oxygen, and water-vapor environments, and after homogenization at 700, 900, and 1200{degrees}C. Transmission electron microscopy (MM) was used to characterize ordered phases and dislocation structure, and optical metallography and scanning electron microscopy (SEM) were used to characterize the grain microstructure and fracture morphology. Tensile properties in the as-cast condition exhibited an environmental effect; tensile ductilities in oxygen atmosphere were greater than those obtained in laboratory air. Homogenized samples of FA-129 alloy exhibited almost twice the ductility found in the as-cast condition. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures provided clues that helped to explain the poor ductility in the as-cast state.

Viswanathan, S.; McKamey, C.G.; Maziasz, P.J.

1995-01-01

208

Tensile Strength of Carbon Nanotubes Under Realistic Temperature and Strain Rate  

NASA Technical Reports Server (NTRS)

Strain rate and temperature dependence of the tensile strength of single-wall carbon nanotubes has been investigated with molecular dynamics simulations. The tensile failure or yield strain is found to be strongly dependent on the temperature and strain rate. A transition state theory based predictive model is developed for the tensile failure of nanotubes. Based on the parameters fitted from high-strain rate and temperature dependent molecular dynamics simulations, the model predicts that a defect free micrometer long single-wall nanotube at 300 K, stretched with a strain rate of 1%/hour, fails at about 9 plus or minus 1% tensile strain. This is in good agreement with recent experimental findings.

Wei, Chen-Yu; Cho, Kyeong-Jae; Srivastava, Deepak; Biegel, Bryan (Technical Monitor)

2002-01-01

209

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

NASA Astrophysics Data System (ADS)

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.

Yokoyama, T.; Nakai, K.

2006-08-01

210

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

211

Determination of the High Temperature Strength of Ceramic. Discussion of Testing Techniques: Flexural and Tensile Tests, Creep Tests with Flexural and Tensile Load.  

National Technical Information Service (NTIS)

High temperature strength of ceramic materials was determined within the service temperature range of an automobile gas turbine. For the use of ceramics as construction materials in gas turbine assemblies, results for flexural and tensile behavior are of ...

W. Gebhard

1981-01-01

212

Tensile strengths and porosities of solar system primitive bodies  

NASA Astrophysics Data System (ADS)

Recent measurements of asteroid bulk densities suggest that rubble-pile asteroids with typical porosities of 30 to 50% may be common (Britt et al., 2006). However, the presence of such objects doesn't mean necessarily that the initial porosity had been preserved (Kerridge, 1993). In fact, the fluffy aggregates produced in laboratory experiments that we expect to be representative of the oldest protoplanetary disk materials, exhibit even higher porosities (Blum et al., 2006). Recent results confirm that primitive meteorites (like e.g. CM carbonaceous chondrites) are compacted samples of the nebula matter exhibiting different density and porosity that their precursors materials (Trigo-Rodríguez et al., 2006). Consequently, aqueous alteration, brecciation, and impact-induced metamorphism make very unlikely to find pristine bodies between the asteroidal population. However, there is clear evidence for the existence of high-porosity bodies between the C-type asteroids like e.g. Mathilde (Housen et al., 1999) or the Tagish Lake parent body (Brown et al., 2002). Although extensive post-accretionary processing of meteorite parent bodies can produce high degrees of porosity, only the most pristine ones seem to preserve more than 50% of porosity. Consequently, we should look for these low strength bodies among the C-type asteroids, or very especially in some unprocessed comets that continue being representative of the precursor materials. Recent suggestion that CI1 chondrites are originated from comets should be studied in this context (Gounelle et al., 2006). Particularly, we think that studies of the porosity and strength of primitive meteorites would provide valuable clues on the origin and nature of their parent bodies. REFERENCES Blum J., R. Schräpler, B.J.R. Davidson and J.M. Trigo-Rodríguez (2006) Astroph. J., submitted. Britt D.T., G.J. Consolmagno, and W.J. Merline (2006) Lunar Planet. Sci. Conf. Abstract #2214. Brown, P. G., D. O. Revelle, E. Tagliaferri, and A.R. Hildebrand (2002) Meteorit. & Planet. Sci. 37, 661-675. 1 Gounelle M., P. Spurny, and P. Bland (2006) Meteorit. & Planet. Sci. 41, 135-150. Housen K.R., K.A. Holsapple and M.E. Voss (1999) Nature 402, 155. Kerridge J.F. (2003) Icarus 106, 135-150. Trigo-Rodríguez J.M., Rubin A.E. and J.T. Wasson (2006) Geochim. et Cosmoch. Acta 70, 1271-1290. 2

Trigo-Rodriguez, J. M.; Llorca, J.; Blum, J.

213

The native tensile strength of the supraspinatus tendon. A biomechanical study  

Microsoft Academic Search

Summary  \\u000a The traumatic tear of the rotator cuff has been discussed very intensively for a long time despite the fact that there do\\u000a not exist representative objective data about the native tensile strength of these tendons. The aim of this study was to evaluate\\u000a the age related native strength of the supraspinatus tendon. 25 fresh frozen cadaver specimen (age: 23–94,

M. Rickert; H. Georgousis; U. Witzel

1998-01-01

214

Effect of matrix texture on tensile strength and oxidation behavior of carbon fiber reinforced carbon composites  

Microsoft Academic Search

Unidirectional carbon fiber reinforced carbon composites (C?C composites) with different matrix textures were prepared from six matrix precursors. Two composites with an optically isotropic matrix showed tensile strength and modulus values that increased on heat treatment of the samples at a high temperature. Composites with an anisotropic matrix, having preferred orientation parallel to fiber surface, were deformed due to shrinkage

Norio Iwashita; Yoshihiro Sawada; Kazuyuki Shimizu; Shigekazu Shinke; Hiroshi Shioyama

1995-01-01

215

Warm and Hot Stamping of Ultra High Tensile Strength Steel Sheets Using Resistance Heating  

Microsoft Academic Search

A warm and hot stamping process of ultra high tensile strength steel sheets using resistance heating was developed to improve springback and formability. In this process, the decrease in temperature of the sheet before the forming is prevented by directly heating the sheets set into the dies by means of the electrical resistance, the so-called Joule heat. Since the heating

K. Mori; S. Maki; Y. Tanaka

2005-01-01

216

Strength of Tensile Loaded Graphite\\/Epoxy Laminates Containing Cracks, Open and Filled Holes  

Microsoft Academic Search

Most methods currently used for predicting tensile strength of composite laminates containing holes and cracks adopt a characteristic distance approach such as the Point Stress Criterion (PSC) or the Average Stress Criterion (ASC). These and similar ap proaches are attractive to designers since they are simple to apply. The limitation of such approaches, however, is that the characteristic distance is

Ingvar Eriksson; Carl-Gustaf Aronsson

1990-01-01

217

Effects of Moisture and Temperature on the Tensile Strength of Composite Materials  

Microsoft Academic Search

The ultimate tensile strengths of Thornel 300\\/Fiberite 1034 graphite epoxy composites were measured with material temperatures ranging from 200 K to 422 K and moisture contents from 0% (dry) to 1.5% (fully saturated). All measurements were performed using 0°, 90° and ?\\/4 laminates. A survey was also made of the existing data showing the effects of temperature and moisture content

Chi-Hung Shen; George S. Springer

1977-01-01

218

Comparison of Tensile Strength of Wounds Closed by Sutures and Cyanoacrylates.  

National Technical Information Service (NTIS)

Skin incisions closed by 3 homologous alpha-alkyl cyanoacrylates were compared with sutured control wounds in rat skin with respect to tensile strength at 6 different times (postoperation days 1, 4, and 7 and postoperation weeks 4,8, and 16). The data ind...

P. B. Lamborn H. B. Solouay T. Matsumoto G. V. Aaby

1969-01-01

219

Simultaneous improvements in the cryogenic tensile strength, ductility and impact strength of epoxy resins by a hyperbranched polymer  

Microsoft Academic Search

Improvements in mechanical properties at low temperatures are desirable for epoxy resins such as diglycidyl ether of bisphenol A (DGEBA) that are often used in cryogenic engineering applications. In this study, a hydroxyl functionalized hyperbranched polymer (H30) is employed to improve the mechanical properties of a DGEBA epoxy resin at liquid nitrogen temperature (77K). The results show that the tensile

Jiao-Ping Yang; Zhen-Kun Chen; Guo Yang; Shao-Yun Fu; Lin Ye

2008-01-01

220

Microstructure and Tensile Properties of Wrought Al Alloy 5052 Produced by Rheo-Squeeze Casting  

NASA Astrophysics Data System (ADS)

The semisolid slurry of wrought Al alloy 5052 was prepared by the indirect ultrasonic vibration (IUV) method, in which the horn was vibrated under the outside of the metallic cup containing molten alloy, and then shaped by direct squeeze casting (SC). Spherical primary ?-Al particles were uniformly dispersed in the matrix and presented a bimodal distribution of grain sizes. The effects of rheo-squeeze casting (RSC) parameters such as squeeze pressure and solid fraction on the microstructure and tensile properties of the semisolid alloy were investigated. The results indicate that average diameters of the primary ?-Al particles decreased with the increase of squeeze pressure, while the tensile properties of the alloy increased. With the increase of solid fraction, the tensile strength increased first and then decreased, but the elongation decreased continuously. The best tensile properties were achieved when the slurry with a solid fraction of 0.17 solidified under 100 MPa. Compared to conventional squeeze casting, RSC process can offer the 5052 alloy better tensile strength and elongation, which were improved by 9.7 pct and 42.4 pct, respectively.

Lü, Shulin; Wu, Shusen; Wan, Li; An, Ping

2013-06-01

221

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

222

Biomechanical properties and collagen fiber orientation of temporomandibular joint discs in dogs: 2. Tensile mechanical properties of the discs.  

PubMed

The tensile properties of TMJ discs in dogs were investigated using soft-tissue tensile and stress-relaxation tests. The data obtained suggested that (1) the mediolateral tensile stiffness (199.7 and 234.0 MPa), tensile strength (46.73 and 69.99 MPa), and equilibrium moduli (30.0 and 30.1 MPa) of anterior and posterior bands of the disc, respectively, were much greater than those of the middle part (46.6, 14.71, and 18.4 MPa, respectively); (2) the difference in fracture strain of various parts was not significant; (3) the physiologic strain region of the discs was about 4%; and (4) the properties of low stress/relaxation rate and nonlinear relationship of the instantaneous elastic response to various strains may represent lower permeability of TMJ discs. PMID:1812136

Teng, S; Xu, Y; Cheng, M; Li, Y

1991-01-01

223

Swelling and tensile properties of neutron-irradiated vanadium alloys  

SciTech Connect

Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600{degree}C to neutron fluences ranging from 0.3 to 1.9 {times} 10{sup 27} neutrons/m{sup 2} (17 to 114 atom displacements per atom (dpa)).

Loomis, B.A.; Smith, D.L.

1990-07-01

224

Tensile properties of irradiated nuclear grade pressure vessel welds for the third HSST irradiation series  

SciTech Connect

The Heavy Section Steel Technology (HSST) Program conducted a series of experiments to investigate the effect of neutron irradiation on the fracture toughness of nuclear pressure vessel materials. Four welds of A 508 class 2 steel were examined in this Third HSST Irradiation Series. The welds were fabricated according to ''early'' (pre-1972) light-water reactor weld practice (i.e., copper-coated electrodes). As part of this study, tensile properties were measured after irradiation to 2 to 10 x 10/sup 22/ neutrons/m/sup 2/ (E > 1 MeV) at temperatures between 250 and 290/sup 0/C. Strength properties of all four welds increased with exposure to irradiation. Yield strength was more sensitive to irradiation than was ultimate strength. Tensile ductility was not affected significantly by exposure to irradiation.

McGowan, J.J.

1985-03-01

225

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

226

An analysis on changes in structure, tensile properties of polytetrafluoroethylene film induced by protons  

NASA Astrophysics Data System (ADS)

Effect of 100 keV proton radiation on the structure and tensile properties of PTFE film was investigated. The change in structure before and after proton radiation was mainly evaluated by means of differential scanning calorimetry. The experimental results show that under radiation of 100 keV protons for the fluence less than 7×10 15 p/cm 2, the DSC characteristics including the phase enthalpy of transformations at room temperature ? Hrt1 and ? Hrt2, the melting enthalpy ? Hm1 and ? Hm2, the crystallization exothermal enthalpy ? Hc, and Tg II were decreased, while the melting temperature was increased a little with the fluence increase. The change in crystallization enthalpy ? Hc indicated the increase of molecular weight of the PTFE film, but for 150 keV when the fluence exceeded the fluence of 10 16/cm 2, the molecular weight decreased gradually. With increasing proton fluence, the thermal gravity loss was decreased, while the initial decomposition temperature increased, demonstrating that crosslinking of molecular chains occurred. With the increase of the proton fluence, for proton with energy less than 150 keV, the tensile fracture strength increased at first, but when the fluence exceeded 10 16/cm 2, the tensile fracture strength showed a decreasing trend. While for the proton of 170 keV, the tensile fracture strength ?f increased abruptly at the fluence of 2×10 13/cm 2, with the fluence increasing further, the tensile fracture strength ?f decreased gradually. The change of tensile properties could be related with the competition of branching crosslinking and the scission degradation.

Peng, Guirong; Geng, Hongbin; Yang, Dezhuang; He, Shiyu

2004-02-01

227

Qualitative femur bone tensile strength analysis in radiographic images using wavelets - biomed 2011.  

PubMed

In this work, the tensile strength of femur bone is qualitatively analyzed using radiographic images. The sub anatomic tensile regions were delineated from conventional planar radiographic femur images using digital image processing algorithms. The normal and abnormal images are then subjected to Daubechies5, coiflet5 and Haar wavelets decomposed at three levels to derive approximation and detail coefficients. The qualitative analyses were also performed on the delineated images to derive apparent mineralization and total area. The values of higher order energy parameter are derived for both approximation and detail coefficients in each level of decomposition and are correlated with apparent mineralization for analysis. Results show that the low values of energy correlates well with abnormalities in all levels of decomposition for all the three wavelets. Among all, the values of energy derived out of approximation coefficient using Haar wavelets show higher degrees of correlations in both primary tensile and secondary tensile regional strength. The variations between normal and abnormal were also found to be statistically significant. Poor correlation was observed in the case of detailed coefficients for all the wavelets irrespective of levels. Among all wavelets, the parameters decomposed at level one approximation coefficient of Haar wavelet appear to be a useful predictor for classifying normal and abnormal samples. This could be attributed to sensitivity of adopted wavelets to the architectural changes and discontinuities in regional distribution of trabecular pattern in tensile region. It appears that this methodology could be used for gross abnormality detection, micro-damage studies and modeling the mechanics of soft tissue in diseases. Thus wavelet extracted feature on tensile trabeculae regions of radiographic femur images could be a used as an index for automated screening of bone strength. PMID:21525609

Sangeetha, S; Sujatha, C M; Ramakrishnan, S

2011-01-01

228

The Effect of Thermocycling on Tensile Bond Strength of Two Soft Liners  

PubMed Central

Objective: Failure of soft liners depends mostly on separation from the denture base resin; therefore measurement of the bond strength is very important. The purpose of this study was to compare the tensile bond strength of two soft liners (Acropars, Molloplast-B) to denture base resin before and after thermocycling. Materials and Methods: Twenty specimens fromeach of the two different soft liners were processed according to the manufacturer’s instructions between two polymethyl methacrylate (PMMA) sheets. Ten specimens in each group were maintained in 37°C water for 24 hours and 10 were thermocycled (5000 cycles) among baths of 5° and 55°C. The tensile bond strength was measured using a universal testing machine at a crosshead speed of 5 mm/min. Mode of failure was determined with SEM (magnification ×30). Two-way ANOVA was used to analyze the data. Results: The mean and standard deviation of tensile bond strength of Acropars and Molloplast-B before thermocycling were 6.59±1.85 and1.51±0.22 MPa, respectively and 5.89±1.52 and1.37±0.18 MPa, respectively after thermocycling. There was no significant difference before and after thermocycling. Mode of failure in Acropars and Molloplast-B were adhesive and cohesive, respectivley. Conclusion: The bond strength of Acropars was significantly higher than Molloplast-B (P<0.05).

Geramipanah, Farideh; Ghandari, Masoumeh; Zeighami, Somayeh

2013-01-01

229

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

NASA Technical Reports Server (NTRS)

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.

Vary, A.; Lark, R. F.

1978-01-01

230

Correlation of fiber composite tensile strength with the ultrasonic stress wave factor  

NASA Technical Reports Server (NTRS)

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) 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.

Vary, A.; Lark, R. F.

1978-01-01

231

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

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

232

Spall experiments for the measurement of the tensile strength and fracture energy of concrete at high strain rates  

Microsoft Academic Search

To study the behavior of concrete under dynamic loads, a Hopkinson-Bar was set up and used. Cylindrical concrete specimens were positioned at the end of the incident bar and the spall event was studied. The purpose of this contribution is to explain the measurement of the tensile strength and the specific fracture energy. To determine the tensile strength, the measured

Harald Schuler; Christoph Mayrhofer; Klaus Thoma

2006-01-01

233

The effect of surface indications on the tensile properties of cast steel  

NASA Astrophysics Data System (ADS)

The objective of this thesis was to study the effect of surface indications on the tensile properties of cast steel. Four cast steel grades were selected for evaluation; these grades include three carbon and low alloy steels (110/80, 165/135, and Eglin) and one high alloy steel (CF8M). Using these steels, tensile specimens were produced, inspected via MT/PT, categorized by surface indications (as-cast or machined), and tested. Bars with natural surface indications were tensile tested and the properties recorded. The presence of a ? inch, ? inch, or ¼ inch flat-bottomed hole drilled through half the thickness mimicked a similar nonlinear worse-case scenario indication. The ¼ inch indication resulted in an ultimate tensile strength loss ranging from 21.5% to 36.0%, with the more ductile materials being impacted least. The percent elongation loss ranged from 38.5% to 69.9%, with the majority of the alloys showing an approximate 60 percent loss in elongation. The modulus decrease ranged from 2.9% to 17.5%. These results were modeled using ANSYS to observe capability in predicting a decrease in properties. The resulting decrease in properties matched the experimental data to an accuracy of 3+/-11%. The results provide a previously undocumented relationship between indication size and tensile properties.

Hamby, Jeff

234

Effects of bathing solution on tensile properties of the cornea.  

PubMed

The cornea is a transparent tissue with the major functions of protecting the inner contents of the eye and refracting incoming light. The biomechanical properties of the cornea strongly depend on the microstructure and composition of the stromal layer, a hydrated bio-gel. The uniaxial strip testing is a convenient and well-accepted experimental technique for characterizing corneal material parameters. It is known that the water content of specimens in this method depends on the osmolality of the bathing solution. The present study was designed to investigate the effects of different bathing solutions on uniaxial tensile material properties of the cornea. The tensile behavior of bovine corneal samples was measured in six different bathing solutions, i.e., hypertonic solution (12% NaCl solution), common preserving isotonic solutions (e.g., phosphate buffer saline, ophthalmic balanced salt solution, and 0.9% NaCl solution), hypotonic solution (distilled water), and neutral solution (mineral oil). It was observed that the bathing solution had significant influence on the tensile behavior of the corneal samples. In particular, the specimens tested in bathing solutions causing less swelling had significantly stiffer tensile properties. Furthermore, a simple mathematical model based on Voigt composite material model was developed to represent the measured solution-dependent tensile properties. The present study suggests that extra attention should be paid to corneal thickness (hydration) in uniaxial tensile experiments. It also provides important data on tensile properties of the cornea; such information could significantly contribute to improving the accuracy of numerical predictions of corneal biomechanics. PMID:24333541

Hatami-Marbini, Hamed; Rahimi, Abdolrasol

2014-03-01

235

Comparison of the Effect of two Denture Cleansers on Tensile bond Strength of a Denture Liner  

PubMed Central

Statement of Problem: One of the most clinical challenging issues in prosthodontics is debonding of soft liners from the denture base. Purpose: The aim of this study was to evaluate and compare tensile bond strength between soft liner and heat-cured acrylic resin when immersed in two different types of denture cleanser and distilled water, at different period of times. Materials and Method: In this experimental in vivo study, 238 heat-cured acrylic blocks were made. A soft liner was embedded between the acrylic blocks. Samples were divided into four groups: 17 samples were in the control group and were not soaked in any solution .The remaining samples were divided into 3 groups (Distilled water, Calgon and Fittydent). Each group was then subdivided into two subcategories, regarding the immersion time variable; 15 and 45 minutes. All samples were placed in tension force and tensile bond strength was recorded with the testing machine. One- way ANOVA and Tucky HSD post-hoc test were adopted to analyze the yielded data (?> 0.05). Results: Specimens which were immersed in two denture cleansers (Fittydent and Calgon) and in distilled water showed significant difference (p= 0.001) in bonding strength when compared to the control group. The subjects immersed in denture cleanser solutions and distilled water did not reveal any significant difference (p= 0.90). For all groups; most of the bonding failures (72%) were cohesive type. Conclusion: The effect of the denture cleansers and distilled water on the bond strength was not statistically different; however, the difference was significant between the immersed groups with the non-immersed group. Moreover, type of the denture cleanser did not show any effect on the tensile strength. The tensile strength increases with time of immersion.

Farzin, M; Bahrani, F; Adelpour, E

2013-01-01

236

Polystyrene foams. III. Structure-tensile properties relationships  

Microsoft Academic Search

In the previous two parts of this series of articles, the relations among the foaming conditions, microstructure, and impact properties of expanded microcellular polystyrene (EPS) were discussed. In this article, the effects of the foaming conditions and structure on the tensile properties of EPS were investigated. A systematic investigation was performed based on a statistical experimental design. Various processing conditions

Saeed Doroudiani; Mark T. Kortschot

2003-01-01

237

Effect of moisture content on tensile properties of paper-based food packaging materials  

Microsoft Academic Search

Tensile properties (tensile strength and elongation at break) of 3 selected paper-based packaging materials, such as a vegetable\\u000a parchment (VP) paper, a Kraft paper, and a solid-bleached-sulfate (SBS) paperboard, were determined with varying moisture\\u000a contents. The monolayer moisture content of the paper samples determined using the Guggenheim-Anderson-de Boer (GAB) model\\u000a were 3.45, 3.01, and 3.18 g water\\/100 g solids for

Jong-Whan Rhim

2010-01-01

238

Tensile, water vapor barrier and antimicrobial properties of PLA\\/nanoclay composite films  

Microsoft Academic Search

PLA-based composite films with different types of nanoclays, such as Cloisite Na+, Cloisite 30B and Cloisite 20A, were prepared using a solvent casting method and their tensile, water vapor barrier and antimicrobial properties were tested. Tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) of control PLA film were 50.45±0.75MPa, 3.0±0.1%, and 1.8×10?11gm\\/m2sPa, respectively. TS and E

Jong-Whan Rhim; Seok-In Hong; Chang-Sik Ha

2009-01-01

239

Fibronectin Matrix Polymerization Increases the Tensile Strength of a Model Tissue  

Microsoft Academic Search

Abstract The composition and organization of the extracellular matrix (ECM) contribute to the mechanical properties of tissues. The polymerization of fibronectin into the ECM increases actin organization and regulates the composition of the ECM. In this study, we examined the ability of cell-dependent fibronectin matrix polymerization to affect the tensile properties of an established tissue model. Our data indicate that

Candace D. Gildner; Amy L. Lerner; Denise C. Hocking

2004-01-01

240

Various conditioning methods for root canals influencing the tensile strength of titanium posts.  

PubMed

Conditioning the root canal is frequently advised to achieve high post-retention when resin composite luting cements are used. However, manufacturers' instructions for this purpose differ widely from one another. The aim of this study was to compare the tensile bond strengths of passive, tapered, titanium root posts that were luted with four different resin composite cements (Compolute Aplicap, Flexi-Flow cem, Panavia 21 EX, Twinlook) in the root canals at three conditions, namely (i) no conditioning, (ii) etching with 37% phosphoric acid, and (iii) etching + bonding agent application. Panavia 21 EX was further tested after using the primer for the post-surface according to the manufacturer's recommendations. The posts luted with zinc phosphate cement (Tenet) acted as the control group. Following endodontic preparation of 140 intact anterior teeth with hand instruments, the post-spaces were prepared using the opening drills of the corresponding size of the posts. The samples were first stored in water at 37 degrees C for 24 h and then thermocycled (5000 cycles, 5-55 degrees C, 30 s). The tensile strength values were measured with the universal testing machine at a crosshead speed of 0.5 mm min(-1). The data were analysed statistically using anova and corrected with Scheffé test due to the significance levels (P < 0.05). The tensile bond strengths of the titanium posts after luting with various cements and thermocycling were affected by the conditioning systems used for the root canals. Tensile bond strengths were the highest with Flexi-Flow (475 +/- 78 N) followed in descending order by Panavia 21 EX (442 +/- 97 N), Twinlook (430 +/- 78 N) and Compolute Aplicap (352 +/- 76 N) after conditioning the root canal. The use of primer on the post improved the tensile bond strength compared with the non-conditioned group for the Panavia 21 EX group (375 +/- 77 N) (P < 0.001). Tensile bond strengths obtained after luting the posts with zinc phosphate cement (414 +/- 102 N) were not significantly different (P < 0.05) than those of resin composite cements. Although the importance of conditioning the root canal was evident for Panavia 21 EX, it was not the case for the other luting cements tested. PMID:15369471

Schmage, P; Sohn, J; Nergiz, I; Ozcan, M

2004-09-01

241

The influence of specimen length on the tensile failure properties of tendon collagen.  

PubMed

Connective tissues such as ligament, tendon and skin are composites of strength-bearing collagen fibers embedded in a hydrated matrix. The tensile response and failure properties of rat-tail tendon are thought to represent those of the collagen fiber itself. In this study, the tensile failure properties of rat-tail tendon (tendon collagen) were determined for specimens of various test length. The experimental results indicated that failure strain, based on the test grip-to-grip dimension, and failure strain energy density decreased as specimen length increased. The failure stress, on the other hand, did not change appreciably with specimen length. Thus, tensile failure data cannot simply be normalized by the grip-to-grip length of the test specimen. Experimental data from various laboratories must clearly document the length of the test specimen. PMID:3793742

Haut, R C

1986-01-01

242

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

SciTech Connect

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.

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

243

Microstructure, hardness profile and tensile strength in welds of AA6013 T6 extrusions  

SciTech Connect

Alloy AA6013 is easily welded by conventional arc welding processes as well as by high-energy-density processes. However, some physical properties, which are inherent to all aluminum alloys, have to be considered during welding. In comparison to steel, the high thermal conductivity of aluminum alloys requires the use of higher heat input for welding. This is realized by a greater welding current during GTAW of aluminum alloys. One of the main problems associated with LBW of aluminum alloys is the high surface reflectivity. In particular, the threshold intensity for the development of a keyhole is much higher for aluminum than for steel. Finally, aluminum alloys, and particularly the heat-treatable alloys, are sensitive to weld cracking. This phenomenon can be avoided by proper filler and base metal alloy selection and adequate filler metal dilution. In order to improve the mechanical integrity of Al-Mg-Si weldments, it would be desirable to study the microstructure of the FZ and of the HAZ, as well as the residual stress distribution. The present study was performed in order to show differences in microstructure, hardness profile and tensile strength of gas tungsten arc (GTA) and laser beam (LB) welded AA6013-T6 extrusions. In addition, grain boundary liquations and hot tearing are discussed.

Guitterez, L.A. [Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research; Neye, G.; Zschech, E. [Daimler-Benz Aerospace Airbus GmbH, Bremen (Germany)

1996-04-01

244

Hydrogen Embrittlement of a 1500-MPa Tensile Strength Level Steel with an Ultrafine Elongated Grain Structure  

NASA Astrophysics Data System (ADS)

A deformation of a tempered martensitic structure ( i.e., tempforming) at 773 K (500 °C) was applied to a 0.6 pct C-2 pct Si-1 pct Cr steel. The hydrogen embrittlement (HE) property of the tempformed (TF) steel was investigated by a slow strain rate test (SSRT) and an accelerated atmospheric corrosion test (AACT). Hydrogen content within the samples after SSRT and AACT was measured by thermal desorption spectrometry (TDS). The tempforming at 773 K (500 °C) using multipass caliber rolling with an accumulative are reduction of 76 pct resulted in the evolution of an ultrafine elongated grain (UFEG) structure with a strong <110>//rolling direction (RD) fiber deformation texture and a dispersion of spheroidized cementite particles. The SSRT of the pre-hydrogen-charged notched specimens and the AACT demonstrated that the TF sample had superior potential for HE resistance to the conventional quenched and tempered (QT) sample at a tensile strength of 1500 MPa. The TDS analysis also indicated that the hydrogen might be mainly trapped by reversible trapping sites such as grain boundaries and dislocations in the TF sample, and the hydrogen trapping states of the TF sample were similar to those of the QT sample. The QT sample exhibited hydrogen-induced intergranular fracture along the boundaries of coarse prior-austenite grains. In contrast, the hydrogen-induced cracking occurred in association with the UFEG structure in the TF sample, leading to the higher HE resistance of the TF sample.

Nie, Yihong; Kimura, Yuuji; Inoue, Tadanobu; Yin, Fuxing; Akiyama, Eiji; Tsuzaki, Kaneaki

2012-05-01

245

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

NASA Technical Reports Server (NTRS)

The variation of ultimate tensile strength with thermal treatment of B-Al composite materials and of boron fibers chemically removed from these composites is studied systematically in an attempt to determine the mechanism of the resulting strength degradation. The results indicate that thermally cycling of B-Al represents a more severe condition than equivalent time at temperature. Degradation of composite tensile strength from about 1.3 GN/sq m to as low as 0.34 GN/sq m was observed after 3000 cycles to 420 C for 203-micron 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. On the basis of various thermal-cycling studies and electron diffraction analysis, a mechanism is favored in which B reacts with Al, freshly exposed by cold working during cycling, to form AlB2. The nonuniform interface reaction leads to a highly flawed and weakened B fiber.

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

1977-01-01

246

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

NASA Astrophysics Data System (ADS)

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.

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

1998-01-01

247

Effects of carbon percentage, Stelmor cooling rate and laying head temperature on tensile strength gain in low carbon steels  

NASA Astrophysics Data System (ADS)

Low carbon steel wire rods are used to produce finished products such as fine wire, coat hangers, staples, and roofing nails. These products are subjected to excessively high work hardening rates during wire drawing process resulting in a variation in wire tensile strength. This research analyzes the effects of carbon percentage, StelmorRTM cooling rate and laying head temperature on the tensile strength gain in wire drawn low carbon steels using design of experiments. The probable reasons for variations in tensile strength gain are analyzed by observing the microstructural changes during experiments. Microstructural analysis was done extensively using optical microscope and Transmission Electron Microscope (TEM) and it was found that the tensile strength gain variation is mainly caused by the increase in the dislocation density in wire rod and wire due to high cooling rate and high laying head temperature, within the range considered. This research concludes that a low carbon wire rod can be produced with minimum tensile strength gain, lower dislocation density and finer ferrite grain size by maintaining a low cooling rate in the StelmorRTM cooling zone and low laying head temperature, which is the temperature at which the wire rod coils are laid on the Stelmor RTM deck. It is also concluded from the results of the present study that: (1) The lowest tensile strength gain is for NS 1006T-3 (0.07 wt.% Carbon) with low cooling rate of 14°F/s and low laying head temperature of 1500°F. (2) The highest tensile strength gain is for NS 1006T-3 with high cooling rate of 26°F/s and high laying head temperature of 1650°F. (3) The effect of StelmorRTM cooling rate and laying head temperature and their interaction are found to be the significant factors causing the variation in wire tensile strength gain. The StelmorRTM cooling rate has the most significant effect on tensile strength gain among the three factors. (4) The effect of carbon percentage on wire tensile strength gain is very minimal. (5) With an increase in the StelmorRTM cooling rate from 14°F/s to 26°F/s, there is a substantial increase in the dislocation densities in the wire rods and wires, which is the primary cause of the increase in the tensile strength gain. (6) The effect of carbon percentage on wire tensile strength gain is very minimal. North Star Steel Texas would benefit substantially from this research by being able to produce better quality wire rods, through better understanding of the factors affecting the tensile strength gain variation. This is expected to lead to a reduction in customer complaints on failure of wire products.

Gade, Surya Prakash

248

First-principles study of He effects in a bcc Fe grain boundary: site preference, segregation and theoretical tensile strength.  

PubMed

We perform a first-principles calculation to investigate the effects of He in an Fe ?5(310)/[001] grain boundary (GB) with the SIESTA code, for which the reliability of the pseudopotential and the basis set are systematically tested. We calculate the formation and segregation energies for different substitutional and interstitial cases in order to determine the site preference and the segregation properties of He in the Fe GB. It is demonstrated that the He segregation either breaks (substitution) or weakens (interstitial) the surrounding interfacial Fe-Fe bonds, leading to the GB tensile strength reduction. PMID:21403193

Zhang, Lei; Shu, Xiaolin; Jin, Shuo; Zhang, Ying; Lu, Guang-Hong

2010-09-22

249

Structure and tensile strength of LaS(1.4)  

NASA Technical Reports Server (NTRS)

The tensile strength of LaS(1.4) has been estimated by diametral stress testing at room temperature, 800 and 1300 K. Brittle, tensile-type failures were obtained at all temperatures when the crosshead speed was 0.0021 mm/s; however, a 1300 K test at 0.00085 mm/s produced plastic flow. The microstructure of LaS(1.4) consisted of two phases with beta-La2S3 comprising about 15 vol percent of the structure and gamma-La2S3 the remainder. Because of the limited amount of material available for testing, no correlation between microstructure and mechanical strength could be drawn.

Whittenberger, J. Daniel; Smoak, Richard H.

1987-01-01

250

Synthesis, characterization, and tensile strength of CVI SiC/BN/SiC composites  

SciTech Connect

Tows of Nicalon yarn were first precoated by CVD with amorphous BN, then infiltrated with SiC by CVD to form single strand composites. Two different methods for the preparation of BN were investigated. The first involved the formation of a BCl3-NH3 adduct; the second consisted of the direct reaction of the gases in hot zone. Tensile strength measurements made on the composites were about 277 MPa and displayed a considerable amount of fiber pull-out and crack bridging. In order to establish their thermal stability, the ends of the composites were cut, exposing the fiber and interface, and annealed in air to 1100 C for 70 h. This annealing process did not result in a decrease in tensile strength. The composites were characterized by AES, SEM, and X-ray diffraction analysis. 16 refs.

Kmetz, M.A.; Laliberte, J.M.; Willis, W.S.; Suib, S.L.; Galasso, F.S.

1991-10-01

251

Dust release and tensile strength of the non-volatile layer of cometary nuclei  

NASA Astrophysics Data System (ADS)

We developed a thermophysical model for cometary nuclei, which is based upon the assumption that comets form by the gravitational instability of an ensemble of dust and ice aggregates. Under this condition, the tensile strength of the ice-free outer layers of a cometary nucleus can be calculated, using the dust-aggregate collision and adhesion model of Weidling et al. (Weidling, R. et al. [2012]. Icarus, 218, 688-700). Based on available laboratory data on the gas permeability and thermal conductivity of ice-free dust layers, we derived the temperature and pressure at the dust-ice interface for pure water and pure carbon dioxide ice. Comparison of the vapor pressure below the dust crust with its tensile strength allows the prediction of dust release from cometary surfaces. Our model predicts dust activity for pure CO2 ice and for heliocentric distances of ?3 AU, whereas pure H2O ice cannot explain the dust emission.

Skorov, Yuri; Blum, Jürgen

2012-09-01

252

Tensile property of H13 die steel with convex-shaped biomimetic surface  

NASA Astrophysics Data System (ADS)

The H13 steel specimens with non-smooth surface were fabricated by biomimetic method and laser technique, and the effect of these biomimetic surfaces on the tensile properties was investigated. The results indicated that the biomimetic surface has an advantageous effect on improving the tensile properties of H13 steel. As the area ratio occupied by non-smooth units on the biomimetic surface grows to 26.7%, the ultimate tensile strength (UTS) and 0.2% yield strength (YS) of materials linearly increase by about 8.4% and 17.2%, respectively. The elongation to fracture of materials reaches to the peak value of about 41.3% at the point of 17.1% area ratio, and further heightening the area ratio can result in a reduced ductility relative to this peak value. This improvement of tensile properties can be attributed to the combined effects of the microstructure characteristics within the unit zone and the unit-distribution features on the surface. Meanwhile, the regressed relation equations of UTS, YS and elongation regarding the area ratio were obtained via statistical theory. The tests of regression significance showed that the confidence of these equations achieved 99% above.

Zhang, Z. H.; Zhou, H.; Ren, L. Q.; Tong, X.; Shan, H. Y.; Cao, Y.

2007-09-01

253

Effect of different surface treatments on tensile bond strength of silicone-based soft denture liner  

Microsoft Academic Search

Failure of the bond between the acrylic resin and resilient liner material is commonly encountered in clinical practice. The\\u000a purpose of this study was to investigate the effect of different surface treatments (sandblasting, Er:YAG, Nd:YAG, and KTP\\u000a lasers) on tensile bond strength of silicone-based soft denture liner. Polymethyl methacrylate test specimens were fabricated\\u000a and each received one of eight surface

Hakan Akin; Faik Tugut; Burcu Mutaf; Gulsah Akin; A. Kemal Ozdemir

254

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

NASA Technical Reports Server (NTRS)

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.

Moore, Thomas J.; Watson, Gordon K.

1994-01-01

255

Effect of steam oxidation on the tensile strength of HTGR structural graphites  

Microsoft Academic Search

The core support system of the General Atomic Company design High Temperature Gas-Cooled Reactor (HTGR) contains type PGX graphite as core support blocks. The change in ultimate tensile strength of PGX graphite specimens with oxidation (burnoff) has been determined in a safety-related experimental program at Brookhaven National Laboratory(BNL). It is shown that Fe, an impurity in PGX graphite, plays a

A. J. Romano; J. G. Y. Chow

1977-01-01

256

Direct mechanical measurement of the tensile strength and elastic modulus of multiwalled carbon nanotubes  

Microsoft Academic Search

We have conducted pulling and bending tests on individual carbon nanotubes in-situ in a transition electron microscope. Based on our observation of the force required to break the tube, a tensile strength of 0.15 TPa was computed. From corresponding bending studies on such nanotubes, the Young's modulus was estimated to be 0.9 TPa (0.8 TPa after ‘sub continuum’ corrections). These

B. G. Demczyk; Y. M. Wang; J. Cumings; M. Hetman; W. Han; A. Zettl; R. O. Ritchie

2002-01-01

257

Tensile Bond Strength and SEM Evaluation of Caries-affected Dentin Using Dentin Adhesives  

Microsoft Academic Search

Tensile bond strength measurements are commonly used for the evaluation of dentin adhesive systems. Most tests are performed using extracted non-carious human or bovine dentin. However, the adhesion of resins to caries-affected dentin is still unclear. The objectives of this study were to test the hypothesis that bonding to caries-affected dentin is inferior to bonding to normal dentin, and that

M. Nakajima; H. Sano; M. F. Burrow; J. Tagami; M. Yoshiyama; S. Ebisu; B. Ciucchi; C. M. Russell; D. H. Pashley

1995-01-01

258

Development of high tensile strength silicon carbide fibre using an organosilicon polymer precursor  

Microsoft Academic Search

THE high tensile strength SiC fibre developed in our laboratory1-5 is extremely heat-resistant and its wettability by metals is good. Metal-matrix composites reinforced with the SiC fibre should therefore be of practical use. Polycarbosilane, the precursor of the fibre, is synthesised by thermal decomposition under high pressure of poly dimethylsilane in an autoclave. To produce the SiC fibre on an

S. Yajima; Y. Hasegawa; K. Okamura; T. Matsuzawa

1978-01-01

259

Tensile strength of mesh fixation methods in laparoscopic incisional hernia repair  

Microsoft Academic Search

  Background: Fixation of the mesh is crucial for the successful laparoscopic repair of incisional hernias. In the present\\u000a experimental study, we used a pig model to compare the tensile strengths of mesh fixation with helical titanium coils (tackers)\\u000a and transabdominal wall sutures. Methods: Thirty-six full-thickness specimens (5 × 7 cm) of the anterior abdominal wall of\\u000a nine pig cadavers were

M. Riet; P. J. Steenwijk; G. J. Kleinrensink; E. W. Steyerberg; H. J. Bonjer

2002-01-01

260

Tensile and creep strengths of hot-pressed Si 3 N 4  

Microsoft Academic Search

Tensile, creep, and stress-rupture data for Norton HS-110 and HS-130 hot-pressed Si3N4 are presented. It is shown that the strength of the material is controlled by the grain-boundary glass phase. At elevated temperatures, >1000‡ C, deformation is controlled by grain-boundary sliding. A model based on the concept of geometrically necessary wedge cracks is then developed which accounts for the observed

Ram Kossowsky; D. G. Miller; E. S. Diaz

1975-01-01

261

Measurement of Indirect Tensile Strength of Anisotropic Rocks by the Ring Test  

Microsoft Academic Search

Summary  \\u000a This paper presents a new approach, combined with the Boundary Element Method (BEM) analysis and the diametrical compression\\u000a on a thin disc with a small central hole, referred to as the ring test, for determining the indirect tensile strength of anisotropic\\u000a rocks. The stress distribution around the hole can be successfully obtained by the proposed single-domain BEM. The complex

C. S. Chen; S. C. Hsu

2001-01-01

262

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

263

Simulation of tensile strength of anisotropic fibre-reinforced composites at low temperature  

NASA Astrophysics Data System (ADS)

This article presents a simulation scheme to predict the effect of fibre anisotropy on composite tensile failure strength at room and low temperatures. The simulation model combines the shear lag equation with the chain of bundles probability model to describe the composite failure behaviour. The effect of fibre anisotropy on thermal stresses developed in composite constituents due to cooling to low temperatures is considered. The failure strength of composites composed of fibres with different degrees of anisotropy is obtained and comparisons are made with experiments. Simulated results for E-glass-, graphite- and Kevlar-epoxy type composites showed close agreement with the experiments.

Abdelmohsen, H. H.

264

Tensile properties of rat anterior cruciate ligament in collagen induced arthritis  

PubMed Central

OBJECTIVES—To investigate the effects of collagen induced arthritis (CIA) on the tensile properties of rat anterior cruciate ligament (ACL).?METHODS—The tensile strength, bone mineral density (BMD), and histology of ACL units from rats with CIA were investigated.?RESULTS—The tensile strength of the ACL unit was significantly lower in the rats with CIA at 10 weeks after immunisation (ultimate failure load, 74.9% of the control; stiffness, 62.0% of the control). The major mode of failure was femoral avulsion, and the BMD was significantly lower in the rats with CIA. A histological examination of the ligament insertion in rats with CIA showed resorption of the cortical bone beneath the ACL insertion and an enlarged mineralised fibrocartilage zone.?CONCLUSIONS—These findings indicate that the decrease in tensile strength of ACL units correlated with histological changes in the ligament-bone attachment, such as bone resorption beneath the ligament insertion site and an enlargement of the mineralised fibrocartilage zone.??

Nawata, K; Enokida, M; Yamasaki, D; Minamizaki, T; Hagino, H; Morio, Y; Teshima, R

2001-01-01

265

Tensile properties of 0.05 to 0.20 Pct C TRIP steels  

Microsoft Academic Search

The uniaxial tensile properties of a series of TRIP steels of varying carbon contents and processing histories were determined\\u000a over a wide range of test temperatures. The yield strengths at room temperature varied both with the deformation temperature\\u000a (over the range 250 to 550C) and with the carbon content (0.05 to 0.20 pct). Possible reasons for these variations are advanced.

G. R. Chanani; V. F. Zackay; Earl R. Parker

1971-01-01

266

Parameters of tensile strength, elongation, and tenacity of 70mm IIaO spectroscopic film  

NASA Technical Reports Server (NTRS)

The 70mm IIaO spectroscopic film was tested to determine its tensile strength, elongation, and breaking strength, using an Instron (strength and compression) 4201 Test Instrument. These data provide information leading to the upper and lower limits of the above parameters for 70mm IIaO spectroscopic film. This film will be developed by a commercial developing machine after the Ultraviolet Telescope Space Shuttle Mission returns to the Earth in the early 1990's; thus, it is necessary to understand these force parameters. Several test strips of approximately 200mm in length were used. The results indicate that when a stress load of 100 kg was applied, the film elongated approximately 1.06mm and the break strength was 19.45 kilograms.

Hammond, Ernest C., Jr.; Peters, Kevin A.

1989-01-01

267

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

Microsoft Academic Search

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

S. A Meguid; Y Sun

2004-01-01

268

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

Microsoft Academic Search

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

V. DePierre; G. Saul

1963-01-01

269

Tensile properties of 9Cr 1Mo martensitic steel irradiated with high energy protons and neutrons  

NASA Astrophysics Data System (ADS)

Tensile specimens of 9Cr-1Mo martensitic steel in three metallurgical conditions (tempered, 20% cold-worked and as-quenched) were irradiated in SINQ target-3 with high energy protons and spallation neutrons at temperatures between about 130 and 310 °C to doses between 4 and 12 dpa. Tensile properties were measured mostly at room temperature but a limited number of tests were performed at 250 and 350 °C. Scanning electron microscopy observations of fracture surfaces as well as reduction of area measurements were performed in selected cases. Results of preliminary TEM investigations carried out on 3 mm discs irradiated together with the tensile specimens are also presented. Tensile properties are compared with earlier results on martensitic steels irradiated in spallation conditions as well as with tensile data obtained for the same heat of 9Cr-1Mo steel after irradiation with fission neutrons in the OSIRIS reactor. The as-quenched specimens displayed a fully brittle behaviour and SEM observations revealed an intergranular fracture mode. The irradiated cold-worked and annealed specimens showed large increases in strength as well as drastic reductions in uniform elongation up to a dose of about 10 dpa. The fracture surface appearances remained however ductile. The few specimens irradiated to higher doses (up to 12 dpa) recovered significant ductility, which is presently not understood on the basis of the available preliminary microstructural data.

Henry, J.; Averty, X.; Dai, Y.; Lamagnère, P.; Pizzanelli, J. P.; Espinas, J. J.; Wident, P.

2003-05-01

270

Dynamic Tensile Strength of Crustal Rocks and Application to Impact Cratering  

NASA Astrophysics Data System (ADS)

Dynamic tensile strengths of two crustal rocks, San Marcos gabbro and Coconino sandstone (Meteor Crater, Arizona), were determined by carrying out flat plate impact experiments. Porosity of San Marcos gabbro is very low, and the reported porosity for Coconino sandstone is approx. 25%. Aluminum flyer plates were used for gabbro with impact velocities of 13 to 50 m/s, which produce tensile stresses in the range of 120 to 450 MPa. PMMA flyer plates were used for sandstone with impact velocities of 5 to 25 m/s, resulting tensile stresses in the range of approx. 13 to 55 MPa. Impact was normal to the bedding of sandstone. Tensile duration times for two cases were approx. 1 and approx. 2.3 microns, respectively. Pre-shot and post-shot ultrasonic P and S wave velocities were measured for the targets. Velocity reduction for gabbro occurred at approx. 150 MPa, very close to the earlier result determined by microscopic examination. The reduction of S wave is slightly higher than that of P wave. This indicates that the impact-induced cracks were either aligned, or there were residual fluids within cracks, or both. Data for sandstone velocity reduction was few and scattered caused by its high porosity. The range of dynamic tensile strength of Coconino sandstone is within 25 and 30 MPa. Obvious radial cracks at certain stresses indicate that deformation was not restricted to one dimensional strain as being assumed. Spall fragmentation occurred above 40 MPa. The combination of impact velocities, U (km/s), and impactor radii, a0)(m, are constrained by Meteor Crater fracture depth, approx. 850 m, and the dynamic tensile fracture strength from our experiments, 40 MPa. Volume of the crater for each impact was calculated using V = 0.009mU1.65, where V is crater volume (cu m), m is the mass of the impactor (kg). Volume of impact with U = 28 km/s, a0 = 10 m is close to the real Meteor Crater volume, 7.6e7 cu m. Impact energy for this case is 3.08 Mt., which agrees well with theoretical calculation (3.3 to 7.4 Mt.).(1 Mt. = 4.18e 15J).

Ai, H.; Ahrens, T. J.

2003-01-01

271

Effect of boron on post irradiation tensile properties of reduced activation ferritic steel (F-82H) irradiated in HFIR  

SciTech Connect

Reduced activation ferritic/martensitic steel, F-82H (Fe-8Cr-2W-V-Ta), was irradiated in the High Flux Isotope Reactor (HFIR) to doses between 11 and 34 dpa at 400 and 500 C. Post irradiation tensile tests were performed at the nominal irradiation temperature in vacuum. Some specimens included {sup 10}B or natural boron (nB) to estimate the helium effect on tensile properties. Tensile properties including the 0.2% offset yield stress, the ultimate tensile strength, the uniform elongation and the total elongation were measured. The tensile properties were not dependent on helium content in specimens irradiated to 34 dpa, however {sup 10}B-doped specimens with the highest levels of helium showed slightly higher yield strength and less ductility than boron-free specimens. Strength appears to go through a peak, and ductility through a trough at about 11 dpa. The irradiation to more than 21 dpa reduced the strength and increased the elongation to the unirradiated levels. Ferritic steels are one of the candidate alloys for nuclear fusion reactors because of their good thermophysical properties, their superior swelling resistance, and the low corrosion rate in contact with potential breeder and coolant materials.

Shiba, Kiyoyuki; Suzuki, Masahide; Hishinuma, Akimichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Dept. of Materials Science and Engineering; Pawel, J.E. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1994-12-31

272

Texture of parenchymatous plant tissue: a comparison between tensile and other instrumental and sensory measurements of tissue strength and juiciness  

Microsoft Academic Search

The cellular basis of textural diversity in selected fruit and root tissue has been investigated using tensile measurements of tissue strength. The mechanism of tissue failure, either cell rupture or cell-to-cell debonding, was determined by examining the fracture surface using Low Temperature Scanning Electron Microscopy (LTSEM). Information provided by tensile measurements was compared with that provided by sensory and other

F. Roger Harker; Margaret G. H. Stec; Ian C. Hallett; Carey L. Bennett

1997-01-01

273

Immediate and delayed micro-tensile bond strength of different luting resin cements to different regional dentin  

PubMed Central

We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin (1 mm below the dentine-enamel junction), deep dentin (1 mm above the highest pulp horn) and cervical dentin (0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction). Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mm/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin (P < 0.001). Micro-tensile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions (P < 0.001). Immediate micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements (P < 0.001). It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.

Ali, Abdelraheem Mohamed; Hamouda, Ibrahim Mohamed; Ghazy, Mohamed Hamed; Abo-Madina, Manal Mohamed

2013-01-01

274

Tensile properties and microstructure of helium implanted EUROFER ODS  

NASA Astrophysics Data System (ADS)

To study the effect of helium (He) on tensile properties and microstructure of oxide dispersion strengthened EUROFER-ODS steel, flat tensile specimens were homogeneously implanted with 30 MeV ?-particles at the NRC KI cyclotron up to 1000 appm He at 573 K and 773 K. High-resolution and energy-filtered transmission electron microscopy showed that partly coherent Y2O3 particles are strong trapping centers for diffusing He atoms (at least up to 773 K) in reduced activation ferritic/martensitic 9Cr-1WMnVTa-0.3Y2O3 steel. After 573 K and 773 K implantation the He bubbles or He filled voids have average diameters of 1.9 and 4.2 nm with concentrations about 8 × 1022 and 7 × 1022 m-3, respectively. Tensile testing after 573 K implantation revealed a uniform elongation of more than 10%, despite an irradiation induced hardening of about 250 MPa. The role that nanoscaled Y2O3 particles play in He distribution, tensile properties, and on the mitigation of He embrittlement are discussed.

Ryazanov, A. I.; Chugunov, O. K.; Ivanov, S. M.; Latushkin, S. T.; Lindau, R.; Möslang, A.; Nikitina, A. A.; Prikhodko, K. E.; Semenov, E. V.; Unezhev, V. N.; Vladimirov, P. V.

2013-11-01

275

A Method for Testing Dynamic Tensile Strength and Elastic Modulus of Rock Materials Using SHPB  

NASA Astrophysics Data System (ADS)

An experimental procedure for testing dynamic tensile strength and elastic modulus of rock materials at high strain rate loading is presented in this paper. In our test the split Hopkinson pressure bar (SHPB) was used to diametrally impact the Brazilian disc (BD) and flattened Brazilian disc (FBD) specimens of marble. A tensile strain rate of about 45 1/s was achieved at the center of the specimen. In order to improve the accuracy of the analysis, the initiation time difference between the strain waves acting on the two flat ends of the FBD specimen was treated properly. Typical failure modes corresponding to different loading conditions were observed. It was verified with a finite-element simulation that the equilibrium condition was established in the specimen before its failure. This numerical simulation validates the experimental procedure and also proves the suitability of formulation for the basic equations.

Wang, Q. Z.; Li, W.; Song, X. L.

2006-06-01

276

Effects of Mechanical and Environmental Factors on the Notch Tensile Strength of 1,300MPa Class SCM435 High-Strength Steel in Hydrogen Gas  

NASA Astrophysics Data System (ADS)

There are several factors that affect the strength of high-strength steel SCM435 as a sharp notched specimen in a hydrogen gas environment. In this paper, tensile tests were carried out in several hydrogen and helium gas environments. The examined factors were the gas pressure, the gas temperature, the cross-head speed and the notch root radius. The results of the tensile tests in the hydrogen gas environments showed a decrease in the tensile strengths for any given environmental factor. This was not observed in the helium gas environments. Additionally, by investigating the area of intergranular fracture, it was found that the tensile strength had a reciprocal relationship with the area of the intergranular fracture regardless of several environmental factors.

Suzuki, Yuichi; Itoga, Hisatake; Noguchi, Hiroshi

277

The influence of freezing on the tensile strength of tendon grafts : a biomechanical study.  

PubMed

We investigated the influence of freezing on the tensile strength of fresh frozen tendon grafts. The biomechanical characteristics of tendons that are less commonly used in knee surgery (tibialis anterior, tibialis posterior, peroneus longus and medial and lateral half of Achilles tendons) were compared to those of a semitendinosus and gracilis graft harvested from the same 10 multi-organ donors. All right side tendons constituted the study group and were frozen at -80 degrees C and thawed at room temperature 5 times. All left side tendons were frozen at -80 degrees C and thawed at room temperature once. There were 59 tendons in the control group and 56 in the study group. The looped grafts were clamped at one side using a custom-made freeze clamp and loaded until failure on an Instron 4505 testing machine. The average ultimate failure load was not significantly different between the control and the study group (p > 0.05). The failure load of the medial tendon Achilles was the lowest in both study and control group (p < 0.001). There was no significant difference in maximum stress, maximum displacement, maximum strain and stiffness between the control and study group (p > 0.05). From our study, we conclude that freezing tendons at -80 degrees C and thawing several times does not influence the maximum load, maximum stress, maximum displacement, maximum strain and stiffness. The medial half of the Achilles tendon is clearly the weakest tendon (p < 0.001). These findings show that tendon grafts can be frozen at -80 degrees C and thawed at room temperature several times without altering their biomechanical properties. PMID:24205775

Arnout, Nele; Myncke, Jan; Vanlauwe, Johan; Labey, Luc; Lismont, Daniel; Bellemans, Johan

2013-08-01

278

Tensile Properties and Deformation Characteristics of a Ni-Fe-Base Superalloy for Steam Boiler Applications  

NASA Astrophysics Data System (ADS)

Ni-Fe-base superalloys due to their good manufacturability and low cost are the proper candidates for boiler materials in advanced power plants. The major concerns with Ni-Fe-base superalloys are the insufficient mechanical properties at elevated temperatures. In this paper, tensile properties, deformation, and fracture characteristics of a Ni-Fe-base superalloy primarily strengthened by ?' precipitates have been investigated from room temperature to 1073 K (800 °C). The results showed a gradual decrease in the strength up to about 973 K (700 °C) followed by a rapid drop above this temperature and a ductility minimum at around 973 K (700 °C). The fracture surfaces were studied using scanning electron microscopy and the deformation mechanisms were determined by the observation of deformed microstructures using transmission electron microscopy. An attempt has been made to correlate the tensile properties and fracture characteristics at different temperatures with the observed deformation mechanisms.

Zhong, Zhihong; Gu, Yuefeng; Yuan, Yong; Shi, Zhan

2014-01-01

279

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

Microsoft Academic Search

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

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

2011-01-01

280

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

NASA Technical Reports Server (NTRS)

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.

Farmer, Serene C.; Sayir, Ali

2001-01-01

281

Effect of Welding and Post-weld Heat Treatment on Tensile Properties of Nimonic 263 at Room and Elevated Temperatures  

NASA Astrophysics Data System (ADS)

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.

Jeon, Minwoo; Lee, Jae-Hyun; Woo, Ta Kwan; Kim, Sangshik

2011-04-01

282

Tensile and Charpy impact properties of irradiated reduced-activation ferritic steels  

SciTech Connect

Tensile tests were conducted on 8 reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on steels irradiated to 26-29 dpa. Irradiation was in Fast Flux Test Facility at 365 C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15- 17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20,000 h at 365 C. Thermal aging had little effect on tensile properties or ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in upper-shelf energy (USE). After 7 dpa, strength increased (hardened) and then remained relatively unchanged through 26-29 dpa (ie, strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness (increased DBTT, decreased USE) remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels had the most irradiation resistance.

Klueh, R.L.; Alexander, D.J.

1996-10-01

283

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

NASA Astrophysics Data System (ADS)

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.

Naito, Kimiyoshi

2014-03-01

284

Strength and barrier properties of MFC films  

Microsoft Academic Search

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

Kristin Syverud; Per Stenius

2009-01-01

285

Hoop Tensile Properties of Ceramic Matrix Composite Cylinders  

NASA Technical Reports Server (NTRS)

Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC ceramic matrix composite cylinders using ring specimens machined form the cylinder ends. The cylinders were fabricated from 2D balanced SiC fabric with several material variants, including wall thickness (6,8, and 12 plies), SiC fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI SiC, and partial CVI SiC plus slurry cast + melt-infiltrated SiC-Si). Fiber ply splices existed in all the hoops. Tensile hoop measurements are made at room temperature and 1200 C using hydrostatic ring test facilities. The failure mode of the hoops, determined through microstructural examination, is presented. The hoop properties are compared with in-plane data measured on flat panels using same material variants, but containing no splices.

Verrilli, Michael J.; DiCarlo, James A.; Yun, HeeMan; Barnett, Terry

2004-01-01

286

New enzyme-based process direction to prevent wool shrinking without substantial tensile strength loss.  

PubMed

In this paper a new enzymatic process direction is described for obtaining machine washable wool with acceptable quality. In general, application of protease enzyme technology in wool processing results in considerable loss of tensile strength by diffusion of the enzyme into the interior of wool fibers. To overcome this disadvantage enzymatic activity has been more targeted to the outer surface of the scales by improving the susceptibility of the outer surface scale protein for proteolytic degradation. This has been realized by a pretreatment of wool with hydrogen peroxide at alkaline pH in the presence of high concentrations of salt. PMID:16791725

Lenting, H B M; Schroeder, M; Guebitz, G M; Cavaco-Paulo, A; Shen, J

2006-05-01

287

Tensile Strength and Microstructural Characterization of Uncoated and Coated HPZ Ceramic Fibers  

NASA Technical Reports Server (NTRS)

Tensile strengths of as-received HPZ fiber and those surface coated with BN, BN/SiC, and BN/Si3N4 have been determined at room temperature using a two-parameter Weibull distribution. Nominally approx. 0.4 micron BN and 0.2 micron SiC or Si3N4 coatings were deposited on the fibers by chemical vapor deposition using a continuous reactor. The average tensile strength of uncoated HPZ fiber was 2.0 +/- 0.56 GPa (290 +/- 81 ksi) with a Weibull modulus of 4.1. For the BN coated fibers, the average strength and the Weibull modulus increased to 2.39 +/- 0.44 GPa (346 +/- 64 ksi) and 6.5, respectively. The HPZ/BN/SiC fibers showed an average strength of 2.0 +/- 0.32 GPa (290 +/- 47 ksi) and Weibull modulus of 7.3. Average strength of the fibers having a dual BN/Si3N4 surface coating degraded to 1.15 +/- 0.26 GPa (166 +/- 38 ksi) with a Weibull modulus of 5.3. The chemical composition and thickness of the fiber coatings were determined using scanning Auger analysis. Microstructural analysis of the fibers and the coatings was carried out by scanning electron microscopy and transmission electron microscopy. A microporous silica-rich layer approx. 200 nm thick is present on the as-received HPZ fiber surface. The BN coatings on the fibers are amorphous to partly turbostratic and contaminated with carbon and oxygen. Silicon carbide coating was crystalline whereas the silicon nitride coating was amorphous. The silicon carbide and silicon nitride coatings are non-stoichiometric, non-uniform, and granular. Within a fiber tow, the fibers on the outside had thicker and more granular coatings than those on the inside.

Bansal, Narottam P.; Wheeler, Donald R.; Dickerson, Robert M.

1996-01-01

288

Analysis of tensile properties for composites with wrinkled fabric  

Microsoft Academic Search

During the fiber preform loading process of resin transfer moldings (RTMs), fabric layers can be wrinkled in the preform,\\u000a which affects the quality of the composite. This study considers several wrinkled models with different wrinkled lengths (L\\u000a \\u000a W\\u000a ) and different numbers of wrinkled layers in the preform. To study the effects of wrinkling on tensile properties, two matrix\\u000a materials

Thanh Trung Do; Dong Joo Lee

2010-01-01

289

Evaluation of Interfacial Tensile Strength in Glass Fiber/Epoxy Resin Interface using the Cruciform Specimen Method  

NASA Astrophysics Data System (ADS)

Glass/epoxy interfacial tensile strength is investigated by the cruciform specimen method. The conventional transverse tensile test for single fiber composite is one of methods for evaluating the interfacial tensile strength, but stress singularity at the specimen edge is a very complicated problem to be solved. A cruciform specimen which has large width only around fiber embedded in transverse direction can potentially prevent the stress singularity problem. The cruciform specimen geometry is first discussed by means of finite element analysis considering experimental conditions. Transverse tensile test is conducted and an interfacial debonding which initiates at the middle of specimen not at edge is observed using the cruciform specimens. The interfacial tensile strength can be obtained by the value of stress concentration factor at interface multiplied by specimen stress. The location which the debonding initiates from is discussed and the validity of the evaluation method in this study is verified when interfacial tensile strength is as high as or lower than interfacial shear strength.

Ogihara, Shinji; Sakamoto, Yoriaki; Koyanagi, Jun

290

Effect of Scandium Additions on the Tensile Properties of Cast Al-6Mg alloys  

NASA Astrophysics Data System (ADS)

Effect of aging on the mechanical properties of Al-6Mg alloy doped with varying concentration of scandium ranging from 0.2 to 0.6 wt.% is analyzed. As-cast samples were aged isochronally for 60 min at different temperatures ranging from 100 to 500 °C. Evaluation of mechanical properties of the aged Al-6Mg (Sc) alloys was done by employing an Instron testing machine. Various strain rate of testing were used to find out the values of strain-rate sensitivity of the experimental alloys. The influence of scandium is much pronounced on yield strength than on the tensile strength. Alloys with higher scandium content have shown higher yield strength and the values of strain-rate sensitivity ‘ m’ at peak-aged condition have been found to be comparatively high at higher scandium concentration. The fracture of the experimental alloys occurs through microvoid coalescence.

Kaiser, M. S.; Datta, S.; Roychowdhury, A.; Banerjee, M. K.

2008-12-01

291

An experimental investigation on the tensile moduli and strengths of graphite/epoxy laminates  

NASA Technical Reports Server (NTRS)

The results of a series of tensile tests on some graphite/epoxy laminates, at rates varying from 0.002 to 2 in./min are examined. The loads were applied at various angles to the fiber directions in each case. The rate-dependent behavior of the stress-strain response is assessed. Evidence is presented to indicate that failure first occurs on inner plies, and that, in some cases, moduli increase with increasing stress (or strain) level. Lamination theory is used to predict the moduli, and comparisons with experiment are given. This theory is also used in conjunction with three failure theories to predict ultimate strengths (with varying degrees of success). Further, two approaches to ply unloading after first-ply failure are used and discussed. One is a standard method found in the literature while the other is a proposed 'strength-of-materials' type of technique which is computationally much simpler.

Yeow, Y. T.; Brinson, H. F.

1977-01-01

292

Tensile properties and fracture reliability of a glass-coated Co-based amorphous microwire  

NASA Astrophysics Data System (ADS)

Co68.15Fe4.35Si12.25B15.25 (at%) amorphous microwires with a smooth surface and a circular cross-section were fabricated by the glass-coated melt spinning method. Their mechanical properties were evaluated through tensile tests of the glass-coated amorphous microwires, and their fracture reliability was estimated using two- and three-parameter Weibull analysis. X-ray diffraction and transmission electron microscopy results showed that these glass-coated Co-based microwires were mostly amorphous. The coated Co-based microwires exhibit a tensile strength of 1145 to 2457 MPa, with a mean value of 1727 MPa and a variance of 445 MPa. Weibull statistical analysis showed that the tensile two-parameter Weibull modulus of the amorphous microwires is 4.16 and the three-parameter Weibull modulus is 1.61 with a threshold value as high as 942 MPa. These results indicate that the fabricated microwires exhibit good tensile properties and fracture reliability, and thus appear to be good candidates for electronics reliability engineering applications.

Wang, Xiao-dong; Wang, Huan; Shen, Hong-xian; Qin, Fa-xiang; Xing, Da-wei; Liu, Jing-shun; Chen, Dong-ming; Sun, Jian-fei

2014-06-01

293

Tensile and impact properties of candidate alloys for high-temperature gas-cooled reactor applications  

SciTech Connect

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.

Bruch, U.; te Heesen, E.; Ennis, F.J.; Schuhmacher, D.

1984-08-01

294

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

NASA Astrophysics Data System (ADS)

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.

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

295

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

PubMed Central

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.

Liu, Jie; Lu, Xiaolong; Wu, Chunrui

2013-01-01

296

Tensile strength of glass fiber posts submitted to different surface treatments.  

PubMed

The aim of this in vitro study was to evaluate the tensile strength of glass fiber posts submitted to different surface treatments. Forty-eight maxillary canines had their crowns sectioned and root canals endodontically treated. The roots were embedded in acrylic resin and distributed into 3 groups according to the surface treatment: Group I: the posts were treated with silane agent for 30 s and adhesive; Group II: the posts were cleaned with alcohol before treatment with silane agent and adhesive; Group III: the posts were submitted to conditioning with 37% phosphoric acid for 30 s before treatment with silane agent and adhesive. Each group was divided into 2 subgroups for adhesive polymerization or not before insertion into the canal: A - adhesive was not light cured and B - adhesive was light cured. All posts were cemented with Panavia F and the samples were subjected to tensile strength test in a universal testing machine at crosshead speed of 1 mm/min. Data were submitted to one-way ANOVA and Tukey's test at 5% significance level. There was statistically significant difference (p<0.01) only between group GIII-B and groups GI-A and GI-B. No significant difference was found among the other groups (p>0.05). It was concluded that the products used for cleaning the posts influenced the retention regardless of adhesive light curing. PMID:24474360

Faria, Maria Isabel A; Gomes, Érica Alves; Messias, Danielle Cristine; Silva Filho, João Manoel; Souza Filho, Celso Bernardo; Paulino, Silvana Maria

2013-01-01

297

Effect of the tensile strength on the stability against rotational breakup of icy bodies  

NASA Astrophysics Data System (ADS)

Focusing on primitive icy minor bodies in the solar system like cometary nuclei, centaurs, transneptunian objects (TNOs), and main-belt comets (MBCs) we investigate the stability of these objects against rotational breakup by comparing their location in (radius - rotational period) space with respect to separation lines of the stable and breakup zones in this plane. We estimate the bulk tensile strength according to new structural and elasto-mechanical models of grain-aggregates, using these tensile strengths to compute separation lines. We note that the process of grain coagulation and growth is highly uncertain in the field of solar system formation and we simply don't know how to grow interstellar grains to aggregates larger than about 1 mm but we apply in our calculations the recently available elasto-mechanical models of grain-aggregates. Accorging to this study most of the observed comets, centaurs, TNOs, and MBCs are stable against rotational breakup, with a few notable exceptions. E.g., we suggest that the rotational fission is a likely scenario for the Haumea-family in the Kuiper belt.

Toth, Imre; Lisse, Carey M.

298

Influence of Laboratory Annealing on Tensile Properties and Design Stress Intensity Limits for Type 304 Stainless Steel.  

National Technical Information Service (NTIS)

The influence of reannealing (laboratory annealing) on yield and ultimate tensile strength values of 19 heats of type 304 stainless steel was determined. Most heats were reannealed at 1065 exp 0 C for 0.5 hr. The reannealed properties were used to determi...

V. K. Sikka M. K. Booker

1977-01-01

299

Measured iron-gallium alloy tensile properties under magnetic fields  

NASA Astrophysics Data System (ADS)

Tension testing is used to identify Galfenol material properties under low level DC magnetic bias fields. Dog bone shaped specimens of single crystal Fe100-xGax, where 17<=x<=33, underwent tensile testing along two crystalographic axis orientations, [110] and [100]. The material properties being investigated and calculated from measured quantities are: Young's modulus and Poisson's ratio. Data are presented that demonstrate the dependence of these material properties on applied magnetic field levels and provide a preliminary assessment of the trends in material properties for performance under varied operating conditions. The elastic properties of Fe-Ga alloys were observed to be increasingly anisotropic with rising Ga content for the stoichiometries examined. The largest elastic anisotropies were manifested in [110] Poisson's ratios of as low as -0.63 in one specimen. This negative Poisson's ratio creates a significant in-plane auxetic behavior that could be exploited in applications that capitalize on unique area effects produced under uniaxial loading.

Yoo, Jin-Hyeong; Flatau, Alison B.

2004-07-01

300

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

Microsoft Academic Search

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

Shao-Yun Fu; Bernd Lauke

1996-01-01

301

49 CFR 192.107 - Yield strength (S) for steel pipe.  

Code of Federal Regulations, 2010 CFR

...whose specification or tensile properties are unknown, the yield strength to be used in the design...of the average yield strength determined by the tensile tests. (ii) The lowest yield strength determined by the tensile tests. (2)...

2009-10-01

302

49 CFR 192.107 - Yield strength (S) for steel pipe.  

Code of Federal Regulations, 2010 CFR

...whose specification or tensile properties are unknown, the yield strength to be used in the design...of the average yield strength determined by the tensile tests. (ii) The lowest yield strength determined by the tensile tests. (2)...

2010-10-01

303

Tensile properties of copper-nickel fine clad prepared by surface activation bonding and subsequent heat treatment  

NASA Astrophysics Data System (ADS)

The tensile properties of a Cu/Ni fine clad prepared by surface activation bonding were investigated as a function of the heat-treatment temperature and the diffusion layer thickness. A negligibly thin diffusion layer, less than 5 nm in thickness, was formed in the as-bonded Cu/Ni fine clad, but the thickness increased significantly after subsequent heat treatments. As the temperature increased, the yield strength and tensile strength increased; this was attributable to the microstructural features of the raw materials. The yield strength values calculated using a rule-of-mixture model were lower than those determined experimentally. We attributed this difference in the values to the diffusion layer and friction at the interfaces between the various phases. The friction strength of the copper/nickel foils was higher than those of the copper foil/diffusion layer and the nickel foil/diffusion layer. The results of the study suggested that the tensile properties of the Cu/Ni fine clad were affected by the following: (1) the volume fraction of the raw materials and their individual strengths, (2) the volume fraction of the diffusion layer and its strength, and (3) the friction strength at the interfaces of the various phases.

Jung, Taek-Kyun; Kim, Kyung-Hoon; Joh, Dong-Woo; Heo, Kyu-Young; Lee, Hyo-Soo; Lim, Sung-Chul; Kwon, Hyouk-Chon

2013-11-01

304

Tensile properties of welded or sensitized 316 stainless steel in high-pressure hydrogen gas  

Microsoft Academic Search

The effect of high-pressure hydrogen gas on the tensile properties of welded or sensitized 316 stainless steel was studied to find out if hydrogen embrittlement occurs. Tensile tests on unnotched and notched specimens in air, 70-MPa helium, and 70-MPa hydrogen were conducted, using the air test results as baseline tensile properties. Results show that all specimens had good ductilities and

E. L. Raymond; R. R. Vandervoort

1976-01-01

305

Restoration of tensile strength in bark samples of Ficus benjamina due to coagulation of latex during fast self-healing of fissures  

PubMed Central

Background and Aims The functions of plant latex have been discussed for a long time. Today, many studies support a defence mechanism as being its main function. A role as a self-healing mechanism was never attributed to the coagulation of latex. In this study we quantified the contribution of the coagulation of Ficus benjamina (weeping fig) latex to a restoration of the mechanical properties of the bark after external lesions. Methods Tensile tests of F. benjamina bark were conducted either immediately after injury or at various latency times after injury. Key Results A significant increase in the tensile strength of bark samples until 30 min after injury was found, and this effect could be attributed to the coagulation of plant latex alone. The tensile strength remains nearly constant until several hours or days after injury. Then, very probably due to other mechanisms such as cell growth and cell proliferation, the tensile strength begins to increase slightly again. Conclusions The coagulation of latex seals lesions and serves as a quick and effective pre-step of subsequent, more effective, long-lasting self-healing mechanisms such as cell growth and proliferation. Thus, a fast self-healing effect can be included in the list of functions of plant latex.

Bauer, Georg; Speck, Thomas

2012-01-01

306

Effects of Irradiation on the Tensile Properties of Nb-1 Zr  

NASA Astrophysics Data System (ADS)

The alloy Nb-1 wt % Zr (Nb-lZr) has been selected for several in-core applications in the SP-100 reactor. Data on the effects of fast neutron irradiation on the tensile properties of Nb-lZr at proposed SP-100 operating temperatures are required to make certain that irradiated components have adequate ductility to preclude brittle failure during reactor transients or overpower conditions. Subsize (SS-1) tensile samples of Nb-lZr with average grain sizes of 22 and 73 ?m were irradiated up to end-of-life fluence at 1290, 1350, and 1400 K in temperature-controlled lithium filled capsules in the Fast Flux Test Facility (FFTF). For tests at 300 K, irradiation resulted in small to modest increases in 0.2% yield strength, no change in ultimate strength, and modest decreases in uniform and total elongations. After irradiation, total elongations remained high at 16 to 25%. At 300 K, the magnitude of the changes due to irradiation increased with increasing fluence and irradiation temperature. For material irradiated at 1290,1350, and 1400 K and tested at the irradiation temperature, the changes in tensile properties were less than the changes observed at 300 K, and the strength and ductility properties were within the scatter band for unirradiated Nb-lZr. Total elongation remained very high at 32 to 37%. At 1290 to 1400 K, the magnitude of the changes due to irradiation decreased with increased irradiation temperature. Results were the same for both grain sizes. After irradiation at SP-100 operating temperatures, Nb-lZr exhibited more than adequate ductility to preclude brittle failure under any anticipated SP-100 loading conditions.

Horak, James A.; Grossbeck, Martin L.; Paxton, Michael M.

1994-07-01

307

Tensile properties of a boron/nitrogen-doped carbon nanotube-graphene hybrid structure.  

PubMed

Doping is an effective approach that allows for the intrinsic modification of the electrical and chemical properties of nanomaterials. Recently, a graphene and carbon nanotube hybrid structure (GNHS) has been reported, which extends the excellent properties of carbon-based materials to three dimensions. In this paper, we carried out a first-time investigation on the tensile properties of the hybrid structures with different dopants. It is found that with the presence of dopants, the hybrid structures usually exhibit lower yield strength, Young's modulus, and earlier yielding compared to that of a pristine hybrid structure. For dopant concentrations below 2.5% no significant reduction of Young's modulus or yield strength could be observed. For all considered samples, the failure is found to initiate at the region where the nanotubes and graphene sheets are connected. After failure, monatomic chains are normally observed around the failure region. Dangling graphene layers without the separation of a residual CNT wall are found to adhere to each other after failure with a distance of about 3.4 Å. This study provides a fundamental understanding of the tensile properties of the doped graphene-nanotube hybrid structures, which will benefit the design and also the applications of graphene-based hybrid materials. PMID:24778956

Xia, Kang; Zhan, Haifei; Wei, Ye; Gu, Yuantong

2014-01-01

308

Back Propagation Neural Networks for Predicting Ultimate Strengths of Unidirectional Graphite/Epoxy Tensile Specimens  

NASA Technical Reports Server (NTRS)

The research presented herein demonstrates the feasibility of predicting ultimate strengths in simple composite structures through a neural network analysis of their acoustic emission (AE) amplitude distribution data. A series of eleven ASTM D-3039 unidirectional graphite/epoxy tensile samples were loaded to failure to generate the amplitude distributions for this analysis. A back propagation neural network was trained to correlate the AE amplitude distribution signatures generated during the first 25% of loading with the ultimate strengths of the samples. The network was trained using two sets of inputs: (1) the statistical parameters obtained from a Weibull distribution fit of the amplitude distribution data, and (2) the event frequency (amplitude) distribution itself. The neural networks were able to predict ultimate strengths with a worst case error of -8.99% for the Weibull modeled amplitude distribution data and 3.74% when the amplitude distribution itself was used to train the network. The principal reason for the improved prediction capability of the latter technique lies in the ability of the neural network to extract subtle features from within the amplitude distribution.

Walker, James L.; Hill, Eric v. K.

1993-01-01

309

The diametral tensile strength and hydrostability of polymer-ceramic nano-composite (pcnc) material prototypes  

NASA Astrophysics Data System (ADS)

Statement of the problem: There is a weak connection between the filler and the resin matrix of dental composites caused primarily by hydrolysis of silane coupling agent, therefore, jeopardizing the mechanical properties of the dental restorations. Purpose: The purpose of this study was to compare the diametral tensile strength (DTS) of a nano-mechanically bonded polymer ceramic nano composite (pcnc) versus the chemically bonding prototype polymer ceramic nano composite (pcnc) fabricated by using hydrolytically stable interphase. Materials and Methods: Composites were made with 60wt % filler, 38% triethyleneglycol dimethacrylate (TEDGMA), 1% camphorquinone (CQ) and 1% 2-(dimethylamino) ethyl methacrylate (DMAEMA). Tests for DTS were performed using a universal testing machine. The disk-shaped specimens were loaded in compression between two supporting plates at a crosshead speed of 0.5 mm/min until fracture. The samples, measuring 3 mm in height and 6 mm in diameter, were produced in a round stainless steel (SS) mold. A total of 144 samples were created. Groups of 48 samples were made for each of three different fillers. Specimens were soaked in artificial saliva at 37° for four time periods, dry(t=0), 1 day, 7 days, 28 days). At the end of each soaking time DTS tests were performed. Results: There where statistically significant differences in the DTS between the filler groups and the soaking times (p=<0.001) as well as for the pairwise comparison between the different filler group values and between the different soaking times as an individual treatment. Overall, longer soaking times resulted in lower mean DTS values. The DTS of the PCNC for filler #1 decreased to 82.4% of the original value after 1 day of soaking, 67.2% after 7 days and 27.2 % after 28 days. For filler #2 decreased to 54.8% of the original value after 1 day of soaking, 62.3% after 7 days and 61.2% after 28 days. For filler #3 decreased to 71.2% of the original value, 67.3% after 7 days and 51.4% after 28 days (Fig 8). Conclusions: Within the limitation of this study it can be concluded that the use of coupling agent will significantly influence the degradation of the material under wet environment. Clinical Implication: Changes within matrix composition and bonding interphase of resin base composites promise improvements of mechanical properties, decreasing the incidence of clinical failure of posterior composite restorations, hence resulting in a more ideal restorative material for use in posterior segment. The results of this investigation showed that the deficiency of hydrostability in dental composites is a detrimental factor in the mechanical behavior. The silanation of the filler particles have a positive influence on the mechanical properties of dental composites but the hydrolysis of the silane coupling agent can dramatically reduce the average lifetime of dental composites.

Yepez, Johanna

310

Fracture toughness and fracture mechanisms of PBT\\/PC\\/IM blends: Part V Effect of PBT-PC interfacial strength on the fracture and tensile properties of the PBT\\/PC blends  

Microsoft Academic Search

To investigate the effect of PBT-PC interfacial strength on the fracture toughness and toughening mechanisms of the PBT\\/PC system, a series of PBT\\/PC blends with different content of in situ formed PBT-PC copolymers were made by melt blending. The in situ copolymer was separately prepared via reactive blending of the PBT and PC in the presence of a transesterification catalyst

Jingshen Wu; Ke Wang; Demei Yu

2003-01-01

311

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

Microsoft Academic Search

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,

Lorenzo Scalise; Daniele Rinaldi; Fabrizio Davì; Nicola Paone

2011-01-01

312

Tensile and impact properties of TZM and Mo-5% Re*1  

NASA Astrophysics Data System (ADS)

Some aspects of the mechanical behaviour of two molybdenum alloys, one belonging to the precipitation hardened sub-family (TZM) and the other is a solid solution Mo 5% rhenium-bearing alloy, have been investigated. Experimental data (tensile mechanical strength, ductility and impact properties of unirradiated materials) show that a difference in behaviour exists between the precipitation hardened and the solid solution strengthened alloy, but at the same time a serious discrepancy has been found between the present results and previously reported ductile to brittle transition temperature values for Mo alloys.

Filacchioni, G.; Casagrande, E.; De Angelis, U.; De Santis, G.; Ferrara, D.

1994-09-01

313

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

NASA Technical Reports Server (NTRS)

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.

OBrien, T. Kevin; Krueger, Ronald

2001-01-01

314

Influence of residual stresses on the tensile strength of composite-metal sandwich laminates  

NASA Technical Reports Server (NTRS)

The tensile strength of boron-epoxy/aluminum sandwich laminates is discussed relative to the residual thermal stresses generated by curing and bonding at elevated temperatures. It is shown that the sandwich laminates investigated exhibit three dinstinct modes of failure, depending upon the fiber orientation of the composite. Sandwich laminates with moderate to high percentage of 0-deg fibers exhibit early failures initiated by edge effect; laminates with moderate to high percentage of 90-deg fibers fail according to a first-ply failure criterion; laminates with moderate to high percentages of plus or minus 45 deg plies fail at strains equal to or greater than the failure strain of the corresponding all-composite laminate.

Herakovich, C. T.; Wong, D. M.

1977-01-01

315

Role of additives on tensile strength of wood-plastic composite  

NASA Astrophysics Data System (ADS)

Wood-plastic composite (WPC) formation has been studied with simul+styrene system at various compositions of styrene with methanol as the swelling solvent. Effect of additives, e.g. multifunctional monomers (MFM) and oligomers used in very low quantity (1% v/v) on the polymer loading (PL) and tensile strength (TS) of the WPC has been elaborately investigated. Enhanced PL and TS values are observed. Inorganic co-additives like Lithium (Li +), Copper (Cu 2+) and acid (H +) and urea (U) used in combinations with additives (MFM or oligomers) have influenced the results of PL and TS in these systems. Li + ion has been a good replacement for H + ion; U has substantially enhanced the PL values with retention of the TS values of WPC. Co-additive Cu 2+ used in these system can act as a preservative and protective agent for WPC.

Khan, Mubarak A.; Ali, K. M. Idriss

316

Discrete simulation of model, loose cohesive powders: plastic consolidation, fractal microstructure and tensile strength  

NASA Astrophysics Data System (ADS)

Isotropic packings of cohesive disks in 2D are studied by discrete, stress-controlled numerical simulations. Depending on the assembling process and on whether contacts possess rolling resistance (RR), configurations form under low pressure P with varying solid fraction ? and fractal dimension dF describing small scale correlations below some blob size ?. The gradual collapse observed under growing P is described as a linear relation between lnP and 1/? within some range, once the influence of initial conditions has faded out, and until a maximum density is approached. This corresponds to a decrease of ? that is compatible with the fractal blob model. The isotropic tensile strength is always considerably smaller than the naive Rumpf estimate, and grows with consolidation. Coordination numbers in systems with small RR change little while density increases by large amounts in consolidation.

Gilabert, Francisco; Roux, Jean-Noël; Castellanos, Antonio

2009-06-01

317

Diametral tensile strength and film thickness of an experimental dental luting agent derived from castor oil  

PubMed Central

The need to develop new dental luting agents in order to improve the success of treatments has greatly motivated research. Objective The aim of this study was to evaluate the diametral tensile strength (DTS) and film thickness (FT) of an experimental dental luting agent derived from castor oil (COP) with or without addition of different quantities of filler (calcium carbonate - CaCO3). Material and Methods Eighty specimens were manufactured (DTS N=40; FT N=40) and divided into 4 groups: Pure COP; COP 10%; COP 50% and zinc phosphate (control). The cements were mixed according to the manufacturers' recommendations and submitted to the tests. The DTS test was performed in the MTS 810 testing machine (10 KN, 0.5 mm/min). For FT test, the cements were sandwiched between two glass plates (2 cm2) and a load of 15 kg was applied vertically on the top of the specimen for 10 min. The data were analyzed by means of one-way ANOVA and Tukey's test (?=0.05). Results The values of DTS (MPa) were: Pure COP- 10.94±1.30; COP 10%- 30.06±0.64; COP 50%- 29.87±0.27; zinc phosphate- 4.88±0.96. The values of FT (µm) were: Pure COP- 31.09±3.16; COP 10%- 17.05±4.83; COP 50%- 13.03±4.83; Zinc Phosphate- 20.00±0.12. One-way ANOVA showed statistically significant differences among the groups (DTS - p=1.01E-40; FT - p=2.4E-10). Conclusion The experimental dental luting agent with 50% of filler showed the best diametral tensile strength and film thickness.

CARMELLO, Juliana Cabrini; FAIS, Laiza Maria Grassi; RIBEIRO, Ligia Nunes de Moraes; CLARO NETO, Salvador; GUAGLIANONI, Dalton Geraldo; PINELLI, Ligia Antunes Pereira

2012-01-01

318

Tensile properties of low density polypropylene (LDPE)/palm kernel shell (PKS) biocomposites: The effect of acrylic acid (AA)  

NASA Astrophysics Data System (ADS)

The surface of palm kernel was modified by acrylic acid (AA). Low density polyethylene (LDPE) was filled by palm kernel shell at various 0, 10, 20, 30 and 40 php. The effect of AA as a coupling agent on LDPE/PKS biocomposites on tensile properties and morphology was investigated. The results show that the increasing of filler content decreased the tensile strength and break elongation but increased the Young's modulus. The presence of AA indicates higher tensile strength and Young's modulus but lower elongation at break compared to untreated LDPE/PKS biocomposites. The scanning electron microscope study show that the better interfacial interaction between palm kernel shell and low density polyethylene with addition of AA.

Romisuhani, A.; Salmah, H.; Akmal, H.

2010-05-01

319

Effect of voids on the tensile properties of vanadium nanowires  

NASA Astrophysics Data System (ADS)

Vanadium alloys are one of the candidates for first-wall materials. Due to the impact of high energy neutrons and transmutation helium during a fusion reaction, voids will be formed and the mechanical properties of the first-wall materials will be degraded. It is necessary to investigate the effect of voids on the mechanical behavior of the material. In the present paper, the tensile properties of vanadium nanowires with a void have been studied with molecular dynamics simulations. During a deformation process, the generation of <1 1 1>/{1 1 2} stacking faults to form twinnings in vanadium nanowires. The void facilitates the nanowire's rupture and alters the deformation behavior of nanowires. For the nanowire with a void, the twin initiates near the vicinity of the void rather than a random location as in a nanowire without void. Twinning boundaries propagate towards the ends of nanowire until the whole wire transforms from the initial orientation (z-<0 0 1>) to a new configuration (z-<1 1 0>) with a rotation of 90° under a tensile stress. The nucleation and growth of the twin is inhibited as void size increases, and the nanowires crack is mainly induced by the disordering of vanadium atoms near the void rather than twinning deformation for large size void. A critical effective cross sectional width is determined for different deformation mechanisms. 2012 Elsevier Science. All rights reserved

Wang, Liang; Deng, Huiqiu; Xiao, Shifang; Hu, Wangyu

2013-05-01

320

Tensile properties of as-cast iron-aluminide alloys  

SciTech Connect

Room-temperature tensile properties of as-cast Fe{sub 3}Al, Fe{sub 3}Al with chromium, and Fe{sub 3}Al-based FA-129 alloy are investigated. Tensile properties were obtained in the as-cast condition and after homogenization at 700, 900, and 1200{degrees}C. Transmission electron microscopy (TEM) was used to characterize ordered phases, and optical metallography and scanning electron microscopy (SEM) were used to characterize the microstructure and fracture morphology. The results indicate that the low ductility of as-cast Fe{sub 3}Al-based alloys may be related to the relatively large grain size in the cast condition, the low dislocation density in as-cast samples, and the presence of the D0{sub 3} ordered phase. Homogenized samples of FA-129 alloy exhibited almost twice the ductility of the as-cast condition. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures may provide a clue to the poor ductility in the as-cast state.

Viswanathan, S.: McKamey, C.G.; Maziasz, P.J.; Sikka, V.K.

1993-07-01

321

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

SciTech Connect

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.

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

1982-06-11

322

Improving Joint Properties of Friction Welded Joint of High Tensile Steel  

NASA Astrophysics Data System (ADS)

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.

Kimura, Masaaki; Kusaka, Masahiro; Seo, Kenji; Fuji, Akiyoshi

323

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

SciTech Connect

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.

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

324

Hydrogen effects on the tensile properties of 21-6-9 stainless steel  

NASA Astrophysics Data System (ADS)

The effect of hydrogen on the mechanical properties of a series of nineteen experimental heats of 21-6-9 stainless steel was investigated. The nineteen material groups covered a variety of forging processes, strength levels, grain sizes, and microstructures. The data show that absorbed hydrogen acts as an interstitial strengthener which increases the flow stress of 21-6-9 similar to the effects of carbon, nitrogen, and other interstitial atoms. The true stress for tensile instability was observed to be ˜1130 MPa for both uncharged and hydrogen charged specimens and appeared to be independent of process variables. Thermal charging and/or tensile testing in high pressure hydrogen indicates this austenitic stainless steel is susceptible to hydrogen-induced cracking at grain boundaries, slip bands, and other interfaces. A lack of hydrogen-induced effects at true stresses below 1100 MPa indicates a lower limit for the hydrogen-induced reduction in interfacial strength. Above a true stress of 1100 MPa the extent of hydrogen induced reductions in interfacial strength is dependent on hydrogen concentration and increases as the hydrogen concentration increases. These observations are discussed in terms of several proposed hydrogen embrittlement theories.

West, Anton J.; Louthan, Mcintyre R.

1982-11-01

325

The effect of HIPing on the fatigue and tensile strength of a case, porous-coated Co-Cr-Mo alloy.  

PubMed

The process required to sinter porous Co-Cr-Mo alloys results in the formation of substrate porosity through carbide dissolution. Since hot isostatic pressing (HIPing) has been shown to eliminate casting porosity in the Co-Cr-Mo alloy, it is possible that it may be equally effective on pores that are generated from the sintering operation. The effect that HIPing a porous-coated Co-Cr-Mo material has on the fatigue and tensile properties was investigated. Fatigue testing was performed on sintered materials as well as sintered and HIPed materials, both with and without a porous coating. Further, the effect of varying coating thickness on the resulting fatigue strength of sintered and HIPed materials was studied. Light microscopy was performed in order to define the microstructural changes brought about by the various thermal cycles. Scanning electron microscopy was utilized to define the crack initiation process. The fatigue strength of uncoated "as sintered" materials was found to be reduced by 34% relative to the "as cast" condition. The same material that was HIPed revealed a fatigue strength slightly lower than the "as cast" condition. It was found that porous coatings created preferential sites for fatigue crack initiation. However, the presence of the coating did not further reduce the fatigue strength of "as sintered" materials because of the already low strength created by the sintering operation. Materials that were sintered exhibited a lowering in both tensile strength and elongation to failure relative to the "as cast" condition. The HIPing of sintered materials improved both fatigue and tensile properties relative to the "as sintered" condition. PMID:3782180

Georgette, F S; Davidson, J A

1986-10-01

326

Laboratory measurements of ice tensile strength dependence on density and concentration of silicate and polymer impurities at low temperatures  

NASA Astrophysics Data System (ADS)

The tensile strength of ice bedrock on Titan should strongly influence the effectiveness of the erosional processes responsible for carving the extensive fluvial drainage networks and other surface features visible in images returned by the Cassini and Huygens probes. Recent measurements of the effect of temperature on the tensile strength of low-porosity, polycrystalline ice, without impurities, suggest that ice bedrock at the Titan surface temperature of 93 K may be as much as five times stronger than ice at terrestrial surface temperatures. However, ice bedrock on Titan and other outer solar system bodies may have significant porosity, and impurities such silicates or polymers are possible in such ices. In this laboratory investigation we are exploring the dependence of tensile strength on the density and concentration of impurities, for polycrystalline ice across a wide range of temperatures. We use the Brazilian tensile splitting test to measure strength, and control temperature with dry ice and liquid nitrogen. The 50 mm diameter ice cores are made from a log-normally distributed seed crystal mixture with a median size of 1.4 mm. To control ice density and porosity we vary the packing density of the seed grains in core molds and vary the degree of saturation of the matrix with added near-freezing distilled water. We also vary ice density by blending in a similarly-sized mixture of angular fragments of two types of impurities, a fine-grained volcanic rock and a polyethylene polymer. Because both types of impurities have greater tensile strength than ice at Earth surface temperatures, we expect higher concentrations of impurities to correlate with increased strength for ice-rock and ice-polymer mixtures. However, at the ultra-cold temperatures of the outer planets, we expect significant divergence in the temperature dependence of ice tensile strength for the various mixtures and resulting densities. These measurements will help constrain the range of possible ice tensile strengths that might occur on Titan and other solar system bodies.

Litwin, K. L.; Beyeler, J. D.; Polito, P. J.; Zygielbaum, B. R.; Sklar, L. S.; Collins, G. C.

2009-12-01

327

Structural and High-Temperature Tensile Properties of Special Pitch-Coke Graphites  

NASA Technical Reports Server (NTRS)

The room-temperature structural properties and the tensile properties up to 5000 F (275O C) were determined for ten grades of specially prepared petroleum-coke coal-tar-pitch graphites which were graphitized at 5430 F (3000 C). One impregnation with coal-tar pitch increased the bulk density from 1.41 to 1.57 g/cm3 and the maximum strength at 4500 F (2500 C) from 4000 to 5700 psi. None of the processing parameters studied had a marked effect on the closed porosity or the X-ray structure or the per cent graphitization. The coarse-particle filler resulted in the lowest coefficient of thermal expansion and the fine-particle filler in the highest coefficient. A marked improvement in uniformity of tensile strength was observed. A standard-deviation analysis gave a one-sigma value of approximately 150 psi for one of these special grades and values of 340-420 psi for three commercial grades.

Kotlensky, W. V.; Martens, H. E.

1961-01-01

328

Simulation of the tensile properties of silica aerogels: the effects of cluster structure and primary particle size.  

PubMed

A new two-level model is proposed to investigate the relationship between the mechanical properties and microstructure of silica aerogels. This two-level model consists of the particle-particle interaction model and the cluster structure model. The particle-particle interaction model is proposed to describe interactions between primary particles, in which the polymerization reaction between primary particles is considered. The cluster structure model represents the geometrical structure of silica aerogels, and it is established using a modified diffusion-limited colloid aggregation (DLCA) algorithm. This two-level model is used to investigate the tensile behavior of silica aerogels based on the discrete element method (DEM). The numerical results show that the primary particle size has significant effects on the elastic modulus and tensile strength of silica aerogels. Moreover, the power-law relationships between tensile properties and aerogel density are dependent on the variation of the primary particle radius with density. The present results can explain the difference among different experimental exponents to a certain extent. In comparison with experimental data within a wide density range, this two-level model provides good quantitative estimations of the elastic modulus and tensile strength of silica aerogels after the size effects of the primary particle are considered. This paper provides a fundamental understanding of the relationship between the mechanical properties and microstructure of silica aerogels. The two-level model can be extended to study the mechanical properties of other aerogels and aerogel composites. PMID:25022232

Liu, Qiang; Lu, Zixing; Zhu, Man; Yuan, Zeshuai; Yang, Zhenyu; Hu, Zijun; Li, Junning

2014-09-01

329

Influence of Welding Parameters on the Tensile Shear Strength of Aluminum Alloy Joint Welded by Resistance Spot Welding  

NASA Astrophysics Data System (ADS)

Aluminum alloy A5052 sheets were welded using the technique of resistance spot welding with cover plates. The effects of welding parameters on the tensile shear strength of the joints were investigated. The results reveal that the technique is feasible to weld aluminum alloy, and that the enhanced electrode force is more effective than the extended down-sloping time for inhibiting pores formation and increasing the strength of the joint.

Qiu, Ranfeng; Zhang, Zhanling; Zhang, Keke; Shi, Hongxin; Ding, Gaojian

2011-04-01

330

Size effects on nominal tensile strength of concrete structures: multifractality of material ligaments and dimensional transition from order to disorder  

Microsoft Academic Search

The nominal tensile strength of concrete structures is constant for relatively large sizes, whereas it decreases with the\\u000a size for relatively small sizes. When, as usually occurs, the experimental investigation does not exceed one order of magnitude\\u000a in the scale range, a unique tangential slope in the bilogarithmic strength versus size diagram is found. On the other hand,\\u000a when the

Alberto Carpinteri; Bernardino Chiaia; Giuseppe Ferro

1995-01-01

331

Predicting tensile strength, hardness and corrosion rate of friction stir welded AA6061-T 6 aluminium alloy joints  

Microsoft Academic Search

AA6061-T6 aluminium alloy (Al–Mg–Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio and good corrosion resistance. The friction stir welding (FSW) process and tool parameters play major role in deciding the joint characteristics. In this research, the tensile strength and hardness along with the corrosion rate of friction-stir-butt welded joints of AA6061-T6

S. Rajakumar; C. Muralidharan; V. Balasubramanian

2011-01-01

332

The tensile strength of black bear ( Ursus americanus) cortical bone is not compromised with aging despite annual periods of hibernation  

Microsoft Academic Search

Black bears (Ursus americanus) may not develop disuse osteoporosis during long periods of disuse (i.e. hibernation) because they may be able to maintain bone formation. Previously, we found that cortical bone bending strength was not compromised with age in black bears tibias, despite annual periods of disuse. Here we showed that cortical bone tensile strength (166–198MPa) also does not decrease

Kristin B. Harvey; Thomas D. Drummer; Seth W. Donahue

2005-01-01

333

Tensile bond strength of Er,Cr:YSGG laser-irradiated human dentin and analysis of dentin–resin interface  

Microsoft Academic Search

ObjectivesAs the bond strength of composite resin to Er,Cr:YSGG laser-irradiated dentin has not yet been evaluated, the objectives of this study were to investigate the tensile bond strength and to analyze the resin–dentin interface among bur-cut\\/acid-etched, Er,Cr:YSGG laser-ablated\\/acid-etched and Er,Cr:YSGG laser-ablated human dentin.

Bor-Shiunn Lee; Po-Yen Lin; Min-Huey Chen; Tseng-Ting Hsieh; Chun-Pin Lin; Juin-Yih Lai; Wan-Hong Lan

2007-01-01

334

Tensile properties of carbon nanotube reinforced aluminum nanocomposite fabricated by plasma spray forming  

Microsoft Academic Search

Uniaxial tensile tests were performed on plasma spray formed (PSF) Al–Si alloy reinforced with multiwalled carbon nanotubes (MWCNTs). The addition of CNTs leads to 78% increase in the elastic modulus of the composite. There was a marginal increase in the tensile strength of CNT reinforced composite with degradation in strain to failure by 46%. The computed critical pullout length of

T. Laha; Y. Chen; D. Lahiri; A. Agarwal

2009-01-01

335

Tensile Strength as a Function of Thermal History of Inconel 718 and Inconel 625 Alloys for Glass-Ceramic Headers.  

National Technical Information Service (NTIS)

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 ...

M. C. Rey W. R. Henderson

1982-01-01

336

A new derivation of the tensile strength of cometary nuclei: Application to comet Shoemaker-Levy 9  

NASA Technical Reports Server (NTRS)

The splitting of comets as exemplified by comet Shoemaker-Levy 9, when it passed near Jupiter, is a common phenomenon. Multiple splitting is also not an uncommon occurrence. It is clear that the comet nucleus is fragile, i.e., its tensile strength is small compared with that of solid materials. We show that aggregates of sub-micron interstellar dust particles presumed to consist of a silicate core, an inner mantle of complex organic refractory molecules, and an outer mantle dominated by H2O ice (Greenberg, 1982) provide the basis for a quantitative derivation of the tensile strength of comet SL9 using molecular interactions at the contact interfaces. In fact, using a mean particle size representing interstellar dust as it would appear in its final presolar state one derives a tensile strength which describes remarkably well the multiple splitting phenomenon. This derivation of the tensile strength of a particle aggregate resulting from molecular interactions is quite general and can be applied to physical situations involving any sorts of aggregates as well as those representing comet nuclei.

Greenberg, J. Mayo; Mizutani, Hitoshi; Yamamoto, Tetsuo

1994-01-01

337

Elastoplastic finite element stress analysis and strength evaluation of adhesive lap joints of hollow shafts subjected to tensile loads  

Microsoft Academic Search

The stress distributions in adhesive lap joints of dissimilar hollow shafts subjected to tensile loads have been analyzed by the elastoplastic finite element method, taking the nonlinear behaviors of the adhesive and the hollow shafts into consideration. A prediction method for the joint strength has been proposed based on the Mises equivalent stress distribution in the adhesive and the frictional

M. Kawawaki; Y. Nakano; T. Sawa

1998-01-01

338

Effects of carbon percentage, Stelmor cooling rate and laying head temperature on tensile strength gain in low carbon steels  

Microsoft Academic Search

Low carbon steel wire rods are used to produce finished products such as fine wire, coat hangers, staples, and roofing nails. These products are subjected to excessively high work hardening rates during wire drawing process resulting in a variation in wire tensile strength. This research analyzes the effects of carbon percentage, StelmorRTM cooling rate and laying head temperature on the

Surya Prakash Gade

2004-01-01

339

Strength Distribution in Paper.  

National Technical Information Service (NTIS)

Tensile strength distributions are studied in four papers samples that exhibit a variety of brittle-to-ductile properties. 1005 tensile specimens were measured in each case. The standard Gumbel and Weibull distributions, and a recently proposed double exp...

M. J. Korteoja L. I. Salminen K. J. Niskanen M. Alava

1997-01-01

340

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

PubMed Central

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.

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

2011-01-01

341

Tensile properties of irradiated nuclear grade pressure vessel plate and welds for the fourth HSST irradiation series. [PWR; BWR  

SciTech Connect

The Heavy Section Steel Technology (HSST) program office is conducting a number of experimental series to determine the effect of neutron irradiation on the fracture toughness of nuclear pressure vessel materials. One plate (HSST plate 02) and four welds of A 533 grade B class 1 steel were examined here as part of the Fourth Irradiation Series. The welds were made by current (about 1979) practices. As part of this study, tensile properties were measured after irradiation to 2 x 10/sup 23/ neutrons/m/sup 2/ (>1 MeV) at 288/sup 0/C. The strength of all four welds increased with irradiation. Yield strength was about 10% more sensitive to irradiation than was ultimate strength. Tensile ductility was not affected significantly by irradiation.

McGowan, J.J.

1985-01-01

342

Temperature dependence of tensile mechanical properties in SiC fiber-reinforced Ti matrix composite  

Microsoft Academic Search

Temperature dependence of longitudinal Young's modulus, tensile strength, and interfacial shear stress in SiC(SCS-6) fiber-reinforced commercially pure Ti matrix composites have been examined experimentally in the temperature range from room temperature to 873 K. Young's modulus and tensile strength of the composite was discussed in relation to the interfacial shear stress transfer mechanism. Young's modulus was independent of interfacial shear

Y. Kagawa; T. Fujita; A. Okura

1994-01-01

343

Influence of high pressure hydrogen environment on tensile and fatigue properties of stainless steels at low temperatures  

NASA Astrophysics Data System (ADS)

Hydrogen environment embrittlement (HEE) of stainless steels in the environment of high pressure and low temperature hydrogen gas was evaluated using a very simple mechanical properties testing procedure. In the method, the high-pressure hydrogen environment is produced just inside the hole in the specimen. In this work, the effects of HEE on fatigue properties for austenitic stainless steels SUS304L and SUS316L were evaluated at 298 and 190 K. The effects of HEE on the tensile properties of higher strength stainless steels, such as strain-hardened 316, SUS630, and other alloys, SUH660 and Alloy 718 were also examined. The less effect of HEE on fatigue properties of SUS316L and tensile properties of strain-hardened 316 were observed compared with SUS304L and other steels at room temperature and 190 K.

Ogata, T.

2012-06-01

344

Strength properties of fly ash based controlled low strength materials.  

PubMed

Controlled low strength material (CLSM) is a flowable mixture that can be used as a backfill material in place of compacted soils. Flowable fill requires no tamping or compaction to achieve its strength and typically has a load carrying capacity much higher than compacted soils, but it can still be excavated easily. The selection of CLSM type should be based on technical and economical considerations for specific applications. In this study, a mixture of high volume fly ash (FA), crushed limestone powder (filler) and a low percentage of pozzolana cement have been tried in different compositions. The amount of pozzolana cement was kept constant for all mixes as, 5% of fly ash weight. The amount of mixing water was chosen in order to provide optimum pumpability by determining the spreading ratio of CLSM mixtures using flow table method. The shear strength of the material is a measure of the materials ability to support imposed stresses on the material. The shear strength properties of CLSM mixtures have been investigated by a series of laboratory tests. The direct shear test procedure was applied for determining the strength parameters Phi (angle of shearing resistance) and C(h) (cohesion intercept) of the material. The test results indicated that CLSM mixtures have superior shear strength properties compared to compacted soils. Shear strength, cohesion intercept and angle of shearing resistance values of CLSM mixtures exceeded conventional soil materials' similar properties at 7 days. These parameters proved that CLSM mixtures are suitable materials for backfill applications. PMID:17331642

Türkel, S

2007-08-25

345

Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes  

NASA Astrophysics Data System (ADS)

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° 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.

Tarawneh, Mou'ad A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi

2009-06-01

346

Effect of Ultrasonic Treatment on The Tensile and Impact Properties of Thermoplastic Natural Rubber Nanocomposites Reinforced with Carbon Nanotubes  

SciTech Connect

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.

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

347

Effect of cooling rate on eutectic cell count, grain size, microstructure, and ultimate tensile strength of hypoeutectic cast iron  

SciTech Connect

This article describes a series of microstructural and strength studies performed on hypoeutectic cast iron, which was sand cast using a variety of end chills (metallic, nonmetallic, water-cooled, and subzero, respectively). The effects of cooling rate on the eutectic cell count (ECC), grain size, and the ultimate tensile strength (UTS) were evaluated. Attempts were also made to explain these effects and to correlate the UTS with ECC. It was found that subzero chilled and water-cool, chilled cast iron exhibit severe undercooling compared to normal sand cast iron. It was concluded from this investigation that nucleation conditions are completely altered but growth conditions prevail as usual. Therefore, undercooling during solidification is considered to be responsible for variation in ECC, grain size, and microstructure, and tensile strength.

Hemanth, J.; Rao, K.V.S. (Siddaganga Inst. of Tech., Karnataka (India). Dept. of Mechanical Engineering)

1999-08-01

348

ESPI TECHNQIUE FOR MEASURING MICRO-TENSILE PROPERTIES OF THIN FILM MATERIALS  

Microsoft Academic Search

In-plane ESPI(electronic Speckle Pattern Interferometric) technique was developed to measure the micro-mechanical properties for thin film materials . The properties were determined from the micro-tensile s tress and strain curve by measuring micro-tensile strain in m icro-sized specimen 0.5 ?m thick and 200 ?m wide. The specimen was monotonically loaded by the micro-tensile loading s ystem developed in this study.

Yong-Hak Huh; Dong-Iel Kim; Chang-Doo Kee

349

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

PubMed

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

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

1982-10-01

350

Tensile and compressive properties of wrought magnesium alloys at high rates of strain  

NASA Astrophysics Data System (ADS)

Impact tensile and compressive properties of three different wrought magnesium alloys (AZ31B-F, AZ61A-F and ZK60A-T5) are determined using two different versions of the split Hopkinson bar. Tension and compression specimens are machined from extruded bars parallel to the extrusion axis. Tensile and compressive stress-strain data at strain rates of 1000-2000/s are presented and compared with those at quasi-static and medium strain rates obtained on an Instron 4505 testing machine. The effects of strain rate and loading mode on the ultimate strength, ultimate strain and absorbed energy are examined in details. It is shown that the wrought magnesium alloys exhibit a pronounced asymmetric yield behavior in tension and compression at both low and high rates of strain. It is also shown that the ultimate strengths increase with increasing strain rate, and the strain rate dependence of the ultimate strain and absorbed energy differs, depending the wrought magnesium alloys tested.

Yokoyama, T.

2003-09-01

351

Tensile Properties and Work Hardening Behavior of Laser-Welded Dual-Phase Steel Joints  

NASA Astrophysics Data System (ADS)

The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength (UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate. While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture.

Farabi, N.; Chen, D. L.; Zhou, Y.

2012-02-01

352

Influence of laboratory annealing on tensile properties and design stress intensity limits for Type 304 stainless steel  

Microsoft Academic Search

The influence of reannealing (laboratory annealing) on yield and ultimate tensile strength values of 19 heats of type 304 stainless steel was determined. Most heats were reannealed at 1065°C for 0.5 hr. The reannealed properties were used to determine the influence of reannealing on time-independent design stress intensity limits (S\\/sub m\\/). The major findings are as follows: 1. Reannealing lowered

V. K. Sikka; M. K. Booker

1977-01-01

353

Room Temperature Tensile Properties of Titanium and Seven Titanium Alloys Prepared by Skull Casting.  

National Technical Information Service (NTIS)

The room temperature tensile properties of commercially pure titanium and seven titanium alloys prepared by skull casting were determined in the as-cast and heat-treated conditions. Data were compared with property data from tensile tests on wrought alloy...

E. D. Calvert R. R. Lowery

1974-01-01

354

Tensile behavior of cortical bone: Dependence of organic matrix material properties on bone mineral content  

Microsoft Academic Search

A porous composite model is developed to analyze the tensile mechanical properties of cortical bone. The effects of microporosity (volksman's canals, osteocyte lacunae) on the mechanical properties of bone tissue are taken into account. A simple shear lag theory, wherein tensile loads are transferred between overlapped mineral platelets by shearing of the organic matrix, is used to model the reinforcement

S. P. Kotha; N. Guzelsu

2007-01-01

355

Effect of molding condition on tensile properties of hemp fiber reinforced composite  

Microsoft Academic Search

In this study, the effect of molding condition on the tensile properties for plain woven hemp fiber reinforced green composite was examined. The tensile properties of the composite were compared with those of the plain woven jute fiber composite fabricated by the same process. Emulsion type biodegradable resin or polypropylene sheet was used as matrix. The composites were processed by

K. Takemura; Y. Minekage

2007-01-01

356

Effects of Molybdenum and Vanadium Addition on Tensile and Charpy Impact Properties of API X70 Linepipe Steels  

NASA Astrophysics Data System (ADS)

This study is concerned with the effects of V and Mo addition on tensile and Charpy impact properties of API X70 linepipe steels. Twelve kinds of steel specimens were produced by varying V and Mo additions and rolling conditions. The addition of V and Mo promoted the formation of acicular ferrite (AF), banitic ferrite (BF), and martensite-austenite (MA) constituents, while suppressing the formation of polygonal ferrite (PF) or pearlite (P). The tensile test results indicated that the tensile strength of the specimens rolled in the two-phase region increased with the addition of V and Mo, while the yield strength did not vary much in these specimens except the water-cooled specimens, which showed the increased yield strength with addition of Mo. The tensile strength of specimens rolled in the single-phase region followed by water cooling increased with increasing V and Mo contents. The yield strength, however, did not vary much with increasing V content or with addition of Mo to the low-V alloy. In these specimens, a substantial increase in the strengths was achieved only when Mo was added to the high-V alloy. The specimens rolled in the single-phase region had higher upper-shelf energy (USE) and lower ductile-brittle transition temperature (DBTT) than the specimens rolled in the two-phase region, because their microstructures were composed of AF and fine PF. According to the electron backscatter diffraction (EBSD) analysis data, the effective grain size in AF was determined by crystallographic packets composed of a few fine grains having similar orientations. Thus, the decreased DBTT in the specimens rolled in the single-phase region could be explained by the decrease in the overall effective grain size due to the presence of AF having smaller effective grain size.

Kim, Young Min; Shin, Sang Yong; Lee, Hakcheol; Hwang, Byoungchul; Lee, Sunghak; Kim, Nack J.

2007-08-01

357

The effect of erbium family laser on tensile bond strength of composite to dentin in comparison with conventional method.  

PubMed

The purpose of this study was to evaluate the effect of Er:YAG and Er,Cr:YSGG laser on tensile bond strength of composite resin to dentine in comparison with bur-prepared cavities. Fifteen extracted caries-free human third molars were selected. The teeth were cut at a level below the occlusal pit and fissure plan and randomly divided into three groups. Five cavities were prepared by diamond bur, five cavities prepared by Er:YAG laser, and the other group prepared by Er,Cr:YSGG laser. Then, all the cavities were restored by composite resin. The teeth were sectioned longitudinally with Isomet and the specimens prepared in dumbbelled shape (n = 36). The samples were attached to special jigs, and the tensile bond strength of the three groups was measured by universal testing machine at a speed of 0.5 mm/min. The results of the three groups were analyzed with one-way ANOVA and Tamhane test. The means and standard deviations of tensile bond strength of bur-cut, Er:YAG laser-ablated, and Er,Cr:YSGG laser-ablated dentine were 5.04 ± 0.93, 13.37 ± 3.87, and 4.85 ± 0.93 MPa, respectively. There is little difference in tensile bond strength of composite resin in Er,Cr:YSGG lased-prepared cavities in comparison with bur-prepared cavities, but the Er:YAG laser group showed higher bond strength than the other groups. PMID:22491942

Shahabi, Sima; Chiniforush, Nasim; Bahramian, Hoda; Monzavi, Abbas; Baghalian, Ali; Kharazifard, Mohammad Javad

2013-01-01

358

The effect of microalloying additions on the tensile properties of polycrystalline NiAl  

NASA Technical Reports Server (NTRS)

The presently evaluated 0.1 at. pct Fe and Ga additions to NiAl, while beneficial in the case of monocrystalline NiAl ductility, does not improve ductility in the polycrystalline case; it also has little effect on tensile properties. A similar microalloying addition of Zr, by contrast, significantly depressed the tensile ductility of NiAl, and nearly doubled the brittle-to-ductile transition temperature (BDTT). The dependence of tensile properties on temperature was in all cases similar; tensile elongations remained low and constant until the BDTT was reached, and then dramatically increased.

Noebe, R. D.; Behbehani, M. K.

1992-01-01

359

Tensile properties of a morphologically split supraspinatus tendon.  

PubMed

The supraspinatus tendon consists morphologically of two sub-regions, anterior and posterior. The anterior sub-region is thick and tubular while the posterior is thin and strap-like. The purpose of this study was to compare the structural and mechanical properties of the anterior and posterior sub-regions of the supraspinatus tendon. The supraspinatus tendons from seven human cadaveric shoulders were morphologically divided into the anterior and posterior sub-regions. Length, width, and thickness were measured. A servo-hydraulic testing machine (MTS Systems Corporation, Minneapolis, MN) was used for tensile testing. The maximal load at failure, modulus of elasticity and ultimate tendon stress were calculated. Repeated measures were used for statistical comparisons. The mean anterior tendon cross-sectional area was 47.3 mm(2) and the posterior was 32.1 mm(2) . Failure occurred most often at the insertion site: anterior (5/7) and posterior (6/7). All parameters of the anterior sub-region were significantly greater than those of the posterior sub-region. The moduli of elasticity at the insertion site were 592.4 MPa in the anterior sub-region and 217.7 MPa in the posterior (P = 0.01). The ultimate failure loads were 779.2 N in the anterior sub-region and 335.6 N in the posterior (P = 0.003). The ultimate stresses were 22.1 MPa in the anterior sub-region and 11.6 MPa in the posterior (P = 0.008). We recognized that the anterior and posterior sub-regions of the SSP tendon have significantly different mechanical properties. In a future study, we need to evaluate how best to repair an SSP tendon considering these region-specific properties. Clin. Anat. 27:702-706, 2014. © 2013 Wiley Periodicals, Inc. PMID:24214830

Matsuhashi, Tomoya; Hooke, Alexander W; Zhao, Kristin D; Goto, Akira; Sperling, John W; Steinmann, Scott P; An, Kai-Nan

2014-07-01

360

Self-assembled smooth muscle cell tissue rings exhibit greater tensile strength than cell-seeded fibrin or collagen gel rings  

PubMed Central

In this study, we created self-assembled smooth muscle cell (SMC) tissue rings (comprised entirely of cells and cell-derived matrix; CDM) and compared their structure and material properties with tissue rings created from SMC-seeded fibrin or collagen gels. All tissue rings were cultured statically for 7 days in supplemented growth medium (with ?-amino caproic acid, ascorbic acid, and insulin-transferrin-selenium), prior to uniaxial tensile testing and histology. Self-assembled CDM rings exhibited ultimate tensile strength and stiffness values that were two-fold higher than fibrin gel and collagen gel rings. Tensile testing of CDM, fibrin gel and collagen gel rings treated with deionized water to lyse cells showed little to no change in mechanical properties relative to untreated ring samples, indicating that the ECM dominates the measured ring mechanics. In addition, CDM rings cultured in supplemented growth medium were significantly stronger than CDM rings cultured in standard, unsupplemented growth medium. These results illustrate the potential utility of self-assembled cell rings as model CDM constructs for tissue engineering and biomechanical analysis of ECM material properties.

Adebayo, Olufunmilayo; Gwyther, Tracy A.; Hu, Jason Z.; Billiar, Kristen L.; Rolle, Marsha W.

2012-01-01

361

Self-assembled smooth muscle cell tissue rings exhibit greater tensile strength than cell-seeded fibrin or collagen gel rings.  

PubMed

In this study, we created self-assembled smooth muscle cell (SMC) tissue rings (comprised entirely of cells and cell-derived matrix; CDM) and compared their structure and material properties with tissue rings created from SMC-seeded fibrin or collagen gels. All tissue rings were cultured statically for 7 days in supplemented growth medium (with ?-amino caproic acid, ascorbic acid, and insulin-transferrin-selenium), prior to uniaxial tensile testing and histology. Self-assembled CDM rings exhibited ultimate tensile strength and stiffness values that were two-fold higher than fibrin gel and collagen gel rings. Tensile testing of CDM, fibrin gel and collagen gel rings treated with deionized water to lyse cells showed little to no change in mechanical properties relative to untreated ring samples, indicating that the ECM dominates the measured ring mechanics. In addition, CDM rings cultured in supplemented growth medium were significantly stronger than CDM rings cultured in standard, unsupplemented growth medium. These results illustrate the potential utility of self-assembled cell rings as model CDM constructs for tissue engineering and biomechanical analysis of ECM material properties. PMID:22865465

Adebayo, Olufunmilayo; Hookway, Tracy A; Hu, Jason Z; Billiar, Kristen L; Rolle, Marsha W

2013-02-01

362

Unique metallic glass formability and ultra-high tensile strength in Al-Ni-Fe-Gd alloys  

SciTech Connect

The metallic glass formability of aluminum-rich Al-Ni-Fe-Gd alloys has been systematically investigated. The critical cooling rate required to form an amorphous state in this system is generally low, and comparable to that of some of the best metallic glass formers, such as Pd-Cu-Si. Amorphous ribbons up to 0.25 mm thick can easily be produced by the single-roller melt-spinning technique. Tensile strengths as high as 1280 MPa and Young's modulus of 75 GPa have been obtained. Bulk amorphous alloys with good mechanical properties are optimized in Al[sub 85]Ni[sub 6]Fe[sub 3]Gd[sub 6]. DSC and DTA studies reveal that the glass formability is unique for Al-based alloys because the reduced glass temperature T[sub rg] for Al-Ni-Fe-Gd can be as low as 0.44. This is much lower than conventional theory would suggest for easy glass forming systems. A mechanism for the unusual glass formability is suggested.

He, Y.; Poon, S.J. (Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics); Dougherty, G.M.; Shiflet, G.J. (Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science)

1993-02-01

363

Structural basis of the tensile strength of protein complexes mediating cell adhesion  

NASA Astrophysics Data System (ADS)

This study explores the behaviour of adhesive complexes of cell adhesion molecules undergoing forced detachment. Molecular-forces measurements combined with Steered Molecular Dynamic (SMD) simulations were used to investigate the mechanical response of the CD2 C58 and hemophilic C-cadherin bonds. The CD2-CD58 adhesive complex, important for the adaptive immune response, contains several salt-bridges in the adhesive interface. SMD simulations showed that these inter-protein salt bridges contribute independently to the tensile strength of the complex. Consistent with this, force measurements with the Surface Force Apparatus (SFA) demonstrated that the elimination of single salt bridges weakens the bond. The corresponding loss in adhesion energy of the CD2-CD58 complex correlates with the importance of the salt bridges observed in the simulations. These findings correlate closely with the effect of the elimination of single salt bridges observed in cell aggregation assays and binding measurements. On the other hand, the hemophilic C-cadherin interaction determines specific cell-cell adhesion during development in Xenopus laevis . Single molecule force spectroscopy was used to characterize the multiple bound states between C-cadherin ectodomains. The experiments showed two short-lived bound states associated with the two outermost ectodomains and two long-lived states associated with the full ectodomain. It is likely that the two short-lived states are involved in the specificity of the interaction since previous studies showed that the corresponding states in E-cadherin have different lifetimes. In addition, SMD simulations of the forced dissociation of the strand dieter of C-cadherin suggested a mechanism for the specificity of cadherin interactions.

Bayas, Marco Vinicio

364

The effects of hydrogen isotopes and helium on the tensile properties of 21-6-9 stainless steel  

SciTech Connect

High-energy-rate-forged (HERF) stainless steels are used as the materials of construction for tritium and deuterium reservoirs. Hydrogen and helium, the decay product of tritium, are known to embrittle stainless steels (1--4). The resistance to hydrogen and helium induced embrittlement is relatively good for HERF stainless steels when compared to annealed stainless steels due to their high number density of dislocations, which act as traps for hydrogen and helium. However, the degree of the embrittlement in these materials can vary considerably because of microstructure and yield strength variations introduced during the forging process. In this study the effect of hydrogen and tritium on the room temperature tensile properties of 21-6-9 stainless steel was measured as a function of HERF yield strength in the range of 500 to 918 MPa. The effect of a microstructures was studied also by conducting tensile tests with both HERF samples and annealed samples.

Morgan, M.J.

1990-12-31

365

The effects of hydrogen isotopes and helium on the tensile properties of 21-6-9 stainless steel  

SciTech Connect

High-energy-rate-forged (HERF) stainless steels are used as the materials of construction for tritium and deuterium reservoirs. Hydrogen and helium, the decay product of tritium, are known to embrittle stainless steels (1--4). The resistance to hydrogen and helium induced embrittlement is relatively good for HERF stainless steels when compared to annealed stainless steels due to their high number density of dislocations, which act as traps for hydrogen and helium. However, the degree of the embrittlement in these materials can vary considerably because of microstructure and yield strength variations introduced during the forging process. In this study the effect of hydrogen and tritium on the room temperature tensile properties of 21-6-9 stainless steel was measured as a function of HERF yield strength in the range of 500 to 918 MPa. The effect of a microstructures was studied also by conducting tensile tests with both HERF samples and annealed samples.

Morgan, M.J.

1990-01-01

366

Effect of rolling on the high temperature tensile and stress-rupture properties of tungsten fiber-superalloy composites  

NASA Technical Reports Server (NTRS)

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.

Petrasek, D. W.

1974-01-01

367

Correlation of microstructure and fatigue properties of two high-strength spring steels  

Microsoft Academic Search

This is a study of correlation of microstructure and fatigue properties of two high-strength steels, i.e., a V- and Cr-containing alloy steel and a 0.84%C steel, used for an automotive diaphragm spring. Fatigue properties were investigated with focuses on microstructures and tensile strengths under the fixed hardness condition. The fatigue test results indicated that the fatigue limits of the two

Jang-Chul Shin; Sunghak Lee; Jae Hwa Ryu

1999-01-01

368

The effect of growth factors on both collagen synthesis and tensile strength of engineered human ligaments.  

PubMed

Growth factors play a central role in the development and remodelling of musculoskeletal tissues. To determine which growth factors optimized in vitro ligament formation and mechanics, a Box-Behnken designed array of varying concentrations of growth factors and ascorbic acid were applied to engineered ligaments and the collagen content and mechanics of the grafts were determined. Increasing the amount of transforming growth factor (TGF) ?1 and insulin-like growth factor (IGF)-1 led to an additive effect on ligament collagen and maximal tensile load (MTL). In contrast, epidermal growth factor (EGF) had a negative effect on both collagen content and MTL. The predicted optimal growth media (50 ?g/ml TGF?, IGF-1, and GDF-7 and 200 ?M ascorbic acid) was then validated in two separate trials: showing a 5.7-fold greater MTL and 5.2-fold more collagen than a minimal media. Notably, the effect of the maximized growth media was scalable such that larger constructs developed the same material properties, but larger MTL. These results show that optimizing the interactions between growth factors and engineered ligament volume results in an engineered ligament of clinically relevant function. PMID:22698725

Hagerty, Paul; Lee, Ann; Calve, Sarah; Lee, Cassandra A; Vidal, Martin; Baar, Keith

2012-09-01

369

Tensile properties of the in vivo human gastrocnemius tendon.  

PubMed

In the present experiment we obtained the tensile properties of the human gastrocnemius tendon, a high-stressed tendon suitable for spring-like action during locomotion. Measurements were taken in vivo in six men. The gastrocnemius tendon elongation during tendon loading-unloading induced by muscle contraction-relaxation was measured using real-time ultrasonography. Tendon forces were calculated from the moment generated during isometric plantarflexion contraction, using tendon moment arm length data obtained in vivo with the tendon travel method. Tendon stiffness data were calculated from the slope of the tendon force-elongation curve, and were then normalized to the tendon's original dimensions, obtained from morphometric analysis of sonographs, to estimate the tendon Young's modulus. Mechanical hysteresis values were obtained from area calculations by numerical integration. The elongation of the tendon increased curvilinearly with the force acting upon it, from 1.7+/-1mm (0.8+/-0.3% strain) at 87.5+/-8.5 N to 11.1+/-3.1mm (4.9+/-1% strain) at 875+/-85 N. The tendon Young's modulus and mechanical hysteresis were 1.16+/-0.15 GPa and 18+/-3%, respectively. These values fall within the range of values obtained from in vitro experiments and are very similar to the respective values recently obtained from in vivo measurements in the less highly stressed human tibialis anterior tendon (1.2 GPa and 19%), thus indicating that the material properties of tendon are independent of physiological loading and function. Combining the present tendon force-elongation data with previously reported Achilles tendon force data recorded during walking indicates that the gastrocnemius tendon would provide approximately 6% of the total external work produced by the locomotor system. This estimate illustrates the contribution of passive elastic mechanisms on the economy and efficiency of walking. The contributions would be greater in more active exercise such as running. PMID:12445617

Maganaris, Constantinos N; Paul, John P

2002-12-01

370

Tensile bond strength of sealants following Er:YAG laser etching compared to acid etching in permanent teeth.  

PubMed

The aim of this in vitro study was to assess the effect of Er:YAG laser surface treatment on the tensile bond strength of a sealant in permanent teeth. A total of 30 sound third molars were selected and embedded in cold-cure acrylic resin. The enamel surfaces were flattened by a grinding. The teeth were randomly divided into three groups and pretreated as follows: (1) 37% phosphoric acid; (2) Er:YAG laser (1.5 ml/min water spray, 100 mJ energy output, 10 Hz frequency, focal distance 17 mm); (3) Er:YAG laser + 37% phosphoric acid. The treated surfaces were isolated by double adhesive Sellotape and after insertion of a split Teflon matrix at an isolated site, sealant was applied. The specimens were thermocycled and stored at 37°C in distilled water for 72 h, then subjected to a tensile bond strength test (50 kgf at 0.5 mm/min). The mean tensile bond strengths (± SD, in megapascals) were: 18.51 ± 5.68 in group 1, 8.06 ± 2.69 in group 2, and 17.33 ± 5.04 in group 3. Data were submitted to analysis of variance and the Tukey test. No significant difference were found between groups 1 (37% phosphoric acid) and group 3 (Er:YAG laser + 37% phosphoric acid) but treatment with the Er:YAG laser alone (group 2) resulted in significantly lower tensile bond strength than seen in the other groups. In this setting, the Er:YAG laser prepared the enamel surface for sealing but did not eliminate the need for acid etching before sealant application. PMID:21336680

Shahabi, Sima; Bagheri, Hossein G; Ramazani, Kosar

2012-03-01

371

Experimental study on clamping effects on the tensile strength of composite plates with a bolt-filled hole  

Microsoft Academic Search

An experimental study was performed to assess the effects of clamp-up on the net-tension failure of laminated composite plates with bolt-filled holes. Graphite\\/epoxy prepreg of T800\\/3900-2 was selected for fabricating the laminates for the tests. The tensile strength and failure response of specimens with an open hole and a bolt-filled hole were evaluated. Both 100% bypass load (no bolt bearing

Y. Yan; W.-D. Wen; F.-K. Chang; P. Shyprykevich

1999-01-01

372

Influences of process parameters on tensile strength of friction stir welded cast A319 aluminium alloy joints  

Microsoft Academic Search

Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking.\\u000a Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been\\u000a made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made

M. Jayaraman; R. Sivasubramanian; V. Balasubramanian; S. Babu

2009-01-01

373

Predicting ultimate tensile and bending strengths of three finger-jointed tropical African hardwoods using acoustic emissions  

Microsoft Academic Search

The acoustic emissions behaviour of finger-joints from three tropical African hardwoods, Obeche (Triplochiton scleroxylon), Makore (Tieghemella heckelii) and Moabi (Baillonella toxisperma) were examined with a view to establishing their potential usefulness for non-destructively predicting ultimate tensile and bending strengths. Stress at first acoustic emission event-count as well as the cumulative event-count at 80 percent of mean failure stress and the

J. Ayarkwa; Y. Hirashima; K. Ando; Y. Sasaki

2000-01-01

374

Determination of mechanical strength properties of hemp fibers using near-infrared fourier transform Raman microspectroscopy.  

PubMed

Fourier transform near-infrared (FT-NIR) Raman microspectroscopy was adopted for analyzing the micro mechanical tensile deformation behavior of cellulosic plant fibers. Mechanical strength parameters such as tensile strength, failure strain, and Young's modulus of diversified hemp fibers were determined within the range of single fiber cells and fiber filaments. The analysis of fiber deformation at the molecular level was followed by the response of a characteristic Raman signal of fiber cellulose that is sensitive to the tensile load applied. The frequency shift of the Raman signal at 1095 cm(-1) to lower wavenumbers was observed when the fibers were subjected to tensile strain. Microstructural investigations using electron microscopy under environmental conditions supported the discussion of mechanical properties of hemp fibers in relation to several fiber variabilities. Generally, mechanical strength properties of diversified hemp fibers were discussed at the molecular, microstructural, and macroscale level. It was observed that mechanical strength properties of the fibers can be controlled in a broad range by appropriate mercerization parameters such as alkali concentration, fiber shrinkage, and tensile stress applied to the fibers during the alkaline treatments. PMID:16808870

Peetla, Padmaja; Schenzel, Karla C; Diepenbrock, Wulf

2006-06-01

375

Effect of heat treatment temperature on tensile properties of a Fe-28Al-5Cr-0.3B-0.003Mg alloy  

SciTech Connect

Until now, the effect of heat treatment on mechanical properties of Fe{sub 3}Al that has elonged flat grains and B2 structure has not been studied. The present work is to study the influence of heat treatment on the mechanical properties of Fe{sub 3}Al with different structures. Heat-treatment has a strong effect on the tensile property of Fe{sub 3}Al by changing the phase structures of Fe{sub 3}Al. Mixed B2 + DO{sub 3} treatment and recrystallization induce low tensile properties and B2 treatment before recrystallization results in higher fracture strength and ductility.

Lu, Y.H.; Xing, Z.Q.; Zhang, H. [Beijing Polytechnic Univ. (China). Division of Advanced Mechanics] [Beijing Polytechnic Univ. (China). Division of Advanced Mechanics

1995-08-15

376

The effects of specimen width on tensile properties of triaxially braided textile composites  

NASA Technical Reports Server (NTRS)

The objective of this study was to examine the effect of the unit cell architecture on the mechanical response of textile reinforced composite materials. Specifically, the study investigated the effect of unit cell size on the tensile properties of 2D triaxially braided graphite epoxy laminates. The figures contained in this paper reflect the presentation given at the conference. They may be divided into four sections: (1) a short definition of the material system tested; (2) a statement of the problem and a review of the experimental results; (3) experimental results consist of a Moire interferometry study of the strain distribution in the material plus modulus and strength measurements; and (4) a short summary and a description of future work will close the paper.

Masters, John E.; Ifju, Peter G.; Pastore, Christopher M.; Bogdanovich, Alexander E.

1993-01-01

377

Tensile properties and thermal shock reliability of Sn-Ag-Cu solder joint with indium addition.  

PubMed

The thermal shock reliability and tensile properties of a newly developed quaternary Sn-1.2Ag-0.5Cu-0.4In (wt%) solder alloy were investigated and compared to those of ternary Sn-Ag-Cu based Pb-free solder alloys. It was revealed that the Sn-1.2Ag-0.5Cu-0.4In solder alloy shows better thermal shock reliability compared to the Sn-1.0Ag-0.5Cu and Sn-3.0Ag-0.5Cu solder alloys. The quaternary alloy has higher strength than Sn-1.0Ag-0.5Cu alloy, and higher elongation than Sn-3.0Ag-0.5Cu alloy. It was also revealed that the addition of indium promotes the formation of Ag3(Sn, In) phase in the solder joint during reflow process. PMID:22849189

Yu, A-Mi; Jang, Jae-Won; Lee, Jong-Hyun; Kim, Jun-Ki; Kim, Mok-Soon

2012-04-01

378

Influence of thermomechanical ageing on tensile properties of 2014 aluminium alloy  

Microsoft Academic Search

2014 aluminium alloy was subjected to various thermomechanical ageing (TMA) treatments which included partial peak ageing (25% and 50%), warm rolling (10% and 20%) and further ageing to peak hardness level at 160 ° C. The tensile tests reveal that TMA treatments cause a substantial improvement in tensile properties and thermal stability. The electron microscopic studies reveal that the TMA

S. Singh; D. B. Goel

1990-01-01

379

Anisotropy of Young's modulus and tensile properties in cold rolled ?? martensite Ti–V–Sn alloys  

Microsoft Academic Search

Young's modulus and tensile properties of cold rolled Ti–8 mass% V and (Ti–8 mass% V)–4 mass% Sn alloy plates consisting of ?? martensite were investigated as a function of tensile axis orientation in this work. A single phase of ?? (hcp) martensite is obtained in Ti–8 mass% V and (Ti–8 mass% V)–4 mass% Sn alloys by quenching after solution treatment.

Hiroaki Matsumoto; Akihiko Chiba; Shuji Hanada

2008-01-01

380

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)

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.

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

2014-05-01

381

Effect of filler loading on tensile and tear properties of SMR L\\/ENR 25 and SMR L\\/SBR blends cured via a semi-efficient vulcanization system  

Microsoft Academic Search

The effects of filler loading on the tensile and tear properties of SMR L\\/ENR 25 and SMR L\\/SBR blends using a semi-efficient vulcanization system was studied. Carbon black (N330), silica (Vulcasil C) and calcium carbonate were used as the fillers and the loading range was from 0 to 40 phr. Tensile strength, M300 (tensile stress at 300% elongation) and tear

B. T. Poh; H. Ismail; K. S. Tan

2002-01-01

382

Simultaneous enhancement of tensile/compressive strength and ductility of magnesium alloy AZ31 using carbon nanotubes.  

PubMed

AZ31 nanocomposite containing carbon nanotube (CNT) reinforcement was fabricated using solidification processing followed by hot extrusion. The CNT reinforcement was integrated with AZ31 using an Al foil method. The AZ31 nanocomposite exhibited slightly smaller grain and intermetallic particle sizes than monolithic AZ31, reasonable CNT distribution, dominant (10 - 11) texture in the transverse and longitudinal directions unlike monolithic AZ31, and 48% higher hardness than monolithic AZ31. Compared to monolithic AZ31, the AZ31 nanocomposite exhibited higher 0.2%TYS, UTS, tensile failure strain and tensile work of fracture (WOF) (+10%, +17%, +68% and +92%, respectively). Similarly, compared to monolithic AZ31, the AZ31 nanocomposite exhibited higher 0.2%CYS, UCS, average compressive failure strain and compressive WOF (+58%, +3%, +5% and +17%, respectively). Inclusive of crystallographic texture changes, the effect of CNT integration on the enhancement of tensile and compressive properties of AZ31 is investigated in this paper. PMID:20352742

Paramsothy, M; Hassan, S F; Srikanth, N; Gupta, M

2010-02-01

383

The effect of ultrasonics on the strength properties of carbon steel processed by cold plastic deformation  

NASA Technical Reports Server (NTRS)

A study was made of the influence of ultrasounds on the mechanical properties of OLT 35 carbon steel tubes cold-drawn on a plug ultrasonically activated by longitudinal waves. Experimental results indicate that: 1. The reduction in the values of the flow limit and tensile strength is proportional to the increase in acoustic energy introduced into the material subjected to deformation. 2. The diminution in influence of ultrasounds on tensile strength and flow rate that is due to an increased degree of deformation is explained by a reduction in specific density of the acoustic energy at the focus of deformation. 3. The relations calculated on the basis of the variation in the flow limit and tensile strength as a function of acoustic energy intensity was verified experimentally.

Atanasiu, N.; Dragan, O.; Atanasiu, Z.

1974-01-01

384

The origins of tritium and helium effects on the tensile properties of metals  

SciTech Connect

In this paper, the effects of internal tritium and helium on the tensile properties of two austenitic stainless steels and an iron-based superalloys have been studied. The materials tested were, forged 21 Cr-6Ni-9Mn and 304L (tested in the annealed condition and tow forged conditions), and a modified A-286 alloy. The accumulation of {sup 3}He from the radioactive decay of tritium caused an increase in the yield strength and a continuous decrease in the ductility in almost all materials tested. Increased {sup 3}He concentrations also caused a change in fracture mode form ductile rupture to predominantly intergranular fracture. The property changes resulted from {sup 3}He bubble-induced strengthening, which produced a change in deformation mode form long-range dislocation activity to deformation twinning. In the deformation-twinning mode, the {sup 3}He-accelerated fracture initiated at the intersections of deformation twins with grain boundaries. High-strength forged 304L was most resistant to {sup 3}He effects owing to the redistribution of {sup 3}He on dislocations.

Robinson, S.L.; Yang, N.Y.C. (Sandia National Labs., Livermore, CA (United States))

1992-03-01

385

Experimental assessments of notch ductility and tensile strength of stainless steel weldments after 120°C neutron irradiation  

Microsoft Academic Search

The Charpy-V (C\\/sub v\\/) properties of AISI 300 series stainless steel plate, weld, and weld heat-affected zone (HAZ) materials from commercial production weldments in 406-mm-diameter pipe (12.7-mm wall) were investigated in unirradiated and irradiated conditions. Weld and HAZ tensile properties were also assessed in the two conditions. The plates and weld filler wires represent different steel melts; the welds were

J. R. Hawthorne; B. H. Menke; N. G. Awadalla; K. R. OKula

1986-01-01

386

Influence of martensite content and morphology on tensile and impact properties of high-martensite dual-phase steels  

SciTech Connect

A series of dual-phase (DP) steels containing finely dispersed martensite with different volume fractions of martensite (V{sub m}) were produced by intermediate quenching of a boron- and vanadium-containing microalloyed steel. The volume fraction of martensite was varied from 0.3 to 0.8 by changing the intercritical annealing temperature. The tensile and impact properties of these steels were studied and compared to those of step-quenched steels, which showed banded microstructures. The experimental results show that DP steels with finely dispersed microstructures have excellent mechanical properties, including high impact toughness values, with an optimum in properties obtained at {approximately}0.55 V{sub m}. A further increase in V{sub m} was found to decrease the yield and tensile strengths as well as the impact properties. It was shown that models developed on the basis of a rule of mixtures are inadequate in capturing the tensile properties of DP steels with V{sub m} > 0.55. Jaoul-Crussard analyses of the work-hardening behavior of the high-martensite volume fraction DP steels show three distinct stages of plastic deformation.

Bag, A. [Bharat Earth Movers Limited, Kolar Gold Fields (India). Materials Science Lab.; Ray, K.K. [Indian Inst. of Tech., Kharagpur (India). Dept. of Metallurgical and Materials Engineering; Dwarakadasa, E.S. [Indian Inst. of Science, Bangalore (India). Dept. of Metallurgy

1999-05-01

387

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

SciTech Connect

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.

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

2006-10-15

388

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

389

Effect of time on the diametral tensile strength of resin-modified restorative glass ionomer cements and compomer.  

PubMed

The aim of this study was to analyze the diametral tensile strengths of three resin-modified restorative glass ionomer cements--Vitremer, Fuji II LC and Photac Fil and one compomer--Dyract. They were tested at 1 hour, 1 day and 1 week. Kratos testing machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed by two-way ANOVA and Tukey's test that showed statistically significant differences among the materials. The tested materials presented an increase in strength from 1 hour to 1 week and were as follows for each material respectively: Vitremer (19.22-27.29), Fuji II LC (23.91-28.67), Photac Fil (19.35-22.86), Dyract (28.83-46.95). Dyract presented the highest strengths. PMID:11696919

Cefaly, D F; Valarelli, F P; Seabra, B G; Mondelli, R F; Navarro, M F

2001-01-01

390

Low-Temperature Tensile Properties of Polyethylene Terephthalate Multifiber Yarn and Polystyrene Foam.  

National Technical Information Service (NTIS)

The low temperature tensile properties of polyethylene terephthalate multifiber yarn and polystyrene foam, manufactured by a new process, were determined. The polyethylene terephthalate multifiber yarn was limited to 220 denier size. Two different foam de...

R. P. Reed R. L. Durcholz J. M. Arvidson

1971-01-01

391

Space environmental effects on graphite-epoxy compressive properties and epoxy tensile properties  

NASA Technical Reports Server (NTRS)

This study characterizes the effects of electron radiation and temperature on a graphite-epoxy composite material. Compressive properties of the T300/934 material system were obtained at -250 F (-157 C), room temperature, and 250 F (121 C). Tensile specimens of the Fiberite 934 epoxy resin were fabricated and tested at room temperature and 250 F (121 C). Testing was conducted in the baseline (nonirradiated) and irradiated conditions. The radiation exposure was designed to simulate 30 year, worst-case exposure in geosynchronous Earth orbit. Mechanical properties tended to degrade at elevated temperature and improve at cryogenic temperature. Irradiation generally degraded properties at all temperatures.

Fox, Derek J.; Sykes, George F., Jr.; Herakovich, Carl T.

1987-01-01

392

Influence of Specimen Preparation and Specimen Size on Composite Transverse Tensile Strength and Scatter  

NASA Technical Reports Server (NTRS)

The influence of specimen polishing, configuration, and size on the transverse tension strength of two glass-epoxy materials, and one carbon-epoxy material, loaded in three and four point bending was evaluated. Polishing machined edges, arid/or tension side failure surfaces, was detrimental to specimen strength characterization instead of yielding a higher, more accurate, strength as a result of removing inherent manufacture and handling flaws. Transverse tension strength was typically lower for longer span lengths due to the classical weakest link effect. However, strength was less sensitive to volume changes achieved by increasing specimen width. The Weibull scaling law typically over-predicted changes in transverse tension strengths in three point bend tests and under-predicted changes in transverse tension strengths in four point bend tests. Furthermore, the Weibull slope varied with specimen configuration, volume, and sample size. Hence, this scaling law was not adequate for predicting transverse tension strength of heterogeneous, fiber-reinforced, polymer matrix composites.

OBrien, T. Kevin; Chawan, Arun D.; DeMarco, Kevin; Paris, Isabelle

2001-01-01

393

Effects of cross-sectional area on resin-enamel tensile bond strength  

Microsoft Academic Search

Objective.It was hypothesized that there is an inverse relationship between resin-enamel bond strength and bonded cross-sectional area, and that there are regional differences in resin-enamel bond strength.

Yasuo Shono; Masamichi Terashital; Edna L. Pashley; Phyllis D. Brewer; David H. Pashley

1997-01-01

394

Tensile property of H13 die steel with convex-shaped biomimetic surface  

Microsoft Academic Search

The H13 steel specimens with non-smooth surface were fabricated by biomimetic method and laser technique, and the effect of these biomimetic surfaces on the tensile properties was investigated. The results indicated that the biomimetic surface has an advantageous effect on improving the tensile properties of H13 steel. As the area ratio occupied by non-smooth units on the biomimetic surface grows

Z. H. Zhang; H. Zhou; L. Q. Ren; X. Tong; H. Y. Shan; Y. Cao

2007-01-01

395

Microstructure and tensile properties of Inconel 718 pulsed Nd-YAG laser welds  

Microsoft Academic Search

Pulsed Nd-YAG laser welding characteristics of Inconel 718 sheet material (2mm thick) were investigated. Welds were subjected to three different post-weld heat treatments: direct aging, 980°C solution treatment+aging (980STA), and 1080°C solution treatment+aging (1080STA). Weld microstructures and room temperature tensile properties were evaluated. Weld tensile properties in direct aged condition were found to be inferior in relation to the base

G. D. Janaki Ram; A. Venugopal Reddy; K. Prasad Rao; G. M. Reddy; J. K. Sarin Sundar

2005-01-01

396

Effects of Mo, Cr, and V Additions on Tensile and Charpy Impact Properties of API X80 Pipeline Steels  

NASA Astrophysics Data System (ADS)

In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.

Han, Seung Youb; Shin, Sang Yong; Seo, Chang-Hyo; Lee, Hakcheol; Bae, Jin-Ho; Kim, Kisoo; Lee, Sunghak; Kim, Nack J.

2009-08-01

397

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

NASA Technical Reports Server (NTRS)

A study was made to determine the relevance of impacter shape to nonvisible damage and tensile residual strength of a 36 mm thick graphite/epoxy motor case. The shapes of the impacters were as follows: 12.7 mm and 25.4 mm diameter hemispheres, a sharp corner, and a 6.3 mm 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 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 and 25.4 mm 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.

Poe, Clarence C., Jr.

1991-01-01

398

Studies of Microtexture and Its Effect on Tensile and High-Cycle Fatigue Properties of Laser-Powder-Deposited INCONEL 718  

NASA Astrophysics Data System (ADS)

The current work studies the microstructure, texture, and mechanical properties of INCONEL 718 alloy (IN718) produced by laser direct metal deposition. The grain microstructure exhibits an alternative distribution of banded fine and coarse grain zones as a result of the rastering scanning pattern. The effects of the anisotropic crystallographic texture on the tensile and high-cycle fatigue (HCF) properties at room temperature are investigated. Tensile test results showed that the tensile strength of laser-deposited IN718 after direct aging or solution heat treatment is equivalent to the minimum-forged IN718 properties. The transverse direction (relative to the laser scanning direction) produces >10 pct stiffer modulus of elasticity but 3 to 6 pct less tensile strength compared to the longitudinal direction due to the preferential alignment of grains having <111> and <100> directions parallel to the tensile loading direction. Laser-deposited IN718 with good metallurgical integrity showed equivalent HCF properties compared to the direct-aged wrought IN718, which can be attributed to the banded grain size variation and cyclic change of inclining grain orientations resulted from alternating rastering deposition path.

Qi, Huan; Azer, Magdi; Deal, Andrew

2012-11-01

399

Friction Stir Welded AZ31 Magnesium Alloy: Microstructure, Texture, and Tensile Properties  

NASA Astrophysics Data System (ADS)

This study was aimed at characterizing the microstructure, texture and tensile properties of a friction stir welded AZ31B-H24 Mg alloy with varying tool rotational rates and welding speeds. Friction stir welding (FSW) resulted in the presence of recrystallized grains and the relevant drop in hardness in the stir zone (SZ). The base alloy contained a strong crystallographic texture with basal planes (0002) largely parallel to the rolling sheet surface and < {11bar{2}0} rangle directions aligned in the rolling direction (RD). After FSW the basal planes in the SZ were slightly tilted toward the TD determined from the sheet normal direction (or top surface) and also slightly inclined toward the RD determined from the transverse direction (or cross section) due to the intense shear plastic flow near the pin surface. The prismatic planes (10bar{1}0) and pyramidal planes (10bar{1}1) formed fiber textures. After FSW both the strength and ductility of the AZ31B-H24 Mg alloy decreased with a joint efficiency in-between about 75 and 82 pct due to the changes in both grain structure and texture, which also weakened the strain rate dependence of tensile properties. The welding speed and rotational rate exhibited a stronger effect on the YS than the UTS. Despite the lower ductility, strain-hardening exponent and hardening capacity, a higher YS was obtained at a higher welding speed and lower rotational rate mainly due to the smaller recrystallized grains in the SZ arising from the lower heat input.

Chowdhury, S. H.; Chen, D. L.; Bhole, S. D.; Cao, X.; Wanjara, P.

2013-01-01

400

Compatibilization by homopolymer: significant improvements in the modulus and tensile strength of PPC/PMMA blends by the addition of a small amount of PVAc.  

PubMed

Poly(propylene carbonate) (PPC), a polymer produced from CO2, has been melt-mixed with 30 wt % poly(methyl methacrylate) (PMMA) with the aim of enhancing the physical properties of PPC for practical use but keeping a relatively high CO2 fixing rate in the compound. The observation of a coarse phase structure with a large PMMA domain size and a large size distribution in the blend indicates the immiscibility between PPC and PMMA. The addition of a small amount of poly(vinyl acetate) (PVAc) not only shifts the glass transition temperatures (T(g)'s) of both PPC and PMMA markedly but also significantly increases the modulus and tensile strength of the blend. The prepared compound with 5 per hundred parts of resin PVAc shows a 26 times higher elastic modulus and an approximately 3.8 times higher tensile strength than pure PPC at room temperature. The morphological investigation indicates that the incorporation to PVAC not only induces the finer dispersion of PMMA in the PPC matrix but also results in the phase transformation from a sea-island to a co-continuous structure. PMID:20355779

Li, Yongjin; Shimizu, Hiroshi

2009-08-01

401

Elevated Temperature Tensile and Creep Properties of M-252 (Bar), Inconel 700 (Bar), and Inconel 713 (Cast) Nickel Base Alloys.  

National Technical Information Service (NTIS)

Room and elevated temperature tensile and elevated temperature creep properties to 1000 hours were determined at three representative application temperatures for M-252 (bar), Inconel 700 (bar), and Inconel 713 (cast). Tabulated tensile and creep data, de...

S. O. Davis

1964-01-01

402

Tensile and fatigue properties of two titanium alloys as candidate materials for fusion reactors  

NASA Astrophysics Data System (ADS)

Titanium alloys have been identified as candidate structural materials for the first wall, the blanket and the magnetic coil structures of fusion reactors. Titanium alloys are interesting materials because of their high specific strength and low elastic modulus, their low swelling tendency and their fast induced radioactivity decay. Other attractive properties are an excellent resistance to corrosion and good weldability, even in thick sections. Furthermore titanium alloys are suitable for components exposed to heat loads since they have a low thermal stress parameter. Titanium alloys with an ? structure are believed to have a good resistance against radiation embrittlement and ?+? alloys should possess the best tolerance to hydrogen embrittlement. Two classical industrially available alloys in the two families, the Ti5Al2.4Sn and the Ti6Al4V alloys have been used in this study. The tensile properties between room temperature and 450°C are reported. A low cycle fatigue analysis has been performed under strain control at total strain ranges between 0.8% and 2% and at a temperature of 350°C. The microstructure of both alloys was investigated before and after both types of deformation. Both alloys exhibit excellent mechanical properties comparable to or better than those of ferritic martensitic steels.

Marmy, P.; Leguey, T.; Belianov, I.; Victoria, M.

2000-12-01

403

The effects of damage accumulation on the tensile strength and toughness of compact bovine bone.  

PubMed

Damage accumulation in compact bovine femur subjected to uniaxial tensile loading was examined by strong light illumination effects of microcracking. Imaging was done using a high-speed camera capturing image at 200 to 1500FPS. The tensile tests were performed in a multipurpose tensile testing system with cross-head speeds ranging from 0.5 to 10mm/min which leads to strain rates of 0.0001 to 0.0012s(-1) (physiologically relevant to walking and running Hansen et al., 2008). The post-failure images were then examined in a scanning electron microscopy (SEM) and effects of microstructure, strain rate, and orientation were evaluated. Correlation of the high-speed images with stress-strain curves indicated that optically visible microcracks were most likely initiated at yielding, and the specimens with dispersed microcracks exhibited a higher energy-absorption capacity compared to the specimens with coalesced local cracks. It was found that damage accumulation negatively correlates to strain rate and that transverse specimens exhibited a different failure pattern compared to the longitudinal specimens. Strain hardening and softening were found in the longitudinal and transverse specimens respectively. The microcracking in the transverse specimens instantly increased to peak after yielding compared to the gradual growth until failure in the longitudinal specimens. The average Young's modulus (21.5GPa) and ultimate stress (93.5MPa) of the specimens loaded in the longitudinal direction were more than twice that of the specimens (10.9GPa and 36.2MPa respectively) loaded in the transverse direction. The current technique has shown potential in relating damage accumulation real time in bone samples subjected to tensile loading condition. This information will be helpful in relating the role of micro damage accumulation in initiating failure and/or remodeling in bone. PMID:23337851

Zhang, Wei; Tekalur, Srinivasan Arjun; Baumann, Melissa; McCabe, Laura R

2013-03-15

404

Influence of excessive filler coating on the tensile properties of LDPE–calcium carbonate composites  

Microsoft Academic Search

Calcium carbonate fillers are usually coated with stearic acid to reduce their surface energy and improve their dispersion in polymers. Commercial products are often over-coated and contain an excess of surfactant. It was found that stearic acid linearly increases the modulus and yield stress of LDPE but reduces its tensile strength, yield strain, and ultimate elongation. The influence of surfactant

Maged A. Osman; Ayman Atallah; Ulrich W. Suter

2004-01-01

405

Tensile and Stress-Rupture Properties of Rolled Pb-Cd-Sb Alloys.  

National Technical Information Service (NTIS)

In a Bureau of Mines investigation to develop lead alloys with improved tensile strength and creep resistance, lead-base alloys containing cadmium and antimony in nominal 1-to-1 atomic ratios were melted in air, cast, and rolled into sheet to 90 percent r...

M. M. Tilman

1969-01-01

406

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

Microsoft Academic Search

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

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

2007-01-01

407

Tensile properties of thin Au-Ni brazes between strong base materials  

Microsoft Academic Search

It has long been known that when relatively strong base materials are joined by thin, soft, interlayer metals such as with brazing or various solid state joining processes, the ultimate tensile strength (UTS) of the bond may be several factors higher than the UTS of the bulk, or unconstrained, interlayer metals. However, earlier work reported by the authors confirmed that

M. C. Tolle; M. E. Kassner

1991-01-01

408

On the tensile strength of rivets in thin sheet materials and fibre metal laminates  

Microsoft Academic Search

The low pull-through strength of mechanically fastened joints in composites is well known. The failure mode is frequently by the fastener head pulling through the laminate. Because experimental studies on multi-row joints in fibre metal laminates (ARALL and GLARE) have demonstrated a significant rivet strength reduction due to a similar failure mode, the problem assumes new importance. A pull-through strength

W. J. Slagter

1995-01-01

409

Tensile strength of the cement-bone interface depends on the amount of bone interdigitated with PMMA cement  

Microsoft Academic Search

An experimental investigation was performed to (1) determine the general mechanical behavior and in particular, the post-yield behavior of the cement-bone interface under tensile loading, (2) determine where interface failure occurs, and (3) determine if the mechanical properties of the interface could be related to the density of bone at the interface and\\/or the amount of cement-bone interdigitation. Seventy-one cement-bone

K. A. Mann; D. C. Ayers; F. W. Werner; R. J. Nicoletta; M. D. Fortino

1997-01-01

410

Apparatus for measuring tensile and compressive properties of solid materials at cryogenic temperatures  

DOEpatents

An apparatus for evaluating the tensile and compressive properties of material samples at very low or cryogenic temperatures employs a stationary frame and a dewar mounted below the frame. A pair of coaxial cylindrical tubes extend downward towards the bottom of the dewar. A compressive or tensile load is generated hydraulically and is transmitted by the inner tube to the material sample. The material sample is located near the bottom of the dewar in a liquid refrigerant bath. The apparatus employs a displacement measuring device, such as a linear variable differential transformer, to measure the deformation of the material sample relative to the amount of compressive or tensile force applied to the sample.

Gonczy, John D. (Oaklawn, IL); Markley, Finley W. (St. Charles, IL); McCaw, William R. (Burr Ridge, IL); Niemann, Ralph C. (Downers Grove, IL)

1992-01-01

411

Tensile Properties of Poly (N-vinyl caprolactam) Gels  

NASA Technical Reports Server (NTRS)

N-vinyl caprolactam was copolymerized with ethylene glycol dimethacrylate using a free-radical initiator in alcohol/water solution. The resulting gels were thermally-responsive in water, undergoing an approximate fivefold reversible volume shrinkage between room temperature and ca. 50 C. Tensile testing showed that the stress-strain behavior was qualitatively different in the collapsed state above the temperature-induced transition. At the higher temperature, gels were stiffer, more ductile, and showed greater time dependence. Implications for the design of gel actuators are briefly discussed.

Morgret, Leslie D.; Hinkley, Jeffrey A.

2004-01-01

412

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

PubMed Central

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.

2014-01-01

413

Influence of core-finishing intervals on tensile strength of cast posts-and-cores luted with zinc phosphate cement.  

PubMed

The core finishing of cast posts-and-cores after luting is routine in dental practice. However, the effects of the vibrations produced by the rotary cutting instruments over the luting cements are not well-documented. This study evaluated the influence of the time intervals that elapsed between the cementation and the core-finishing procedures on the tensile strength of cast posts-and-cores luted with zinc phosphate cement. Forty-eight bovine incisor roots were selected, endodontically treated, and divided into four groups (n = 12): GA, control (without finishing); GB, GC, and GD, subjected to finishing at 20 minutes, 60 minutes, and 24 hours after cementation, respectively. Root canals were molded, and the resin patterns were cast in copper-aluminum alloy. Cast posts-and-cores were luted with zinc phosphate cement, and the core-finishing procedures were applied according to the groups. The tensile tests were performed at a crosshead speed of 0.5 mm/min for all groups, 24 hours after the core-finishing procedures. The data were subjected to one-way analysis of variance (ANOVA) and Tukey's test (? = 0.05). No significant differences were observed in the tensile strengths between the control and experimental groups, regardless of the time interval that elapsed between the luting and finishing steps. Within the limitations of the present study, it was demonstrated that the core-finishing procedures and time intervals that elapsed after luting did not appear to affect the retention of cast posts-and-cores when zinc phosphate cement was used. PMID:22790502

Iglesias, Michele Andrea Lopes; Mesquita, Gabriela Campos; Pereira, Analice Giovani; Dantas, Lucas Costa de Medeiros; Raposo, Luís Henrique Araújo; Soares, Carlos José; Mota, Adérito Soares da

2012-01-01

414

Waiting time for coronal preparation and the influence of different cements on tensile strength of metal posts.  

PubMed

This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16?mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP) cement or resin cement (RC), the specimens were divided into 3 groups (n = 10) according to the waiting time for core preparation: no preparation (control), 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5?mm/min) until failure. Two-way ANOVA (time versus cement) and the Tukey tests (P < 0.05) showed significantly higher (P < 0.05) tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation. PMID:22291705

Oliveira, Ilione Kruschewsky Costa Sousa; Arsati, Ynara Bosco de Oliveira Lima; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes

2012-01-01

415

Waiting Time for Coronal Preparation and the Influence of Different Cements on Tensile Strength of Metal Posts  

PubMed Central

This study aimed to assess the effect of post-cementation waiting time for core preparation of cemented cast posts and cores had on retention in the root canal, using two different luting materials. Sixty extracted human canines were sectioned 16?mm from the root apex. After cast nickel-chromium metal posts and cores were fabricated and luted with zinc phosphate (ZP) cement or resin cement (RC), the specimens were divided into 3 groups (n = 10) according to the waiting time for core preparation: no preparation (control), 15 minutes, or 1 week after the core cementation. At the appropriate time, the specimens were subjected to a tensile load test (0.5?mm/min) until failure. Two-way ANOVA (time versus cement) and the Tukey tests (P < 0.05) showed significantly higher (P < 0.05) tensile strength values for the ZP cement groups than for the RC groups. Core preparation and post-cementation waiting time for core recontouring did not influence the retention strength. ZP was the best material for intraradicular metal post cementation.

Oliveira, Ilione Kruschewsky Costa Sousa; Arsati, Ynara Bosco de Oliveira Lima; Basting, Roberta Tarkany; Franca, Fabiana Mantovani Gomes

2012-01-01

416

The tensile and thermal properties of modified CNT-reinforced basalt\\/epoxy composites  

Microsoft Academic Search

In this study, the effect of carbon nanotube (CNT) modification on the tensile and thermal properties of CNT\\/basalt\\/epoxy composites was investigated. CNT\\/basalt\\/epoxy composites were fabricated by impregnating woven basalt fibers into epoxy resin mixed with CNTs. Three groups of composites were fabricated, consisting of unmodified, acid-modified (oxidized), and silane-modified (silanized) CNTs, each at 1wt.%. Tensile tests and dynamic mechanical analysis

J. H. Lee; K. Y. Rhee; S. J. Park

2010-01-01

417

Effect of Iodine on Fatigue Properties of Zircaloy2 Fuel Cladding under Cyclic Tensile Stress  

Microsoft Academic Search

Effects of iodine on the cyclic tensile properties of Zircaloy-2 have been investigated at 350°C. Notched specimens, which were grooved circumferentially, and unnotched specimens were machined from the stress-relieved fuel cladding. Cyclic tensile stress was loaded on the specimens in order to get the fatigue life and failure ductility in air and in an Ar atmosphere containing iodine.The fatigue life

Masafumi NAKATSUKA; Yo HAYASHI

1981-01-01

418

Temperature effects on the tensile properties of cast and heat treated aluminum alloy A319  

Microsoft Academic Search

In this work, the tensile properties and ductility of an Al-A319 alloy were investigated as a function of temperature and heat treatment. Tensile testing was carried out at temperatures ranging from ?90 to 400°C for the alloy in (a) the as-cast condition, (b) after solid solution at 485°C (T4) and (c) after solid solution followed by ageing at 230°C (T7).

E. Rincon; H. F. Lopez; M. M. Cisneros; H. Mancha

2009-01-01

419

Casting defects and the tensile properties of an Al Si Mg alloy  

Microsoft Academic Search

Samples containing either entrapped dross and oxide films, gas porosity or small drilled holes have been used to study the effect of different types of defects on the tensile behaviour of an Al7Si0.4Mg casting alloy. The tensile properties show little or no correlation with the bulk porosity content, especially in the case of samples containing dross and oxide films. In

C. H. Cáceres; B. I. Selling

1996-01-01

420

Effect of cyclic loading on tensile properties of PC and PC\\/ABS  

Microsoft Academic Search

The effects of cyclic loading on tensile fracture properties of polycarbonate (PC) and the alloy of polycarbonate and acrylonitrile–butadiene–styrene (PC\\/ABS) are experimentally investigated in the paper. Two digital cameras are used to record simultaneously the tensile deformation of specimens and the large deformation and the necking process of these polymers are discussed. Two lateral contractions are not identical at the

Qin-Zhi Fang; T. J. Wang; H. G. Beom; H. M. Li

2008-01-01

421

Microstructural dependence of fracture energy and toughness of ceramics and ceramic composites versus that of their tensile strengths at 22 °C  

Microsoft Academic Search

The microstructural dependence of fracture energy and toughness of ceramics and ceramic particulate, platelet, and whisker composites is compared with the corresponding dependence of their tensile (flexure) strengths at 22 °C. These comparisons show that fracture energy and toughness often do not have the same porosity, or grainor particle-size dependence as strength. This is attributed to the scale of the

R. W. Rice

1996-01-01

422

Tensile strength at elevated temperature and its applicability as an accelerated testing methodology for unidirectional composites  

NASA Astrophysics Data System (ADS)

The applicability of a macroscopic time-temperature superposition principle (TTSP) to unidirectional composite strength is discussed based on the microscopic Simultaneous Fiber-Failure (SFF) model that has been presented by Koyanagi et al. (J. Compos. Mater. 43:1901-1914, 2009a). The SFF model estimates composite strengths as functions of fiber, matrix, and interface strengths. This paper first investigates the applicability of SFF to the complicated temperature dependence of composite strengths, i.e., one composite exhibits significant temperature dependence and another does not, considering the temperature dependence of the components, which results in successful estimations for the two composite systems used in the present study. The long-term durability predicted by the SFF and that predicted by the TTSP are then compared. They typically correspond to each other in various cases; accelerated testing methodology (ATM) employing TTSP is thus proved to be valid from the micromechanical viewpoint, assuming the SFF applicability.

Koyanagi, Jun; Nakada, Masayuki; Miyano, Yasushi

2012-02-01

423

Effects of environment and temperature on ceramic tensile strength–grain size relations  

Microsoft Academic Search

Overall strength (s)–grain size (G), i.e. s–G-1\\/2, relations retain the same basic two-branched character to at least 1200–1300°C. However, some polycrystalline as well as single crystal strength shifts or deviations are seen relative to each other, and especially relative to Young's moduli versus temperature for poly- and single crystals. The variety and complexity of these deviations are illustrated mainly by

R. W. RICE

1997-01-01

424

Tensile properties and transition behaviour of RAFM steel plate and welds irradiated up to 10 dpa at 300 °C  

NASA Astrophysics Data System (ADS)

Reduced activation ferritic/martensitic (RAFM) steels have been irradiated in a large irradiation campaign in the high flux reactor at a target temperature of 300 °C up to target dose levels of 2.5, 5, and 10 dpa. Tensile and impact properties have been determined of RAFM plate, tungsten inert gas (TIG) welds and Electron beam (EB) welds. The dose level dependence of both properties is evaluated. In addition, impact properties of F82H powder hot isostatic pressing after 2.5 dpa and transition fracture toughness of F82H-mod. plate after 5 dpa have been measured. The tensile properties at irradiation temperature of F82H-mod. plate and welds show an increase in yield and ultimate strength up to about 5 dpa, after which saturation seems to set in. The elongation data show evidence of increasing localisation of deformation at higher doses. Impact properties of untempered EB welds and not sufficiently tempered NF616 show the need for good tempering treatment. Impact properties of various zones of irradiated TIG welds further illustrate the influence of the microstructural state of 8-9Cr steels on the irradiation response.

Rensman, J.; van Hoepen, J.; Bakker, J. B. M.; den Boef, R.; van den Broek, F. P.; van Essen, E. D. L.

2002-12-01

425

Stress Analysis and Strength Evaluation of Scarf Adhesive Joints with Dissimilar Adherends Subjected to Static Tensile Loadings  

NASA Astrophysics Data System (ADS)

The interface stress distributions in scarf adhesive joints with dissimilar adherends under static tensile loadings are analyzed using two-dimensional and three-dimensional finite element calculations. The effects of the adherends and adhesive Young's modulus, the scarf angle and the adhesive thickness on the interface stress distributions are examined. In addition, the joint strength is predicted using the interface stress distributions based on the maximum principal stress theory. It is found that when the scarf angle is around 60°, the singular stress at the edges of the interfaces is minimum in the 3-Dimensional FEM calculations. Furthermore, it is noticed that the strength of the joints with dissimilar adherends is smaller than that of the joints with similar adherends. For verification of the FEM calculations, the strains in the adherends and the joint strengths were measured in the experiments. The measured strains are in fairly good agreement with those obtained from FEM calculations. Also, the measured joint strength is fairly consistent with the calculated results.

He, Dan; Sawa, Toshiyuki; Karami, Atsushi

426

Tensile properties influencing variables in eutectic Al-Si casting alloys  

SciTech Connect

Efforts to identify and characterize the physical properties of aluminum castings alloys are envisaged to lead to a new guideline from which the mechanical behavior of these alloys can be accurately predicted. For aluminum-silicon (Al-Si) casting alloys the tensile properties of a specific composition are observed to vary depending on the production parameters. The difference in the tensile properties appears to be mainly due to the microstructural features concomitant with the imposed production parameters. The present study aims to identify, quantitatively, the tensile properties influencing variables in high purity eutectic Al-Si casting alloy produced under a variety of solidification cooling rate with different strontium (Sr) additions, as a modifying agent. The correlation between the fracture characteristics and the microstructures has also been investigated.

Hafiz, M.F. (Al-Azhar Univ., Cairo (Egypt). Dept. of Mechanical Engineering); Kobayashi, Toshiro (Toyohashi Univ. of Technology, Aichi (Japan). Dept. of Production Systems Engineering)

1994-09-15

427

Shear strength properties of wet granular materials  

Microsoft Academic Search

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

Vincent Richefeu; Moulay Saïd El Youssoufi; Farhang Radjaï

2006-01-01

428

Hot strength properties of filamentary nickel alloys  

Microsoft Academic Search

The results of an investigation of the hot strength properties of several nickel- and cobalt-based alloys are given. These materials, having as minor constituents such elements as aluminum, tungsten, chromium, etc., were chosen for their possibilities as efficient primary electron emitters (when coated with alkaline earth oxides). The diameters of these filaments were all 0.001 inch or less. The general

B. Wolk

1958-01-01

429

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

NASA Technical Reports Server (NTRS)

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.

Poe, C. C., Jr.

1990-01-01

430

Microstructure and tensile properties of Fe-40 at. pct Al alloys with C, Zr, Hf, and B additions  

NASA Technical Reports Server (NTRS)

The influence of small additions of C, Zr, and Hf, alone or in combination with B, on the microstructure and tensile behavior of substoichiometric FeAl was investigated. Tensile properties were determined from 300 to 1100 K on powder which was consolidated by hot extrusion. All materials possessed some ductility at room temperature, although ternary additions generally reduced ductility compared to the binary alloy. Adding B to the C- and Zr-containing alloys changed the fracture mode from intergranular to transgranular and restored the ductility to approximately 5 percent elongation. Additions of Zr and Hf increased strength up to about 900 K. Fe6Al6Zr and Fe6Al6Hf precipitates, both with identical body-centered tetragonal structures, were identified as the principal second phase in these alloys. Strength decreased steadily as temperature increased above 700 K, as diffusion-assisted mechanisms became operative. Although all alloys had similar strengths at 1100 K, Hf additions significantly improved high-temperature ductility by suppressing cavitation.

Gaydosh, D. J.; Draper, S. L.; Nathal, M. V.

1989-01-01

431

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

NASA Technical Reports Server (NTRS)

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.

Dreshfield, R. L.; Johnson, W.

1982-01-01

432

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

PubMed

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

Rubo, J H; Pegoraro, L F

1995-09-01

433

Assessing microstructural changes in alloy 625 using ultrasonic waves and correlation with tensile properties  

Microsoft Academic Search

Alloy 625 was aged at various temperatures in the range 923–1123 K to produce different microstructures. Ultrasonic velocity was measured to characterise the microstructures. Tensile properties and hardness were determined using ball indentation technique. A direct correlation has been observed between ultrasonic velocity and mechanical properties.

P. Palanichamy; M. D. Mathew; S. Latha; T. Jayakumar; K. Bhanu Sankara Rao; S. L. Mannan; Baldev Raj

2001-01-01

434

Tensile mechanical properties of bovine articular cartilage: variations with growth and relationships to collagen network components  

Microsoft Academic Search

One approach to repairing articular defects is to regenerate cartilage by recapitulating the changes that occur during fetal and postnatal growth into adulthood, and to thereby restore functional biomechanical properties, especially those of the normally strong superficial region. The objectives of this study were (1) to characterize and compare tensile biomechanical properties of the superficial region of articular cartilage of

Amanda K. Williamson; Albert C. Chen; Koichi Masuda; Eugene J.-M. A. Thonar; Robert L. Sah

2003-01-01

435

Residual strength of composite laminates subjected to tensile-compressive fatigue loading  

NASA Technical Reports Server (NTRS)

Results are presented on the measurements of the residual strengths of T300/934 graphite epoxy laminates, in tension and in compression, after the samples were exposed to tension-compression fatigue loading (R = -1). Four laminate ocnfigurations were tested: unidirectional, cross-ply, angle-ply, and quasi-isotropic. It was found that the fatigue behavior of laminates was dependent on the quasi-static strengths and the specific structure of the laminate. No direct correlation was found between remaining residual strengths and the percentage of average fatigue life. However, a correlation scheme was developed for the individual specimen under test, based on a cumulative damage model and a stiffness change of the material.

Rotem, Assa; Nelson, H. G.

1990-01-01

436

Elastic properties and fracture strength of quasi-isotropic graphite/epoxy composites  

NASA Technical Reports Server (NTRS)

A research program is described which was devised to determine experimentally the elastic properties in tension and bending of quasi-isotropic laminates made from high-modulus graphite fiber and epoxy. Four laminate configurations were investigated, and determinations were made of the tensile modulus, Poisson's ratio, bending stiffness, fracture strength, and fracture strain. The measured properties are compared with those predicted by laminate theory, reasons for scatter in the experimental data are discussed, and the effect of fiber misalignment on predicted elastic tensile properties is examined. The results strongly suggest that fiber misalignment in combination with variation in fiber volume content is responsible for the scatter in both elastic constants and fracture strength.

Sullivan, T. L.

1977-01-01

437

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

NASA Technical Reports Server (NTRS)

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.

Poe, C. C., Jr.

1984-01-01

438

Deformation and fracture behavior of notched and unnotched unidirectional C\\/CMg composite with Young's modulus 520 GPa and tensile strength 1 GPa  

Microsoft Academic Search

Experimental study on tensile fracture behavior of the newly developed C\\/C-Mg composite, prepared by infiltration of Mg into the pores in the C\\/C composite heat-treated at 3000°C, was carried out. The volume fraction of the filled Mg was 9–10%. The composite had a specific density 2.1, Young's modulus 520 GPa and Poisson's ratio 0.26. The average tensile strength measured for

S. Ochiai; H. Okuda; N. Suzuki; M. Tanaka; M. Hojo; E. Tsushima

2003-01-01

439

Simplified method measures changes in tensile yield strength using least number of specimens  

NASA Technical Reports Server (NTRS)

Simplified method determines yield strength due to heat treat, irradiation or mechanical treatment. Each specimen in a group of specimens is tested for yield stress point, subjected to heat treat or irradiation, and retested for new yield stress point which is a measure of change in material.

Dixon, C. E.