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1

Tensile strength and fracture energy of pressed metal powder by diametral compression test  

Microsoft Academic Search

A critical property in the metal powder pressing process is the strength of the green body. Diametral compression test or the Brazilian disc test is one method to characterise green tensile strength. Pre-alloyed water atomised iron powder has been pressed into discs with different densities. The characteristics of the fracture development and load response are studied in detail. Crack initiation

P. Jonsén; H.-Å. Häggblad; K. Sommer

2007-01-01

2

Measurement of the Tensile Strength of Dental Restorative Materials by Use of a Diametral Compression Test  

Microsoft Academic Search

The effect of specimen size on tensile strength of restorative materials by use of the disk diametral compression test was evaluated. The results indicate that a miniature specimen can be used to give values and ranking for materials that agree with subjective practical experience.

P. D. Williams; D. C. Smith

1971-01-01

3

Comparision of diametral tensile strength of microwave and oven-dried investment materials  

Microsoft Academic Search

Statement of problem. Microwave drying technique for investment materials is believed to be timesaving by accelerating the elimination of free water content. Purpose. This study compared the diametral tensile strength of 4 investment materials used in removable partial denture framework fabrication. The investment materials were subjected to microwave and conventional oven drying at different time intervals. Material and methods. Type

?enay Canay; Nur Hersek; Yalēin Ēiftēi; Kivanē Akēa

1999-01-01

4

Evaluation of flexural, diametral tensile, and shear bond strength of composite repairs.  

PubMed

SUMMARY Objective : Repairing composite restorations may be a more conservative treatment than replacing the entire restoration. The objective of this in vitro study was to determine the best repair method by measuring flexural, diametral tensile, and shear bond strength of repaired composites in which the surfaces were treated with chemical primers (Add & Bond or Silane Bond Enhancer), a bonding agent (Optibond Solo Plus [OBSP]), or mechanical retention with a bonding agent. Methods : Filtek Supreme Ultra shade B1B was placed in special molds to fabricate specimens that served to test the flexural, diametral tensile, or shear strength of the inherent resin substrate. The same molds were modified to make specimens for testing repair strength of the resin. Repairs were made immediately or after aging in deionized water at 37°C for seven days. All repair sites were finished with coarse Sof-Lex discs to simulate finishing new restorations or partially removing aged restorations. Repair surfaces were treated with one of the following: 1) phosphoric-acid etching and OBSP; 2) Add & Bond; 3) phosphoric-acid etching, Silane Bond Enhancer, and OBSP; or 4) quarter round bur, phosphoric-acid etching, and OBSP. Specimens were placed back in the original molds to fabricate specimens for diametral tensile or flexural testing or in an Ultradent jig to make specimens for shear bond testing. Composite resin in shade B5B was polymerized against the treated surfaces to make repairs. Two negative control groups for the three testing methods consisted of specimens in which repairs were made immediately or after aging without any surface treatments. Controls and experimental repairs were aged (water 37°C, 24 hours) before flexural, diametral tensile, or shear testing in an Instron Universal testing machine at a crosshead speed of 0.5 mm/min. Results : Experimental flexural repair strengths ranged from 26.4% to 88.6% of the inherent substrate strength. Diametral tensile repair strengths ranged from 40% to 80% of the inherent substrate strength, and shear bond strength repairs ranged from 56% to 102%. Geometric means were statistically analyzed with two-way analysis of variance on their log-transformed values. Significant differences were determined using Tukey honestly significant difference (p<0.05). Conclusions : Depending on the mechanical property being tested, surface treatments produced different results. OBSP produced more consistent results than chemical primers. PMID:25084105

Imbery, Ta; Gray, T; DeLatour, F; Boxx, C; Best, Am; Moon, Pc

2014-01-01

5

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. PMID:22437672

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

2012-01-01

6

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

7

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

PubMed Central

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

FONSECA, Rodrigo Borges; BRANCO, Carolina Assaf; QUAGLIATTO, Paulo Sergio; GONCALVES, Luciano de Souza; SOARES, Carlos Jose; CARLO, Hugo Lemes; CORRER-SOBRINHO, Lourenco

2010-01-01

8

A new method for the measurement of the tensile strength of rice grains by using the diametral compression test  

Microsoft Academic Search

Breakage of rice grains during milling can be attributed to the presence of fissures, caused by stresses related to shrinkage during drying. These fissures are usually caused by a tensile failure in the center of the grain. Very few data of the tensile strength of rice grains have been published, which is related to experimental difficulties. An attractive method for

G. F. Kamst; J. Vasseur; C. Bonazzi; J. J. Bimbenet

1999-01-01

9

Diametral and compressive strength of dental core materials  

Microsoft Academic Search

Statement of problem. Strength greatly influences the selection of core materials. Many disparate material types are now recommended for use as cores. Cores must withstand forces due to mastication and parafunction for many years. Purpose. This study compared the compressive and diametral tensile strengths of 8 core materials of various material classes and formulations (light-cured hybrid composite, autocured titanium containing

George C. Cho; Leslie M. Kaneko; Terence E. Donovan; Shane N. White

1999-01-01

10

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

11

7 CFR 29.3061 - Strength (tensile).  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 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...

2011-01-01

12

7 CFR 29.3061 - Strength (tensile).  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 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...

2013-01-01

13

7 CFR 29.3061 - Strength (tensile).  

... 2014-01-01 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...

2014-01-01

14

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

15

7 CFR 29.3061 - Strength (tensile).  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 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...

2012-01-01

16

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

17

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

18

Tensile strength of type IV dental stones dried in a microwave oven  

Microsoft Academic Search

Statement of Problem. It is known that drying dental stones in a microwave oven can save time, but the strength of the material may be affected by different drying methods. Purpose. This study evaluated the diametral tensile strength (DTS) of 5 type IV gypsum products at different time intervals using microwave and air-drying methods. Material and Methods. A total of

Nur Hersek; ?enay Canay; Kivanē Akēa; Yalēin Ēiftēi

2002-01-01

19

Note on the use of the diametral compression test for the strength measurement of ceramics  

Microsoft Academic Search

The strength of brittle materials is usually measured by a bend test, but when the material is of tubular form the method is troublesome. An apparently better way to measure the strength in such cases is to test rings cut from the material. The most convenient method of testing the rings is the so-called diametral compression test in which a

1984-01-01

20

High-temperature diametral compression strength of microwave-sintered mullite  

Microsoft Academic Search

The mechanical strength of mullite materials sintered by the conventional route or by microwave was evaluated by diametral compression at room temperature and 1400°C. Crack patterns and fracture mechanisms were analyzed and the results were discussed in terms of the final microstructures. The conventional and microwave sintered materials showed similar densification degrees and homogeneous microstructures with small equiaxial grains. Independent

P. M. Souto; M. A. Camerucci; A. G. Tomba Martinez; R. H. G. A. Kiminami

2011-01-01

21

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

22

The Tensile Strength of Liquid Nitrogen  

Microsoft Academic Search

The tensile strength of liquids has been a puzzling subject. On the one hand, the classical nucleation theory has met great success in predicting the nucleation rates of superheated liquids. On the other hand, most of reported experimental values of the tensile strength for different liquids are far below the prediction from the classical nucleation theory. In this study, homogeneous

Jian Huang

1992-01-01

23

49 CFR 230.26 - Tensile strength of shell plates.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 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...

2011-10-01

24

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

25

49 CFR 230.26 - Tensile strength of shell plates.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 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...

2012-10-01

26

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

27

Analysis of diametral strain in uniaxial tensile and compression testing of round specimens of anisotropic materials  

Microsoft Academic Search

The development of elliptical cross sections in initially round test pieces of anisotropic materials makes it difficult to measure the true strain on a cross section using a transverse extensometer. In this paper, an analysis is given of the diametral strain and strain rate on a round cross section. Based on the experimental observation that static and dynamic microstructural changes

Henry S. Yang; Xiao-Ping S. Su; Bingzhe Bai

2000-01-01

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

Tensile strength of dentin after bleaching treatment.  

PubMed

The mechanical properties of dentin are changed after bleaching, although the effects of the bleaching conditions on the tensile strength of dentin have not been determined. In the current study, a tensile test of bovine dentin was conducted after bleaching and the effects of the bleaching conditions were investigated, including the number of bleaching times, the location where the bleaching agent was applied, and the kind of illumination. The weight of organic content in dentin before and after application of the agent was also measured. The results showed that the tensile strengths did not change after three times office bleaching procedure, and the location where the bleaching agent was applied, the kind of bleaching agent and the kind of illumination did not have influence on the tensile strength. On the other hand, organic component in dentin significantly decreased after application of the agent (p<0.05). Since the bleaching agent would potentially affect tensile strength with deterioration of collagen matrix, the frequency of bleaching treatment should be minimized in clinical use. PMID:19845163

Tamura, Tomohiro; Tonami, Ken-ichi; Takahashi, Hidekazu; Mataki, Shiro; Araki, Kouji; Kurosaki, Norimasa

2008-03-01

36

Loading Rate Effect on the Tensile Failure of Concrete and Its Constituents using Diametrical Compression and Direct Tension  

Microsoft Academic Search

\\u000a The loading rate effect on the tensile failure strength of concrete and its constituent materials has been investigated. Concrete\\u000a is inherently weaker in tension than compression so tensile failure represents the dominant failure mode. Understanding the\\u000a failure characteristics of concrete, particularly at high loading rate, is important for developing modeling capabilities,\\u000a in particular for predicting spallation damage and fragmentation. Several

Samuel Weckert; Tusit Weerasooriya; C. Allan Gunnarson

37

Tensile & shear strength of porous dust agglomerates  

E-print Network

Context.Within the sequential accretion scenario of planet formation, planets are build up through a sequence sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small dust particles to planetesimals. In this work we determine the necessary material properties of dust aggregates as a function the porosity. Aims: Continuum models such as SPH that are capable of simulating collisions of macroscopic dust aggregates require a set of material parameters. Some of them such as the tensile and shear strength are ?difficult to obtain from laboratory experiments. The aim of this work is to determine these parameters from ab-initio molecular dynamics simulations. Methods: We simulate the behavior of porous dust aggregates using a detailed micro-physical model of the interaction of spherical grains that includes adhesion forces, rolling, twisting, and sliding. Using different methods of preparing the samples we study the strength behavior of our samples with varying porosity and coordination number of the material. Results: For the tensile strength, we can reproduce data from laboratory experiments very well. For the shear strength, there are no experimental data available. The results from our simulations differ significantly from previous theoretical models, which indicates that the latter might not be sufficient to describe porous dust aggregates. Conclusions: We have provided functional behavior of tensile and shear strength of porous dust aggregates as a function of the porosity that can be directly applied in continuum simulations of these objects in planet formation scenarios.

Alexander Seizinger; Roland Speith; Wilhelm Kley

2013-08-23

38

Transverse strength of SCS6 silicon carbide fibers  

Microsoft Academic Search

A diametral compression test was used to measure the transverse strength of SCS-6 SiC fibers before and after heat treatment. Subjecting fibers to diametral compression successfully produced transverse tensile failure in the form of fiber cracking along the same diametral plane in which the compressive load was applied. An analysis of the hoop stress along the diametral plane, in which

Jeffrey I. Eldridge; Jonathan P. Wiening; Terry S. Davison; Marek-Jerzy Pindera

1993-01-01

39

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

40

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

41

Tensile & shear strength of porous dust agglomerates  

E-print Network

Context.Within the sequential accretion scenario of planet formation, planets are build up through a sequence sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small dust particles to planetesimals. In this work we determine the necessary material properties of dust aggregates as a function the porosity. Aims: Continuum models such as SPH that are capable of simulating collisions of macroscopic dust aggregates require a set of material parameters. Some of them such as the tensile and shear strength are ?difficult to obtain from laboratory experiments. The aim of this work is to determine these parameters from ab-initio molecular dynamics simulations. Methods: We simulate the behavior of porous dust aggregates using a detailed micro-physical model of the interaction of spherical grains that includes adhesion forces, rolling, twisting, and sliding. Using different methods of preparing the samples we study the strength behavior of our samples...

Seizinger, Alexander; Kley, Wilhelm

2013-01-01

42

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

43

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

44

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

45

Fracture energy based constitutive models for tensile fracture of metal powder compacts  

Microsoft Academic Search

Diametral compression test or the Brazilian disc test is commonly used to characterise the tensile strength of brittle materials. A general fracture model based on energy assumptions is proposed for simulation of the discrete and localised tensile fracturing process in metal powder. The characteristics of the tensile fracture development of the central crack in diametral tested specimen is numerically studied.

P. Jonsén; H.-Å. Häggblad

2007-01-01

46

Characterizing Curing-Cement Slurries by Permeability, Tensile Strength,  

E-print Network

Characterizing Curing-Cement Slurries by Permeability, Tensile Strength, and Shrinkage K.R. Backe, permeability, tensile strength, and total chemical shrinkage during hydration. We will in turn discuss, such as gel- ling, shrinkage, temperature, pressure, filter loss, cement structure and strength buildup

Backe, Knut

47

Stress analysis of an orthotropic material under diametral compression  

Microsoft Academic Search

The diametral compression test is commonly used to determine the tensile strength of brittle materials. For isotropic materials\\u000a a simple relation based on specimen geometry and the applied load at failure is used to calculate the tensile strength. Previous\\u000a to this work the effect of material orthotropy and material orientation on the specimen stress state had not been completely\\u000a determined.

R. K. Lemmon; D. M. Blackketter

1996-01-01

48

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

49

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

50

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

PubMed

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

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

2013-12-01

51

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

52

Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene  

NASA Astrophysics Data System (ADS)

In this paper, the effects of the intensity of electron beam and the variation with time after irradiation of electron beam on the tensile strength of the polypropylene (PP), which is widely used as medicine containers, were investigated. PP with and without colorants were used first and samples irradiated under various intensity of EB. A tensile test on the irradiated samples with elapsed time after the irradiation of the electron beam was carried out. The effects of those factors on the tensile strength were discussed. The following results were obtained (1) The tensile strength of PP decreased due to the influence of the electron beam irradiation, however the rate of the decrease in strength was small compared with the original one. Furthermore, the rate of the decrease in strength was very small owing to the variation with time after the EB irradiation. (2) The tensile rupture strength of PP increased and the rupture strain owing to the influence of the electron beam irradiation compared with the original one. In addition, these rupture strength increased and the rupture strain decreased along with time after the irradiation of the electron beam. (3) The tensile rupture strain energy of PP decreased owing to the influence of the electron beam irradiation compared with the original one. In addition, the strain energy decreases with time after the irradiation of the electron beam. Moreover, the strength characteristics of PP with colorants received greater influence of electron beam compared with the one without colorants.

Yamada, Hiroshi; Ikeda, Masayuki; Shimbo, Minoru; Miyano, Yasushi

53

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

54

Influence of silica fume on the tensile strength of concrete  

Microsoft Academic Search

The present paper is directed towards developing a better understanding on the isolated contribution of silica fume on the tensile strengths of high-performance concrete (HPC). Extensive experimentation was carried out over water–binder ratios ranging from 0.26 to 0.42 and silica fume–binder ratios from 0.0 to 0.3. For all the mixes, compressive, flexural and split tensile strengths were determined at 28

S. Bhanja; B. Sengupta

2005-01-01

55

Effect of Tensile Strength by Variations in Peel Strength in Laminated Film for Liquid Package  

NASA Astrophysics Data System (ADS)

Good tensile strength of a laminated film for packaging is an indispensable property in preventing leakage. It is known that the peel strength between laminated film layers is closely related to the tensile strength of the film. In this study, we have measured the tensile strength for various peel strengths of two kinds of three layered laminated film; Nylon + Aluminum + Polyethylene and Nylon + Polyester + Polyethylene. These films have two peel layers, so we escalated one peel strength and fix another one. Then we found that the peel strength between the sealant and the boundaries strongly influences the tensile strength. About Nylon + Polyester + Polyethylene film, we researched applied amount of adhesive and observed cross section of specimen at measurement of peel strength. Then we found that there is difference in specimen condition at measurement of peel strength, and examined about relationship of peel strength and stiffness of specimen.

Machida, Yukihiko; Shimamoto, Akira; Aoki, Hiroyuki; Futase, Katsunori

56

Comparison of tensile and peel bond strengths of resilient liners.  

PubMed

Previous studies have shown little agreement between the test methods used to assess the bond strength and the mode of failure of resilient liners. This study evaluated the bond strength characteristics of resilient liners by means of 180-degree peeling and butt tensile strength testing. Seventy-two specimens were divided into peel bond and tensile bond specimen groups and were then subdivided into four test groups to evaluate each resilient liner. Tests were conducted with an Instron universal testing machine at a cross-head speed of 2 mm/minute for the tensile specimens and 5 mm/min for the peel specimens. Tensile bond strength and peel bond strength varied significantly among resilient liners except between Novus and Palasiv-62 liners in tensile testing. The mode of failure of Molloplast-B and Novus liners was significantly different between the tensile bond and peel bond test methods. It was concluded that bond strength characteristics can vary according to the test method used. PMID:8006851

Kutay, O

1994-05-01

57

Correlation of Yield Strength and Tensile Strength with Hardness for Steels  

Microsoft Academic Search

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

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

2008-01-01

58

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

59

Tensile strength measurements of frangible bullets using the diametral compression test  

Microsoft Academic Search

Frangible bullets are designed to disintegrate on impact against rigid surfaces to avoid ricochet hazards in recreational shooting ranges or law enforcement training facilities. Their impact behavior against protective soft body armor is therefore quite different than conventional lead bullets, which are designed to expand on impact rather than shatter into fragments. Models to predict the impact of frangible bullets

Steven P. Mates; Richard Rhorer; Stephen Banovic; Eric Whitenton; Richard Fields

2008-01-01

60

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

61

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

62

Using hardness to model yield and tensile strength  

SciTech Connect

The current direction in hardness research is towards smaller and smaller loads as nano-scale materials are developed. There remains, however, a need to investigate the mechanical behavior of complex alloys for severe environment service. In many instances this entails casting large ingots and making numerous tensile samples as the bounds of the operating environment are explored. It is possible to gain an understanding of the tensile strength of these alloys using room and elevated temperature hardness in conjunction with selected tensile tests. The approach outlined here has its roots in the work done by Tabor for metals and low alloy and carbon steels. This research seeks to extend the work to elevated temperatures for multi-phase, complex alloys. A review of the approach will be given after which the experimental data will be examined. In particular, the yield stress and tensile strength will be compared to their corresponding hardness based values.

Hawk, Jeffrey A.; Dogan, Omer N.; Schrems, Karol K.

2005-02-01

63

Evaluation of press-and-sinter parameters for tantalum pentoxide by the diametral compression test  

Microsoft Academic Search

Submicron TaāOā powder was consolidated by cold pressing using pressures between 24 MPa and 240 MPa followed by sintering at temperatures in the range 1300 degrees C to 1500 degrees C. The resulting disks were fractured in diametral compression tests (DCT) to determine the tensile strength. The strength, mode of fracture, and fracture surface were subsequently used to identify potential

Z. Livne; R. J. Fields; A. Agulyansky

1997-01-01

64

Dynamic tensile behavior of multi phase high yield strength steel  

Microsoft Academic Search

Results of uni-axial tensile testing of multi phase 800 High Yield strength steel (MP800HY) at different strain rates (0.001–750s?1) are reported here. Flat specimens having gauge length 10mm, width 4mm and thickness 2mm were tested to determine the mechanical properties of MP800HY under tensile loads. The quasi-static tests (0.001s?1) were performed on electromechanical universal testing machine, whereas, hydro-pneumatic machine and

N. K. Singh; E. Cadoni; M. K. Singha; N. K. Gupta

2011-01-01

65

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

66

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

67

Correlation of Yield Strength and Tensile Strength with Hardness for Steels  

Microsoft Academic Search

Hardness values as well as yield and tensile strength values were compiled for over 150 nonaustenitic, hypoeutectoid steels\\u000a having a wide range of compositions and a variety of microstructures. The microstructures include ferrite, pearlite, martensite,\\u000a bainite, and complex multiphase structures. The yield strength of the steels ranged from approximately 300 MPa to over 1700 MPa.\\u000a Tensile strength varied over the range of

E. J. Pavlina; C. J. Van Tyne

2008-01-01

68

Tensile strength of cementitious materials under triaxial loading  

NASA Astrophysics Data System (ADS)

A general tension-compression-compression (sigmasb1, sigmasb2=sigmasb3) failure criterion for brittle materials is mathematically developed using FEM analysis and experimentally verified by use of the cementitious composite axial tensile test (CCATT). This tensile failure criterion is based on the stress concentration derived from the classical theory of elasticity. This analytical approach shows the upper bound of the tension-compression-compression failure surface for brittle materials. Since the CCATT applies confining hydraulic pressure, a tensile specimen is subjected to triaxial loading defined by the principal stress ratio sigmasb1/|sigmasb2|. When lateral pressure increases, tensile strength decreases; therefore, stress concentration is defined as a function of the principal stress ratio. The model has three distinct regions of behavior corresponding to the principal stress ratio, 0?sigmasb1/|sigmasb2|<0.9 (high-lateral pressure), 0.9?sigmasb1/|sigmasb2|<3.0 (medium-lateral pressure), 3.0?sigmasb1/|sigmasb2| (low-lateral pressure). The experimental failure line shows true tensile strength of cementitious materials under low-lateral pressure. The predicted nominal stress fsb{ta} with large size specimens for the CCATT is written as$fsb{ta}=gamma*{1/{Kt}}*alpha* pwhere gamma$ is the size effect obtained by experimental results; Kt is the stress concentration factor derived from triaxial loading. Tensile strength values from the CCATT are compared to experimental results from other tests such as the uniaxial tensile test and the split cylinder test. CCATT results are analyzed using Weibull theory to measure material reliability and to develop characteristic stresses for construction design. Failure analysis using fractography was conducted on fractured cementitious materials and composites. The failure analysis on test specimens correlated well with FEM stress distributions and with the principal stress ratio. The observed fracture behavior (fracture patterns) was correlated to different strength regions of the model. Additionally, a failure model of fiber wrapped cementitious composite is developed. Using data on load-extension behavior from the UTT and ultimate strength from the CCATT models for fiber wrapped cementitious composites were developed. These models predict the mechanical behavior of fiber sheets subjected to cycles of wetting and drying in a simulated seawater environment; therefore, the tensile strength using the CCATT is applicable to a wide range of brittle materials including cementitious composites.

Tsubota, Shuji

1998-11-01

69

Tensile Strength of Sheet Materials under Impact Loading  

Microsoft Academic Search

Test procedures are described and strength and plasticity results are presented for a 1.0-mm mild sheet steel and a 0.75-mm D16T high-strength aluminum alloy investigated under impact loading. The experimental investigations include tensile tests of sheet metal specimens with a short test portion and symmetric sharp edge notches. As is shown, the switch from static to impact loading over the

G. V. Stepanov; V. I. Zubov; A. N. Olisov; V. M. Tokarev

2000-01-01

70

Tensile strength of butt-joined epoxy-aluminum plates  

Microsoft Academic Search

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

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

1970-01-01

71

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

72

Tensile strength and fracture toughness of brittle materials  

Microsoft Academic Search

The fracture properties of brittle materials under tension have been explained by many authors; however, questions such as the dependence of the tensile strength on the crack tip radius of curvature and the scatter of fracture toughness are still not well explained from fundamental principles. This work aims to address this question by using a force-atomistic approach: we analyze the

Francisco G. Emmerich

2007-01-01

73

Tensile and shear strength of porous dust agglomerates  

NASA Astrophysics Data System (ADS)

Context. Within the sequential accretion scenario of planet formation, planets are built up through a sequence of sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small dust particles to planetesimals. In this work we determine the necessary material properties of dust aggregates as a function of porosity. Aims: Continuum models such as SPH that are capable of simulating collisions of macroscopic dust aggregates require a set of material parameters. Some of them, such as the tensile and shear strength, are difficult to obtain from laboratory experiments. The aim of this work is to determine these parameters from ab initio molecular dynamics simulations. Methods: We simulated the behavior of porous dust aggregates using a detailed micro-physical model of the interaction of spherical grains that includes adhesion forces, rolling, twisting, and sliding. Using different methods of preparing the samples, we studied the strength behavior of our samples with varying porosity and coordination number of the material. Results: For the tensile strength, we can reproduce data from laboratory experiments very well. For the shear strength, there are no experimental data available. The results from our simulations differ significantly from previous theoretical models, which indicates that the latter might not be sufficient to describe porous dust aggregates. Conclusions: We have provided the functional behavior of tensile and shear strength of porous dust aggregates as a function of the porosity, which can be directly applied to continuum simulations of these objects in planet formation scenarios.

Seizinger, A.; Speith, R.; Kley, W.

2013-11-01

74

Tensile strength and fracture toughness of brittle materials  

NASA Astrophysics Data System (ADS)

The fracture properties of brittle materials under tension have been explained by many authors; however, questions such as the dependence of the tensile strength on the crack tip radius of curvature and the scatter of fracture toughness are still not well explained from fundamental principles. This work aims to address this question by using a force-atomistic approach: we analyze the forces that act in the solid down to the smallest dimensions in an atomistic context, verifying the satisfaction of the static equilibrium condition given by Newton's second law up to the beginning of the rupture. We take into account the forces due to the applied stress, which may be very large at crack tips, and the material cohesion forces, particularly at the point of largest local strain and stress concentration, where the local hyperelasticity of the material plays a governing role. By considering and connecting microstructure and atomicity, and using an experimentally proved maximum tensile-stress criterion for fracture, here we obtain an expression for the tensile strength of the brittle materials, where an effective local cohesive stress is defined. Thus, we explain in a unified framework from fundamental principles a set of established experimental results of brittle fracture of materials under tension, including the dependence of the tensile strength on the crack tip radius of curvature and some scatter in reported values of fracture toughness and cleavage surface energy. This work can be useful to make more realistic predictions of fracture properties of brittle materials taking into account microstructure and atomicity.

Emmerich, Francisco G.

2007-10-01

75

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

PubMed Central

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

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

2013-01-01

76

Tensile Fracture Strength of Brisbane Tuff by Static and Cyclic Loading Tests  

NASA Astrophysics Data System (ADS)

This research presents the results of laboratory experiments during the investigation of tensile strength-strain characteristics of Brisbane tuff disc specimens under static and diametral cyclic loading. Three different cyclic loading methods were used; namely, sinusoidal cyclic loading, type I and II increasing cyclic loading with various amplitude values. The first method applied the stress amplitude-cycle number (s-n) curve approach to the measurement of the indirect tensile strength (ITS) and fracture toughness ( K IC) values of rocks for the first time in the literature. The type I and II methods investigated the effect of increasing cyclic loading on the ITS and K IC of rocks. For Brisbane tuff, the reduction in ITS was found to be 30 % under sinusoidal loading, whereas type I and II increasing cyclic loading caused a maximum reduction in ITS of 36 %. The maximum reduction of the static K IC of 46 % was obtained for the highest amplitude type I cyclic loading tested. For sinusoidal cyclic loading, a maximum reduction of the static K IC of 30 % was obtained. A continuous irreversible accumulation of damage was observed in dynamic cyclic tests conducted at different amplitudes and mean stress levels. Scanning electron microscope images showed that fatigue damage in Brisbane tuff is strongly influenced by the failure of the matrix because of both inter-granular fracturing and trans-granular fracturing. The main characteristic was grain breakage under cyclic loading, which probably starts at points of contact between grains and is accompanied by the production of very small fragments, probably due to frictional sliding within the weak matrix.

Erarslan, N.; Alehossein, H.; Williams, D. J.

2014-07-01

77

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

78

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

SciTech Connect

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

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

2008-06-15

79

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

80

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

81

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

82

Improved Tensile Adhesion Specimens for High Strength Epoxy Systems in Aerospace Applications  

NASA Technical Reports Server (NTRS)

An improved tensile adhesion button has been designed and tested that results in higher measured tensile adhesion strength while providing increased capability for testing high strength epoxy adhesive systems. The best attributes of two well-established tensile button designs were combined and refined into an optimized tensile button. The most significant design change to the tensile button was to improve alignment of the bonded tensile button specimens during tensile testing by changing the interface between the tensile button and the tensile test machine. The established or old button design uses a test fixture that pulls from a grooved annulus or anvil head while the new button design pulls from a threaded hole in the centerline of the button. Finite element (FE) analysis showed that asymmetric loading of the established anvil head tensile button significantly increases the stress concentration in the adhesive, causing failure at lower tensile test loads. The new tensile button was designed to eliminate asymmetric loading and eliminate misalignment sensitivity. Enhanced alignment resulted in improved tensile adhesion strength measurement up to 13.8 MPa (2000psi) over the established button design. Another design change increased the capability of the button by increasing the threaded hole diameter allowing it to test high strength epoxy systems up to 85 MPa(less than 12,000 psi). The improved tensile button can be used in button- to-button or button-to-panel configurations.

Haddock, M. Reed; McLennan, Michael L.

2000-01-01

83

Tensile Strength and the Mining of Black Holes  

E-print Network

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

Adam R. Brown

2012-07-13

84

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

85

Tensile Strength and the Mining of Black Holes  

E-print Network

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

Brown, Adam R

2012-01-01

86

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

87

Strength Evaluation Test of Pressureless-Sintered SiC and Reaction-Sintered Si sub 3 N sub 4 at Room Temperature.  

National Technical Information Service (NTIS)

Strength characteristics were studied at room temprature. The strength evaluating-method of ceramic materials, bending-tests of bars, tensile tests of rectangular plates, spin-tests of inner-peripherally notched disks, and diametrical compression tests of...

K. Matsusue, K. Takahara, R. Hashimoto

1981-01-01

88

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

89

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

90

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

E-print Network

Effect of surface treatment on the hydrolytic stability of E-glass fiber bundle tensile strength E surface treatment on the hydrolytic stability of tensile strength is investigated for E-glass fiber and silane, starch and wax, and epoxy surface treatments are tested following exposure to 10%, 40%, 80

Sottos, Nancy R.

91

Tensile strength of green concrete with fly ash and chemical admixtures  

Microsoft Academic Search

The effect of Class F fly ash of marginal quality, as partial replacement of fine sand, and of chemical admixtures (water-reducing and retarding and high-range water reducer) on the tensile strength of green concrete was investigated. The tests show that the fly ash significantly increased (by 25 to 40 percent) the tensile strength at 2 to 4 hours after mixing,

Dan Ravina

1995-01-01

92

Flexural and tensile strength developments of various shape carbon fiber-reinforced lightweight cementitious composites  

SciTech Connect

Effects of three types of carbon fiber shapes (C, round, and hollow shape) on tensile and flexural strength developments of randomly oriented carbon-fiber-reinforced lightweight cement composites (CFRLC) were investigated. C-shape CFRLC (C-CFRLC) showed higher tensile and flexural strength development than any other shape. C-CFRLC loading V{sub f} = 3% in particular increased about 40% in tensile and flexural strength, compared to round shape CFRLC (R-CFRLC). Hollow-shape CFRLC (H-CFRLC) showed slightly higher tensile and flexural strength than R-CFRLC. C-CFRLC presented stronger fiber-matrix interfacial adhesive force, due to mechanical anchorage into the matrix, than any other fibers. Silica fume significantly influences the increase of tensile and flexural strength for the CFRLC.

Kim, T.J.; Park, C.K. [Ssangyong Research Center, Taejon (Korea, Republic of)] [Ssangyong Research Center, Taejon (Korea, Republic of)

1998-07-01

93

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

94

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

NASA Astrophysics Data System (ADS)

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

Yoshihara, Shoichiro; Iwamatsu, Go

2014-10-01

95

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

96

Ultimate Strength and Failure Mechanism of Resistance Spot Weld Subjected to Tensile, Shear, or Combined Tensile\\/Shear Loads  

Microsoft Academic Search

Strength tests were performed to reveal the failure mechanisms of spot weld in lap-shear and cross tension test samples. It is shown the while the lap-shear (cross tension) sample is subjected to shear (normal) load at the structural level the failure mechanism at the spot weld is tensile (shear) mode at the materials level. Based on the observed failure mechanism,

Yuh J. Chao

2003-01-01

97

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

98

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

99

Concrete Material Models Concrete_1: Concrete Model with No Tensile Strength  

E-print Network

Concrete Material Models Concrete_1: Concrete Model with No Tensile Strength INPUT Concrete_1, matID Ā¢f fc cu u, , ,e e0 Definitions (Fig. 1): fc : concrete compressive strength at 28 days (compression is negative) A0 : concrete strain at maximum strength (compression is negative) fcu : concrete crushing

Filippou, Filip C.

100

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

E-print Network

A modified test for measuring the interlaminar tensile strength of fiber-reinforced ceramic) strength of ceramic composites with two-dimensional fiber architectures presents serious challenges 2007 Elsevier Ltd. All rights reserved. Keywords: A. Ceramic matrix composites; B. Strength; C. Finite

Zok, Frank

101

Tensile bond strength of resin luting cement to a porcelain-fusing noble alloy.  

PubMed

This study evaluated the tensile bond strength of resin composites to a noble alloy for ceramic bonding after various surface treatments. The flat end of bars cast in the alloy were used as test specimens. Eighteen clinically relevant combinations of luting agent, airborne particle abrasion, and surface treatment were applied. After surface treatment, two bars were bonded together. Resin cement, either dual-polymerizing (Twinlook) or chemically polymerizing (Panavia EX, Panavia 21, or RBBC), was used as a luting agent. The specimens were subjected to 1,000 thermal cycles between 15 degrees C and 60 degrees C before tensile bond strength testing. The highest median bond strengths were obtained using the Silicoater MD method/Twinlook (20.6 to 26.1 MPa) or with tin-plating/ Panavia EX (24.0 MPa), but more low values were recorded among the latter specimens. Tin-plating/Panavia 21 gave median tensile bond strengths (18.1 MPa) similar to tin-plating/Panavia EX. The Silicoater MD method resulted in similar bond strengths with or without the addition of a layer of Opaquer. The traditional Silicoater method (8.0 to 12.4 MPa) gave significantly lower median tensile bond strength values, and the lost sugar crystals method resulted in a tensile bond strength of 15.4 MPa. PMID:8957870

Stoknorm, R; Isidor, F; Ravnholt, G

1996-01-01

102

Molecular-Level Study of the Effect of Prior Axial Compression/Torsion on the Axial-Tensile Strength  

E-print Network

degrades their longitudinal-tensile strength and only slightly modifies the associated probability density reductions in the PPTA-fiber longitudinal-tensile strength and appre- ciable changes in the associatedMolecular-Level Study of the Effect of Prior Axial Compression/Torsion on the Axial-Tensile

Grujicic, Mica

103

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

104

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

Microsoft Academic Search

The low interlaminar tensile (ILT) strength of ceramic composites with two-dimensional fiber architectures presents serious challenges in the design of thermostructural components. Existing protocols for measuring ILT strength remain contentious because of the presence of free edges. The principal objective of the present study is to introduce a modified test that eliminates machined edges (and associated flaws) from the volume

Jared H. Weaver; James Yang; Anthony G. Evans; Frank W. Zok

2008-01-01

105

DOI: 10.1002/adma.200800214 High Tensile Ductility and Strength in Bulk  

E-print Network

multimodal and bimodal NS Ni with tensile ductility of 42% and 49%, and yield strengths of 457 and 312 MPa that can be used in applications requiring both high ductility and strength. Bulk NS materials are usually of yielding.[3] In a recent study, the material was consolidated in situ via an approach involving cryomilling

Zhu, Yuntian T.

106

Prediction of tensile yield strength of rigid inorganic particulate filled thermoplastic composites  

Microsoft Academic Search

Advances in the study of the tensile yield strength of rigid inorganic particulate filled thermoplastic composites have been reviewed and brief comments on the existing expressions for predicting it have been made in the present paper. The main factors affecting the yield strength of such composites are: (i)the interfacial adhesion between the fillers and the matrix; (ii)the shape, size and

J. Z. Liang; R. K. Y. Li

1998-01-01

107

The effect of tensile strength on the fatigue life of spot-welded sheet steels  

SciTech Connect

Tensile-shear spot-weld specimens were tested to determine the effect of base-metal tensile properties on fatigue life. Four sheet thicknesses (t) were investigated. Base-metal yield strength ranged between 186 and 757 MPa (27 and 110 ksi). Results showed that fatigue life was independent of base-metal strength for lives greater than 10/sup 4/ cycles. At shorter lives, fatigue performance improved with increasing base-metal strength. For a given cyclic load range, fatigue life increased at all lives with increasing sheet thickness. (t). Fatigue results from both this and a previous study were used to develop a spot-weld fatigue design curve.

Davidson, J.A.; Imhof, E.J. Jr.

1984-01-01

108

A single-particle model for theoretical estimation of tensile strength of dual-phase steels  

SciTech Connect

A single-particle model based on shear lag analysis has been developed to determine the theoretical tensile strength of dual-phase (d-p) steels while taking into account the shape of the embedded second phase particles and work hardening term. Three plain carbon steels with varying carbon content have been used to develop d-p (ferrite-martensite) structure by following intercritical heat treatment cycle. The experimental values of tensile strength of d-p steels plotted as a function of martensite volume fraction (MVF) together with theoretically calculated tensile strength, show a good correspondence. However, when the shape of the particle is assumed as spherical, the maching between theoretical and experimental strength values as a function of MVF is very poor.

Nath, S.K.; Ray, S.; Mathur, V.N.S.; Kapoor, M.L. [Univ. of Roorkee (India). Dept. of Metallurgical Engineering

1993-12-31

109

Tensile testing methods of high strength and high magnetic field composite wires  

NASA Astrophysics Data System (ADS)

Tensile tests to measure the ultimate tensile strength of full-section high strength composite wire have been improved by using tabs that are bonded directly to the metal. Reduced section specimens are not always desirable due to the non-uniform properties of the composite wire. The use of friction grips on tensile tests of full-section wire without tabs creates combined stresses in the material in the grip region usually resulting in premature failure. For a tabbed specimen, the stress concentration is decreased making failure within the gage section possible. Analysis is included to show that, by using tabs, direct contact of the wire to serrated friction grips is eliminated, reducing the high stress-concentration factor. The net results are higher ultimate strength values that better approximate the wire's actual strength.

Toplosky, V. J.; Walsh, R. P.

2002-05-01

110

Power consumption profile analysis and tensile strength measurements during moist agglomeration.  

PubMed

This study was performed to elucidate the influences of process and formulation design on the granulation process using power consumption and tensile strength measurements. In order to record and analyze the power consumption profile "in process" a computer program was developed to be used for optimal end-point control in reproducible granule production. The program analyzes and calculates a characteristical point, the turning point of the S-shaped ascent of the profile. The tensile strength expresses the cohesiveness between the powder particles, which is dependent on saturation and capillary pressure. In order to investigate the influence of the amount of liquid present in the granular material on tensile strength a device was developed. The maxima of tensile strength occurred at 90% saturation, whereas the maxima of power consumption were determined at 100% saturation. The measured tensile strength sigma (N/m(2)) equals to the volume specific cohesion (J/m(3)). The present work proved that the power consumption measurement is an alternative, simple and inexpensive method to determine the cohesion of powder particles. The turning point is introduced as a signature of the starting material and furthermore as a parameter for the cohesiveness of the starting material and therefore for optimal end-point detection at an early stage. PMID:12550777

Betz, Gabriele; Bürgin, Pascale Junker; Leuenberger, Hans

2003-02-18

111

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

112

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

113

Correlation Between Tensile Strength and Hardness of Electron Beam Welded TC4-DT Joints  

NASA Astrophysics Data System (ADS)

Correlation between tensile strength and hardness for damage-tolerant Ti-6Al-4V (TC4-DT) alloy and its electron beam welded joints was investigated. Yield strength (YS), ultimate tensile strength (UTS) and strain hardening coefficient of base metal and weld metal were obtained using uniaxial tensile tests. Microhardness of the base metal, heat affected zone, and weld metal was measured. Then, the linear correlations among the yield strength, tensile strength, and hardness were proposed. Moreover, correlation between strain hardening coefficient and the ratio of YS to UTS (YS/UTS) was established. The results indicate that microhardness can be used to predict the YS and UTS of the TC4-DT welded joint successfully. In addition, the strain hardening coefficient can be predicted by the YS/UTS. The prediction of strength and strain hardening coefficient is in agreement with the experiments. The correlations are applicable and valuable for the strength prediction of narrow welded fusion zone and heat affected zone based on the microhardness measurement.

Lu, Wei; Shi, Yaowu; Li, Xiaoyan; Lei, Yongping

2013-06-01

114

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

115

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

116

Aluminum-Based Amorphous Alloys with Tensile Strength above 980 MPa (100 kg\\/mm2)  

Microsoft Academic Search

New Al-based amorphous alloys with high strength and good ductility were produced in an Al-Y-Ni system by liquid quenching. The tensile fracture strength (sigmaf) and Vickers hardness reach 1140 MPa and 300 DPN for Al87Y8Ni5. The specific strength defined by the ratio of sigmaf to density is as high as 38, being much higher than that for conventional alloy steels.

Akihisa Inoue; Katsumasa Ohtera; An-Pang Tsai; Tsuyoshi Masumoto

1988-01-01

117

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

118

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

PubMed

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

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

2011-09-01

119

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

120

Deformation and failure of polymer bonded explosives under diametric compression test  

Microsoft Academic Search

The tensile deformation and failure of polymer bonded explosives (PBXs), a particulate composite, is studied in this paper. Two HMX-based PBXs with different binder were selected for study. A diametric compression test, in which a disc-shaped specimen is loaded diametrically, was chosen to generate tensile failure in the materials. The quasi-static tensile properties and the tensile creep properties were studied

Pengwan Chen; Huimin Xie; Fenglei Huang; Tao Huang; Yansheng Ding

2006-01-01

121

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

122

Roller compacted concrete-tensile strength of horizontal joints  

Microsoft Academic Search

Roller Compacted Concrete is a very dry material consolidated by the use of a powerful external vibatory compaction. This\\u000a material is used mainly in gravity or arch\\/gravity dams, and pavements. RCC dam construction methodology, by concrete layers,\\u000a involves a high number and an extensive area of horizontal joints. These joints are the weakest parts of RCC in terms of strength

A. C. Bettencourt Ribeiro; J. Dķez-Cascón; A. F. Gonēalves

2001-01-01

123

Comparison of adhesion formation and tensile strength after three laparoscopic herniorrhaphy techniques.  

PubMed

Several techniques for laparoscopic inguinal herniorrhaphy have been described in the literature: laparoscopic extraperitoneal mesh repair (EXTRA), transabdominal preperitoneal mesh repair (TAPP), and intraperitoneal onlay mesh repair (IPOM). To evaluate the incidence of adhesion formation and the tensile properties of these techniques, young male pigs underwent mesh placement using the above techniques. The animals had follow-up for 6 weeks, and no trocar site adhesions were observed. No intraperitoneal adhesions resulted in the group that underwent EXTRA technique. One case of filmy omental adhesions was observed with the TAPP technique, and two cases of adhesions were associated with the IPOM technique, one minimal and one case of dense adhesions to the bladder. The tensile strength of mesh incorporation into abdominal fascia was compared for the three techniques and measured using a tensiometer. The IPOM technique resulted in the weakest tensile strength of 0.53 +/- 0.01 kg (mean +/- SEM), whereas both the EXTRA and TAPP were comparable and significantly stronger (p < 0.05), with tensiometric values of 0.69 +/- 0.03 and 0.60 +/- 0.02 kg, respectively. We concluded that IPOM, although technically the easiest procedure to perform, is associated with the highest risk of adhesion formation and the lowest tensile strength. In comparison, the EXTRA and the TAPP techniques had the advantages of better tissue incorporation and tensile strength. Adhesion formation was not observed with the EXTRA technique, in which the peritoneum was not violated, and was uncommon and minimal with the TAPP technique. PMID:9109243

Rasim, Z M; Alzahrani, M A; Sigman, H H; Meakins, J L; Fried, G M

1997-04-01

124

Predicting the tensile modulus and strength of single and hybrid natural fibre reinforced thermoplastic composites  

NASA Astrophysics Data System (ADS)

Natural fibre reinforced thermoplastics (NFRT) are used in a variety of commercial applications, but there is little theoretical modeling of structure/property relationships in these materials. In this thesis, micromechanical models available in the short-fibre literature were adapted to predict the tensile modulus and strength of some NFRT formulations. Hemp, 20 and 40-mesh hardwood, rice hulls and E-glass fibres were blended into HDPE to produce single and hybrid composites. Changes in fibre density and moisture content that occur during composite manufacturing were included in the micromechanical models. To account for fibre densification, the Young's modulus of the natural fibres was determined on a cell wall basis. A modified hybrid rule of mixtures (HROM) equation that uses experimental data from single NFRT was developed and found to adequately predict the tensile modulus of the hybrid composites. The tensile modulus for both the single and hybrid composites was found to linearly increase with an increase in fibre loading. The failure mechanism for all composite specimens was due to fibre pullout followed by matrix failure. Consequently the tensile strength of the NFRT was predicted using a ROM strength equation, which was modified with a derived semi-empirical fibre clustering parameter. The clustering parameter correctly predicted that as fibre loading increased, the average fibre stress would decrease. By assuming no contact between different types of fibres it was possible to use a modified HROM strength equation to predict the tensile strength of the hybrid composites. As a result parameters taken from the respective single fibre systems could be applied directly to the HROM equation. The modified ROM and HROM strength equations adequately predicted the tensile strength of various single and hybrid fibre reinforced composites over a wide range of composite loading. In this study experiments were conducted to shed light on the effect of a coupling agent (maleic anhydride) on the tensile strength and stiffness of various NFRT. Coupling agents, which alter the interfacial shear strength between the fibre and matrix, were determined to have a minimal effect on composite stiffness but produced increases in composite strength.

Facca, Angelo George

125

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

126

A comparison of direct and indirect methods of determining tensile strength of concrete  

E-print Network

or transverse strength and was detez- mined by sub)ecting beam specimens to a bending force until failuze. Briquettes with hour glass shapes~ as used in the standazd ASTN mortar tensile test, were the common form oi' specimens used in the study of cement... or transverse strength and was detez- mined by sub)ecting beam specimens to a bending force until failuze. Briquettes with hour glass shapes~ as used in the standazd ASTN mortar tensile test, were the common form oi' specimens used in the study of cement...

Brown, James Timon

2012-06-07

127

Effect of Gap Distance on Tensile Strength of Preceramic Base Metal Solder Joints  

PubMed Central

Background and aims In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Materials and methods Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. Results The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. Conclusion There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints. PMID:22991610

Fattahi, Farnaz; Motamedi, Milad

2011-01-01

128

Effective volume of specimens in diametral compression  

Microsoft Academic Search

A calculation was performed to find the effective tensile volume for diametral compression tests of brittle materials. Both\\u000a disc and spherical geometries were investigated. The effective volume equation for disc specimens separates into materials-dependent\\u000a and geometry-dependent functions, which are separately solved. The effective volume equation for spherical specimens is mathematically\\u000a more difficult and less enlightening.

L. J NEERGAARD; D. A NEERGAARD; M. S NEERGAARD

1997-01-01

129

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

130

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

131

Tensile strength of five types of retention for resin-bonded prostheses.  

PubMed

The tensile bond strengths of five retention techniques for bonded cast restorations were tested. The retentive methods were the electrolytic etch, Rochette's perforations, retention beads, the recessed surface, and soldered orthodontic mesh. The electrolytic etch and recessed surface methods gave the highest values of bond strength, followed by retention beads. Rochette's perforations and the soldered orthodontic mesh failed to surpass the bond strength of the control group (no additional retention) after 1 hour and provided the lowest bond strength after 24 hours. PMID:1687153

Bastos, M T; Mondelli, J; Ishikiriama, A; Navarro, M F

1991-12-01

132

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-Rodrķguez 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-Rodrķguez (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-Rodrķguez 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.

133

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

134

Tensile strength of a surgeon's or a square knot  

PubMed Central

Objective To test the integrity of surgeon’s knots and flat square knots using four different suture materials. Study Design Chromic catgut, polyglactin 910, silk, and polydioxanone sutures were tied in the two types of knot configurations. For all sutures, a 0-gauge United States Pharmacopeia suture was used. Knots were tied by a single investigator (JB). Suture was soaked in 0.9 % sodium chloride for 60 seconds and subsequently transferred to a tensiometer where the tails were cut to 3 mm length. We compared the knots, measuring knot strength using a tensiometer until the sutures broke or untied. Results A total of 119 knots were tied. We found no difference in mean tension at failure between a surgeon’s knot (79.7 Newtons) and a flat square knot (82.9 Newtons). Using a Chi-square test, we did not find a statistically significant difference in the likelihood of knots coming untied between surgeon’s knots (29%) and flat square knots (38%). Conclusions Under laboratory conditions, surgeon’s knots and flat square knots did not differ in tension at failure or likelihood of untying. PMID:20816357

Muffly, Tyler M.; Boyce, Jamie; Kieweg, Sarah L.; Bonham, Aaron J.

2014-01-01

135

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

136

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

137

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

138

Tensile bond strengths of composites to a gold-palladium alloy after thermal cycling  

Microsoft Academic Search

Statement of Problem. Many different materials and methods have been used to fabricate or repair veneer facings with composites, but only a few of these have been studied. Purpose. This study compared the tensile bond strengths of composites to a gold-palladium alloy with the use of several surface treatment methods. Material and Methods. Forty alloy specimens were cast in Eclipse

Jeffrey Chai Chang; Sheila H. Koh; John M. Powers; Joseph H. Duong

2002-01-01

139

Point load testing of brittle materials to determine tensile strength and relative brittleness  

Microsoft Academic Search

Most brittle solids are relatively weak in tension and this weakness can be very significant in determining their performance in structures and excavations. There are now 3 distinct approaches being used to determine the tensile strength of brittle materials. These are shown schematically. The fist method consists of simply pulling the specimen apart by applying an axial load. Although this

Reichmuth

1968-01-01

140

SOBRE A RESISTŹNCIA Ą TRACĒĆO DINĀMICA DE ROCHAS ON THE DYNAMIC TENSILE STRENGTH OF ROCKS  

Microsoft Academic Search

A series of exploratory investigations on the measurement of the tensile strength of rock materials and concrete submitted to dynamic stresses is described. Due to the absence of national and international standards on the determination of th is mechanical property for geologic materials, various systems of impact application have been attempted, namely the following types: a) By means of impacts

DINIS DA GAMA

141

Correlation of Tensile Strength with Bursting Pressure in the Evaluation of Intestinal Anastomosis  

Microsoft Academic Search

Background: Although bursting pressure and tensile strength have long been measured to evaluate anastomotic techniques, it has yet to be clarified whether or not they are correlated, what implications they have, and which should be used as a gold standard. Material and Methods: Using an experimental model to estimate pressure and tension in the same colonic anastomosis, the following variables

Daisuke Ikeuchi; Hisashi Onodera; Tun Aung; Shugen Kan; Kazuyuki Kawamoto; Masayuki Imamura; Shunzo Maetani

1999-01-01

142

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

SciTech Connect

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

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

2009-04-01

143

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

144

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

145

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

146

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

147

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

148

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

149

Effect of interfacial reaction layer continuity on the tensile strength of resistance spot welded joints between aluminum alloy and steels  

Microsoft Academic Search

We have joined aluminum alloy A5052 to cold-rolled steel SPCC and austenitic stainless steel SUS304 using resistance spot welding. The interfacial microstructures have been observed using scanning electron microscopy and the tensile strength of the joints have been examined by cross tension testing. We have investigated the effect of interfacial reaction layer on the tensile strength of the joints based

Ranfeng Qiu; Shinobu Satonaka; Chihiro Iwamoto

2009-01-01

150

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

151

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

152

FE Analysis of Buckling Behavior Caused by Welding in Thin Plates of High Tensile Strength Steel  

NASA Astrophysics Data System (ADS)

The target of this study was to investigate buckling behavior during the entire welding process which consists of the heating and the cooling processes. For thin plate structures made of high tensile strength steel, not only residual buckling during or after cooling down but also transient buckling during heating may occur. The thermal elastic plastic FE analysis to investigate welding-induced buckling during the entire welding process is presented. Because of the high yield stress of high tensile strength steel, larger longitudinal compressive thermal stress is produced near the welding line compared with that in the case of carbon steel. Therefore, the plate may buckle due to thermal expansion, before the material nears yielding. During cooling down, the longitudinal compressive thermal stress close to the welding line disappears, and longitudinal tensile residual stress is produced due to contraction. Meanwhile, longitudinal compressive residual stress occurs far from the welding line to balance the tensile stress close to the welding line. This distribution of longitudinal residual stress would change the deformed dish shape of transient buckling into a saddle buckling type when the stress exceeds the critical buckling condition.

Wang, Jiangchao; Rashed, Sherif; Murakawa, Hidekazu

2014-09-01

153

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

154

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

E-print Network

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. (2011). 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

2011-01-01

155

Tensile strength of a surgeon’s or a square knot  

E-print Network

Tensile strength of a surgeon’s or a square knot Tyler M. Muffly, MD a , Jamie Boyce, DO b , Sarah L. Kieweg, PhD c , and Aaron J. Bonham, MS d a Section of Urogynecology and Pelvic Reconstructive Surgery, Department of Obstetrics and Gynecology... H - P A A u t h o r M a n u s c r i p t N I H - P A A u t h o r M a n u s c r i p t N I H - P A A u t h o r M a n u s c r i p t Keywords Suture Techniques; Tensile Strength; Suture end length; Polyglactin 910 Introduction There is a...

Muffly, Tyler M.; Boyce, Jamie; Kieweg, Sarah L.; Bonham, Aaron J.

2014-09-19

156

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

157

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

158

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

159

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

160

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

161

Strength and deformability of mineral wool slabs under short-term compressive, tensile and shear loads  

Microsoft Academic Search

The results obtained in the experimental study of mineral wool slabs under short-term compressive, tensile and shear loads, used for insulating flat roofs, cast-in-place floors, curtain and external basement walls, as well as for sound insulation of floors, are presented. To describe the experimental data of strength and deformability of mineral wool slabs, the regression equations of the linear form,

I. Gnip; S. V?jelis; V. Keršulis; S. Vaitkus

2010-01-01

162

Copper alloy–stainless steel bonded laminates for fusion reactor applications: tensile strength and microstructure  

Microsoft Academic Search

The tensile strength of copper alloy–stainless steel bi-layer panels joined by hot isostatic pressing or explosive bonding was tested over a temperature range 25–350°C. The bonding processes caused changes in interfacial microstructures which affected the interfacial mechanical properties. Hot isostatic pressed materials studied included: precipitation strengthened CuNiBe or dispersion strengthened Cu–Al2O3 bonded to 316L stainless steel plates and Cu–Al2O3 bonded

K. D Leedy; J. F Stubbins

2001-01-01

163

Comparative study of water sorption, solubility, and tensile bond strength of two soft lining materials  

Microsoft Academic Search

Statement of problem. Two soft denture lining materials with distinct chemical compositions were evaluated to determine whether these compositional variations manifest themselves in property differences. Purpose. This study evaluated and compared the water sorption, solubility, and tensile bond strength of a recently introduced silicone-based soft liner (Luci-sof) and a plasticized acrylic resin soft liner (Permasoft) using 2 processing techniques, laboratory-processed

Amany El-Hadary; James L. Drummond

2000-01-01

164

Distribution and tensile strength of Hornbeam ( Carpinus betulus ) roots growing on slopes of Caspian Forests, Iran  

Microsoft Academic Search

Biomechanical characteristics of the root system of hornbeam (Carpinus betulus) were assessed by measuring Root Area Ratio (RAR) values and tensile strength of root specimens of eight hornbeam trees growing\\u000a on hilly terrain of Northern Iran. RAR values of the roots were obtained using profile trenching method at soil depth of the\\u000a top 0.1 m. In total 123 root specimens

Ehsan Abdi; Baris Majnounian; Hassan Rahimi; Mahmud Zobeiri

2009-01-01

165

Acute tensile strength analysis of collagen solder for mesh fixation to the peritoneal surface  

Microsoft Academic Search

Background: In this study, we assessed the feasibility of laser-assisted tissue welding as a means of fixing mesh prostheses to the peritoneum. We then tested the initial tensile strength of the bonds. Methods: Fresh porcine peritoneal coupons were lapjoint bonded with laser-activated solder. Anesthetized New Zealand white rabbits and Yorkshire pigs also underwent laparotomy. Vicryl mesh (2.0 · 1.0 cm)

R. J. Lanzafame; B. A. Soltz; I. Stadler; M. A. Soltz; R. Soltz; D. P. DeVore

2005-01-01

166

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

167

Effect of laser welding on the titanium ceramic tensile bond strength  

PubMed Central

Titanium reacts strongly with elements, mainly oxygen at high temperature. The high temperature of titanium laser welding modifies the surface, and may interfere on the metal-ceramic tensile bond strength. Objective The influence of laser welding on the titanium-ceramic bonding has not yet been established. The purpose of this in vitro study was to analyze the influence of laser welding applied to commercially pure titanium (CpTi) substructure on the bond strength of commercial ceramic. The influence of airborne particle abrasion (Al2O3) conditions was also studied. Material and Methods Forty CpTi cylindrical rods (3 mm x 60 mm) were cast and divided into 2 groups: with laser welding (L) and without laser welding (WL). Each group was divided in 4 subgroups, according to the size of the particles used in airborne particle abrasion: A - Al2O3 (250 µm); B - Al2O3 (180 µm); C - Al2O3 (110 µm); D - Al2O3 (50 µm). Ceramic rings were fused around the CpTi rods. Specimens were invested and their tensile strength was measured at fracture with a universal testing machine at a crosshead speed of 2.0 mm/min and 200 kgf load cell. Statistical analysis was carried out with analysis of variance and compared using the independent t test (p?0.05). Results Significant differences were found among all subgroups (p<0.05). The highest and the lowest bond strength means were recorded in subgroups WLC (52.62 MPa) and LD (24.02 MPa), respectively. Conclusion Airborne particle abrasion yielded significantly lower bond strength as the Al2O3 particle size decreased. Mechanical retention decreased in the laser-welded specimens, i.e. the metal-ceramic tensile bond strength was lower. PMID:21956585

GALO, Rodrigo; RIBEIRO, Ricardo Faria; RODRIGUES, Renata Cristina Silveira; PAGNANO, Valeria de Oliveira; de MATTOS, Maria da Gloria Chiarello

2011-01-01

168

The dependence of bedrock erodibility on rock material properties: is tensile strength enough?  

NASA Astrophysics Data System (ADS)

Rock resistance to fluvial abrasion by bedload sediment impacts has been shown experimentally to depend on the square of rock tensile strength across the full range of rock strengths encountered in the field. This result is consistent with fracture mechanics theory which predicts that fractures propagate when the capacity of brittle materials to store impact energy by elastic deformation is exceeded. Strain energy depends on the square of tensile strength, but also on the elastic modulus. Log-log linear regression of laboratory measurements of bedrock erosion rates against tensile strength shows order-of -magnitude variability about the power-law fit, particularly for stronger rocks. In this investigation we seek to explain this variability in terms of other rock material properties. In particular we are examining elastic modulus, crystal grain size, mineralogy, degree of cementation, rock bulk density and porosity. We have access to the same rocks used in previous bedrock abrasion experiments, as well as artificial bedrock made from controlled mixtures of sand and portland cement. We measure tensile strength by the Brazilian splitting test, and estimate elastic modulus from measurements of the velocity of ultrasonic pulses through core samples. We are analyzing thin sections and photomicrographs to measure crystal grain size, and mineral and cement composition. Bulk density, as well as porosity, are measured by comparison of dry and saturated weights for known volumes of material. Preliminary results suggest that coarse-grained rocks, such as granite and some sandstones, are less erodible for a given measured tensile strength than the fine-grained rocks tested, which include greenstone, andesite and limestone. We also find, with a small subset of rock types tested to-date, that inclusion of elastic modulus in a multiple regression reduces the uncertainty in the regression slope estimate, but that substantial variability remains to be explained. This work may have broad applicability in understanding erodibility of terrestrial bedrock by fluvial as well as eolian mechanisms, as well as controls on the surface erodibility of ice ‘bedrock’ on outer solar system satellites such as Titan.

Beyeler, J. D.; Sklar, L. S.; Litwin, K.; Johnson, J. P.; Collins, G. C.; Whipple, K. X.

2009-12-01

169

Studies on the reduction of tensile strength of tablets after roll compaction/dry granulation.  

PubMed

Roll compaction/dry granulation is a widely used technique for granulation. A major drawback is the reduction of tablet tensile strength compared to other granulation methods. The purpose of this study was to determine the reasons for the partial loss in compactibility. Microcrystalline cellulose of different particle sizes was roll-compacted/dry-granulated. The granules were sieved to obtain two sieve cuts and then compressed into tablets. The particle-size distribution within the sieve cut was determined using image analysis. The specific surface area of sieve cut was obtained by nitrogen adsorption. Heckel equation was used to determine the change in compressibility. The work-hardening phenomenon was found to be caused by a combination of particle-size enlargement and hardening of material. Although particle size of granules was equal, the use of smaller particles as raw material resulted in tablets with higher tensile strength due to higher specific surface area. Both work-hardening and particle-size enlargement cause the partial loss in compactibility. The reduction in tensile strength could be compensated by producing smaller granules or using raw materials with small particle sizes. PMID:18511247

Herting, Michael G; Kleinebudde, Peter

2008-09-01

170

Influence of Tm:YAP laser irradiation on tensile strength for bracket debonding  

NASA Astrophysics Data System (ADS)

The investigation of tensile strength needed for bracket debonding was the aim of study. A diode pumped Tm: YAP microchip laser generating a continuous 2um radiation with the maximum output power of 4W was used for debonding purposes. The group of 60 brackets was debonded using classical and laser irradiation methods - the doze from 1W to 4 W, 60s. The tensile strength without laser irradiation was in the range from 39.6 N (full ceramic bracket group) to 63.7 N (ceramic bracket with metal slot group). After irradiation the tensile strength was decreased from 35.1 N (full ceramic bracket group) to 48.8 N (ceramic bracket with metal slot group). The results of our study generally agree with the previous studies, substantiating the fact that lasers can be used effectively to thermally soften the adhesive resin for removal of ceramic brackets. From the practical point of view is conclusion that during laser irradiation, thermal ablation occurs and the bracket is removed from the enamel together with the rest of the adhesive resin. Laser debonding is easier and little heat diffusion occurred.

Dostalova, Tatjana; Jelinkova, Helena; Sulc, Jan; Koranda, Petr; Nemec, Michal; Fibrich, Martin; Jelinek, Michal; Michalik, Pavel; Miyagi, Mitsunobu

2011-03-01

171

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.

172

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

173

Comparative tensile strength test of repair mortars used in the restoration of porous limestones  

NASA Astrophysics Data System (ADS)

The present paper focuses on the influence of strength parameters of repair mortars that are used in the restoration of porous limestone. Mortars with different aggregate percentages were tested. The pure product and the mixture of binder and grinded limestone aggregate of 50% were used to prepare test specimens. 6 types of mortar with 2 different mixtures (18 series) were analyzed under laboratory conditions. Ultimate tensile strength measurements were performed after 28 days of casting the specimens. Durability was measured by comparing strength test results of samples prepared on porous limestone surface with and without pre-treatment, and with different aggregate ratio. The influences of aggregate ratio, casting preparation and pre-treatment are discussed. Strength reduction has been determined due to the increased aggregate volume, and the decreased pre-treatment process. The research focused on the compatibility of repair mortars with natural stones and the importance of the proper treatment during loss compensation of stones.

Szemerey-Kiss, Balįzs; Török, Įkos

2013-04-01

174

Relationship between plasticizer content and tensile bond strength of soft denture liners to a denture base resin.  

PubMed

The purpose of this study was to determine the influence of plasticizer content on the tensile bond strength of heat-cured acrylic soft denture liners to a denture base resin. Differences among materials were significant, except for 100 wt% Dibutyl Sebacate (DBS) and 80 wt% DBS of tensile bond strength. The bond strength of all materials to the denture base increased with an increase in thermal cycles significantly except for 40 wt% DBS. The tensile bond strength of soft denture liners to the denture base resin significantly decreased with an increase of plasticizer contents. Differences were found among the difference plasticizer contents in failure types between the denture base resin and soft denture liners. The results suggest that the tensile bond strengths of heat-cured acrylic soft denture liners to the denture base resin were lower with an increase in plasticizer content. PMID:15287552

Hong, Guang; Murata, Hiroshi; Hamada, Taizo

2004-06-01

175

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

NASA Technical Reports Server (NTRS)

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

Bansal, Narottam P.

1998-01-01

176

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

SciTech Connect

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

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

2005-01-10

177

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

178

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

E-print Network

Energy Landscape and Isotropic Tensile Strength of n-Alkane Glasses Vincent K. Shen, Pablo G, 8, 16, 24, and 48. The ultimate isotropic tensile strength was determined by constructing the equation of state of energy landscape for this homologous series. The tensile strength depends

Stillinger, Frank

179

Identification of anisotropic tensile strength of cortical bone using Brazilian test.  

PubMed

For a proper analysis of cortical bone behaviour, it is essential to take into account both the elastic stiffness and the failure criteria. While ultrasound methods allow complete identification of the elastic orthotropic coefficients, tests used to characterise the various failure mechanisms and to identify the brittle tensile strength in all directions are currently inadequate. In the present work we propose the Brazilian test as a complement to conventional tensile tests. In fact, this experimental technique, rarely employed in the biomechanics field, has the potential to provide an accurate description of the anisotropic strength of cortical bone. Additionally, it allows us to assess the scale influence on failure behaviour which may be attributed to an intrinsic length in correlation with the cortical bone microstructure. In order to correctly set up the Brazilian test, several aspects such as the machining, the geometrical parameters of the specimen and the loading conditions were determined. The finite element method was used to evaluate the maximal tensile stress at the centre of a 2D anisotropic elastic specimen as a simple function of the loading. To validate the protocol, the Brazilian test was carried out on 29 cortical bovine cylindrical specimens with diameters ranging from 10mm to 4mm. PMID:25051151

Allena, Rachele; Cluzel, Christophe

2014-10-01

180

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

E-print Network

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

Whitesel, Dean Adam

2012-06-07

181

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

182

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

183

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

184

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

185

Tensile strength of carbyne chains in varied chemical environments and structural lengths  

NASA Astrophysics Data System (ADS)

Carbyne and carbyne-based low-dimensional structures are promising for several applications including ultra-compact circuits and purification devices. Designing any applied carbyne-based structure requires a fundamental understanding of the mechanical strength of carbyne chains with different lengths at different temperatures and operating chemical environment. Here we use molecular dynamics simulations to investigate the strength of carbyne chains with different lengths at different temperatures. A theoretical framework based on statistical mechanics and molecular dynamics results is presented, proving a fast and insightful method for predicting the rupture force and its physical mechanism. The effect of water molecules’ interaction is also studied on the mechanical properties and it is shown that both the tensile strength and rupture strain are improved by the water interaction. The results of this work can be used for designing and analyzing the robustness and reliability of various carbyne-based materials and applied devices for varies working conditions.

Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J.

2014-09-01

186

Tensile strength of carbyne chains in varied chemical environments and structural lengths.  

PubMed

Carbyne and carbyne-based low-dimensional structures are promising for several applications including ultra-compact circuits and purification devices. Designing any applied carbyne-based structure requires a fundamental understanding of the mechanical strength of carbyne chains with different lengths at different temperatures and operating chemical environment. Here we use molecular dynamics simulations to investigate the strength of carbyne chains with different lengths at different temperatures. A theoretical framework based on statistical mechanics and molecular dynamics results is presented, proving a fast and insightful method for predicting the rupture force and its physical mechanism. The effect of water molecules' interaction is also studied on the mechanical properties and it is shown that both the tensile strength and rupture strain are improved by the water interaction. The results of this work can be used for designing and analyzing the robustness and reliability of various carbyne-based materials and applied devices for varies working conditions. PMID:25148690

Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J

2014-09-19

187

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

PubMed

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

Bora, Limpon; Das, Reshmi; Gohain, Dibakar

2014-09-01

188

Effect of abnormal grain growth on tensile strength of Al–Cu–Mg alloy friction stir welded joints  

Microsoft Academic Search

An Al-4.5%Cu-1.5%Mg aluminum alloy with a T4 temper was friction stir welded, and the effect of the abnormal grain growth\\u000a on the tensile strength of joints was investigated. Abnormal grain growth usually happens during post weld heat treatment.\\u000a It is found that the tensile strength and elongation of the heat-treated joint will increase significantly if this phenomenon\\u000a completely happens in

M. A. Safarkhanian; M. Goodarzi; S. M. A. Boutorabi

2009-01-01

189

Standard test method for splitting tensile strength for brittle nuclear waste forms  

E-print Network

1.1 This test method is used to measure the static splitting tensile strength of cylindrical specimens of brittle nuclear waste forms. It provides splitting tensile-strength data that can be used to compare the strength of waste forms when tests are done on one size of specimen. 1.2 The test method is applicable to glass, ceramic, and concrete waste forms that are sufficiently homogeneous (Note 1) but not to coated-particle, metal-matrix, bituminous, or plastic waste forms, or concretes with large-scale heterogeneities. Cementitious waste forms with heterogeneities >1 to 2 mm and 5 mm can be tested using this procedure provided the specimen size is increased from the reference size of 12.7 mm diameter by 6 mm length, to 51 mm diameter by 100 mm length, as recommended in Test Method C 496 and Practice C 192. Note 1—Generally, the specimen structural or microstructural heterogeneities must be less than about one-tenth the diameter of the specimen. 1.3 This test method can be used as a quality control chec...

American Society for Testing and Materials. Philadelphia

1989-01-01

190

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

191

Relationship of the diameter and tensile strength of nylon sutures to the USP specification and the effect of preconditioning.  

PubMed

Nylon monofilament sutures were tested in a straight pull as well as a conventional knot pull tensile test. In each test, sutures were evaluated following storage under prevailing atmospheric conditions or saturation in whole human blood. Blood saturation decreased the ultimate tensile strength by as much as 20%. The present investigation of sutures that were stored under prevailing atmospheric conditions substantiated the proposal previously made for polypropylene monofilaments--that 60% of the ultimate tensile strength could be established as a fundamental USP criterion for Class I monofilament sutures. PMID:10148999

Whitley, J Q; Prewitt, M J; Kusy, R P

1990-01-01

192

Addition of zinc methacrylate in dental polymers: MMP-2 inhibition and ultimate tensile strength evaluation  

Microsoft Academic Search

This study evaluated the effect of zinc methacrylate (ZM) on the inhibition of matrix metalloproteinase 2 (MMP-2) and the\\u000a ultimate tensile strength (UTS) of an experimental polymer. Enzymes secreted from mouse gingival tissues were analyzed by\\u000a gelatin zymography in buffers containing 5 mM CaCl2 (Tris–CaCl2) in 50 mM Tris–HCl buffer with various concentrations of ZM (0.5, 1, 2, 4, 8, and 16 mM).

Sandrina Henn; Rodrigo Varella de Carvalho; Fabrķcio Aulo Ogliari; Ana Paula de Souza; Sergio Roberto Peres Line; Adriana Fernandes da Silva; Flįvio Fernando Demarco; Adriana Etges; Evandro Piva

193

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

194

Measurement of the tensile and yield strength of boiler steels by sm all punch and tensile test methods  

Microsoft Academic Search

Miniature disk-shaped specimens have been used to evaluate the tensile properties of boiler steels 20, 12Ch1MF, 12Ch11V2MF and 16GNM at room temperature by using the small punch test. Conventional uniaxial tensile tests of standard cylindrical specimens from the same materials have been also performed for comparison. On the basis of comparative analysis a correlation between the maximum punch force and

Ivan Klevtsov; Andrei Dedov; Artjom Molodtsov

2009-01-01

195

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

196

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

PubMed

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

Liu, Jie; Lu, Xiaolong; Wu, Chunrui

2013-01-01

197

Effects of strain-rate and pre-fatigue on tensile properties of laser welded joint of high strength steel plates  

Microsoft Academic Search

The impact tensile properties of laser welded butt joints of two kinds of high strength steel plates with the tensile strength level of 590 MPa and 780 MPa (denoted by HR590 and HR780, respectively), were investigated using split Hopkinson bar tensile testing apparatus. Impact tension tests for the joint specimens pre-fatigued were also carried out to examine the effect of

H. Kobayashi; M. Daimaruya; H. Tsuda; K. Horikawa

2006-01-01

198

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

199

Effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded high strength aluminium alloy  

Microsoft Academic Search

This paper reveals the effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded AA7075 aluminium alloy. This alloy has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength

V. Balasubramanian; V. Ravisankar; G. Madhusudhan Reddy

2007-01-01

200

Addition of zinc methacrylate in dental polymers: MMP-2 inhibition and ultimate tensile strength evaluation.  

PubMed

This study evaluated the effect of zinc methacrylate (ZM) on the inhibition of matrix metalloproteinase 2 (MMP-2) and the ultimate tensile strength (UTS) of an experimental polymer. Enzymes secreted from mouse gingival tissues were analyzed by gelatin zymography in buffers containing 5 mM CaCl(2) (Tris-CaCl(2)) in 50 mM Tris-HCl buffer with various concentrations of ZM (0.5, 1, 2, 4, 8, and 16 mM). The matrix metalloproteinases present in the conditioned media were characterized by immunoprecipitation. The polymer UTS evaluation was performed in eight groups with various concentrations of ZM (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt.%), in a mechanical testing machine. MMP-2 (62 kDa) was detected in the zymographic assays and inhibited by ZM in all tested concentrations. UTS data were submitted to one-way ANOVA and Tukey's test (??=?0.05), and no significant differences were observed among groups, except in the polymer containing 30% ZM, presenting a significantly lower value when compared with the control group (p?tensile strength of the polymer. Zinc methacrylate is a metalloproteinase inhibitor that can be copolymerized with other methacrylate monomers. Yet, the addition of ZM did not affect the resin bond strength. Thus, in vivo tests should be performed to evaluate the performance of this material. PMID:21448634

Henn, Sandrina; de Carvalho, Rodrigo Varella; Ogliari, Fabrķcio Aulo; de Souza, Ana Paula; Line, Sergio Roberto Peres; da Silva, Adriana Fernandes; Demarco, Flįvio Fernando; Etges, Adriana; Piva, Evandro

2012-04-01

201

Comparison of the flexural strength of six reinforced restorative materials.  

PubMed

This study calculated the flexural strength for six reinforced restorative materials and demonstrated that flexural strength values can be determined simply by using physical parameters (diametral tensile strength and Young's modulus values) that are easily determined experimentally. A one-way ANOVA analysis demonstrated a statistically significant difference between the two reinforced glass ionomers and the four composite resin materials, with the composite resin being stronger than the glass ionomers. PMID:12017792

Cohen, B I; Volovich, Y; Musikant, B L; Deutsch, A S

2001-01-01

202

Tensile strength of ash cake beds at high-temperature conditions  

SciTech Connect

The Energy and Environmental Research Center (EERC) is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The primary deliverable will be a graphics-driven computer model that can be used as an engineering tool to help predict ash-related hot-gas filter problems based on analyses of coal and sorbent, as well as system operating parameters. This paper presents preliminary testing data on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions. The range in temperatures for tensile testing is ambient to 900 C. The simulated gas atmosphere includes carbon dioxide, water vapor, oxygen, sulfur dioxide, sodium chloride, hydrochloric acid, and nitrogen. At present, all testing has been performed using ash from the Westinghouse advanced particle filter (APF) at the American Electric Power Service Corporation (AEP) Tidd pressurized fluidized-bed combustor (PFBC) demonstration plant in Ohio. Other sources of filter ashes, including several from non-American PFBC systems, will also be evaluated.

Dockter, B.A.; Hurley, J.P.

1996-12-31

203

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

204

Reinforcement of nylon 6 with functionalized silica nanoparticles for enhanced tensile strength and modulus.  

PubMed

Pristine and functionalized silica (SiO(2)) nanoparticles were dispersed into nylon 6 and drawn into filaments through melt extrusion. The loading fraction of particles in both cases was 1.0 wt%. Fourier transform infrared (FTIR) studies revealed that reinforcement of pristine silica nanoparticles enhances the bond strength of each of the three basic bonds of nylon 6 namely, hydroxyl, amide, and carbonyl. As a result, the improvement over neat nylon in strength and modulus was 36% and 28% respectively, without any loss of fracture strain (80%). A silane coupling agent was then used through wet chemical treatment to functionalize silica nanoparticles. Functionalization induced an additional covalent Si-O-Si (siloxane) bond between silica particles and nylon backbone polymer while the enhancement in the basic bonds was retained. FTIR and x-ray photoelectron spectroscopy (XPS) studies confirmed the formation of the siloxane bond. This added chemical bond resulted in 76% and 55% improvement in tensile strength and modulus, and still retained 30% fracture strain. Calculation of the upper bound on Young's modulus indicates that one can reach within 5% of the bound with pristine silica particles, but it is exceeded by 15% when particles are functionalized. PMID:21832744

Mahfuz, Hassan; Hasan, Mohammad; Dhanak, Vinod; Beamson, Graham; Stewart, Justin; Rangari, Vijaya; Wei, Xin; Khabashesku, Valery; Jeelani, Shaik

2008-11-01

205

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

206

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

207

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

208

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

209

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

210

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

211

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

Microsoft Academic Search

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

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

1997-01-01

212

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. PMID:22088916

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

2011-01-01

213

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

214

DEM simulation of diametrical compression test on particle compounds  

Microsoft Academic Search

A 2 Dimensional discrete element analysis is carried out with diametrical stressing condition to understand the fracture behaviour of particle compounds. The new surface generation and particle size distributions are also analysed to study an efficiency of the crushing system. Concrete spheres of 150 mm diameter with properties of B35 (35 N\\/mm2 compressive strength) are chosen to represent particle compounds.

Manoj Khanal; Wolfgang Schubert; Jürgen Tomas

2005-01-01

215

Structural disorder effects on the tensile strength distribution of heterogeneous brittle materials with emphasis on fiber networks  

NASA Astrophysics Data System (ADS)

Understanding the interplay of structural disorder and strength properties at various length scales can lead to improvements in the strength reliability of heterogeneous brittle materials. Various studies in ordered fiber- matrix composites have shown the existence of critical clusters of breaks and macroscopic weak-link scaling behavior. The fiber network in paper is structurally disordered. We verify experimentally that the tensile strength of newsprint samples follows weak-link scaling and obtain an estimate for the link and critical-cluster sizes. However, a slight nonlinear behavior is observed in the Weibull plots of the experimental strength distributions. We propose that this is due to mesoscopic structural disorder (e.g., at length scales between millimeters and centimeters), which we incorporate in the strength distribution of the links by averaging over the elastic stress variations. The prevailing industry perception is that mesoscopic disorder controls the strength reliability. In contrast, we find that it does not significantly affect the crucial lower tail of the strength distribution. Based on our analysis, we suggest a more reliable measurement approach for the tensile strength of newsprint paper. We also obtain explicit expressions for the effects of disorder on stress variations and the macroscopic Young’s modulus, including dependence on the shear modulus and anisotropic effects.

Hristopulos, Dionissios T.; Uesaka, Tetsu

2004-08-01

216

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

217

Research on tensile strength characteristics of bridge deck pavement bonding layers  

NASA Astrophysics Data System (ADS)

As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

Wu, Shaopeng; Han, Jun

2010-03-01

218

Research on tensile strength characteristics of bridge deck pavement bonding layers  

NASA Astrophysics Data System (ADS)

As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

Wu, Shaopeng; Han, Jun

2009-12-01

219

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

NASA Astrophysics Data System (ADS)

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, microstructure, and tensile strength.

Hemanth, J.; Rao, K. V. S.

1999-08-01

220

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

221

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

222

Effect of soldering techniques and gap distance on tensile strength of soldered Ni-Cr alloy joint  

PubMed Central

PURPOSE The present study was intended to evaluate the effect of soldering techniques with infrared ray and gas torch under different gap distances (0.3 mm and 0.5 mm) on the tensile strength and surface porosity formation in Ni-Cr base metal alloy. MATERIALS AND METHODS Thirty five dumbbell shaped Ni-Cr alloy specimens were prepared and assigned to 5 groups according to the soldering method and the gap distance. For the soldering methods, gas torch (G group) and infrared ray (IR group) were compared and each group was subdivided by corresponding gap distance (0.3 mm: G3 and IR3, 0.5 mm: G5, IR5). Specimens of the experimental groups were sectioned in the middle with a diamond disk and embedded in solder blocks according to the predetermined distance. As a control group, 7 specimens were prepared without sectioning or soldering. After the soldering procedure, a tensile strength test was performed using universal testing machine at a crosshead speed 1 mm/min. The proportions of porosity on the fractured surface were calculated on the images acquired through the scanning electronic microscope. RESULTS Every specimen of G3, G5, IR3 and IR5 was fractured on the solder joint area. However, there was no significant difference between the test groups (P > .05). There was a negative correlation between porosity formation and tensile strength in all the specimens in the test groups (P < .05). CONCLUSION There was no significant difference in ultimate tensile strength of joints and porosity formations between the gas-oxygen torch soldering and infrared ray soldering technique or between the gap distance of 0.3 mm and 0.5 mm. PMID:21264189

Lee, Sang-Yeob

2010-01-01

223

Individual and interacting effects of formulation variables on the tensile strength and microbial survival in diclofenac tablets  

Microsoft Academic Search

A work has been done to study the individual and interacting effects of formulation variables, using a 23 fractional factorial\\u000a design. The effects of five variables, namely, relative density of tablets, nature and concentration of binder, compression\\u000a process, and compression speed on the tensile strength and percent survival of Bacillus subtilis spores in Diclofenac tablet\\u000a formulations were determined. The effects

John O. Ayorinde; Oludele A. Itiola

2010-01-01

224

Effects of material properties and speed of compression on microbial survival and tensile strength in diclofenac tablet formulations.  

PubMed

A work has been done to study the effects of material properties and compression speed on microbial survival and tensile strength in diclofenac tablet formulations. Tablets were produced from three formulations containing diclofenac and different excipients (DC, DL and DDCP). Two types of machines (Hydraulic hand press and single punch press), which compress the tablets at different speeds, were used. The compression properties of the tablets were analyzed using Heckel and Kawakita equations. A 3-dimensional plot was produced to determine the relationship between the tensile strength, compression speed and percentage survival of Bacillus subtilis in the diclofenac tablets. The mode of consolidation of diclofenac was found to depends on the excipient used in the formulation. DC deformed mainly by plastic flow with the lowest Py and Pk values. DL deformed plastically at the initial stage, followed by fragmentation at the later stage of compression, whereas DDCP deformed mainly by fragmentation with the highest Py and Pk values. The ranking of the percentage survival of B. subtilis in the formulations was DDCP > DL > DC, whereas the ranking of the tensile strength of the tablets was DDCP > DL > DC. Tablets produced on a hydraulic hand press with a lower compression speed had a lower percentage survival of microbial contaminants than those produced on a single punch press, which compressed the tablets at a much higher speed. The mode of consolidation of the materials and the speed at which tablet compression is carried out have effects on both the tensile strength of the tablets and the extent of destruction of microbial contaminants in diclofenac tablet formulations. PMID:23471558

Ayorinde, J O; Itiola, O A; Odeniyi, M A

2013-03-01

225

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

Microsoft Academic Search

The aim of this in vitro study was to assess the effect of Er:YAG laser surface treatment on the tensile bond strength of\\u000a a sealant in permanent teeth. A total of 30 sound third molars were selected and embedded in cold-cure acrylic resin. The\\u000a enamel surfaces were flattened by a grinding. The teeth were randomly divided into three groups and

Sima Shahabi; Hossein G. Bagheri; Kosar Ramazani

226

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

SciTech Connect

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

Jonsen, P.; Haeggblad, H.-A. [Division of Solid Mechanics, Department of Applied Physics and Mechanical Engineering, Luleaa University of Technology, 971 87 Luleaa (Sweden)

2007-05-17

227

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

NASA Astrophysics Data System (ADS)

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

Jonsén, P.; Häggblad, H.-A.?.

2007-05-01

228

A scaffold-enhanced light-activated surgical adhesive technique: surface selection for enhanced tensile strength in wound repair  

NASA Astrophysics Data System (ADS)

An ex vivo study was conducted to determine the effect of the irregularity of the scaffold surface on the tensile strength of repairs formed using our Scaffold-Enhanced Biological Adhesive (SEBA). Two different scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biological material, small intestinal submucosa, manufactured by Cook BioTech. The scaffolds were doped with protein solder composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser. The tensile strength of repairs performed on bovine thoracic aorta, liver, spleen, small intestine and lung, using the smooth and irregular surfaces of the above scaffold-enhanced materials were measured and the time-to-failure was recorded. The tensile strength of repairs formed using the irregular surfaces of the scaffolds were consistently higher than those formed using the smooth surfaces of the scaffolds. The largest difference was observed on repairs formed on the aorta and small intestine, where the repairs were, on average, 50% stronger using the irregular versus the smooth scaffold surfaces. In addition, the time-to-failure of repairs formed using the irregular surfaces of the scaffolds were between 50% and 100% longer than that achieved using the smooth surfaces of the scaffolds. It has previously been shown that distributing or dispersing the adhesive forces over the increased surface area of the scaffold, either smooth or irregular, produces stronger repairs than albumin solder alone. The increase in the absolute strength and longevity of repairs seen in this new study when the irregular surfaces of the scaffolds are used is thought to be due to the distribution of forces between the many independent micro-adhesions provided by the irregular surfaces.

Soller, Eric C.; Hoffman, Grant T.; Heintzelman, Douglas L.; Duffy, Mark T.; Bloom, Jeffrey N.; McNally-Heintzelman, Karen M.

2004-07-01

229

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

230

Structural safety of coolant channel components under excessively high pressure tube diametral expansion rate at garter spring location  

NASA Astrophysics Data System (ADS)

Structural safety of coolant channel assembly in the event of high diametral expansion of pressure tube in a 220 MWe pressurised heavy water reactor was investigated using axisymmetric and 3-D finite element models. The axisymmetric analyses were performed and stresses were evaluated for pressure tube, girdle wire and calandria tube at different point of time for diametral expansion rates of 0.2%, 0.25% and 0.3% per year of the pressure tube inside diameter. The results of this study indicated that for the case of 0.3% per year of diametral expansion rate (worst case scenario), occurrence of complete circumferential interference of garter spring with calandria tube at the location of maximum expansion would take place much earlier at around 14 years or 4.2% of the total expansion of pressure tube as opposed to its anticipated design life (30 years). This fact was further corroborated by 3-D finite element analysis performed for the actual assembly configuration under actual loadings. The latter analysis revealed that net section yielding of calandria tube occurs in just 1 year after the occurrence of total circumferential interference between calandria tube and garter spring spacer. It has also been observed that the maximum stress intensity in girdle wire does not increase beyond the ultimate tensile strength even when maximum stress intensity in calandria tube reaches its yield strength. These analyses also revealed that the structural as well as functional integrity of pressure tube and the garter spring is not affected as result of this interference.

Aravind, M.; Sinha, S. K.

2013-08-01

231

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

232

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

233

Effect of Two Strength Reducing Techniques on the Ultimate Tensile Strength of AISI 4130 Steel: Rocket Motor Case Venting.  

National Technical Information Service (NTIS)

This work is part of a continuing program to find an economical, but safe and reliable, way to vent rocket motors subjected to an external fire. In this study, the effect on the ultimate strength of rocket motor case material of two methods of strength re...

M. S. Wright, R. F. Kubin

1984-01-01

234

Measurements of Young's modulus, Poisson's ratio, and tensile strength of polysilicon  

Microsoft Academic Search

New techniques and procedures are described that enable one to measure the mechanical properties of polysilicon films that are 3.5 ?m thick. Polysilicon is deposited onto a silicon substrate which is then etched away to leave a tensile specimen in the middle of the die. The grip ends of the structure are glued to the grips of a linear air

William N. Sharpe; Bin Yuan; R. Vaidyanathan; R. L. Edwards

1997-01-01

235

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

236

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

237

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

238

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

PubMed

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 with age (2-14 years) in black bear tibias. There were also no significant age-related changes in cortical bone porosity in black bear tibias. It is likely that the ability of black bears to maintain bone formation during hibernation keeps bone porosity low (2.3-8.6%) with aging, notwithstanding annual periods of disuse. This low porosity likely preserves ultimate stress with aging. Female bears give birth and nurse during hibernation; however, we found no significant differences between male and female tensile material properties, mineral content, or porosity. Our findings support the idea that black bears, which hibernate 5-7 months annually, have evolved biological mechanisms to mitigate the adverse effects of disuse on bone porosity and strength. PMID:16115638

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

2005-11-01

239

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

NASA Astrophysics Data System (ADS)

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

Hidayat, Irpan; Siauwantara, Alice

2014-03-01

240

Diametral compression of non-circular diaphyseal bone sections  

Microsoft Academic Search

Many research endeavors involve strength testing of long bones, frequently using whole-bone four-point bending models. Recently, diametral compression of short sections has been used to quantify local mechanical parameters and effects of treatment, but testing of biologically derived samples entails a number of added complications, such as the non-circularity of bone sections, ambiguity of load orientation during testing, thickness variation

Wesley J. Womack; Brandon G. Santoni; Christian M. Puttlitz

2008-01-01

241

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

PubMed

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

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

2012-11-01

242

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

243

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

244

AEREX 350 alloy: A 220 ksi minimum tensile strength fastener alloy for service up to 1350{degree}F  

SciTech Connect

AEREX{trademark} 350 Alloy is a new high strength, high temperature, corrosion resistant fastener material which has been developed to service the more demanding requirements typical of newer gas turbine engines. It exhibits the highest creep- and stress-rupture resistance known for any fastener material between 620 and 760 C (1,150 and 1,400 F). Furthermore, its coefficient of thermal expansion is equivalent to conventional nickel base superalloys, such as Waspaloy and Udimet 720. These characteristics combined with its excellent tensile and impact strengths, thermal stability and resistance to stress relaxation suggest that AEREX 350 Alloy is an excellent candidate for high temperature fastener applications, such as those existing in aircraft and land-based gas turbine engines.

Buzolits, S.R.; Lawler, M.J. [SPS Technologies, Inc., Jenkintown, PA (United States); Erickson, G.L. [Cannon-Muskegon Corp., Muskegon, MI (United States); Maloney, J.L. [Latrobe Steel Co., PA (United States)

1995-12-31

245

Water-solid interactions. III. Effect of glass transition temperature, Tg, and processing on tensile strength of compacts of lactose and lactose/polyvinyl pyrrolidone.  

PubMed

The effect of moisture sorption at different relative humidities on the tensile strength and the physical stability of compacts of crystalline and partly amorphous lactose, alone and in binary mixtures with PVP, has been studied. Furthermore, the role of moisture as a plasticizer and its effect on the glass transition temperature, Tg, are related to the compactibiltiy. Samples were conditioned for 2 hr using a climate test chamber at different relative humidities. Moisture sorption was determined, the radial crushing strength for compacts was measured immediately and after storage, and the tensile strength was calculated. The glass transition temperature, Tg, was determined using DSC. The tensile strength of the compacts was found to depend on both the conditioning humidity and the humidity during storage. An increase in humidity to a level at which the glass transition temperature, Tg, fell below the operating temperature, T, resulted in transition from a rigid glassy state to a mobile rubbery state. For compacts of partly amorphous lactose, an increase in the tensile strength was observed during storage of tablets, due to recrystallization of the amorphous regions above Tg. Tablets of mixtures of lactose and PVP exhibit a sharp decrease in tensile strength at humidities above 70% RH, due to the glass-to-rubber transition of PVP. PMID:9552346

Stubberud, L; Arwidsson, H G; Hjortsberg, V; Graffner, C

1996-07-01

246

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

PubMed Central

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

TURKMEN, Cafer; DURKAN, Meral; CIMILLI, Hale; OKSUZ, Mustafa

2011-01-01

247

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

248

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

249

Tensile strength of composite sheets with unidirectional stringers and crack-like damage  

NASA Technical Reports Server (NTRS)

The damage tolerance characteristics of metal tension panels with riveted and bonded stringers are well known. The stringers arrest unstable cracks and retard propagation of fatigue cracks. Residual strengths and fatigue lives are considerably greater than those of unstiffened or integrally stiffened sheets. The damage tolerance of composite sheets with bonded composite stringers loaded in tension was determined. Cracks in composites do not readily propagate in fatigue, at least not through fibers. Moreover, the residual strength of notched composites is sometimes even increased by fatigue loading. Therefore, the residual strength aspect of damage tolerance, and not fatigue crack propagation, was investigated. About 50 graphite/epoxy composite panels were made with two sheet layups and several stringer configurations. Crack-like slots were cut in the middle of the panels to simulate damage. The panels were instrumented and monotonically loaded in tension to failure. The tests indicate that the composite panels have considerable damage tolerance, much like metal panels. 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

250

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.

1967-01-01

251

A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite  

NASA Technical Reports Server (NTRS)

A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semicircular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semicircular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is underway to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout).

Hiel, Clement C.; Sumich, Mark; Chappell, David P.

1991-01-01

252

A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite  

NASA Technical Reports Server (NTRS)

A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semi-circular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semi-circular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is under way to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout).

Hiel, Clement C.; Sumich, Mark; Chappell, David P.

1990-01-01

253

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

254

Comparison of in vitro tensile bond strengths of luting cements to metallic and tooth-colored posts.  

PubMed

The aim of this study was to compare the tensile bond strength of tooth-colored ceramic and carbon-fiber post materials as well as titanium and stainless steel post materials luted with three different kinds of luting cements. Disks of alloy post materials were polished with 600-grit SiC paper, air abraded, and ultrasonically cleaned. Ceramic surfaces were pretreated with hydrofluoric acid and silanized. Panavia F, Vitremer, and ProTec Cem cements were bonded to the post specimens and placed in a humidor for 24 hours. Specimens were placed in a jig, and the debonding values were obtained using a universal testing machine. Means and standard deviations were analyzed by two-way ANOVA. Panavia F provided the highest bond strengths for all types of post materials. ProTec Cem bonded more strongly to stainless steel and titanium than to zirconium oxide. Vitremer results were the lowest. Bonds to carbon-fiber post materials were weaker than to metallic post materials, but stronger than to zirconium oxide. In general, higher bond strengths resulted in a higher percentage of cohesive failures. PMID:15227773

Sahmali, Sevil; Demirel, Figen; Saygili, Gülbin

2004-06-01

255

Effect of the fiber-matrix interphase on the transverse tensile strength of the unidirectional composite material  

NASA Technical Reports Server (NTRS)

A simple one-dimensional fiber-matrix interphase model has been developed and analytical results obtained correlated well with available experimental data. It was found that by including the interphase between the fiber and matrix in the model, much better local stress results were obtained than with the model without the interphase. A more sophisticated two-dimensional micromechanical model, which included the interphase properties was also developed. Both one-dimensional and two-dimensional models were used to study the effect of the interphase properties on the local stresses at the fiber, interphase and matrix. From this study, it was found that interphase modulus and thickness have significant influence on the transverse tensile strength and mode of failure in fiber reinforced composites.

Tsai, H. C.; Arocho, A. M.

1992-01-01

256

A Discrete Element Model for Predicting Shear Strength and Degradation of Rock Joint by Using Compressive and Tensile Test Data  

NASA Astrophysics Data System (ADS)

A discrete element model is proposed to examine rock strength and failure. The model is implemented by UDEC, which is developed for this purpose. The material is represented as a collection of irregular-sized deformable particles interacting at their cohesive boundaries. The interface between two adjacent particles is viewed as a flexible contact whose constitutive law controls the material fracture and fragmentation properties. To reproduce rock anisotropy, an orthotropic cohesive law is developed for the contacts, which allows their shear and tensile behaviors to be different from each other. Using a combination of original closed-form expressions and statistical calibrations, a unique set of the contact microparameters are found based on the uniaxial/triaxial compression and Brazilian tension test data of a plaster. Applying the obtained microparameters, joint specimens, made of the same plaster, are simulated, where the comparison of the obtained results to laboratory data shows a reasonable agreement.

Kazerani, T.; Yang, Z. Y.; Zhao, J.

2012-09-01

257

Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study  

PubMed Central

Background: The condition of the denture bearing tissues may be adversely affected by high stress concentration during function. Chairside Denture (Hard and Soft) reliners are used to distribute forces applied to soft tissues during function. Tensile and shear bond strength has been shown to be dependent on their chemical composition. A weak bond could harbor bacteria, promote staining and delamination of the lining material. To investigate tensile and shear bond strength of 4 different commercially available denture relining materials to conventional heat cured acrylic denture base resin. Materials & Methods: 4 mm sections in the middle of 160 Acrylic cylindrical specimens (20 mm x 8 mm) were removed, packed with test materials (Mollosil, G C Reline Soft, G C Reline Hard (Kooliner) and Ufi Gel Hard and polymerized. Specimens were divided into 8 groups of 20 each. Tensile and shear bond strength to the conventional heat cured acrylic denture base resin were examined by Instron Universal Tensile Testing Machine using the equation F=N/A (F-maximum force exerted on the specimen (Newton) and A-bonding area= 50.24 mm2). One-way ANOVA was used for multiple group comparisons followed by Bonferroni Test and Hsu’s MCB for multiple pairwise comparisons to asses any significant differences between the groups. Results: The highest mean Tensile bond strength value was obtained for Ufi Gel Hard (6.49+0.08 MPa) and lowest for G C Reline Soft (0.52+0.01 MPa). The highest mean Shear bond strength value was obtained for Ufi Gel Hard (16.19+0.1 MPa) and lowest for Mollosil (0.59+0.05 MPa). The Benferroni test showed a significant difference in the mean tensile bond strength and the mean shear bond strength when the two denture soft liners were compared as well as when the two denture hard liners were compared. Hsu’s MCB implied that Ufi gel hard is better than its other closest competitors. Conclusion: The Tensile and Shear bond strength values of denture soft reliners were significantly lower than denture hard reliners. How to cite the article: Lau M, Amarnath GS, Muddugangadhar BC, Swetha MU, Das KA. Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study. J Int Oral Health 2014;6(2):55-61. PMID:24876703

Lau, Mayank; Amarnath, G S; Muddugangadhar, B C; Swetha, M U; Das, Kopal Anshuraj Ashok Kumar

2014-01-01

258

An Investigation of the Tensile Strength of a Composite-To-Metal Adhesive Joint  

NASA Astrophysics Data System (ADS)

The present study examines the feasibility of a simple concept composite-to-metal butt joint through the performance of both numerical and experimental studies. The composite part is made of glass/epoxy unidirectional layers made with the vacuum bag method. The geometry of the joint is typical for marine applications and corresponds to a low stiffness ratio. Two major parameters are investigated, namely the overlap length and the surface preparation of the steel adherent. Manufacturing of specimens and the procedure of the tensile tests are described in detail, giving hints for obtaining a better quality joint. Axial elongation and strains at various places of the joint were monitored and also numerically calculated. The tests revealed that the joint is quite effective, irrespectively of the steel surface preparation method. The failure loads are comparable and in some cases superior to other corresponding values found in the literature. The numerical models proved to adequately predict the structural response of the joint up to the loading where debonding starts.

Tsouvalis, Nicholas G.; Karatzas, Vassilios A.

2011-04-01

259

Predicting tensile strength of friction stir welded AA6061 aluminium alloy joints by a mathematical model  

Microsoft Academic Search

AA6061 aluminium alloy (Al–Mg–Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to weight ratio and good corrosion resistance. Compared to the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being

K. Elangovan; V. Balasubramanian; S. Babu

2009-01-01

260

Optimizing friction stir welding parameters to maximize tensile strength of AA2219 aluminum alloy joints  

Microsoft Academic Search

AA2219 aluminium alloy (Al-Cu-Mn alloy) has gathered wide acceptance in the fabrication of lightweight structures requiring\\u000a a high strength-to-weight ratio and good corrosion resistance. In contrast to the fusion welding processes that are routinely\\u000a used for joining structural aluminium alloys, the friction stir welding (FSW) process is an emerging solid state joining process\\u000a in which the material that is being

S. Babu; K. Elangovan; V. Balasubramanian; M. Balasubramanian

2009-01-01

261

Tensile bond strength to and SEM evaluation of ground and intact enamel surfaces  

Microsoft Academic Search

Objectives: The aim of this study was to evaluate the bonding of four commercially available adhesive systems to ground and intact enamel surfaces.Methods: Extracted human teeth were used to measure the microtensile bond strength to enamel and a field-emission scanning electron microscopy (FE-SEM) was used to observe the bonded interface and the effect of the surface conditioning of each material.

N Kanemura; H Sano; J Tagami

1999-01-01

262

Dynamic Tensile Strength of Low Temperature Ice and Kuiper Belt Size Distributions  

Microsoft Academic Search

We model mutual gravitationally driven impact interactions in a nearly gas-free environment of the Kuiper belt (KB) and use low-temperature (< 100 K) ice dynamic strength dependent collisional out-come (accretion vs. erosion and fragmentation) models. These lead to theoretically predictable distributions of object number density, vs. mass distributions. These derived mass distributions are comparable to the now rapidly growing KB

Thomas J. Ahrens; O. V. Fat'yanov; H. Engelhardt; W. C. Fraser

2009-01-01

263

Effect of Beverages on the Hardness and Tensile Bond Strength of Temporary Acrylic Soft Liners to Acrylic Resin Denture Base  

PubMed Central

Statement of Problem: Two potential problems commonly identified with a denture base incorporating a resilient liner are failure of the bond between acrylic resin and soft liner material, and loss of resiliency of the soft liner over time. Since patients may drink different beverages, it is important to evaluate their effects on physical properties of soft lining materials. Purpose: The objective of this in vitro study was to evaluate the effect of different beverages on the hardness of two temporary acrylic-based soft lining materials and their bond strength to the denture base resin. Materials and Method: For the hardness test; a total of 80 rectangular specimens (40mm×10mm×3mm) were fabricated from a heat-polymerized polymethylmethacrylate. Two commercially auto-polymerized acrylic resin-based resilient liners; Coe-Soft and Visco-gel were prepared according to the manufacturers’ instructions and applied on the specimens. For the tensile test, 160 cylindrical specimens (30mm×10mm) were prepared. The liners were added between specimens with a thickness of 3 mm. The specimens of both soft liners were divided into 4 groups (n=10) and immersed in distilled water as the control group, Coca-Cola, 8% and 50% ethanol. All groups were stored in separate containers at 37oC for 12 days. All beverages were changed daily. The hardness was determined using a Shore A durometer and tensile bond strength was determined in a ZwickRoell testing machine at a cross-head speed of 5mm/min. The results were analyzed using two-way ANOVA. Results: There was no significant interaction between the soft liners and the drinks for both hardness (p= 0.748) and bond strength (p= 0.902). There were statistically significant differences between all drinks for both hardness (p< 0.001) and bond strength (p< 0.05). Conclusion: Within the limitations of this study, it seems that drinking Coca-Cola and alcoholic beverages would not be potentially causing any problems for the temporary acrylic soft liners. PMID:24724142

Safari, A; Vojdani, M; Mogharrabi, S; Iraji Nasrabadi, N; Derafshi, R

2013-01-01

264

An evaluation of the +/-45 deg tensile test for the determination of the in-plane shear strength of composite materials  

NASA Technical Reports Server (NTRS)

The applicability of the +/-45 deg tensile test for the determination of the in-plane shear strength of advanced composite laminates is studied. The assumptions used for the development of the shear strength formulas were examined, and factors such as the specimen geometry and stacking sequence were assessed experimentally. It was found that the strength of symmetric and balanced +/-45 deg laminates depends primarily upon the specimen thickness rather than the specimen width. These findings have important implications for the +/-45 deg tensile test which is recommended by several organizations for the determination of the in-plane shear stress/strain response and the shear strength of continuous fiber reinforced composites. Modifications to the recommended practices for specimen selection and shear strength determination are suggested.

Kellas, S.; Morton, J.; Jackson, K. E.

1991-01-01

265

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

PubMed

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

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

2014-07-01

266

Tensile strength and adhesion formation of mesh fixation systems used in laparoscopic incisional hernia repair  

Microsoft Academic Search

Background  Mesh tearoff from the tissue is the most common reason for hernia recurrence after hernia surgery involving the use of a synthetic\\u000a mesh. Various fixation systems were critically compared in terms of their retention strength and the formation of adhesions.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  In a prospective study with 25 Sprague–Dawley rats, two pieces of Parietex composite meshes measuring 2 × 3 cm were fixed\\u000a intraperitoneally in

Christian Hollinsky; Thomas Kolbe; Ingrid Walter; Anja Joachim; Simone Sandberg; Thomas Koch; Thomas Rülicke; Albert Tuchmann

2010-01-01

267

Metalloproteases meprin ? and meprin ? are C- and N-procollagen proteinases important for collagen assembly and tensile strength  

PubMed Central

Type I fibrillar collagen is the most abundant protein in the human body, crucial for the formation and strength of bones, skin, and tendon. Proteolytic enzymes are essential for initiation of the assembly of collagen fibrils by cleaving off the propeptides. We report that Mep1a?/? and Mep1b?/? mice revealed lower amounts of mature collagen I compared with WT mice and exhibited significantly reduced collagen deposition in skin, along with markedly decreased tissue tensile strength. While exploring the mechanism of this phenotype, we found that cleavage of full-length human procollagen I heterotrimers by either meprin ? or meprin ? led to the generation of mature collagen molecules that spontaneously assembled into collagen fibrils. Thus, meprin ? and meprin ? are unique in their ability to process and release both C- and N-propeptides from type I procollagen in vitro and in vivo and contribute to the integrity of connective tissue in skin, with consequent implications for inherited connective tissue disorders. PMID:23940311

Broder, Claudia; Arnold, Philipp; Vadon-Le Goff, Sandrine; Konerding, Moritz A.; Bahr, Kerstin; Muller, Stefan; Overall, Christopher M.; Bond, Judith S.; Koudelka, Tomas; Tholey, Andreas; Hulmes, David J. S.; Moali, Catherine; Becker-Pauly, Christoph

2013-01-01

268

Metalloproteases meprin ? and meprin ? are C- and N-procollagen proteinases important for collagen assembly and tensile strength.  

PubMed

Type I fibrillar collagen is the most abundant protein in the human body, crucial for the formation and strength of bones, skin, and tendon. Proteolytic enzymes are essential for initiation of the assembly of collagen fibrils by cleaving off the propeptides. We report that Mep1a(-/-) and Mep1b(-/-) mice revealed lower amounts of mature collagen I compared with WT mice and exhibited significantly reduced collagen deposition in skin, along with markedly decreased tissue tensile strength. While exploring the mechanism of this phenotype, we found that cleavage of full-length human procollagen I heterotrimers by either meprin ? or meprin ? led to the generation of mature collagen molecules that spontaneously assembled into collagen fibrils. Thus, meprin ? and meprin ? are unique in their ability to process and release both C- and N-propeptides from type I procollagen in vitro and in vivo and contribute to the integrity of connective tissue in skin, with consequent implications for inherited connective tissue disorders. PMID:23940311

Broder, Claudia; Arnold, Philipp; Vadon-Le Goff, Sandrine; Konerding, Moritz A; Bahr, Kerstin; Müller, Stefan; Overall, Christopher M; Bond, Judith S; Koudelka, Tomas; Tholey, Andreas; Hulmes, David J S; Moali, Catherine; Becker-Pauly, Christoph

2013-08-27

269

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

NASA Astrophysics Data System (ADS)

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

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

2000-08-01

270

Effect of different stages of tensile deformation on micromagnetic parameters in high-strength, low-alloy steel  

SciTech Connect

The influence of tensile deformation on the magnetic Barkhausen emissions (MBE) and hysteresis loop has been studied in a high-strength, low-alloy steel (HSLA) and its weldment. The magnetic measurements were made both in loaded and unloaded conditions for different stress levels. The root-mean-square (RMS) voltage of the MBE has been used for analysis. This study shows that the preyield and postyield deformation can be identified from the change in the MBE profile. The initial elastic deformation showed a linear increase in the MBE level in the loaded condition, and the MBE level remained constant in the unloaded condition. The microplastic yielding, well below the macroyield stress, significantly reduces the MBE, indicating the operation of grain-boundary dislocation sources below the macroyield stress. This is indicated by the slow increase in the MBE level in the loaded condition and the decrease in the MBE level in the unloaded condition. The macroyielding resulted in a significant increase in the MBE level in the loaded condition and, more clearly, in the unloaded condition. The increase in the MBE level during macroyielding has been attributed to the grain rotation phenomenon, in order to maintain the boundary integrity between adjacent grains, which would preferentially align the magnetic domains along the stress direction. This study shows that MBE during tensile deformation can be classified into four stages: (1) perfectly elastic, (2) microplastic yielding, (3) macroyielding, and (4) progressive plastic deformation. A multimagnetic parameter approach, combining the hysteresis loop and MBE, has been suggested to evaluate the residual stresses.

Vaidyanathan, S.; Moorthy, V.; Kalyanasundaram, P.; Jayakumar, T.; Raj, B. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Metallurgy and Materials Group

1999-08-01

271

Dependence of ultimate tensile strength of friction stir welded AA2024-T6 aluminium alloy on friction stir welding process parameters  

Microsoft Academic Search

parameters. The present research work is aimed to evaluate the interaction effects of four process parameters viz., tool rotational speed N, welding speed S, tool pin diameter D and tool axial plunging force F on the tensile strength of FS welded AA2024 -T6 joints fabricated using the newly developed tool. Response surface method (RSM) was em- ployed to develop the

N. Shanmuga Sundaram; N. Murugan

272

On the role of axial load and the effect of interface position on the tensile strength of a friction stir welded aluminium alloy  

Microsoft Academic Search

This investigation highlights the influence of axial load, and the effect of position of the interface with respect to the tool axis on tensile strength of the friction stir welded joint. The axial load is continuously varied by linearly increasing the interference between the tool shoulder and the surface of the base material. The interface position with respect to the

K. Kumar; Satish V. Kailas

2008-01-01

273

Estimation of tensile strengths at 4K of 316LN forging and hot rolled plate for the ITER toroidal field coils  

NASA Astrophysics Data System (ADS)

A prediction method for both yield and tensile strengths of stainless steels from room temperature to liquid helium temperature (4K) has been developed by JAEA in order to rationalize qualification tests of cryogenic structural materials used in large superconducting magnet for a fusion device. This method is to use quadratic curves which are expressed as a function of carbon and nitrogen contents and strengths at room temperature. This study shows results of tensile tests at 4K and confirmation of accuracy of prediction method for tensile strengths at 4K for large forgings and thick hot rolled plates of austenitic stainless steels, which can be used in the actual coil case of the International Thermonuclear Experimental Reactor (ITER) toroidal field (TF) coils. These products are 316LN having high nitrogen and maximum thickness is 600mm. As the results, it was confirmed that the materials which satisfied ITER design requirement can be manufactured and the tensile strengths of these products at 4K can be predicted by using appropriate quadratic curves.

Iguchi, M.; Saito, T.; Kawano, K.; Takano, K.; Tsutsumi, F.; Chida, Y.; Nakajima, H.

2012-06-01

274

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

NASA Astrophysics Data System (ADS)

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

Gottnek, Mihįly; Süvegh, Kįroly; Pintye-Hódi, Klįra; Regdon, Géza

2013-08-01

275

Influence Of Holes On The In-Plane Tensile Strength And Fatigue Durability Of A NICALON(Trademark)/Si-N-C Ceramic Matrix Composite  

NASA Technical Reports Server (NTRS)

Effects of different sizes of holes as well as different percentages of open areas on the in-plane tensile strength and fatigue durability of the SiC/Si-N-C composite were investigated in this study. Test specimens with no holes, four different diameters of holes (1.0 to 3.2 mm), and four different open areas (20 to 35%) were machined. All mechanical testing was performed in air at a temperature of 910 C. Fatigue tests were conducted with a load ratio, R = 0.05, and a frequency of 0.33 Hz. In general, both the in-plane tensile strength of the composite and its fatigue durability decreased with an increase in the size of the hole and percentage of the open area. Reductions in the in-plane tensile strength and cyclic fatigue life of the composite were described by empirical equations with the diameter of the hole and the percent open area as the independent variables. The validity of these two empirical equations was verified with additional tensile and fatigue test data generated on the composite specimens.

Kalluri, Sreeramesh; Verrilli, Michael J.

2003-01-01

276

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. PMID:22207613

Bauer, Georg; Speck, Thomas

2012-01-01

277

CARBON COMPOSITES BASED ON MULTI-AXIAL MULTI-PLY STITCHED PREFORMS: STIFFNESS DEGRADATION AND TENSILE STRENGTH EVOLUTION DURING FATIGUE  

Microsoft Academic Search

The fatigue properties of a 0°\\/90° carbon fibre non-crimp fabric reinforced epoxy composite were studied. Tensile-tensile fatigue cycling was carried out at load levels corresponding to the onset of damage in a static tensile test. Samples were tested in machine, cross and bias direction. Specimens in machine and cross direction did not fail up to 106 cycles; specimens in bias

Katleen Vallons; Mengmeng Zong; Stepan V. Lomov; Ignaas Verpoest

278

AN ANALYSIS OF A CYLINDRICAL GRAPHITE TUBE SUBJECTED TO DIAMETRAL COMPRESSION (thesis)  

Microsoft Academic Search

Installation of a segmented graphite sleeve column was proposed as a ; method of alleviating a control rod operational problem in a nuclear reactor. ; Diametral compression strength and deflection characteristics of each sixteen ; inch long segment of sleeve column were required to evaluate the adequacy of the ; proposed sleeve. These data also establish minimum requirements of alternate

Kempf

1962-01-01

279

Analysis of the diametrical compression test and the applicability to plastically deforming materials  

Microsoft Academic Search

The effect of contact flattening and material properties on the fracture stress calculation for the diametrical compression test used to evaluate compact strength was examined through finite element simulations. Two-dimensional simulations were carried out using linear elastic, elastoplastic, and porous elastoplastic models with commercial finite element software. A parametric study was performed by varying the elastic modulus (E), Poisson's ratio

A. T. Procopio; A. Zavaliangos; J. C. Cunningham

2003-01-01

280

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

281

An enhanced continuum modeling of the ideal strength and the angle of twist in tensile behavior of single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

By utilizing the fourth-, sixth-, eighth-, and tenth-order elastic moduli tensors of graphene a highly nonlinear constitutive model for it is proposed. Subsequently, an accurate analytical formulation, describing the entire tensile behavior of single-walled carbon nanotubes (SWCNTs) from their initial unloaded states through their ideal strengths, is made possible. The angle of twist which is a critical parameter that varies with the tensile loading is also calculated within the current framework. The estimated value of the theoretical strength of SWCNTs with different chiralities and radii as well as that of graphene ranges from 0.39 to 0.44 TPa. Some peculiarities associated with chirality of 15° are observed.

Delfani, M. R.; Shodja, H. M.

2013-08-01

282

Hair Regrowth and Increased Hair Tensile Strength Using the HairMax LaserComb for Low-Level Laser Therapy  

Microsoft Academic Search

The authors wished to confirm the efficacy of low level laser therapy (LLLT) using a Hair- Max LaserComb for the stimulation of hair growth and also to determine what effect LLLT with this device had on the tensile strength of hair. Thirty-five patients, 28 males and 7 fe- males, with androgenetic alopecia (AGA) underwent treatment for a six-month period. Both

John L. Satino; Michael Markou

2003-01-01

283

Optimization of process parameters of boro-carburized low carbon steel for tensile strength by Taquchi method with grey relational analysis  

Microsoft Academic Search

The results of study on the boro-carburizing and boronizing of AISI 1015 steel on tensile strength was carried out by Taquchi-grey relational method. The orthogonal array L9(34) was used to conduct the experiment. The thickness of boride layer increased with increase in process temperature and time. The thickness of boride layers for boronized AISI 1015 steel was more than the

Manoj Mathew; P. K. Rajendrakumar

2011-01-01

284

Artificial neural network a tool for predicting failure strength of composite tensile coupons using acoustic emission technique  

Microsoft Academic Search

A series of 18 tensile coupons were monitored with an acoustic emission (AE) system, while loading them up to failure. AE\\u000a signals emitted due to different failure modes in tensile coupons were recorded. Amplitude, duration, energy, counts, etc.,\\u000a are the effective parameters to classify the different failure modes in composites, viz., matrix crazing, fiber cut, and delamination,\\u000a with several subcategories

S. Rajendraboopathy; T. Sasikumar; K. M. Usha; E. S. Vasudev

2009-01-01

285

Revisiting the Recommended Geometry for the Diametrally Compressed Ceramic C-Ring Specimen  

Microsoft Academic Search

A study conducted several years ago found that a stated allowable width\\/thickness (b\\/t) ratio in ASTM C1323 (Standard Test Method for Ultimate Strength of Advanced Ceramics with Diametrally Compressed C-Ring Specimens at Ambient Temperature) could ultimately cause the prediction of a non-conservative probability of survival when the measured C-ring strength was scaled to a different size. Because of that problem,

Osama M. Jadaan; Andrew A Wereszczak

2009-01-01

286

Effects of pulsed Nd:YAG laser on tensile bond strength and caries resistance of human enamel.  

PubMed

This study aims to evaluate the effects of pulsed Nd:YAG laser on the tensile bond strength (TBS) of resin to human enamel and caries resistance of human enamel. A total of 201 human premolars were used in this in vitro study. A flat enamel surface greater than 4 × 4 mm in area was prepared on each specimen using a low-speed cutting machine under a water coolant. Twenty-one specimens were divided into seven groups for morphology observations with no treatment, 35% phosphoric acid etching (30 seconds), and laser irradiation (30 seconds) of pulsed Nd:YAG laser with five different laser-parameter combinations. Another 100 specimens were used for TBS testing. They were embedded in self-cured acrylic resin and randomly divided into 10 groups. After enamel surface pretreatments according to the group design, resin was applied. The TBS values were tested using a universal testing machine. The other 80 specimens were randomly divided into eight groups for acid resistance evaluation. Scanning electron microscope (SEM) results showed that the enamel surfaces treated with 1.5 W/20 Hz and 2.0 W/20 Hz showed more etching-like appearance than those with other laser-parameter combinations. The laser-parameter combinations of 1.5 W/15 Hz and 1.5 W/20 Hz were found to be efficient for the TBS test. The mean TBS value of 14.45 ± 1.67 MPa in the laser irradiated group was significantly higher than that in the untreated group (3.48 ± 0.35 MPa) but lower than that in the 35% phosphoric acid group (21.50 ± 3.02 MPa). The highest mean TBS value of 26.64 ± 5.22 MPa was identified in the combination group (laser irradiation and then acid etching). Acid resistance evaluation showed that the pulsed Nd:YAG laser was efficient in preventing enamel demineralization. The SEM results of the fractured enamel surfaces, resin/enamel interfaces, and demineralization depths were consistent with those of the TBS test and the acid resistance evaluation. Pulsed Nd:YAG laser as an enamel surface pretreatment method presents a potential clinical application, especially for the caries-susceptible population or individuals with recently bleached teeth. PMID:23919623

Wen, X; Zhang, L; Liu, R; Deng, M; Wang, Y; Liu, L; Nie, X

2014-01-01

287

Hardness and Tensile Strength of Multifilamentary Metal-matrix Composite Superconductors for the Large Hadron Collider (LHC)  

E-print Network

Conventional indentation hardness measurements to obtain load independent Vickers hardness values for the different phases in multifilamentary superconducting (SC) wires are described. The concept of composite hardness is validated for a binary metal-matrix metal-filament Nb-Ti/Cu composite wire. The tensile materials properties of the individual wire components are estimated from their indentation hardness. The potential and limitations of this approach are critically discussed, based on a comparison with tensile test results obtained for wires and extracted Nb-Ti filaments.

Scheuerlein, C; Leroy, D; Oberli, L; Rehmer, B

2007-01-01

288

An in vitro Comparative Evaluation of Micro Tensile Bond Strength of Two metal bonding Resin Cements bonded to Cobalt Chromium alloy  

PubMed Central

Background: The purpose of this study was to evaluate and compare the micro tensile bond strength of two metal bonding resin cements to sandblasted cobalt chromium alloy. Materials & Methods: Eight, Cobalt chromium alloy blocks of dimensions 10x5x5 mm were cast, finished and polished. One of the faces of each alloy block measuring 5x5mm was sandblasted with 50 ?m grit alumina particles. The alloy blocks were then cleaned in an ultrasonic cleaner for 1 min and then air dried with an air stream. The Sandblasted surfaces of the two alloy blocks were bonded together with 2 different metal bonding resin systems (Panavia F Kuraray and DTK Kleber – Bredent). The samples were divided into 2 groups (n=4). Group 1- Two Co-Cr blocks were luted with Panavia cement. Group 2- Two Co-Cr blocks were luted with DTK Kleber-Bredent cement. The bonded samples were cut with a diamond saw to prepare Microtensile bars of approximately 1mm x 1mm x 6mm. Thirty bars from each group were randomly separated into 2 subgroups (n=15) and left for 3hrs (baseline) as per manufacturer's instructions while the other group was aged for 24hrs in 370C water, prior to loading to failure under tension at a cross head speed of 1mm/min. Failure modes were determined by means of stereomicroscopy (sm). Statistical analysis was performed through one way – ANOVA. Results: Significant variation in micro-tensile bond strength was observed between the two metal bonding resin systems. Conclusion: DTK showed higher mean bond strength values than Panavia F cement both at baseline and after aging. How to cite this article: Musani S, Musani I, Dugal R, Habbu N, Madanshetty P, Virani D. An in vitro Comparative Evaluation of Micro Tensile Bond Strength of Two metal bonding Resin Cements bonded to Cobalt Chromium alloy. J Int Oral Health 2013;5(5):73-8. PMID:24324308

Musani, Smita; Musani, Iqbal; Dugal, Ramandeep; Habbu, Nitin; Madanshetty, Pallavi; Virani, Danish

2013-01-01

289

Compressive and tensile failure of inclined well bores and determination of in situ stress and rock strength  

Microsoft Academic Search

In this paper we investigate the occurrence of compressive and tensile failures of arbitrarily inclined well bores under a wide variety of stress conditions. The principal assumptions in this analysis are that the rock is isotropic and that it deforms elastically to the point of failure. As has been shown by previous investigators, for a given stress state and well

Pavel Peska; Mark D. Zoback

1995-01-01

290

Influence of Specimen Preparation and Specimen Size on the Transverse Tensile Strength and Scatter of Glass Epoxy Laminates  

NASA Technical Reports Server (NTRS)

The influence of specimen polishing, specimen configuration, and specimen size on the transverse tension strength of two glass epoxy materials loaded in three and four point bending was evaluated. Polishing machined edges, and/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 sensitive to span length due to the classical weakest link effect. However, strength was less sensitive to volume changes achieved by increasing specimen width. The Weibull scaling law 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, the utility of this scaling law for predicting transverse tension strength is unclear.

OBrien, T. Kevin; Chawan, Arun D.; DeMarco, Kevin

1999-01-01

291

Damage Initiation and Ultimate Tensile Strength of Scaled [0 deg n/90 deg n/0 deg n]sub T Graphite-Epoxy Coupons  

NASA Technical Reports Server (NTRS)

Previous research on scaling effects in composite materials has demonstrated that the stress levels at first ply failure and ultimate failure of composite laminates are dependent on the size of the laminate. In particular, the thickness dimension has been shown to be the most influential parameter in strength scaling of composite coupons loaded in tension. Geometrically and constitutively scaled laminates exhibit decreasing strength with increasing specimen size, and the magnitude of the strength-size effect is a function of both material properties and laminate stacking sequence. Some of the commonly used failure criteria for composite materials such as maximum stress, maximum strain, and tensor polynomial (e.g., Tsai-Wu) cannot account for the strength-size effect. In this paper, three concepts are developed and evaluated for incorporating size dependency into failure criteria for composite materials. An experimental program of limited scope was performed to determine the first ply failure stress in scaled cross-ply laminates loaded in tension. Test specimens were fabricated of AS-4/3502 graphite-epoxy composite material with laminate stacking sequences of [0 deg n/90 deg n/o deg n]subT where n=1-6. Two experimental techniques were used to determine first ply failure, defined as a transverse matrix crack in the 90 deg ply: (1) step loading with dye penetrant x-ray of the specimen at each load interval, and (2) acoustic emission. The best correlation between first ply failure analysis and experimental data was obtained using a modified Weibull approach which incorporated the residual thermal stress and the outer ply constraint, as well as the ply thickness effect. Finally, a second set of experiments was performed to determine the tensile response and ultimate failure of the scaled cross-ply laminates. The results of these experiments indicated no influence of specimen size on tensile response or ultimate strength.

Jackson, Karen E.; Prosser, William H.

1997-01-01

292

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

293

Artificial Neural Network Prediction of Ultimate Strength of Unidirectional T-300\\/914 Tensile Specimens Using Acoustic Emission Response  

Microsoft Academic Search

Acoustic Emission (AE) Monitoring was used to evaluate unidirectional carbon epoxy specimens when tensile loaded with a 100\\u000a kN Universal Testing Machine. A series of eighteen samples were loaded to failure to generate AE data for this analysis. After\\u000a data acquisition, AE response from each test was filtered to include only data collected up to 50% of the actual failure load

T. Sasikumar; S. Rajendraboopathy; K. M. Usha; E. S. Vasudev

2008-01-01

294

Failure strength prediction of unidirectional tensile coupons using acoustic emission peak amplitude and energy parameter with artificial neural networks  

Microsoft Academic Search

Acoustic emission studies have been carried out on 18 numbers of ASTM-3039 unidirectional carbon\\/epoxy tensile specimens, while loading to failure with a 100kN Universal Testing Machine. AE response from each of the specimens was filtered and the data acquired up to 50% of actual failure load was only considered for further analysis. Significant AE parameters like peak amplitude, event duration

T. Sasikumar; S. RajendraBoopathy; K. M. Usha; E. S. Vasudev

2009-01-01

295

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

296

Biphasic calcium phosphate loading on polycaprolactone/poly(lacto-co-glycolic acid) membranes for improved tensile strength, in vitro biocompatibility, and in vivo tissue regeneration.  

PubMed

Electrospun polycaprolactone and poly(lacto-co-glycolide) membranes were loaded with biphasic calcium phosphate powder to facilitate osteoconductivity. Different concentrations of biphasic calcium phosphate powder were added to the polymer solution, and successful loading was confirmed by X-ray diffraction analysis, transmission electron microscope, and scanning electron microscope with energy-dispersive spectroscopy visualization. The effect of the added biphasic calcium phosphate on the polymer membrane was investigated in terms of the material's tensile strength and strain, in vitro cytocompatibility, and in vivo tissue regeneration. It was observed that the tensile strength of the membranes increased with the addition of the biphasic calcium phosphate powder. Immersion in simulated body fluid solution for seven days leads to the formation of apatite-like deposits in the fibers, which further improved the mechanical stability. Moreover, proliferation and adhesion of osteoblast-like cells were more apparent upon the addition of the biphasic calcium phosphate powder as seen with the increasing cell density from (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and micrographs from scanning electron microscope and confocal microscopy. Sample membranes were also implanted to investigate the membrane's ability to regenerate bone in a rat calvarium. Histological staining and micro-CT histomorphometric analyses showed neo-bone formation in the implanted rat skull. PMID:24014247

Franco, Rose Ann; Sadiasa, Alexander; Seo, Hyung Seok; Lee, Byong-Taek

2014-04-01

297

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. PMID:24468201

2014-01-01

298

Numerical simulations of diametrical compression tests on agglomerates  

Microsoft Academic Search

The paper reports discrete element simulations of the diametrical compression test applied to two spherical agglomerates: one a dense agglomerate and the other a loosely packed agglomerate. The results obtained for the dense agglomerate show that the agglomerate fractures along a slightly inclined, approximately diametrical plane. Outwardly, the agglomerate shows all the characteristics of brittle fracture but half of the

C Thornton; M. T Ciomocos; M. J Adams

2004-01-01

299

Stresses and failure in the diametral compression test  

Microsoft Academic Search

The validity of the diametral disc test with a small flat ground has been established. The stress distribution was determined by a finite element method for a range of loading conditions. The results show that for the case of a point load, the failure is due to shear and compressive stresses at the loading point. Application of the diametral disc

M. K. Fahad

1996-01-01

300

Compressive and tensile failure at high fluid pressure where preexisting fractures have cohesive strength, with application to the San Andreas fault  

USGS Publications Warehouse

In thrusting and strike-slip situations, when the maximum principal horizontal stress S1 acts nearly normal to a fault (a misoriented fault, such as the San Andreas), pore-fluid pressure > the lithostatic load, Pf > Sv, is required to reactivate movement on that fault. Pf > Sv may be achieved without causing hydraulic tensile fracturing if (1) previously existing cracks have regained cohesive strength by chemical processes, (2) subcritical crack growth has been blunted, and (3) the least principal horizontal stress S3 nearly equals Sv. Where Pf > Sv has been attained within a misaligned fault, increasing the stress difference (S1 - S3) at constant Pf > Sv will not lead to shear failure, while a decrease in (S1 - S3) can lead to shear failure of that fault. However, where the cohesive strength of material in a broad misaligned fault zone is less than that of the surrounding intact rock, increasing (S1 - S3) while Pf > Sv can result in shear failure of fractures at near optimum angles to S1, but confined within this weak fault zone. If this faulting results in the local short-lived attainment of Pf > Sv (cataclastic deformation and frictional heating overcoming dilation) and a simultaneous decrease in (S1 - S3), this combination of effects can trigger movement along the main trace of the misaligned fault. When increasing Pf results in hydraulic failure, anisotropy in tensile strength or fracture toughness resulting from foliation within faults allows fractures to propagate along the planes of weakness rather than across the foliation perpendicular to S3.

Fournier, R.O.

1996-01-01

301

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

Microsoft Academic Search

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

S. Gopalakrishnan; N. Murugan

2011-01-01

302

Characterization of the influences of FSW tool geometry on welding forces and weld tensile strength using an instrumented tool  

Microsoft Academic Search

FSW process automation is essential to making consistent and reliable friction stir welds and this requires an understanding of how tool design can influence process parameters, which in turn can provide high joint strength and performance. Tool optimisation hinges on a better understanding of the effect of tool parameters on forces during welding, on the tool torque and tool temperature.

D. G. Hattingh; C. Blignault; T. I. van Niekerk; M. N. James

2008-01-01

303

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

NASA Astrophysics Data System (ADS)

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

Okayasu, Mitsuhiro; Takeuchi, Shuhei; Ohfuji, Hiroaki

2014-11-01

304

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

SciTech Connect

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

Boehlert, C.J.; Majumdar, B.S.; Krishnamurthy, S. [UES, Inc., Dayton, OH (United States); Miracle, D.B. [Wright Lab. Materials Directorate, Wright-Patterson AFB, OH (United States)

1997-02-01

305

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

NASA Technical Reports Server (NTRS)

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

Yun, Hee Mann; DiCarlo, James A.

1997-01-01

306

Effect of Load Rate on Tensile Strength of Various CFCCs at Elevated Temperatures: An Approach to Life Prediction Testing  

NASA Technical Reports Server (NTRS)

Strength of three continuous fiber-reinforced ceramic composites, including SiC/CAS-11, SiC/MAS-5 and SiC/SiC, was determined as a function of test rate in air at 1100 - 1200 C. All three composite materials exhibited a strong dependency of strength on 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) suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law tyw of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology even for the composite materials at least for the short range of lifetime.

Choi, Sung R.; Gyekenyesi, John P.

2001-01-01

307

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

308

Tensile strength of acrylic plastics (PPM) in the presence of a temperature gradient over the thickness of the material  

Microsoft Academic Search

Experimental values of the strength and deformation are presented for SO-95, SO-120, and SO-140 acrylic plastics (polymethyl methacrylate: plasticized, unplasticized, and copolymer) stressed in unaxial tension at v=10 mm\\/min, stationary temperature gradients of from 2.5 to 17.5 deg\\/mm over the thickness of the material, and a constant cold-face temperature of 25°C. The deformation properties under these conditions are described: in

B. I. Panshin; V. D. Kasyuk

1969-01-01

309

Comparative Evaluation of Tensile Bond Strength between Silicon Soft Liners and Processed Denture Base Resin Conditioned by Three Modes of Surface Treatment: An Invitro Study.  

PubMed

Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base. PMID:24431747

Surapaneni, Hemchand; Ariga, Padma; Haribabu, R; Ravi Shankar, Y; Kumar, V H C; Attili, Sirisha

2013-09-01

310

Rock tests in nonuniform fields of tensile stresses  

NASA Astrophysics Data System (ADS)

This paper presents experimental data on the strength of samples tested for bending and diametrically compressed core-shaped samples with a central hole. The obtained strengths of the samples are compared with the strength of samples under uniaxial tension using nonlocal strength criteria. It is shown that the calculated and measured strengths of the rock samples are in good agreement with each other when using a common approach to strength evaluation based on the Neuber-Novozhilov integral fracture criterion.

Efimov, V. P.

2013-09-01

311

Simultaneous determination of the impurity and radial tensile strength of reduced glutathione tablets by a high selective NIR-PLS method  

NASA Astrophysics Data System (ADS)

This paper establishes a high-throughput and high selective method to determine the impurity named oxidized glutathione (GSSG) and radial tensile strength (RTS) of reduced glutathione (GSH) tablets based on near infrared (NIR) spectroscopy and partial least squares (PLS). In order to build and evaluate the calibration models, the NIR diffuse reflectance spectra (DRS) and transmittance spectra (TS) for 330 GSH tablets were accurately measured by using the optimized parameter values. For analyzing GSSG or RTS of GSH tablets, the NIR-DRS or NIR-TS were selected, subdivided reasonably into calibration and prediction sets, and processed appropriately with chemometric techniques. After selecting spectral sub-ranges and neglecting spectrum outliers, the PLS calibration models were built and the factor numbers were optimized. Then, the PLS models were evaluated by the root mean square errors of calibration (RMSEC), cross-validation (RMSECV) and prediction (RMSEP), and by the correlation coefficients of calibration (Rc) and prediction (Rp). The results indicate that the proposed models have good performances. It is thus clear that the NIR-PLS can simultaneously, selectively, nondestructively and rapidly analyze the GSSG and RTS of GSH tablets, although the contents of GSSG impurity were quite low while those of GSH active pharmaceutical ingredient (API) quite high. This strategy can be an important complement to the common NIR methods used in the on-line analysis of API in pharmaceutical preparations. And this work expands the NIR applications in the high-throughput and extraordinarily selective analysis.

Li, Juan; Jiang, Yue; Fan, Qi; Chen, Yang; Wu, Ruanqi

312

Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin.  

PubMed

This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin. PMID:24190486

Jiang, Qianzhou; Chen, Minle; Ding, Jiangfeng

2013-12-01

313

Simultaneous determination of the impurity and radial tensile strength of reduced glutathione tablets by a high selective NIR-PLS method.  

PubMed

This paper establishes a high-throughput and high selective method to determine the impurity named oxidized glutathione (GSSG) and radial tensile strength (RTS) of reduced glutathione (GSH) tablets based on near infrared (NIR) spectroscopy and partial least squares (PLS). In order to build and evaluate the calibration models, the NIR diffuse reflectance spectra (DRS) and transmittance spectra (TS) for 330 GSH tablets were accurately measured by using the optimized parameter values. For analyzing GSSG or RTS of GSH tablets, the NIR-DRS or NIR-TS were selected, subdivided reasonably into calibration and prediction sets, and processed appropriately with chemometric techniques. After selecting spectral sub-ranges and neglecting spectrum outliers, the PLS calibration models were built and the factor numbers were optimized. Then, the PLS models were evaluated by the root mean square errors of calibration (RMSEC), cross-validation (RMSECV) and prediction (RMSEP), and by the correlation coefficients of calibration (R(c)) and prediction (R(p)). The results indicate that the proposed models have good performances. It is thus clear that the NIR-PLS can simultaneously, selectively, nondestructively and rapidly analyze the GSSG and RTS of GSH tablets, although the contents of GSSG impurity were quite low while those of GSH active pharmaceutical ingredient (API) quite high. This strategy can be an important complement to the common NIR methods used in the on-line analysis of API in pharmaceutical preparations. And this work expands the NIR applications in the high-throughput and extraordinarily selective analysis. PMID:24556136

Li, Juan; Jiang, Yue; Fan, Qi; Chen, Yang; Wu, Ruanqi

2014-05-01

314

Hardness and tensile strength of zircon particles and TiB 2 reinforced Al-A356.1 alloy matrix composites: comparative study  

NASA Astrophysics Data System (ADS)

Aluminum matrix composites are important engineering materials in automotive, aerospace, thermal, wear, and other applications because of excellent low weight, high specific strength, and better physical and mechanical properties compared to pure aluminum. In this paper, zircon and TiB II ceramic particles with different amounts were incorporated into Al-A356.1 alloy by stir-casting route. The ceramic particles size and adding temperature were 1 micron and 750°C respectively. Microstructure of samples has been investigated by scanning electron microscopy (SEM); hence the dispersion of reinforcement was noted. Situation of compounds of composites was examined by XRD. Mechanical tests such as hardness measurement, tensile and physical (density) tests were used. Results showed that the mechanical properties and microstructure behavior of composites have improved compared to monolithic alloy. Microstructures of the composites in as-cast conditions show uniform distribution particles and reveal better bonding in the case of zircon reinforced composite compare to TiB II, but increasing the amount of reinforcement shows better conditions in the case of TiB II reinforced composite. It is observed that TiB II reinforced composites have a better wetting condition compare to zircon reinforced composites.

Shirvani Moghaddam, K.; Abdizadeh, H.; Baharvandi, H. R.; Ehsani, N.; Abdi, F.

2007-07-01

315

Effect of Pre-Fatigue on Dynamic and Static Tensile Properties of Laser Welded Butt Joints Between Different High Strength Steel Plates  

Microsoft Academic Search

In this research, the effects of pre-fatigue on the dynamic and quasi-static tensile properties of laser welded butt joints between three kinds of steel plates, i.e. HR270, HR590 and HR780 steels, were investigated using tensile split Hopkinson bar apparatus. There were no significant effects of pre-fatigue on the dynamic and static tensile properties of HR780-HR270 and HR780-HR590 joints. Their fracture

H. Kobayashi; M. Daimaruya; H. Tsuda; K. Horikawa; Y. Yamada

2008-01-01

316

Compression of nanowires using a flat indenter: diametrical elasticity measurement.  

PubMed

A new experimental approach for the characterization of the diametrical elastic modulus of individual nanowires is proposed by implementing a micro/nanoscale diametrical compression test geometry, using a flat punch indenter. A 250 nm diameter single crystal silicon nanowire is compressed inside of a scanning electron microscope. Since silicon is highly anisotropic, the wire crystal orientation in the compression axis is determined by electron backscatter diffraction. In order to analyze the load-displacement compression data, a two-dimensional analytical closed-form solution based on a classical contact model is proposed. The results of the analytical model are compared with those of finite element simulations and to the experimental diametrical compression results and show good agreement. PMID:22432959

Wang, Zhao; Mook, William M; Niederberger, Christoph; Ghisleni, Rudy; Philippe, Laetitia; Michler, Johann

2012-05-01

317

Reexamination of the present stress state of the Atera fault system, central Japan, based on the calibrated crustal stress data of hydraulic fracturing tests obtained by measuring the tensile strength of rocks  

NASA Astrophysics Data System (ADS)

To investigate past faulting activity and the present physical state of intraplate faults in Japan, we reexamined the crustal stress measured by hydraulic fracturing tests (HFTs) incorporating the tensile strength of rocks. The tensile strength was measured by fracturing hollow cylindrical rock samples which were obtained close to the Atotsugawa, the Atera, and the Rokko-Awaji fault systems in central Japan, where in situ stress measurements had been conducted with HFTs. The measured tensile strength data reveal that the reopening pressure was obviously biased in the conventional HFT with a large compliance system. We reestimated the reopening pressure using the measured tensile strength and recalculated the in situ stress around the Atera fault system. We found that the shear stress decreases toward the fault. Although the past long-term slip direction of the Atera fault system has been considered to be left-lateral from the geomorphological features, the reestimated stress suggests that the present slip direction is right-lateral, a finding that is also supported by the present-day horizontal crustal deformation observed by triangulation and GPS surveys. The amount of accumulated right-lateral dislocation estimated from the stress data using the dislocation model of Okada (1992) was 2.1 m. Because the current slip rate from the GPS survey is 1.9 ± 1.4 mm/yr, the accumulation period of the right-lateral dislocation becomes approximately 1100 ± 800 years if the slip rate is stable. This estimation suggests that during the latest earthquake the Atera fault system underwent right-lateral dislocation.

Yamashita, Futoshi; Mizoguchi, Kazuo; Fukuyama, Eiichi; Omura, Kentaro

2010-04-01

318

Diametral compression tests of silicon carbide fibre-reinforced glass  

Microsoft Academic Search

Diametral compression tests were carried out for unidirectionally aligned silicon carbide fibrereinforced borosilicate glass. The fracture load dependence on the angle between the loading axis and the fibre alignment was investigated. The stress components in the fibre-aligned plane were calculated to evaluate the effect of the shear stress on fracture. Weibull statistics were employed to estimate the fracture load dependence

Akira Okada

1990-01-01

319

Observation of cracks propagating in diametrically-compressed rock discs  

Microsoft Academic Search

This study considers the cracking mechanism of diametrically-compressed rock disks. The crack initiation point, crack propagation velocity, and the stress field due to the dynamic crack running were studied using the strain gages as a crack detector. The troublesome problem concerning the determination of the crack initiation point encountered in the Brazilian test was solved directly. The experimental results show

I. Ito; O. Sano; M. Terada; T. Yanagidani

1978-01-01

320

Psychosis and autism as diametrical disorders of the social brain  

E-print Network

Psychosis and autism as diametrical disorders of the social brain Bernard Crespi Killam Research-correlated, in that autism involves a general pattern of constrained overgrowth, whereas schizophrenia involves undergrowth of autistic-spectrum and psychotic-spectrum conditions. Keywords: autism, cognition, genomic conflict, genomic

Haig, David

321

Diametric gene-dosage effects as windows into neurogenetic architecture  

E-print Network

, the development of pharmacological therapies, and mechanisms for the evolution of human brain and behavior diametric changes in gene dosage influence neurological development and function? Recent studies, and sex-chromosome aneuploidies are revealing examples of `mirror-extreme' brain and behavior phenotypes

Crespi, Bernard J.

322

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

323

Tensile city  

E-print Network

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

Chakkour, Mario Henri

1987-01-01

324

Optical diametric drive acceleration through action-reaction symmetry breaking  

NASA Astrophysics Data System (ADS)

Newton's third law of motion is one of the pillars of classical physics. This fundamental principle states that the forces two bodies exert on each other are equal and opposite. Had the resulting accelerations been oriented in the same direction, this would have instead led to a counterintuitive phenomenon, that of diametric drive. In such a hypothetical arrangement, two interacting particles constantly accelerate each other in the same direction through a violation of the action-reaction symmetry. Although in classical mechanics any realization of this process requires one of the two particles to have a negative mass and hence is strictly forbidden, it could nevertheless be feasible in periodic structures where the effective mass can also attain a negative sign. Here we report the first experimental observation of such diametric drive acceleration for pulses propagating in a nonlinear optical mesh lattice. The demonstrated reversal of action-reaction symmetry could enable altogether new possibilities for frequency conversion and pulse-steering applications.

Wimmer, Martin; Regensburger, Alois; Bersch, Christoph; Miri, Mohammad-Ali; Batz, Sascha; Onishchukov, Georgy; Christodoulides, Demetrios N.; Peschel, Ulf

2013-12-01

325

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

Microsoft Academic Search

This study considers the finite element analysis (FEA) simulation and Weibull effective size analysis for the diametral compression (DC) or Brazil specimen loaded with three different push-rod geometries. Those geometries are a flat push-rod, a push-rod whose radius of curvature is larger than that for the DC specimen, and a push-rod whose radius of curvature matches that of the DC

Osama M. Jadaan; Andrew A Wereszczak

2009-01-01

326

Diametral compression test: validation using finite element analysis  

Microsoft Academic Search

The validation of the diametral disk compression test with a small flat ground and soft pad utilization has been established.\\u000a The stress distribution was determined by the finite element analysis for a range of loading conditions. The results showed\\u000a that for the case of a point load, the fracture is due to shear and compressive stresses at the loading point.

Mahir H. Es-Saheb; Abdulmohsen Albedah; Faycal Benyahia

327

Parametric study of the diametral compression test for ceramics  

Microsoft Academic Search

The effects of sample size and padding material on the results obtained from the diametral compression test are presented and discussed. A series of uniform alumina samples ranging from 6.35 mm in diameter and 3.175 mm long to 12.70 mm in diameter and 12.70 mm long were tested. Tests were conducted using Cu, Al, Pb and polystyrene pads, IBM cards

R. H. Marion; J. K. Johnstone

1977-01-01

328

49 CFR 571.221 - Standard No. 221; School bus body joint strength.  

Code of Federal Regulations, 2012 CFR

...a force of 60 percent of the tensile strength of the weakest joined body panel...joint strength, determine the tensile strengths of the joined body components...that material's thickness and tensile strength per unit of area shown in...

2012-10-01

329

49 CFR 571.221 - Standard No. 221; School bus body joint strength.  

Code of Federal Regulations, 2013 CFR

...a force of 60 percent of the tensile strength of the weakest joined body panel...joint strength, determine the tensile strengths of the joined body components...that material's thickness and tensile strength per unit of area shown in...

2013-10-01

330

The effect of bone ingrowth depth on the tensile and shear strength of the implant-bone e-beam produced interface.  

PubMed

New technologies, such as selective electron beam melting, allow to create complex interface structures to enhance bone ingrowth in cementless implants. The efficacy of such structures can be tested in animal experiments. Although animal studies provide insight into the biological response of new structures, it remains unclear how ingrowth depth is related to interface strength. Theoretically, there could be a threshold of ingrowth, above which the interface strength does not further increase. To test the relationship between depth and strength we performed a finite element study on micro models with simulated uncoated and hydroxyapatite (HA) coated surfaces. We examined whether complete ingrowth is necessary to obtain a maximal interface strength. An increase in bone ingrowth depth did not always enhance the bone-implant interface strength. For the uncoated specimens a plateau was reached at 1,500 ?m of ingrowth depth. For the specimens with a simulated HA coating, a bone ingrowth depth of 500 ?m already yielded a substantial interface strength, and deeper ingrowth did not enhance the interface strength considerably. These findings may assist in optimizing interface morphology (its depth) and in judging the effect of bone ingrowth depth on interface strength. PMID:21858722

Tarala, M; Waanders, D; Biemond, J E; Hannink, G; Janssen, D; Buma, P; Verdonschot, N

2011-10-01

331

Stresses and failure in rings of rock loaded in diametral tension or compression  

Microsoft Academic Search

The failure of rock materials in the form of rings subjected to line loadings on either their internal or external surfaces is studied. Formulae for the stresses and some numerical values are given. Experimental results for three fine-grained rocks are given and values of the tensile strengths so obtained are compared with those from direct tension, indirect tension (Brazilian) and

J C Jaeger; E R Hoskins

1966-01-01

332

Nanoscale Strength Measurements and Standards  

E-print Network

grips. The test specimen is diametrally compressed via instrumented indentation, or nanoindentationNanoscale Strength Measurements and Standards CERAMICS To develop new mechanical test structures device reliability. Test specimens include as-deposited thin films, in addition to theta and C

Perkins, Richard A.

333

The influence of compression failure on the bending, impact bending and tensile strength of spruce wood and the evaluation of non-destructive methods for early detection  

Microsoft Academic Search

Bending strength (MOR) and bending Young’s modulus (MOE) according to DIN 52186 and MOE calculated on the basis of eigenfrequency and sound velocity were tested on small clear wood specimens of Norway spruce wood with and without compression failure. One group of specimens was climatised in a normal climate of 20°C and 65% relative humidity, while the other group was

W. Sonderegger; P. Niemz

2004-01-01

334

Structure of the Space of Diametrically Complete Sets in a Minkowski Space  

E-print Network

Structure of the Space of Diametrically Complete Sets in a Minkowski Space JosĀ“e Pedro Moreno and Rolf Schneider Abstract We study the structure of the space of diametrically complete sets in a finite di- mensional normed space. In contrast to the Euclidean case, this space is in general not convex

Schneider, Rolf

335

Investigation of strength of a hybrid adhesive anchor system used in precast concrete welded repair applications subjected to tensile and eccentric shear loading  

NASA Astrophysics Data System (ADS)

A common precast industry repair for missing or misplaced connection plates is the use of an adhesive anchor system to fasten repair plates to precast members. Typically, the repair plate will experience elevated temperatures during the welding of the loose erection plate to the repair plate. Limited testing and theoretical data are currently available to provide design guidelines on how the elevated temperatures induced by welding affect the behavior and capacity of the adhesive anchoring systems. This dissertation outlines bond tests, eccentric shear tests, and a temperature investigation performed using a hybrid adhesive system in precast concrete repair applications. In addition, limited bond strength testing data using a high strength two-part epoxy adhesive is also included. The overall aim of this work is to provide test data and guidance to the industry and design professionals when designing adhesive anchoring systems for repair applications exposed to welding.

Eilers, Michael Glenn

336

Establishing empirical relationships to predict grain size and tensile strength of friction stir welded AA 6061-T6 aluminium alloy joints  

Microsoft Academic Search

AA 6061-T6 aluminium alloy (Al-Mg-Si alloy) has gathered wide acceptance in the fabrication of light weight structures requiring a high specific strength and good corrosion resistance. Compared with the fusion welding processes that are routinely used for joining structural aluminium alloys, friction stir welding (FSW) process is an emerging solid state joining process in which the material welded does not

S. RAJAKUMAR; C. MURALIDHARAN; V. BALASUBRAMANIAN

2010-01-01

337

Modelling of the break force of tablets under diametrical compression.  

PubMed

A numerical method to predict the break force of curved faced tablets is proposed. The constitutive model and the failure criteria necessary to obtain predictions consistent with experimental data are identified. A modified Drucker-Prager cap model together with a maximum principal stress based failure criteria was found sufficient to predict the break force of tablets under diametrical compression loading. The conditions for the validity of the method were identified with reference to practical tablet shapes and failure patterns. Under these conditions the numerical procedures can be used as a practical tool to predict tablet breakage as an alternative to the empirical methods currently used in pharmaceutical product design and process development. PMID:23357256

Shang, C; Sinka, I C; Pan, J

2013-03-10

338

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

Code of Federal Regulations, 2012 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)...

2012-10-01

339

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

Code of Federal Regulations, 2013 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)...

2013-10-01

340

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

341

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

Code of Federal Regulations, 2011 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)...

2011-10-01

342

Identification of a keratinase-producing bacterial strain and enzymatic study for its improvement on shrink resistance and tensile strength of wool- and polyester-blended fabric.  

PubMed

A wool-degrading bacterium was isolated from decomposition wool fabrics in China. The strain, named 3096-4, showed excellent capability of removing cuticle layer of wool fibers, as demonstrated by removing cuticle layer completely within 48 h. According to the phenotypic characteristics and 16S rRNA profile, the isolate was classified as Pseudomonas. Bacteria growth and keratinase activity of the isolate were determined during cultivation on raw wool at different temperatures, initial pH, and rotation speed using orthogonal matrix method. Maximum growth and keratinase activity of the bacterium were observed under the condition including 30 °C, initial pH 7.6, and rotational speeds 160 rpm. The keratinase-containing crude enzyme prepared from 3096-4 was evaluated in the treatment of wool fabrics. The optimal condition of our enzymatic improvement of shrink resistance was the combination of 30 °C, initial pH 7.6, and rotation speeds 160 rpm. After the optimized treatment, the wool fabrics felting shrink was 4.1% at 6 h, and textile strength was not lost. PMID:20607444

Cai, Shao-Bo; Huang, Zheng-Hua; Zhang, Xing-Qun; Cao, Zhang-Jun; Zhou, Mei-Hua; Hong, Feng

2011-01-01

343

An in vitro study to compare the effect of two etching techniques on the tensile bond strength of resin cement bonded to base metal alloy and enamel.  

PubMed

Resin-bonded retainers are being preferred for anterior restorations. To increase the retentive strength of the metal fixed to the tooth, the retainer surface has to be etched. Different etching techniques are described in the literature with different researchers expressing the superiority of one technique over the other. This study was conducted to compare electro chemical and chemical etching techniques and the mode of bond failure. Twenty human maxillary premolars with the crown portion separated from root were embedded in resin block such that mesial or distal portion of it was exposed on the top of the block. 4 × 5 mm area was marked on the tooth, and wax pattern was prepared to cover the exact area, with the opposite end having a hook like structure which was later attached to universal testing machine. Wiron99 Ni-Cr alloy was used for casting. Once the casting and etching procedures were finished, wax patterns were invested, casted and half the samples were etched chemically using Aqua-regia and the other half samples were etched electrochemically. The castings were cleaned and cemented to tooth structure using Rely-X ARC (3 M ESPE, USA) resin cement. Specimens were fixed to universal testing machine and de-bonded. The load required to de-bond and mode of de-bonding was noted. Results were subjected to five different statistical tests, each test specific to the variable being tested. The mean failure load was calculated as 5.95 kg for electrochemically etched samples and that of chemically etched samples was calculated as 11.15 kg. The standard deviation of the force required to debond the specimens (Kgf) was calculated and found to be 0.65 for electrochemically etched samples and 1.11 for chemically etched samples. The following conclusions have been drawn from the study. 1. Chemical etching of the samples created better retentive surfaces than electrochemical etching. 2. The results of mode of de-bonding show that in case of chemical etching maximum debonding occurred at resin-enamel interface and in electrochemical type it occurred at resin-metal interface. PMID:24431780

Sudheer, Arunachalam; Shetty, Gautam

2013-12-01

344

Direct Lentiviral-Cyclooxygenase 2 Application to the Tendon-Bone Interface Promotes Osteointegration and Enhances Return of the Pull-Out Tensile Strength of the Tendon Graft in a Rat Model of Biceps Tenodesis  

PubMed Central

This study sought to determine if direct application of the lentiviral (LV)-cyclooxygenase 2 (COX2) vector to the tendon-bone interface would promote osteointegration of the tendon graft in a rat model of biceps tenodesis. The LV-COX2 gene transfer strategy was chosen for investigation because a similar COX2 gene transfer strategy promoted bony bridging of the fracture gap during bone repair, which involves similar histologic transitions that occur in osteointegration. Briefly, a 1.14-mm diameter tunnel was drilled in the mid-groove of the humerus of adult Fischer 344 rats. The LV-COX2 or ?gal control vector was applied directly into the bone tunnel and onto the end of the tendon graft, which was then pulled into the bone tunnel. A poly-L-lactide pin was press-fitted into the tunnel as interference fixation. Animals were sacrificed at 3, 5, or 8 weeks for histology analysis of osteointegration. The LV-COX2 gene transfer strategy enhanced neo-chondrogenesis at the tendon-bone interface but with only marginal effect on de novo bone formation. The tendon-bone interface of the LV-COX2-treated tenodesis showed the well-defined tendon-to-fibrocartilage-to-bone histologic transitions that are indicative of osteointegration of the tendon graft. The LV-COX2 in vivo gene transfer strategy also significantly enhanced angiogenesis at the tendon-bone interface. To determine if the increased osteointegration was translated into an improved pull-out mechanical strength property, the pull-out tensile strength of the LV-COX2-treated tendon grafts was determined with a pull-out mechanical testing assay. The LV-COX2 strategy yielded a significant improvement in the return of the pull-out strength of the tendon graft after 8 weeks. In conclusion, the COX2-based in vivo gene transfer strategy enhanced angiogenesis, osteointegration and improved return of the pull-out strength of the tendon graft. Thus, this strategy has great potential to be developed into an effective therapy to promote tendon-to-bone healing after tenodesis or related surgeries. PMID:24848992

Wergedal, Jon E.; Stiffel, Virginia; Lau, Kin-Hing William

2014-01-01

345

Ceramic granule strength variability and compaction behavior  

Microsoft Academic Search

Diametral compression strength distributions and the compaction behavior and of irregular shape 150--200 Ī¼m ceramic granules and uniform-size 210 Ī¼m glass spheres were measured to determine how granule strength variability relates to compaction behavior of granular assemblies. High variability in strength, represented by low Weibull modulus values (m<3) was observed for ceramic granules having a distribution of sizes and shapes,

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

1995-01-01

346

LEARNINGACTIVITY#2 Test the Strength of  

E-print Network

the factors that affect the tensile strength and the compressive strength of a structural member. n Design a testing program to determine the strength of structural members. n Determine the tensile strengthLEARNINGACTIVITY#2 Test the Strength of Structural Members Learning Activity #2: Overview

Bowen, James D.

347

Strength and toughness of barium titanate ceramics  

Microsoft Academic Search

The effect of processing variables on the mechanical and electrical properties of holmium-doped barium titanate ceramics with a positive temperature coefficient of resistance has been investigated. This paper contains details of the tests used to measure the mechanical properties of ceramics prepared using four compositional mixes. Two methods of measuring strength were used: diametral compression of disc samples and four-point

J. M. Blamey; T. V. Parry

1993-01-01

348

Effect of the strain-induced melt activation (SIMA) process on the tensile properties of a new developed super high strength aluminum alloy modified by Al-5Ti-1B grain refiner  

SciTech Connect

In this study, the effect of Al-5Ti-1B grain refiners and modified strain-induced melt activation process on an Al-Zn-Mg-Cu alloy was studied. The optimum level of Ti was found to be 0.1 wt.%. The specimens subjected to deformation ratio of 40% (at 300 Degree-Sign C) and various heat treatment times (10-40 min) and temperature (550-600 Degree-Sign C) regimes were characterized in this study. Reheating condition to obtain a fine globular microstructure was optimized. Microstructural examinations were conducted by optical and scanning electron microscopy coupled with an energy dispersive spectrometry. The optimum temperature and time in strain-induced melt activation process are 575 Degree-Sign C and 20 min, respectively. T6 heat treatment including quenching to room temperature and aging at 120 Degree-Sign C for 24 h was employed to reach to the maximum strength. Significant improvements in mechanical properties were obtained with the addition of grain refiner combined with T6 heat treatment. After the T6 heat treatment, the average tensile strength increased from 283 MPa to 587 and 332 MPa to 617 for samples refined with 2 wt.% Al-5Ti-1B before and after strain-induced melt activation process and extrusion process, respectively. Ultimate strength of Ti-refined specimens without SIMA process has a lower value than globular microstructure specimens after SIMA and extrusion process. - Highlights: Black-Right-Pointing-Pointer The effect of Al-5Ti-1B on the aluminum alloy produced by SIMA process was studied. Black-Right-Pointing-Pointer Al-5Ti-1B is an effective in reducing the grain and reagent fine microstructure. Black-Right-Pointing-Pointer Reheating condition to obtain a fine globular microstructure was optimized. Black-Right-Pointing-Pointer The optimum temperature and time in SIMA process are 575 Degree-Sign C and 20 min respectively. Black-Right-Pointing-Pointer UTS of globular structure specimens have a more value than Ti-refined specimens.

Haghparast, Amin [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)] [School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Nourimotlagh, Masoud [Young Researchers Club, Dareshahr Branch, Islamic Azad university (Iran, Islamic Republic of)] [Young Researchers Club, Dareshahr Branch, Islamic Azad university (Iran, Islamic Republic of); Alipour, Mohammad, E-mail: Alipourmo@ut.ac.ir [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)] [School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

2012-09-15

349

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

Microsoft Academic Search

Lightning strikes can cause structural damage, ignite flammable materials, and produce circuit malfunctions in missiles, aircraft, and ground systems. Lightning arrestor connectors (LAC's) are used to divert harmful lightning energy away from these systems by providing less destructive breakdown paths. Ceramic granules in the size range of 150-200 micrometers are used in LAC's to provide physical and electrical separation of

S. J. Glass; C. Newton

1994-01-01

350

Tensile Properties of GRCop-84  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

351

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

352

Tensile behavior of functionally graded steels produced by electroslag remelting  

Microsoft Academic Search

Tensile behavior of functionally graded steels produced by electroslag refining has been studied. Functionally graded steels\\u000a containing layers of ferrite, austenite, bainite, and martensite may be fabricatedvia diffusion of alloying elements during electroslag remelting. Tensile strength of the composites depends on the composition\\u000a and number of layers and those have been modeled based on the tensile behavior of individual phases.

J. Aghazadeh Mohandesi; R. Parastar Namin; M. H. Shahosseinie

2006-01-01

353

Evaluation of Press-and-Sinter Parameters for Tantalum Pentoxide by the Diametral Compression Test.  

National Technical Information Service (NTIS)

Submicron Ta2O5 powder was consolidated by cold pressing using pressures between 24 MPa and 240 MPa followed by sintering at temperatures in the range 1300 degrees C to 1500 degrees C. The resulting disks were fractured in diametral compression tests (DCT...

Z. Livne, R. J. Fields, A. Agulyansky

1997-01-01

354

Factors influencing the strength differential of high strength steels  

Microsoft Academic Search

Room temperature tensile and compressive true stress-true strain curves of various high strength steels (quenched and tempered\\u000a 4340 steel, 410 martensitic stainless steel, and H-11 steel; and aged 300-grade 18 Ni maraging steel) were analyzed to determine\\u000a the effect of the various microstructures, on what has been termed the strength differential (SD),i.e., the strength level difference between the tensile and

R. Chait

1972-01-01

355

Weldability evaluation of high tensile plates using GMAW process  

Microsoft Academic Search

High tensile plates, SAILMA-450 high impact (HI) (yield strength, 45 kg\\/mm2 minimum; ultimate tensile strength, 57 kg\\/mm2 minimum; elongation, 19% minimum; Charpy impact energy 2.0 kg.m at ?20 C minimum) were successfully developed at the Steel\\u000a Authority of India Ltd., up to 32 mm plate thickness. Since then the steel has been extensively used for the fabrication of\\u000a impellers, bridges,

R. Datta; D. Mukerjee; K. L. Rohira; R. Veeraraghavan

1999-01-01

356

Tensile properties of orthodontic elastomeric chains.  

PubMed

The purpose of this investigation was to assess the permanent elongation, tensile strength and toughness of elastomeric chains. Two types (open and closed chains, i.e. with and without an intermodular link) of three brands of elastomeric module yielding six groups were included in the study. Specimens with equal numbers of loops were measured and classified into four groups based on their ageing state: (a) as-received; (b) subjected to a 24 hour steady strain in air determined as 50 per cent of original length; (c) exposed intraorally for 24 hours; and (d) retrieved following 3 weeks of intraoral exposure. All specimens were subjected to tensile stress and their behaviour was analysed with three-way ANOVA and Tukey's multiple comparison test at alpha = 0.05 level of significance, with brand, type (open or closed chains), and treatment variables serving as discriminating variables. Modular geometry or design were found not to have significant effects on elongation, probably due to the substantial variation in chain shape, modular size, and link length among products of the same category. Similarly, no correlation was identified between specimen treatment and the tensile strength of elastomers. The toughness results were not consistent with the group rankings for tensile strength, probably because of variation in the elastic and plastic deformation of specimens upon loading. PMID:15130038

Eliades, T; Eliades, G; Silikas, N; Watts, D C

2004-04-01

357

Approaches for Tensile Testing of Braided Composites  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

358

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

359

Application of the method of caustics to the centre-cracked diametral compression test specimen  

Microsoft Academic Search

Normalized Mode I stress intensity factors,N1(a\\/R), for symmetrical radial cracks in diametral compression test specimens were experimentally evaluated using disc specimens of polymethyl methacrylate and the method of caustics. The method of caustics was first employed with precracked three-point bend specimens to assess the optical constant for the test material. This material property and the diameters of the caustics as

D. Singh; D. K. Shetty

1988-01-01

360

Determination of stresses and displacements in a thin annular disk subjected to diametral compression  

Microsoft Academic Search

Results of an analysis of the plane stress state of a thin annular disk subjected to uniform pressure on two diametrically\\u000a opposite segments of the rim are presented. Some features of the stress distribution are investigated by means of both theoretical\\u000a technique and experimental testing. Analytical expressions for the components of the displacement vector that correspond to\\u000a the stress state

Yu. V. Tokovyy; K.-M. Hung; C.-C. Ma

2010-01-01

361

Validation of single-edge V-notch diametral compression fracture toughness test for porous alumina  

Microsoft Academic Search

The objectives of this study were to validate a single-edge V-notch diametral compression fracture toughness technique for ceramics. Rounded notches and sharpened “V-notches” were introduced into porous, fine-grained alumina samples, and the fracture toughness results were compared. A theory linking the toughness of the material to the degree of densification fit the fracture toughness results well. The data for the

J. K. Clobes; D. J. Green

2002-01-01

362

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

363

Tensile behavior of nanocrystalline copper  

SciTech Connect

High density nanocrystalline copper produced by inert gas condensation was tested in tension. Displacements were measured using foil strain gauges, which greatly improved the accuracy of the strain data. The Young`s modulus of nanocrystalline copper was found to be consistent with that of coarse-grained copper. Total elongations of {approx} 1% were observed in samples with grain sizes less than 50 nm, while a sample with a grain size of 110 nm exhibited more than 10% elongation, perhaps signifying a change to a dislocation-based deformation mechanism in the larger-grained material. In addition, tensile tests were performed as a function of strain rate, with a possible trend of decreased strength and increased elongation as the strain rate was decreased.

Sanders, P.G.; Weertman, J.R. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering; Eastman, J.A. [Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science and Engineering]|[Argonne National Lab., IL (United States). Materials Science Div.

1995-11-01

364

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

365

Tensile testing apparatus  

Microsoft Academic Search

An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip

L. B. Blackburn; J. R. Ellingsworth

1985-01-01

366

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

NASA Astrophysics Data System (ADS)

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

Liu, Ke; Takagi, Hitoshi; Yang, Zhimao

367

Improve the Strength of PLA/HA Composite Through the Use of Surface Initiated Polymerization and Phosphonic Acid Coupling Agent  

PubMed Central

Bioresorbable composite made from degradable polymers, e.g., polylactide (PLA), and bioactive calcium phosphates, e.g., hydroxyapatite (HA), are clinically desirable for bone fixation, repair and tissue engineering because they do not need to be removed by surgery after the bone heals. However, preparation of PLA/HA composite from non-modified HA usually results in mechanical strength reductions due to a weak interface between PLA and HA. In this study, a calcium-phosphate/phosphonate hybrid shell was developed to introduce a greater amount of reactive hydroxyl groups onto the HA particles. Then, PLA was successfully grafted on HA by surface-initiated polymerization through the non-ionic surface hydroxyl groups. Thermogravimetric analysis indiated that the amount of grafted PLA on HA can be up to 7 %, which is about 50 % greater than that from the literature. PLA grafted HA shows significantly different pH dependent ?-potential and particle size profiles from those of uncoated HA. By combining the phosphonic acid coupling agent and surface initiated polymerization, PLA could directly link to HA through covalent bond so that the interfacial interaction in the PLA/HA composite can be significantly improved. The diametral tensile strength of PLA/HA composite prepared from PLA-grafted HA was found to be over twice that of the composite prepared from the non-modified HA. Moreover, the tensile strength of the improved composite was 23 % higher than that of PLA alone. By varying additional variables, this approach has the potential to produce bioresorbable composites with improved mechanical properties that are in the range of natural bones, and can have wide applications for bone fixation and repair in load-bearing areas. PMID:22399838

Wang, Tongxin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Ting, Andy Hai; Dong, Quanxiao; Yang, Mingshu; Mitchell, James W.

2012-01-01

368

Grips for Lightweight Tensile Specimens  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

369

Controlling factors in tensile deformation of nanocrystalline cobalt and nickel  

NASA Astrophysics Data System (ADS)

In an effort to understand and enhance the tensile ductility of truly nanocrystalline metals, we have investigated and compared the mechanical behavior, especially the tensile behavior, of hexagonal close-packed (hcp) nanocrystalline cobalt (˜20 nm) and face-centered cubic (fcc) nanocrystalline nickel (˜28 nm). Although both materials exhibit obvious plasticity in tension, their uniform tensile ductility, tensile elongation-to-failure, and fracture behavior are drastically different. In-situ synchrotron x-ray diffraction and ultra-small angle x-ray scattering reveal distinct deformation disparity in terms of residual strain development, texture evolution, nanovoid formation, and subsequent strain-hardening and strain-rate-hardening behavior. The dependence of tensile property on the strain rate and temperature is examined and discussed. Factors that influence the strength and ductility of nanocrystalline metals are considered and prioritized according to the current findings. A new Hall-petch relationship is proposed for nanocrystalline nickel.

Wang, Y. M.; Ott, R. T.; van Buuren, T.; Willey, T. M.; Biener, M. M.; Hamza, A. V.

2012-01-01

370

Processing and tensile properties of hydroxyapatite-whisker-reinforced polyetheretherketone  

Microsoft Academic Search

Polyetheretherketone (PEEK) was reinforced with 0–50vol% hydroxyapatite (HA) whiskers using a novel powder processing and compression molding technique which enabled uniform mixing at high whisker content. Texture analysis showed that viscous flow during compression molding produced a preferred orientation of whiskers along the specimen tensile axis. Consequently, the elastic modulus or ultimate tensile strength of HA-whisker-reinforced PEEK was able to

Gabriel L. Converse; Weimin Yue; Ryan K. Roeder

2007-01-01

371

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

SciTech Connect

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

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

2008-01-01

372

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

E-print Network

Tensile Yield Stress (MPa) 41.0 Ultimate Tensile Strength (MPa) 76.3 Ultimate Tensile Strain (%) 4.20 0.2% Offset Compressive Yield Stress (MPa) -64.7 Ultimate Compressive Strength (MPa) -91.0 Ultimate3-D Static Elastic Constants and Strength Properties of a Glass/Epoxy Unidirectional Laminate

373

Tensile testing apparatus  

NASA Astrophysics Data System (ADS)

An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

Blackburn, L. B.; Ellingsworth, J. R.

1985-08-01

374

Tensile testing apparatus  

NASA Technical Reports Server (NTRS)

An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

Blackburn, L. B.; Ellingsworth, J. R. (inventors)

1985-01-01

375

Effects of food/oral simulating fluids on microstructure and strength of dentine bonding agents.  

PubMed

This study evaluated the effect a food simulating solution, 75% v/v ethanol/water, and an artificial saliva, Moi-Stir, have on the microstructure and on the diametral tensile strength (DTS) of three dentine bonding agents (Tenure, Scotchbond Multi-Purpose and Optibond). The microstructure was examined by using a scanning electron microscope (SEM). The DTS data were analysed using ANOVA and the Tukey LSD test. The microstructural observations were compared with changes in DTS. The SEM observation revealed deterioration of all bonding agents due to conditioning in the solutions for 30 days. The different solutions appeared to cause different reactions in the bonding agents. However, these effects may be exaggerated due to the presence of an air-inhibited surface layer. Those conditioned in Moi-Stir showed swelling. The presence of filler particles in the Optibond bonding agent appears to decrease the deterioration resulting from soaking. Materials conditioned in ethanol exhibited both dissolution and thinning. Diametral samples of each bonding material were tested after being conditioned in the above-mentioned solutions for 1, 7, 14 and 30 days. Conditioning significantly decreased the DTS of all bonding agents, except Optibond in Moi-Stir. Filled Optibond maintained its DTS longer than did the two unfilled bonding agents. The decrease in DTS of all the ethanol-conditioned groups is a function of the square root of time (P < 0.001) and conforms to Fick's laws of diffusion. The filled Optibond showed a lower ethanol diffusivity (0.5 x 10(-5) cm2 s-1) than the other two unfilled bonding agent systems (average 1.2 x 10(-5) cm2 s-1) (P < 0.05). The high ethanol diffusivities were thought to be due to the presence of HEMA, a hydrophilic resin, in the bonding agent. These results also suggest that solution uptake occurred through the resin matrix. Filler particles may therefore play an important role in weathering resistance of these materials to oral environment solutions. The physical appearance and strength of dentine bonding agents are significantly altered by exposure to oral environment solutions. PMID:8736449

Lee, S Y; Greener, E H; Covey, D A; Menis, D L

1996-05-01

376

The Ideal Strength of Diamond  

NASA Astrophysics Data System (ADS)

We present calculations of both the ideal shear and tensile strengths of diamond using pseudopotential density functional theory, within the local density approximation. Our calculations show a transition to a graphitic state under large shear stress, as has recently been seen in nanoindentation studies. We also compare the ideal shear strength with the maximum shear stress observed in diamond anvil cell experiments.

Roundy, David; Cohen, Marvin L.

2001-03-01

377

A TRANSVERSELY ISOTROPIC LAW FOR THE DETERMINATION OF THE CIRCUMFERENTIAL YOUNG'S MODULUS OF BAMBOO WITH DIAMETRIC COMPRESSION TESTS  

Microsoft Academic Search

Bamboo is a highly anisotropic natural material widely used in structural applica- tions. A transversely isotropic constitutive equation is proposed here as the simplest law able to capture main anisotropic features of bamboo. Diametric compression tests were undertaken to determine the circumferential Young's modulus of two bamboo species based on the transversely isotropic model and using a simple formula of

L. A. TORRES; K. GHAVAMI; J. J. GARCĶA

2007-01-01

378

Are the autism and positive schizotypy spectra diametrically opposed in empathizing and systemizing?  

PubMed

Crespi and Badcock's (Behaviour Brain Sci 31: 241-261, 2008) novel theory, which presents autism and positive schizophrenia as diametrical opposites on a cognitive continuum, has received mixed support in the literature to date. The current study aimed to further assess the validity of this theory by investigating predictions in relation to empathizing and systemizing. Specifically, it is predicted by Crespi and Badcock that while mild autistic traits should be associated with a cognitive profile of superior mechanistic cognition (which overlaps with systemizing) but reduced mentalistic cognition (which overlaps with empathizing), positive schizotypy traits should be associated with the opposite profile of superior mentalistic but reduced mechanistic cognition. These predictions were tested in a student sample using a battery of self-report and behavioural measures. The pattern of results obtained provides no support for Crespi and Badcock's theory. PMID:22829244

Russell-Smith, Suzanna N; Bayliss, Donna M; Maybery, Murray T; Tomkinson, Rosy L

2013-03-01

379

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

380

Tensile Fracture of Ductile Materials. M.S. Thesis  

NASA Technical Reports Server (NTRS)

For brittle materials, circular voids play an important role relative to fracture, intensifing both tensile and compressive stresses. A maximum intensified tensile stress failure criterion applies quite well to brittle materials. An attempt was made to explore the possibility of extending the approach to the tensile fracture of ductile materials. The three dimensional voids that exist in reality are modelled by circular holes in sheet metal. Mathematical relationships are sought between the shape and size of the hole, after the material is plastically deformed, and the amount of deformation induced. Then, the effect of hole shape, size and orientation on the mechanical properties is considered experimentally. The presence of the voids does not affect the ultimate tensile strength of the ductile materials because plastic flow wipes out the stress intensification caused by them. However, the shape and orientation of the defect is found to play an important role in affecting the strain at fracture.

Pai, D. M.

1984-01-01

381

Column strength of magnesium alloy AM-57S  

NASA Technical Reports Server (NTRS)

Tests were made to determine the column strength of extruded magnesium alloy AM-57S. Column specimens were tested with round ends and with flat ends. It was found that the compressive properties should be used in computations for column strengths rather than the tensile properties because the compressive yield strength was approximately one-half the tensile yield strength. A formula for the column strength of magnesium alloy AM-57S is given.

Holt, M

1942-01-01

382

Tensile Tests of NACA and Conventional Machine-countersunk Flush Rivets  

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets.

Bartone, Leonard M.; Mandel, Merven W.

1944-01-01

383

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

NASA Astrophysics Data System (ADS)

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

Kita, Takuya; Saitoh, Shou; Iwamori, Satoru

384

The uniaxial compressive and tensile tests of frozen saturated clay in Shanghai area  

Microsoft Academic Search

The compressive and tensile strengths of frozen clay are important parameters for frozen wall design in artificial freezing\\u000a excavation of tunnels and foundation pits. Up to now, nobody has conducted the compressive and tensile test of frozen clays\\u000a in Shanghai area. In this paper, the unconfined compressive and tensile tests of frozen clay specimens drilled from the soil\\u000a horizons 3–5

Youliang Chen; Rafig Azzam; Ming Wang; Shan Xu; Lequn Chang

385

Neural network analysis of strength and ductility of welding alloys for high strength low  

E-print Network

and the weld cooling rate. The outputs consisted of the yield and ultimate tensile strengths, elongation 550 Ā­ 690 MPa yield strength steels for surface ships and submarines. The objective of the programmeNeural network analysis of strength and ductility of welding alloys for high strength low alloy

Cambridge, University of

386

Application of reliability and fiber probabilistic strength distribution concepts to composite vessel burst strength design  

Microsoft Academic Search

A composite pressure vessel design approach that is based on reliability and probabilistic fiber strength distribution concepts is discussed. The method is based on the fiber strain-strength interference reliability theory. The way in which fiber strength distribution parameters generated by two tensile tests of impregnated carbon fiber strands can be used in pressure vessel strength design is examined. It is

David Cohen

1992-01-01

387

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

388

Influence of repair welding of aged 18Ni 250 maraging steel weldments on tensile and fracture properties  

Microsoft Academic Search

The effects of repair welding on tensile strength and fracture toughness of aged weldments of 18 Ni 250-grade maraging steel have been studied. It has been established that aged weldments in the steel can be repaired and approximately 95% of the tensile strength of the initial welds could be achieved by postrepair aging treatment. Also, the repairs had practically no

P. P. Sinha; S. Arumugham; K. V. Nagarajan

1993-01-01

389

Tensile Behavior of Fabric Cement-Based Composites: Pultruded and Cast  

E-print Network

Tensile Behavior of Fabric Cement-Based Composites: Pultruded and Cast A. Peled1 and B. Mobasher2 processing methods, casting and pultrusion, on the tensile properties of fabric-cement composites. Four after casting. Pressed composites showed an increase in flexural strength but a reduction

Mobasher, Barzin

390

Theoretical nonlinear response of complex single crystal under multi-axial tensile loading  

E-print Network

-axial tensile loading. The results reveal a complex nonlinear and loading-path dependent behavior with evolving anisotropy for the HAP crystal. Further, we have introduced a failure envelope index to quantify the strength behavior for comparison of similar...

Misra, Anil; Ching, W. Y.

2013-03-19

391

Relation between tensile properties and microstructure in type 316 stainless steel SA weld metal  

Microsoft Academic Search

Tensile properties of a thick, multipass, submerged-arc (SA) weld-deposited type 316 are investigated by tests at room temperature and at 400 ° C and by microstructural and compositional analyses. The as-deposited metal, which shows a lower yield strength, a comparable ultimate tensile strength and a lower total elongation compared to the (solution-annealed) parent metal, is characterized by systematic variations in

G. Piatti; M. Vedani

1990-01-01

392

Manufacturing of Plutonium Tensile Specimens  

SciTech Connect

Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

Knapp, Cameron M [Los Alamos National Laboratory

2012-08-01

393

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

NASA Astrophysics Data System (ADS)

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

Wang, Wenhai

394

Velocity anti-correlation of diametrically opposed galaxy satellites in the low-redshift Universe  

NASA Astrophysics Data System (ADS)

Recent work has shown that the Milky Way and the Andromeda galaxies both possess the unexpected property that their dwarf satellite galaxies are aligned in thin and kinematically coherent planar structures. It is interesting to evaluate the incidence of such planar structures in the larger galactic population, because the Local Group may not be a representative environment. Here we report measurements of the velocities of pairs of diametrically opposed satellite galaxies. In the local Universe (redshift z < 0.05), we find that satellite pairs out to a distance of 150 kiloparsecs from the galactic centre are preferentially anti-correlated in their velocities (99.994 per cent confidence level), and that the distribution of galaxies in the larger-scale environment (out to distances of about 2 megaparsecs) is strongly clumped along the axis joining the inner satellite pair (>7? confidence). This may indicate that planes of co-rotating satellites, similar to those seen around the Andromeda galaxy, are ubiquitous, and their coherent motion suggests that they represent a substantial repository of angular momentum on scales of about 100 kiloparsecs.

Ibata, Neil G.; Ibata, Rodrigo A.; Famaey, Benoit; Lewis, Geraint F.

2014-07-01

395

Velocity anti-correlation of diametrically opposed galaxy satellites in the low-redshift Universe.  

PubMed

Recent work has shown that the Milky Way and the Andromeda galaxies both possess the unexpected property that their dwarf satellite galaxies are aligned in thin and kinematically coherent planar structures. It is interesting to evaluate the incidence of such planar structures in the larger galactic population, because the Local Group may not be a representative environment. Here we report measurements of the velocities of pairs of diametrically opposed satellite galaxies. In the local Universe (redshift z < 0.05), we find that satellite pairs out to a distance of 150 kiloparsecs from the galactic centre are preferentially anti-correlated in their velocities (99.994 per cent confidence level), and that the distribution of galaxies in the larger-scale environment (out to distances of about 2 megaparsecs) is strongly clumped along the axis joining the inner satellite pair (>7? confidence). This may indicate that planes of co-rotating satellites, similar to those seen around the Andromeda galaxy, are ubiquitous, and their coherent motion suggests that they represent a substantial repository of angular momentum on scales of about 100 kiloparsecs. PMID:25043008

Ibata, Neil G; Ibata, Rodrigo A; Famaey, Benoit; Lewis, Geraint F

2014-07-31

396

Phase-Dependent Tensile Properties of 9Cr-1Mo(V, Nb) Ferritic/Martensitic Steel  

NASA Astrophysics Data System (ADS)

Phase-dependent tensile properties of 9Cr-1Mo(V, Nb) ferritic/martensitic steel were evaluated in the temperature range 300 K to 1073 K (27 °C to 800 °C) to quantify differences in the tensile behavior of different phases of this material. The results showed considerable difference in the tensile properties such as yield strength, ultimate tensile strength, and elongation of the three phases of this material—tempered martensite, metastable austenite, and martensite—which can exist at a common temperature. This has been discussed on the basis of structural hysteresis in this material when subjected to thermal cycles causing excursions across various phase fields.

Kumar, Santosh; Kushwaha, Ram Pratap; Maji, Bikas Chandra; Bhanumurthy, Karanam; Dey, Gautam Kumar

2014-02-01

397

Rod Has High Tensile Strength And Low Thermal Expansion  

NASA Technical Reports Server (NTRS)

Thoriated tungsten extension rod fabricated to replace stainless-steel extension rod attached to linear variable-differential transformer in gap-measuring gauge. Threads formed on end of rod by machining with special fixtures and carefully chosen combination of speeds and feeds.

Smith, D. E.; Everton, R. L.; Howe, E.; O'Malley, M.

1996-01-01

398

Modeling Landfast Sea Ice by Adding Tensile Strength  

Microsoft Academic Search

Landfast ice is sea ice that forms and remains fixed along a coast, where it is attached either to the shore or held between shoals or grounded icebergs. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice behavior, for example the persistence of landfast sea ice under the effect of offshore winds.

CHRISTOF KONIG BEATTY; DAVID M. HOLLAND

2009-01-01

399

Laser Forming of Tailored Blanks of High Tensile Strength Steels  

NASA Astrophysics Data System (ADS)

Tailor welded blanks with two different materials (SPCC-SPFC980Y) were V bent by laser forming which is a bending method with thermal stress induced by rapid heating by means of laser irradiation, and it is suitable for bending of large spring back sheets since spring back is not affected. Forming conditions for SPCC part and SPFC980Y part were changed. A 50W CW YAG laser was employed with laser scanning number of 10 and defocus length of 25mm. When same laser power (38W) was employed for SPCC and SPFC980Y parts, bending angle of SPCC part was greater than that of SPFC980Y part. However, when laser power was 40W for SPFC980Y part and 36W for SPCC part, the bending angle of both parts were almost same and this means constant bending angle was obtained by controlling the laser power. Uniform bending angle was also obtained by controlling the laser scanning velocity as well as the laser power.

Otsu, Masaaki; Ishii, Akira; Takashima, Kazuki

400

Biocomposites from abaca strands and polypropylene. Part I: Evaluation of the tensile properties.  

PubMed

In this paper, abaca strands were used as reinforcement of polypropylene matrix and their tensile mechanical properties were studied. It was found relevant increments on the tensile properties of the abaca strand-PP composites despite the lack of good adhesion at fiber-matrix interface. Afterwards, it was stated the influence of using maleated polypropylene (MAPP) as compatibilizer to promote the interaction between abaca strands and polypropylene. The intrinsic mechanical properties of the reinforcement were evaluated and used for modeling both the tensile strength and elastic modulus of the composites. For these cases, the compatibility factor for the ultimate tensile strength was deduced from the modified rule of mixtures. Additionally, the experimental fiber orientation coefficient was measured, allowing determining the interfacial shear strengths of the composites and the critical fiber length of the abaca strand reinforcement. The mechanical improvement was compared to that obtained for fiberglass-reinforced PP composites and evaluated under an economical and technical point of view. PMID:19700312

Vilaseca, Fabiola; Valadez-Gonzalez, Alex; Herrera-Franco, Pedro J; Pčlach, M Angels; López, Joan Pere; Mutjé, Pere

2010-01-01

401

Weld width indicates weld strength  

NASA Technical Reports Server (NTRS)

Width of butt weld in 2219-T87 aluminum has been found to be more reliable indicator of weld strength than more traditional parameters of power input and cooling rate. Yield stress and ultimate tensile strength tend to decrease with weld size. This conclusion supports view of many professional welders who give priority to weld geometry over welding energy or cooling rate as indicator of weld quality.

Nunes, A. C. J.; Novak, H. L.; Mcllwain, M. C.

1982-01-01

402

High strength concrete containing natural pozzolan and silica fume  

Microsoft Academic Search

Various combinations of a local natural pozzolan and silica fume were used to produce workable high to very high strength mortars and concretes with a compressive strength in the range of 69–110 MPa. The mixtures were tested for workability, density, compressive strength, splitting tensile strength, and modulus of elasticity. The results of this study suggest that certain natural pozzolan–silica fume

M. J Shannag

2000-01-01

403

Effective utilization of high-yield strength steels in fatigue  

Microsoft Academic Search

The subcommittee for Effective Utilization of Yield Strength was established under the Materials Division of the Pressure Vessel Research Committee of the Welding Research Council to study the effects of strain hardening and the yield strength to tensile strength ratio on the various failure modes of pressure vessels. Specifically their purpose is to determine if high-strength steels can be more

R. A. May; A. Stuber; S. T. Rolfe

1978-01-01

404

A family of weakest link models for fiber strength distribution  

Microsoft Academic Search

It is well known that the most widely used distribution function for fiber tensile strength, the two-parameter Weibull distribution, does not always adequately describe the experimentally observed fiber strength scatter and the strength dependence on fiber length. To remedy this discrepancy, modifications of the Weibull distribution have been proposed that, while providing a good empirical fit to the strength data,

Yu. Paramonov; J. Andersons

2007-01-01

405

286 / JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING / MARCH 2000 shear strength before reinforcement rupture, which is not sup-  

E-print Network

after failure initiation is attributed to the loss of reinforcement tensile strength due to breakage) tensile strength because stability would be evaluated in this case using residual soil shear strength286 / JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING / MARCH 2000 shear strength before

Zornberg, Jorge G.

406

Dynamic Tensile Failure in Rocks.  

National Technical Information Service (NTIS)

A fracture model is being developed based on the hypothesis that dynamic tensile failure in rocks occurs by the activation of preexisting flaws which propagate and may coalesce to produce fragments of various size. During the previouus year the first two ...

D. A. Shockey

1972-01-01

407

Tensile Mechanics of Bamboo Strips  

NASA Astrophysics Data System (ADS)

Mechanical properties of Semantan bamboo (Gigantochloa scortechinii) strips loaded in tensile parallel to grain were documented. The specimens were taken from bottom, middle and top portions of bamboo culms. In each portion, specimens were taken from internodes and node parts. Specimens from internodes part indicated absence of node while specimens from nodes indicated presence of node at the middle section of each specimen. From the results, there was an increment of tensile mechanic values for Semantan bamboo strips in bottom to top portions, due to the increment of fibro vascular bundles amount in the respective portions. Generally, the failures modes of bamboo strips loaded in tensile were divided into Splintering (Mode I) and Brittle Splintering (Mode II). Mode I occurred in internodes of all portions while Mode II occurred in node. Mode I presented higher tensile mechanic values due to the fibres behaviour of bamboo strips, which is more compact, longer and parallel with axial and uniform grain orientation, compared to the short, forked and crossed fibres as well as uneven orientation of vascular bundles in Mode II.

Bahari, S. A.; Ahmad, M.; Nordin, K.; Jamaludin, M. A.

2010-03-01

408

On the prediction of tensile properties from hardness tests  

Microsoft Academic Search

The possibility of correlating the hardness to the tensile properties of a material has been investigated using Assab 760 steel, mild steel and API Std 5LX grade X60 pipeline steel that have been heat-treated for different times at various tempering temperatures and 6063-T1 aluminium that has been solution heat-treated. It is found that the strain hardening coefficient and the strength

M. O. Lai; K. B. Lim

1991-01-01

409

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

410

Mechanical and numerical modeling of a porous elastic–viscoplastic material with tensile failure  

Microsoft Academic Search

The objective of this paper is to develop simple but comprehensive constitutive equations that model a number of physical phenomena exhibited by dry porous geological materials and metals. For geological materials the equations model: porous compaction; porous dilation due to distortional deformation and tensile failure; shear enhanced compaction; pressure hardening of the yield strength; damage of the yield strength due

M. B. Rubin; O. Yu. Vorobiev; L. A. Glenn

2000-01-01

411

Tensile behavior of unnotched and notched tungsten-copper laminar composites  

NASA Technical Reports Server (NTRS)

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

Hoffman, C. A.

1976-01-01

412

Constraint correction of high strength steel  

Microsoft Academic Search

This study presents a practical procedure for application of constraint correction of high strength steels and its weldments. Tests have been carried out on single edge notch bend (SENB) specimens with shallow and deep notch and SENT (single edge notch tensile) specimen with shallow notch, to cover the constraint effect. The yield strength of the material was 700 MPa. In

Christian Thaulow; Erling Ųstby; Bård Nyhus; Zhiliang L. Zhang; Bjųrn Skallerud

2004-01-01

413

Impact Strength of Glass and Glass Ceramic  

NASA Astrophysics Data System (ADS)

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

Bless, Stephan; Tolman, John

2009-06-01

414

Cavitation Strength of Liquids with Large Molecules  

NASA Astrophysics Data System (ADS)

The cavitation strength of liquids has been studied at atmospheric pressure by applying tensile stress pulses of duration up to 3 ?s and amplitude up to 20 MPa within the temperature range from room temperature to the temperature of explosive boiling-up of the liquid. At high temperatures, where in absolute value the tensile strength does not exceed 1-2 times the critical pressure, agreement between classical nucleation theory and experiment is observed within the experimental error. With a decrease of the temperature the tensile strength of the liquid increases, but the experimental values of the breaking strength are lower than those predicted from theory. The dependence of the degree of discrepancy between theory and experiment on the number of atoms in the molecules of the liquids investigated is shown.

Vinogradov, Vladimir E.; Pavlov, Pavel A.

2013-09-01

415

Tensile and cyclic fatigue properties of SiC whisker-reinforced Al(sub 2)O(sub 3).  

National Technical Information Service (NTIS)

Uniaxial tensile and cyclic fatigue data are reported for a commercial grade of SiC whisker-reinforced Al(sub 2)O(sub 3) matrix composite tested at room temperature. Test results show that the average tensile strength of this composite material was 432 MP...

K. C. Liu, C. O. Stevens, C. R. Brinkman

1991-01-01

416

A tensile deformation model for in-situ dendrite/metallic glass matrix composites.  

PubMed

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

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

2013-01-01

417

Manual for LDEF tensile tests  

NASA Technical Reports Server (NTRS)

One of the experiments aboard the NASA Long Duration Exposure Facility (LDEF) consists of a tray of approximately one hundred tensile specimens of several candidate space structure composite materials. During the LDEF flight the materials will be subjected to the space environment and to possible contamination during launch and recovery. Tensile tests of representative samples were made before the LDEF flight to obtain baseline data. Similar tests will be made on control specimens stored on earth for the length of the LDEF flight and on recovered flight specimens. This manual codifies the details of testing, data acquisition, and handling used in obtaining the baseline data so that the same procedures and equipment will be used on the subsequent tests.

Witte, W. G., Jr.

1985-01-01

418

Tensile properties of nitrile elastomers  

E-print Network

Elastomers are an important material to the oil industry. An understanding of the material response of elastomers under load is necessary in order to effecnvely design with elastomers. Strain energy functions, which are used to describe the stress...-strain behavior of elastomers, require equilibrium stress-strain information. However, there is no clear defininon of what equilibrium is. An initial study of the tensile properties of nitrile elastomers has been conducted. Constant separation rate testing...

Fairbrother, Debora Ann

2012-06-07

419

Green strength testing of pressed compacts: An analysis of the different methods  

Microsoft Academic Search

This paper presents a comparative study of three- and four-point bending tests and diametral compression (DC) tests, used to measure the mechanical strength of green pressed compacts. The study has been conducted on pressed ceramic test pieces, formed at different pressing conditions. It was found that Weibull statistics largely explained the differences in the results of the three-point and four-point

J. L. Amorós; V. Cantavella; J. C. Jarque; C. Felķu

2008-01-01

420

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

421

Microstructure and tensile properties of thixoformed A356 alloy  

SciTech Connect

In the research work presented here, mechanical properties of a thixoformed A356 alloy were measured and compared with the mechanical properties of rheocast and gravity-cast alloy with the same composition. In the thixoforming process, a 60% solid fraction rheocast alloy was reheated to 600 deg. C or 610 deg. C, held about 10 min, and then reduced by 30% or 50% reduction of cross section. Microstructural and mechanical properties of the alloys were investigated. The results obtained show that the tensile strength, yield strength and elongation-to-failure of the alloy thixoformed at 600 deg. C was greater than that thixoformed at 610 deg. C. Moreover, the tensile strength, yield strength and elongation-to-failure of the thixoformed alloy were higher than those of the rheocast and gravity-cast samples. The improvement in the mechanical properties due to thixoforming is attributed to morphological aspects of the silicon phase, as well as to the non-dendritic structure produced.

Tahamtan, S. [Isfahan University of Technology (Iran, Islamic Republic of); Golozar, M.A. [Isfahan University of Technology (Iran, Islamic Republic of)], E-mail: golozar@cc.iut.ac.ir; Karimzadeh, F.; Niroumand, B. [Isfahan University of Technology (Iran, Islamic Republic of)

2008-03-15

422

Tensile properties of free films cast from aqueous ethylcellulose dispersions.  

PubMed

Free films of two commercially available formulations of aqueous ethylcellulose dispersion differing only in plasticizer content (Sure-lease/E-7-7050 without silica and E-7-7060 containing dibutyl sebacate and glyceryl tricaprylate/caprate as plasticizers, respectively) were cast and coalesced at temperatures ranging between 30 and 70 degrees C. Mechanical properties of these films were measured using tensile stress analysis. Three mechanical parameters, namely, tensile strength, work of failure, and elastic modulus, were computed from the load-time profiles of these films. The results showed that the tensile strength and elastic modulus values of the films cast from both formulations increased with the corresponding increase in coalescence temperature up to 60 degrees C, beyond which no significant differences were observed. In the case of work of failure, however, the difference between the two formulations was observed above 60 degrees C. The films cast from Surelease/E-7-7050 formulation without silica (dibutyl sebacate as the plasticizer) were relatively softer than those from Surelease/E-7-7060 formulation (glyceryl tricaprylate/caprate as the plasticizer). At coalescence temperatures above 50 degrees C, the films cast from both formulations exhibited temperature-dependent plastic deformation. PMID:8321847

Parikh, N H; Porter, S C; Rohera, B D

1993-06-01

423

Tensile Hoop Behavior of Irradiated Zircaloy-4 Nuclear Fuel Cladding  

SciTech Connect

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

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

2007-03-01

424

Apple Strength Issues  

SciTech Connect

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

Syn, C

2009-12-22

425

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

NASA Astrophysics Data System (ADS)

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

Naito, Kimiyoshi

2014-08-01

426

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

NASA Astrophysics Data System (ADS)

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

Naito, Kimiyoshi

2014-11-01

427

Tensile test of pressureless-sintered silicon nitride at elevated temperature  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

428

Ultrahigh Torsional Stiffness and Strength of Boron Nitride Jonathan Garel,  

E-print Network

, the stiffest and strongest material discovered so far, in terms of both elastic modulus and tensile strength.1Ultrahigh Torsional Stiffness and Strength of Boron Nitride Nanotubes Jonathan Garel, Itai Leven or CNT bundles markedly decreases their effective stiffness and strength.3,9 CNT-based fibers have still

Hod, Oded

429

Some characteristics of high strength fiber reinforced lightweight aggregate concrete  

Microsoft Academic Search

The effect of polypropylene and steel fibers on high strength lightweight aggregate concrete is investigated. Sintered fly ash aggregates were used in the lightweight concrete; the fines were partially replaced by fly ash. The effects on compressive strength, indirect tensile strength, modulus of rupture, modulus of elasticity, stress–strain relationship and compression toughness are reported. Compared to plain sintered fly ash

O Kayali; M. N Haque; B Zhu

2003-01-01

430

Tensile stress acoustic constants of unidirectional graphite/epoxy composites  

SciTech Connect

Previously, the stress acoustic constants (SACs) of unidirectional graphite/epoxy composites were measured to determine the nonlinear moduli of this material. These measurements were made under compressive loading in order to obtain the sufficient number of values needed to calculate these moduli. However, because their strength in tension along fiber directions can be several times greater, most composites are used under tensile loading. Thus, it is important to characterize the nonlinear properties of these materials in tension as well. The SACs which are defined as the slope of the normalized change in ultrasonic natural velocity as a function of stress were measured in a unidirectional laminate of T300/5208 graphite/epoxy. Tensile load was applied along the fiber axis with the ultrasonic waves propagating perpendicular to the fiber direction. Changes in velocity were measured using a pulsed phase locked loop ultrasonic interferometer with the nominal frequency of the ultrasonic waves being 2.25 MHz. 6 refs.

Prosser, W.H. (NASA, Langley Research Center, Hampton, VA (USA))

1990-03-01

431

Tensile Stress Acoustic Constants of Unidirectional Graphite/Epoxy Composites  

NASA Technical Reports Server (NTRS)

Previously, the stress acoustic constants (SAC's) of unidirectional graphite/epoxy composites were measured to determine the nonlinear moduli of this material. These measurements were made under compressive loading in order to obtain the sufficient number of values needed to calculate these moduli. However, because their strength in tension along fiber directions can be several times greater, most composites are used under tensile loading. Thus, it is important to characterize the nonlinear properties of these materials in tension as well. The SAC's which are defined as the slope of the normalized change in ultrasonic "natural" velocity as a function of stress were measured in a unidirectional laminate of T300/5208 graphite/epoxy. Tensile load was applied along the fiber axis with the ultrasonic waves propagating perpendicular to the fiber direction. Changes in velocity were measured using a pulsed phase locked loop ultrasonic interferometer with the nominal frequency of the ultrasonic waves being 2.25 MHz.

Prosser, W. H.

1990-01-01

432

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

433

New Developments with CMnNi in High Strength Steel Weld Metals --Part B. Mechanical Properties  

E-print Network

to increase yield strength to 912 MPa while still maintaining toughness at over 60 J at Ā­100 Ā°C. Increasing yield strength and the highest tensile strength. The optimal combination of strength and impact with a variety of welding processes and generated yield strengths ranging from below 500 MPa to above 1000 MPa

Cambridge, University of

434

Galvanic corrosion induced degredation of tensile properties in micromachined polycrystalline silicon  

NASA Astrophysics Data System (ADS)

Immersion of polycrystalline silicon in hydrofluoric acid-based solutions is often utilized in microsystem fabrication to liberate mechanical structures. The authors demonstrate, using microfabricated tensile specimens, that such etching can cause a catastrophic reduction in tensile strength and elastic modulus in silicon galvanically coupled to a metallic layer, such as commonly used gold. Galvanically corroded silicon exhibits grain-boundary attack leading to intergranular fracture and/or generalized material removal. The severity of damage and corresponding losses in strength and modulus depend on etch duration and etch chemistry. In contrast, without a metallic layer, uncorroded silicon fails transgranularly and independent of etch duration or chemistry.

Miller, David C.; Boyce, Brad L.; Gall, Ken; Stoldt, Conrad R.

2007-05-01

435

Fracture Mechanics Analysis of Cracked Discs of Anisotropic Rock Using the  

E-print Network

(SIFs) and the fracture toughness of anisotropic rocks from the results of diametral compression tests compression (Brazilian test) of discs of rock. It is shown how a new formulation of the Boundary Element with the determi- nation of the deformability, tensile strength and fracturing of anisotropic rocks by diametral

Pan, Ernie

436

Strength loss in kraft pulping  

Microsoft Academic Search

Unbleached kraft pulps from two U.S. mills were 21% and 26% weaker than comparable laboratory pulps from the same chip sources, when assessed as the tear index at a tensile index of 70 kN.m\\/kg. The phenomena involved were clarified by characterizing the differences between the mill and laboratory pulps in terms of fundamental fiber properties. All of the strength loss

Jose Iribarne

1999-01-01

437

Characterisation and Development of Nanostructured, Ultrahigh Strength, and Ductile Bainitic Steels  

E-print Network

plasticity UE Uniform elongation UTS Ultimate tensile strength, also TS YR Yield ratio YS Yield strength Z The zero-angle calibration error Chapter 1 Bainitic Steels—Literature Review Bainite† is a non-equilibrium transformation product of austenite which... transformation tem- perature was held responsible for the decrease in the yield strength. Figure 1.12 also shows that the ultimate tensile strength is generally less sensitive to retained austenite content except at the higher transformation 1.7 Bainite...

Sherif, Mohamed

438

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

NASA Technical Reports Server (NTRS)

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

Grenoble, Ray W.; Johnston, William M.

2013-01-01

439

In situ tensile fracture toughness of surficial cohesive marine sediments  

NASA Astrophysics Data System (ADS)

This study reports the first in situ measurements of tensile fracture toughness, K IC, of soft, surficial, cohesive marine sediments. A newly developed probe continuously measures the stress required to cause tensile failure in sediments to depths of up to 1 m. Probe measurements are in agreement with standard laboratory methods of K IC measurements in both potter's clay and natural sediments. The data comprise in situ depth profiles from three field sites in Nova Scotia, Canada. Measured K IC at two muddy sites (median grain size of 23-50 ?m) range from near zero at the sediment surface to >1,800 Pa m1/2 at 0.2 m depth. These profiles also appear to identify the bioturbated/mixed depth. K IC for a sandy site (>90% sand) is an order of magnitude lower than for the muddy sediments, and reflects the lack of cohesion/adhesion. A comparison of K IC, median grain size, and porosity in muddy sediments indicates that consolidation increases fracture strength, whereas inclusion of sand causes weakening; thus, sand-bearing layers can be easily identified in K IC profiles. K IC and vane-measured shear strength correlate strongly, which suggests that the vane measurements should perhaps be interpreted as shear fracture toughness, rather than shear strength. Comparison of in situ probe-measured values with K IC of soils and gelatin shows that sediments have a K IC range intermediate between denser compacted soils and softer, elastic gelatin.

Johnson, Bruce D.; Barry, Mark A.; Boudreau, Bernard P.; Jumars, Peter A.; Dorgan, Kelly M.

2012-02-01

440

Rationale for Simplifying the Strength Formulae for the Design of Multi-row Bolted Connections  

E-print Network

thickness Testing often has outer plates of steel (ASTM and EN standards). Tensile load Tensile load BoltsASCE Standard Ā­Ā­ Net tension StrengthNet tension Strength Net-tension failure for connections with two rows for stress concentrations causing failurePeak stresses are at points A 66 ASCE StandardASCE Standard Ā­Ā­ Net

Mottram, Toby

441

Analysis of knitted fabric reinforced composites: Part II. Stiffness and strength  

Microsoft Academic Search

The influence of the knit structure on the stiffness and strength in tensile and in share loading of glass warp knitted fabric epoxy composites is studied. The average strength depends on the fibre content and on the linear density of the yarn. The anisotropy in tensile and shear properties is related to the orientation tensor components a1111 and a1122, respectively.

B. Gommers; I. Verpoest; P. Houtte

1998-01-01

442

Shear Strength  

NSDL National Science Digital Library

Dr. John Atkinson, of the University of the West of England, developed a site for undergraduate students wanting to learn more about soil classification. His site addresses issues such as: shear strength, peak strength, and residual strength testing. Filled with charts, diagrams, statistics, the information is pertinent and easily understood by almost any audience.

Atkinson, John

2008-10-07

443

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

2014-08-01

444

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

2010-04-01

445

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

446

Analysis of elevated-temperature tensile and creep properties of normalized and tempered 2 1\\/4 Cr1 Mo steel  

Microsoft Academic Search

Tensile and creep data were collected for normalized and tempered 2 1\\/4 Cr-1 Mo steel from American, Japanese, British, French, and German sources. These included creep data obtained at temperatures from 427 to 600Ā°C (800 to 1112Ā°F) and tensile data from room temperature to 550Ā°C (1022Ā°F). Properties examined included yield strength, ultimate tensile strength, 10āµ-h creep-rupture strength, and 10ā»āµ%\\/h creep

M. K. Booker; B. L. P. Booker; R. W. Swindeman

1982-01-01

447

THE INFLUENCE OF RETAINED AUSTENITE ON THE THICK SECTION MECHANICAL PROPERTIES OF A COMMERCIAL LOW ALLOY ULTRA-HIGH STRENGTH STEEL  

E-print Network

material does show a significant change in yield strengthyield strength and fracture toughness vs. cooling rate. All materialyield strength Oil quenched and ultimate tensile strength (UTS) properties for 300-M. and air cooled material

Horn, R.M.

2010-01-01

448

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

449

Perspectives of SiC-Based Ceramic Composites and Their Applications to Fusion Reactors 5.Development of Evaluation and Application Techniques of SiC?SiC Composites for Fusion Reactors  

Microsoft Academic Search

Evaluation techniques and mechanical properties of silicon carbide composites (SiC?SiC composites) reinforced with highly crystalline fibers are reviewed for fusion applications. The SiC?SiC composites used were fabricated by means of the CVI method. The evaluation includes in-plane tensile strength by in-plane tensile test, transthickness tensile strength by transthickness tensile test and diametral compression test and shear strength by compression test

Tatsuya Hinoki

2004-01-01

450

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

451

Fundamental mechanisms of tensile fracture in aluminum sheet undirectionally reinforced with boron filament  

NASA Technical Reports Server (NTRS)

Results are presented from an experimental study of the tensile-fracture process in aluminum sheet unidirectionally reinforced with boron filament. The tensile strength of the material is severely limited by a noncumulative fracture mechanism which involves the initiation and sustenance of a chain reaction of filament fractures at a relatively low stress level. Matrix fracture follows in a completely ductile manner. The minimum filament stress for initiation of the fracture mechanism is shown to be approximately 1.17 GN/sq m (170 ksi), and appears to be independent of filament diameter, number of filament layers, and the strength of the filament-matrix bond. All the commonly observed features of tensile fracture surfaces are explained in terms of the observed noncumulative fracture mechanism.

Herring, H. W.

1972-01-01