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1

Tensile properties of short fiber composites with fiber strength distribution  

Microsoft Academic Search

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

M. Maalej

2001-01-01

2

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

NASA Technical Reports Server (NTRS)

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

Miyoshi, K.; Buckley, D. H.

1982-01-01

3

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

4

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

5

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

6

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

7

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

8

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

9

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

10

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

11

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

12

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

13

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

14

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

15

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

16

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

17

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

18

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

19

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

20

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

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

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

2013-08-01

23

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

24

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

25

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

26

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

27

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

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

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

41

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

42

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

43

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

44

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

45

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

46

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

47

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

48

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

49

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

50

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

51

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

52

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

53

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

54

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

55

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

56

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

57

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

58

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

59

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

60

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

61

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

62

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

63

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

64

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

65

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

66

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

67

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

68

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

69

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

70

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

71

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

72

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

73

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

74

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

75

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

76

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

77

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

78

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

79

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

80

SOBRE A RESISTÊNCIA À TRACÇÃO DINÂMICA 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

81

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

82

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

83

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

84

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

85

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

86

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

87

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

88

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

89

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

90

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

91

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

92

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

93

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

94

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

95

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

96

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

97

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

98

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

99

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

100

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

101

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

102

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

103

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

104

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

105

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

106

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

107

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

108

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

109

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

110

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

111

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

112

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

113

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

114

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

115

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.

116

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

117

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; Pèlach, M Angels; López, Joan Pere; Mutjé, Pere

2010-01-01

118

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

119

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

120

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

121

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

122

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

123

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

124

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

125

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

126

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

127

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

128

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

129

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

130

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

131

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 ¢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.

132

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

133

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

134

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

135

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

136

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

137

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

138

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

139

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; Kivanç Akça; Yalçin Çiftçi

2002-01-01

140

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.

141

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

142

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

143

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

144

Elevated-temperature tensile and creep properties of several ferritic stainless steels  

NASA Technical Reports Server (NTRS)

The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.

Whittenberger, J. D.

1977-01-01

145

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

146

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

147

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

148

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

149

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

150

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

151

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

152

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

153

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

154

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

155

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

156

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. Díez-Cascón; A. F. Gonçalves

2001-01-01

157

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

158

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

159

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

160

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

161

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

162

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

163

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

164

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

165

Mechanical properties of high-strength concrete  

NASA Astrophysics Data System (ADS)

This report summarizes an experimental program conducted to investigate production techniques and mechanical properties of high strength concrete in general and to provide recommendations for using these concretes in manufacturing precast/prestressed bridge girders. Test variables included total amount and composition of cementitious material (portland cement, fly ash, and silica fume), type and brand of cement, type of silica fume (dry densified and slurry), type and brand of high-range water-reducing admixture, type of aggregate, aggregate gradation, maximum aggregate size, and curing. Tests were conducted to determine the effects of these variables on changes in compressive strength and modulus of elasticity over time, splitting tensile strength, modulus of rupture, creep, shrinkage, and absorption potential (as an indirect indicator of permeability). Also investigated were the effects of test parameters such as mold size, mold material, and end condition. Over 6,300 specimens were cast from approximately 140 mixes over a period of 3 years.

Mokhtarzadeh, Alireza

166

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

167

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

168

Tensile strengths and porosities of solar system primitive bodies  

NASA Astrophysics Data System (ADS)

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

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

169

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

170

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

171

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

172

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

173

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

174

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

175

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

176

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

177

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; Yalçin Çiftçi; Kivanç Akça

1999-01-01

178

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

179

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

180

A review on the tensile properties of natural fiber reinforced polymer composites  

Microsoft Academic Search

This paper is a review on the tensile properties of natural fiber reinforced polymer composites. Natural fibers have recently become attractive to researchers, engineers and scientists as an alternative reinforcement for fiber reinforced polymer (FRP) composites. Due to their low cost, fairly good mechanical properties, high specific strength, non-abrasive, eco-friendly and bio-degradability characteristics, they are exploited as a replacement for

H. Ku; H. Wang; N. Pattarachaiyakoop; M. Trada

2011-01-01

181

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

182

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

183

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

184

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

185

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

186

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

187

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

SciTech Connect

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

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

2008-09-15

188

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

189

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

190

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

191

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

192

Tensile Properties of Austenitic Stainless Steel  

E-print Network

; The choices we make, not the chances we take, determine our destiny. #12; Preface This dissertation 2002. This dissertation contains less than 15,000 words. Except where acknowledgement and reference; Abstract The short­term mechanical properties of austenitic stainless steels can be affected by a myriad

Cambridge, University of

193

Tensile Properties of Austenitic Stainless Steel  

E-print Network

choices we make, not the chances we take, determine our destiny. #12;Preface This dissertation 2002. This dissertation contains less than 15,000 words. Except where acknowledgement and reference;Abstract The short-term mechanical properties of austenitic stainless steels can be affected by a myriad

Cambridge, University of

194

Microstructure and tensile property of the ECAPed pure magnesium  

Microsoft Academic Search

Microstructure and texture development of the equal channel angular pressed (ECAP) pure Mg with different rotation routes of A, Bc and C were investigated and related to the tensile mechanical property. Results showed that grain size was greatly decreased after 1 pass but varied with processing routes after the following ECAP. Due to a relatively high processing temperature, the refinement

W. M. Gan; M. Y. Zheng; H. Chang; X. J. Wang; X. G. Qiao; K. Wu; B. Schwebke; H.-G. Brokmeier

2009-01-01

195

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

196

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

197

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

198

Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers  

NASA Astrophysics Data System (ADS)

The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

Naito, Kimiyoshi

2014-09-01

199

Structure-tensile properties of polyurethanes  

Microsoft Academic Search

A series of hydroxyl terminated polybutadiene-(HTPB) based polyurethanes (PUs) were synthesized by solution polymerization with different types of diisocyanates, hard segment contents, NCOOH ratio and polymerization methods. Spectroscopic and stress-strain studies were carried out to elucidate the structure-property relationships existing in these polymers. It was found that the binding of the hard segment and the flexibility of soft segments had

Shih-Liang Huang; Juin-Yih Lai

1997-01-01

200

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

201

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

202

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

203

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

204

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

205

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

206

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

207

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

208

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

209

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

210

Tensile properties and fracture mechanism of Al–Mg alloy subjected to equal channel angular pressing  

Microsoft Academic Search

Casting Al–2.77wt.% Mg alloy was subjected to equal channel angular pressing (ECAP) and subsequent low-temperature annealing treatment. Tensile properties and fracture modes of as-ECAPed and annealed samples were investigated. It is found that the strength of the Al–Mg alloy increases with increasing the number of ECAP passes, while its elongation decreases. After annealing, the elongation is recovered to a large

D. R. Fang; Q. Q. Duan; N. Q. Zhao; J. J. Li; S. D. Wu; Z. F. Zhang

2007-01-01

211

Tensile properties of 0.05 to 0.20 Pct C TRIP steels  

Microsoft Academic Search

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

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

1971-01-01

212

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

213

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

214

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

215

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.

216

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

217

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, Balázs; Török, Ákos

2013-04-01

218

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

219

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

220

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

221

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

222

Tensile properties and microstructure of helium implanted EUROFER ODS  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

223

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

224

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

225

Effect of slag and silica fume on mechanical properties of high strength concrete  

SciTech Connect

This paper presents the study on changes of the mechanical properties, including compressive strength, split tensile strength and rupture strength of four high strength concretes, caused by the addition of ground blast-furnace slag and silica fume. The study indicates that the mechanical properties of high strength concrete were improved to a great extent at later ages when cement used in concrete was replaced by slag and silica fume by 25% by weight.

Li Jianyong; Tian Pei [China Building Materials Academy, Beijing (China). Building Materials and Concrete Research Inst.] [China Building Materials Academy, Beijing (China). Building Materials and Concrete Research Inst.

1997-06-01

226

Effect of silica fume and steel fibers on some properties of high-strength concrete  

Microsoft Academic Search

The main disadvantage of high-strength concrete is its highly brittle behavior and this can beovercome by adding fibers to the concrete. This would also improve some other mechanical properties of high-strength concrete such as tensile strength and compressive strength. These properties are not very well established for high-strength steel-fiber reinforced concrete (HSFRC) yet. In this study the influence of silica

Özgür Eren; Tahir Çelik

1997-01-01

227

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

228

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

229

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

230

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

NASA Astrophysics Data System (ADS)

Nimonic 263 has been developed for the improved ductility in welded assemblies and is a candidate material for gas turbine combustor and transition pieces along with its good weldability and mechanical properties at room and elevated temperatures. In this study, the tensile behavior of an as-welded Nimonic 263 specimen at room temperature and 1053 K (780 °C) was examined in conjunction with microstructural evolution during welding and postweld heat treatment (PWHT). With the welding and the PWHT, the yield strength (YS), ultimate tensile strength (UTS), and tensile elongation of Nimonic 263 varied in a complex manner. It was observed that the PWHT of resolutionization at 1423 K (1150 °C) for 2 hours gave the highest YS and UTS values, whereas the tensile elongation was the lowest, at both testing temperatures. With increasing resolutionization time, the YS and UTS tended to decrease along with the increase in tensile ductility. The tensile behaviors of as-welded Nimonic 263 specimens was affected by several factors, including grain size, residual stress, possible microsegregation of ?' forming elements, a tendency for interdendritic or intergranular fracture and a morphological change in both M23C6 and MC type carbides, depending on the testing temperature and the PWHT. The complex changes in tensile properties of Nimonic 263 with welding and PWHT at room temperature and 1053 K (780 °C) were discussed based on the micrographic and fractographic observations.

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

2011-04-01

231

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

SciTech Connect

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

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

1996-10-01

232

Hoop Tensile Properties of Ceramic Matrix Composite Cylinders  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

233

Tensile properties of extruded ZK60–RE alloys  

Microsoft Academic Search

ZK60–RE alloys were made by melting ZK60 alloy and cerium-rich rare earth (RE) metal in an electric furnace. The content of RE is 0, 0.5, 1, 1.5, 2, 3 wt.% RE, respectively. The influence of RE on microstructure and tensile mechanical properties of ZK60 magnesium alloys was studied. The results showed that cerium-rich misch metal (MM) had an obvious effect

Chunjiang Ma; Manping Liu; Guohua Wu; Wenjiang Ding; Yanping Zhu

2003-01-01

234

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

235

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

236

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

237

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

238

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; Fabrício Aulo Ogliari; Ana Paula de Souza; Sergio Roberto Peres Line; Adriana Fernandes da Silva; Flávio Fernando Demarco; Adriana Etges; Evandro Piva

239

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

240

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

241

Microstructure and tensile properties of squeeze cast magnesium alloy AM50  

NASA Astrophysics Data System (ADS)

High-pressure die cast magnesium alloy AM50 is currently used extensively in large and complex shaped thin-wall automotive components. For further expansion of the alloy usage in automobiles, novelmanufacturing processes need to be developed. In this study, squeeze casting of AM50 alloy with a relatively thick cross section was carried out using a hydraulic press with an applied pressure of 70 MPa. Microstructure and mechanical properties of the squeeze cast AM50 with a cross-section thickness of 10 mm were characterized in comparison with the die cast counterpart. The squeeze cast AM50 alloy exhibits virtually no porosity in the microstructure as evaluated by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength and elongation, for the squeeze cast samples over the conventional high-pressure die cast parts. The analysis of tensile behavior show that the strain-hardening rate during the plastic deformation of the squeeze cast specimens is constantly higher than that of the die cast specimens. The scanning electron microscopy fractography evidently reveals the ductile fracture features of the squeeze cast alloy AM50.

Zhou, Ming; Hu, Henry; Li, Naiyi; Lo, Jason

2005-08-01

242

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

243

A new tensile stage for in situ electron microscopy examination of the mechanical properties of 'superelastic' specimens  

SciTech Connect

We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of ''superelastic'' materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch (''roll on'') any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.

Dragnevski, Kalin I.; Fairhead, Trevor W.; Balsod, Rik; Donald, Athene M. [Department of Physics, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)

2008-12-15

244

Evaluation of Tensile Deformation Properties of Friction Stir Processed Pure Copper: Effect of Processing Parameters and Pass Number  

NASA Astrophysics Data System (ADS)

In this work, the tensile behavior of pure copper including ultimate tensile stress, yield stress, and elongation in the specimens friction stir processed under different processing parameters and pass adding was investigated in detail. The effect of strain hardening, grain refinement, and heat input on the tensile properties of these specimens was explained as well. It was observed that, regarding the aforementioned factors, the processing parameters and pass number could have considerable effects on the tensile deformation properties of the pure copper such as 300 and 47% enhancements in elongation and ultimate strength, respectively. It was demonstrated that higher passes resulted in the development of ultrafine grains (up to 700-800 nm) in the specimens. The fracture surface morphology was also used to further support the elongation results.

Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Jafari, Jalal

2014-01-01

245

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

246

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 600°C (800 to 1112°F) and tensile data from room temperature to 550°C (1022°F). Properties examined included yield strength, ultimate tensile strength, 10⁵-h creep-rupture strength, and 10⁻⁵%\\/h creep

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

1982-01-01

247

Measured iron-gallium alloy tensile properties under magnetic fields  

NASA Astrophysics Data System (ADS)

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

Yoo, Jin-Hyeong; Flatau, Alison B.

2004-07-01

248

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

249

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

250

Tensile and impact properties of iron-aluminum alloys  

SciTech Connect

Tensile and impact tests have been conducted on specimens from a series of five heats of iron-aluminum alloys. These results have been compared to data for the iron aluminide alloy FA-129. The transition temperatures of all of the Fe{sub 3}Al-based alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys [based on Fe-8Al (wt %)] had lower transition temperatures and higher upper-shelf energy levels than the Fe{sub 3}Al-type alloys. The reduced aluminum alloy with yttrium showed excellent tensile properties, with a room temperature total elongation of 40%, and a very high upper-shelf energy level. Despite the high tensile ductility at room temperature, the transition temperature of the yttrium-containing alloy was still about 150 C, compared to approximately 300 C for FA-129. In general, the microstructures were coarse and anisotropic. The fracture processes were dominated by second-phase particles.

Alexander, D.J.; Sikka, V.K.

1993-12-31

251

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

252

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

253

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

254

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

255

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

256

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

257

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

258

Chondroitinase ABC treatment results in greater tensile properties of self-assembled tissue-engineered articular cartilage.  

PubMed

Collagen content and tensile properties of engineered articular cartilage have remained inferior to glycosaminoglycan (GAG) content and compressive properties. Based on a cartilage explant study showing greater tensile properties after chondroitinase ABC (C-ABC) treatment, C-ABC as a strategy for cartilage tissue engineering was investigated. A scaffold-less approach was employed, wherein chondrocytes were seeded into non-adherent agarose molds. C-ABC was used to deplete GAG from constructs 2 weeks after initiating culture, followed by 2 weeks culture post-treatment. Staining for GAG and type I, II, and VI collagen and transmission electron microscopy were performed. Additionally, quantitative total collagen, type I and II collagen, and sulfated GAG content were measured, and compressive and tensile mechanical properties were evaluated. At 4 wks, C-ABC treated construct ultimate tensile strength and tensile modulus increased 121% and 80% compared to untreated controls, reaching 0.5 and 1.3 MPa, respectively. These increases were accompanied by increased type II collagen concentration, without type I collagen. As GAG returned, compressive stiffness of C-ABC treated constructs recovered to be greater than 2 wk controls. C-ABC represents a novel method for engineering functional articular cartilage by departing from conventional anabolic approaches. These results may be applicable to other GAG-producing tissues functioning in a tensile capacity, such as the musculoskeletal fibrocartilages. PMID:19344291

Natoli, Roman M; Revell, Christopher M; Athanasiou, Kyriacos A

2009-10-01

259

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, Fabrício Aulo; de Souza, Ana Paula; Line, Sergio Roberto Peres; da Silva, Adriana Fernandes; Demarco, Flávio Fernando; Etges, Adriana; Piva, Evandro

2012-04-01

260

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

261

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

NASA Astrophysics Data System (ADS)

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

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

1994-07-01

262

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

PubMed Central

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

Xia, Kang; Zhan, Haifei; Wei, Ye

2014-01-01

263

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

264

High Temperature Tensile Properties of Unidirectional Hi-Nicalon/Celsian Composites In Air  

NASA Technical Reports Server (NTRS)

High temperature tensile properties of unidirectional BN/SiC-coated Hi-Nicalon SiC fiber reinforced celsian matrix composites have been measured from room temperature to 1200 C (2190 F) in air. Young's modulus, the first matrix cracking stress, and the ultimate strength decreased from room temperature to 1200 C (2190 F). The applicability of various micromechanical models, in predicting room temperature values of various mechanical properties for this CMC, has also been investigated. The simple rule of mixtures produced an accurate estimate of the primary composite modulus. The first matrix cracking stress estimated from ACK theory was in good agreement with the experimental value. The modified fiber bundle failure theory of Evans gave a good estimate of the ultimate strength.

Gyekenyesi, John Z.; Bansal, Narottam P.

2000-01-01

265

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

266

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

267

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

268

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

269

Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk  

NASA Astrophysics Data System (ADS)

Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

2014-09-01

270

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

271

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

272

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, Lígia Nunes de Moraes; CLARO NETO, Salvador; GUAGLIANONI, Dalton Geraldo; PINELLI, Lígia Antunes Pereira

2012-01-01

273

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

274

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

NASA Astrophysics Data System (ADS)

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

West, Anton J.; Louthan, Mcintyre R.

1982-11-01

275

Non-linear Correlation Between Uniaxial Tensile Properties and Shear-Edge Hole Expansion Ratio  

NASA Astrophysics Data System (ADS)

Stretch flanging of steel sheets is an important formability issue for automobile industry. Finite element simulation study confirms that the edge of the hole deforms in a uniaxial tensile manner during the hole expansion process. To understand the effect of various tensile properties on hole expansion ratio, current experimental data and collected data from published work have been used. Yield stress, ultimate tensile stress, coefficient of normal anisotropy, total elongation, and post uniform elongation are closely related to hole expansion ratio. A non-linear relationship between hole expansion ratio and tensile properties (ultimate tensile stress, coefficient of normal anisotropy, and total elongation) is developed in the present investigation.

Paul, Surajit Kumar

2014-07-01

276

Non-linear Correlation Between Uniaxial Tensile Properties and Shear-Edge Hole Expansion Ratio  

NASA Astrophysics Data System (ADS)

Stretch flanging of steel sheets is an important formability issue for automobile industry. Finite element simulation study confirms that the edge of the hole deforms in a uniaxial tensile manner during the hole expansion process. To understand the effect of various tensile properties on hole expansion ratio, current experimental data and collected data from published work have been used. Yield stress, ultimate tensile stress, coefficient of normal anisotropy, total elongation, and post uniform elongation are closely related to hole expansion ratio. A non-linear relationship between hole expansion ratio and tensile properties (ultimate tensile stress, coefficient of normal anisotropy, and total elongation) is developed in the present investigation.

Paul, Surajit Kumar

2014-10-01

277

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

278

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

279

Effect of strain rate and temperature on the tensile properties of MANET II steel  

SciTech Connect

MANET II, a modified 12% Cr steel with the German designation DIN 1.4914, is a candidate structural material for the first wall and blanket in fusion reactors. In the present study, the tensile properties of this steel were investigated in the temperature range of 25 to 350 C at strain rates of 5 {times} 10{sup {minus}5}, 1.2 {times} 10{sup {minus}4}, and 1.2 {times} 10{sup {minus}3}s{sup {minus}1}. Both microstructure and fracture surfaces were examined using optical and scanning electron microscopic (SEM) techniques. The results showed that the steel suffers dynamic strain aging, although no serrated flow was observed. Yield strength, ultimate strength, and elongation showed negative strain rate sensitivity. Dynamic strain aging also affected the strain hardening rate. Results are discussed with regard to the chemical composition and fracture surface morphology.

Ghoneim, M.M. [Atomic Energy Authority, Cairo (Egypt)

1997-08-01

280

Predicting fracture and fatigue crack growth properties using tensile properties  

Microsoft Academic Search

The safe-life assessment of components requires information such as the plane stress (Kc), plane strain (KIc), part-through fracture toughness (KIe), and the fatigue crack growth rate properties. A proposed parametric\\/theoretical approach, based on an extended Griffith theory is used to derive fracture toughness properties and generate fatigue crack growth rate data for a range of alloys. The simplicity of the

Bahram Farahmand; Kamran Nikbin

2008-01-01

281

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

282

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

283

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

284

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

285

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

286

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

287

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

NASA Astrophysics Data System (ADS)

This study investigates the effect of ultrasonic treatment on the mechanical properties of thermoplastic natural rubber (TPNR) nanocomposites reinforced with multi-walled nanotubes. The TPNR nanocomposites were prepared using melt blending method from polypropylene (PP), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer, respectively, with 1% of Multi-wall nanotubes. The nanocomposite was prepared using the indirect technique (IDT) with the optimum processing parameters at 180° C with 80 rpm mixing speed and 11 minutes processing time. The results have showed that the good dispersion on nanotubes was achieved by ultrasonic treatment. The optimization of ultrasonic time indicated that the maximum tensile and impact properties occurred with 1 h ultrasonic treatment. The Young's modulus, tensile strength, elongation at break and impact strength have increased by almost 11%, 21%, 43% and 50%, respectively. The results from our study indicate that nanotubes have as excellent reinforcement filler in TPNR matrix.

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

2009-06-01

288

Effect of storage conditions on the tensile properties of eco-friendly chitosan films by response surface methodology  

Microsoft Academic Search

The effect of temperature (4–50°C), relative humidity (RH, 40–80%), and storage period (3–9 days) on the mechanical properties such as tensile strength (TS), percent elongation (%E) and modulus of elasticity (ME) of biodegradable chitosan film was studied by applying response surface methodology and Box–Behnken design of experiment. The results of ANOVA indicated that all the independent variables exhibited significant effect

P. C. Srinivasa; R. Ravi; R. N. Tharanathan

2007-01-01

289

Tensile properties and fracture behavior in electron-beam-welded P\\/M aluminum alloy X7091  

Microsoft Academic Search

Electron-beam bead-on-plate welds have been produced on P\\/M 7091 aluminum alloy plates. Tensile properties of weld specimens heat-treated to the T651 (peak-aged) and T7470 (overaged) condition have been measured and correlated with weld fusion zone microstructure and fracture behavior. Strength levels of weld specimens after post-weld heat treatment are comparable to conventional I\\/M 7XXX series alloys. However, the ductility values

2008-01-01

290

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

291

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

292

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

293

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

294

Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints  

Microsoft Academic Search

The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied. Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure, and fracture surface morphology of continuous current gas tungsten arc welding

AK Lakshminarayanan; K Shanmugam; V Balasubramanian

2009-01-01

295

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

E-print Network

Effect of particle size and volume fraction on tensile properties of fly ash/polyurea composites, 9500 Gilman Drive, La Jolla, CA 92093-0416, USA ABSTRACT Fly ash, which consists of hollow particles of the composites. The tensile properties of the pure polyurea and fly ash/polyurea (FA/PU) composites were tested

Nemat-Nasser, Sia

296

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

Microsoft Academic Search

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

K. Takemura; Y. Minekage

2007-01-01

297

Fracture toughness and tensile properties of nano-structured ferritic steel 12YWT  

NASA Astrophysics Data System (ADS)

The oxide dispersion strengthened (ODS) steels are being developed and investigated for fission and fusion structural applications in Japan, Europe, and the United States. In this paper, the fracture toughness and tensile properties of an ODS steel with nominal composition Fe-12Cr-2.5W-0.4Ti-0.25Y 2O 3 (designated 12YWT) were investigated and compared to commercial reduced-activation ferritic/martensitic (RAFM) steels. Small, 1.6-mm thick and 3.2-mm wide, 3-point bend specimens were used for fracture toughness characterization of this steel. Specimens were fatigue pre-cracked to initial crack length ( a) to width ( W) ratio of 0.45 and tested quasi-statically in the temperature range from -50 °C to 550 °C. Specimens tested up to 50 °C exhibited elastic-plastic cleavage fracture that was typical for the transition region in ferritic steels. The master curve transition temperature, T0, for the 12YWT alloy was determined to be 102 °C. Specimens tested at 100 °C and higher exhibited ductile stable crack growth. In these cases, the J-integral at the onset of stable crack growth ( JIc) was determined from the J- R curves. Their equivalent values in terms of stress intensity factor, K, were about 93 MPa?m at 100 °C and decreased to 53 MPa?m at 550 °C. This study showed that oxide dispersion strengthening resulted in significant decreases in the toughness properties compared to commercial RAFM steels, although appreciable level of toughness was still retained. Tensile tests were performed at temperatures between room temperature and 800 °C. As expected, this material exhibited very high yield strength, ˜1300 MPa, at room temperature. For comparison, the yield strength of commercial RAFM steels is about 550 MPa. Yield strength of 12YWT decreases as test temperature increases and at 800 °C it is about 323 MPa.

Sokolov, M. A.; Hoelzer, D. T.; Stoller, R. E.; McClintock, D. A.

2007-08-01

298

Effect of Postweld Heat Treatment on Microstructure, Hardness, and Tensile Properties of Laser-Welded Ti-6Al-4V  

NASA Astrophysics Data System (ADS)

The effects of postweld heat treatment (PWHT) on 3.2-mm- and 5.1-mm-thick Ti-6Al-4V butt joints welded using a continuous wave (CW) 4-kW Nd:YAG laser welding machine were investigated in terms of microstructural transformations, welding defects, and hardness, as well as global and local tensile properties. Two postweld heat treatments, i.e., stress-relief annealing (SRA) and solution heat treatment followed by aging (STA), were performed and the weld qualities were compared with the as-welded condition. A digital image correlation technique was used to determine the global tensile behavior for the transverse welding samples. The local tensile properties including yield strength and maximum strain were determined, for the first time, for the laser-welded Ti-6Al-4V. The mechanical properties, including hardness and the global and local tensile properties, were correlated to the microstructure and defects in the as-welded, SRA, and STA conditions.

Kabir, Abu Syed H.; Cao, Xinjin; Gholipour, Javad; Wanjara, Priti; Cuddy, Jonathan; Birur, Anand; Medraj, Mamoun

2012-11-01

299

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

NASA Technical Reports Server (NTRS)

An investigation was conducted to determine the effects of mechanical working on the 1093 C (2000 F) tensile and stress-rupture strength of tungsten alloy/superalloy composites. Hot pressed composites containing either conventional tungsten lamp filament wire or tungsten-1% ThO2 wire and a nickel base alloy matrix were hot rolled at 1093 C (2000 F). The hot pressed and rolled composite specimens were then tested in tension and stress-rupture at 1093 C (2000 F). Rolling decreased the degree of fiber-matrix reaction as a function of time of exposure at 1093 C (2000 F). The stress-rupture properties of the rolled composites were superior to hot pressed composites containing equivalent diameter fibers. Rolling did not appreciably affect the 1093 C (2000 F) ultimate tensile strength of the composites.

Petrasek, D. W.

1974-01-01

300

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

301

Nanoscale steel-brass multilayer laminates made by cold rolling: Microstructure and tensile properties  

SciTech Connect

The thrust of this study is to fabricate steel-brass multilayer laminates with layer thicknesses in the nanometer range and to evaluate their mechanical properties. Repeated cold rolling of multilayer stacks was adopted to produce the laminates, because the relative simplicity and the low-cost nature of this process can allow the scaling-up of the technique to the level of commercial-scale production. This work is a continuation of a previous study, in which steel-brass laminates with layer thicknesses in the micrometer range were fabricated for the first time and their tensile properties were evaluated. The present work, however, emphasizes making multilayers with layer thicknesses in the nanometer range and evaluating their mechanical properties. The dependence of strength and ductility on the layer spacing in the nanometer range, is highlighted. It is shown that strength levels comparable to quenched and tempered low alloy steels can be achieved in the laminates by rolling down to the low end of nanometer range. The relevant strengthening mechanisms are also discussed.

Kavarana, F.H.; Ravichandran, K.S.; Sahay, S.S.

2000-05-10

302

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

303

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

304

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

305

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

306

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

307

Statistical properties of microcracking in polyurethane foams under tensile test, influence of temperature and density  

E-print Network

1 Statistical properties of microcracking in polyurethane foams under tensile test, influence; Power-law scaling Abstract We report tensile failure experiments on polyurethane (PU) foams. Experiments. Specifically, we have used polyurethane foams recognized as ductile at room temperature. We record acoustic

Boyer, Edmond

308

Structure and tensile properties of polypropylene/carbon nanotubes composites prepared by melt extrusion  

NASA Astrophysics Data System (ADS)

Polypropylene/carbon nanotubes (PP/CNTs) nancomposites were prepared with a single screw extruder by adding maleic anhydride-grafted poplypropylene (PP-g-MAH) as compatibilizer to polypropylene (PP) with different amounts of carbon nanotubes (CNTs) in the range of 0.1-0.7 wt.%. Structure and morphology of the prepared samples were examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), polarizing light microscopy (PLM) and X-ray diffraction (XRD). The results showed that PP spherulites decreased in size when CNTs were introduced into the polymer. Mechanical properties of the samples were also studied. Tensile tests showed that with increasing amount of CNTs the strain at break decreased whereas the Young's modulus was improved of 16.41 % to 36.05 % and tensile strength of 36.67 % to 64.70 % compared to pristine PP. The SEM microphotographs showed that majority of the CNTs were dispersed individually and oriented along the shear flow direction.

Liu, Yanhui; Zuo, Jicheng; Qin, Jie; Li, Chengwu

2014-08-01

309

Effect of boron on tensile properties of B2 BeAl  

NASA Technical Reports Server (NTRS)

Small additions of boron were shown to improve the room temperature ductility of the intermetallic compound Ni3Al. Boron is believed to segregate to the gain boundaries and strengthen them, allowing the inheret ductility of the grains to be achieved. The present study was undertaken to see if boron has a similar effect on the low temperature tensile properties of the equiatomic intermetallic compound FeAl. A binary alloy without boron is compared with an alloy containing 0.78 at % B (0.2 wt %) B, by tensile testing over the temperature range of 300 K to 640 K. Both alloys were processed by powder metallurgy. Results showed that 0.78 at % B addition to FeAl does indeed change the room temperature fracture mode from intergranular to transgranular, suggesting a strengthening of grain boundaries. The alloy containing boron is, however, still brittle at room temperature. A slight decrease in the ductile to brittle transition temperature is, nevertheless, observed. In addition a significant increase in strength of the alloy is observed with boron addition.

Crimp, M.; Vedula, K.

1986-01-01

310

Characterization and modeling of the tensile properties of plain weft-knit fabric-reinforced composites  

Microsoft Academic Search

This paper describes analytical models for predicting tensile properties of knitted fabric-reinforced composites. Initially, tensile properties of plain weft-knit glass-fiber fabric-reinforced epoxy composites were determined experimentally in the wale and course directions. Elastic properties were predicted by using a ‘cross-over model’ and laminated plate theory. The analytical model expresses the crossing over of looped yarns of knitted fabric, and fiber-

S. Ramakrishna

1997-01-01

311

Short-term mechanical properties of high-strength light-weight concrete  

NASA Astrophysics Data System (ADS)

An experimental investigation was undertaken to establish the mechanical properties of high-strength light-weight concrete. Concretes having compressive strengths ranging from 2,564 to 8,585 psi, and densities between 90 and 103 pcf were tested. The results include a comprehensive study of the engineering properties of light-weight concrete. Data are presented on compressive strength gain with age, speciment size effect, static modulus of elasticity, Poisson's ratio, modulus of rupture, splitting tensile strength, and drying effects. Results are compared to data on normal-weight concrete. The deformation characteristics of light-weight concrete are studied in detail.

Morales, S. M.

1982-08-01

312

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

313

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

314

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

315

Space environmental effects on graphite-epoxy compressive properties and epoxy tensile properties  

NASA Technical Reports Server (NTRS)

This study characterizes the effects of electron radiation and temperature on a graphite-epoxy composite material. Compressive properties of the T300/934 material system were obtained at -250 F (-157 C), room temperature, and 250 F (121 C). Tensile specimens of the Fiberite 934 epoxy resin were fabricated and tested at room temperature and 250 F (121 C). Testing was conducted in the baseline (nonirradiated) and irradiated conditions. The radiation exposure was designed to simulate 30 year, worst-case exposure in geosynchronous Earth orbit. Mechanical properties tended to degrade at elevated temperature and improve at cryogenic temperature. Irradiation generally degraded properties at all temperatures.

Fox, Derek J.; Sykes, George F., Jr.; Herakovich, Carl T.

1987-01-01

316

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

317

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

318

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

319

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

320

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

321

The effect of processing on the microstructure and tensile properties of a {gamma}-TiAl based alloy  

SciTech Connect

Compositional and microstructural control, and alloying additions have been the primary methods used to increase the low temperature ductility of TiAl-based alloys. However, very little has been done to characterize the effect of processing on ductile {gamma}-TiAl alloys. This study examines effect of processing on microstructure and properties of cast, wrought and powder metallurgy TiAl-based alloys with a similar nominal composition. The alloy was Ti-48Al-2Nb-2Cr (at. %). After processing, all of the samples were heat treated in the {alpha} + {gamma} phase field. Microstructures were characterized by optical, scanning electron and transmission electron microscopy. Tensile properties were evaluated in the temperature range 25--1000C in air. The powder processed alloys exhibited the highest strength and ductility at test temperatures up to 850C. All of the alloys exhibited similar tensile properties at 1000C. Examination of fracture surfaces indicated that tensile failure occurred by predominantly transgranular cleavage at temperatures below 700C. However, above 850C, significant plastic deformation was observed, particularly in the powder metallurgy samples. The inter-relationships of processing-microstructure-mechanical properties of Ti-48Al-2Nb-2Cr (at. %) will be discussed.

Fuchs, G.E.

1993-02-01

322

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

323

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

324

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

325

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

326

Elastic properties and fracture strength of quasi-isotropic graphite/epoxy composites  

NASA Technical Reports Server (NTRS)

The layups of the studied laminates are (0, + or - 60) sub s, (0, + or - 45, 90) sub s, (0, + or - 30, + or - 60, 90) sub s (0, + or - 22 1/2, + or - 45, + or - 67 1/2, 90) sub s. The properties determined were tensile modulus, Poisson's ratio, bending stiffness, fracture strength and fracture strain. Measured properties and properties predicted using laminate theory were found to be in reasonable agreement. Reasons for data scatter were determined.

Sullivan, T. L.

1977-01-01

327

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

328

Tensile and fracture toughness properties of MA957: implications to the development of nanocomposited ferritic alloys  

Microsoft Academic Search

A study to explore approaches to optimizing nanocomposited ferritic alloys was carried out on dispersion strengthened mechanically alloyed (MA) MA957, in the form of extruded bar stock. Previous studies had indicated that this alloy manifested superior high temperature strength and radiation stability, but was extremely brittle in notch impact tests. Thus our objective was to develop a combination of tensile,

M. J. Alinger; G. R. Odette; G. E. Lucas

2002-01-01

329

Improving the tensile properties of carbon fiber reinforced cement by ozone treatment of the fiber  

SciTech Connect

The tensile strength, modulus and ductility of carbon fiber reinforced cement paste were increased by ozone treatment of the fibers prior to using the fibers. Increases were observed whether or not the paste contained methylcellulose/silica fume/latex. The ozone treatment involved exposure to O{sub 3} gas (0.3 vol.%, in air) for 10 min at 160 C.

Fu, X.; Lu, W.; Chung, D.D.L. [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.] [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.

1996-10-01

330

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

331

Effect of service usage on tensile, fatigue, and fracture properties of 7075-T6 and 7178-T6 aluminum alloys  

NASA Technical Reports Server (NTRS)

A study has been made to determine the effects of extensive service usage on some basic material properties of 7075-T6 and 7178-T6 aluminum alloy materials. The effects of service usage were determined by comparing material properties for new material (generally obtained from the literature) with those for material cut from the center wing box of a C-130B transport airplane with 6385 flight-hours of service. The properties investigated were notched and unnotched fatigue strengths, fatigue-crack-growth rate, fracture toughness, and tensile properties. For the properties investigated and the parameter ranges considered (crack length, stress ratio, etc.), the results obtained showed no significant difference between service and new materials.

Everett, R. A., Jr.

1975-01-01

332

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

333

Apparatus for measuring tensile and compressive properties of solid materials at cryogenic temperatures  

DOEpatents

An apparatus for evaluating the tensile and compressive properties of material samples at very low or cryogenic temperatures employs a stationary frame and a dewar mounted below the frame. A pair of coaxial cylindrical tubes extend downward towards the bottom of the dewar. A compressive or tensile load is generated hydraulically and is transmitted by the inner tube to the material sample. The material sample is located near the bottom of the dewar in a liquid refrigerant bath. The apparatus employs a displacement measuring device, such as a linear variable differential transformer, to measure the deformation of the material sample relative to the amount of compressive or tensile force applied to the sample.

Gonczy, John D. (Oaklawn, IL); Markley, Finley W. (St. Charles, IL); McCaw, William R. (Burr Ridge, IL); Niemann, Ralph C. (Downers Grove, IL)

1992-01-01

334

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

335

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

336

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

337

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

338

Tensile Properties of Some Structural Sheet Materials Under Rapid-Heating Conditions  

NASA Technical Reports Server (NTRS)

The results of the NACA tests to determine the tensile strength of some structural sheet materials heated to failure at temperature rates from 0.2 deg. F to 100 deg F per second under constant load conditions are reviewed . Yield and rupture stresses obtained under rapid-heating conditions are compared with the results of conventional elevated-temperature tensile tests. The relation between rapid-heating tests, short-time creep tests, and conventional creep tests is discussed . The application of a phenomenological theory for calculating rapid-heating curves is shown. Methods are given for predicting yield and rupture stresses and temperatures from master curves and temperature-rate parameters

Heimerl, George J.

1957-01-01

339

Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.  

PubMed

Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. PMID:22057343

Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

2012-06-01

340

Effect of copper-rich regions on tensile properties of VPPA weldments of 2219-T87 aluminum  

NASA Technical Reports Server (NTRS)

This study examines the relations between tensile properties and microstructural features of variable polarity plasma arc (VPPA) weldments of 2219-T87 aluminum. Crack initiation and weld failure of transverse tensile specimens of single and multipass weldments were studied. The specimens fractured on the rising portion of the stress-strain curve prior to necking, signifying that an increase in strength would accompany an increase in ductility. Of particular interest is a shallow, typically 0.001-0.003-in. (0.03-0.08-mm) deep, copper-rich region located in the crown and root corners of the weld. This region is a primary source of crack initiation and growth, due to its brittle nature and highly strained location. The brittle regions were removed by electropolishing and machining to determine their effect on weld tensile properties. The removal increased the ductility of the weld specimens, and in the case of single pass welds, actually increased the load carrying capacity. Local strain measurements and metallographic and chemical analyses are presented.

Hartman, J. A.; Beil, R. J.; Hahn, G. T.

1987-01-01

341

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

342

Tuning electronic and magnetic properties of partially hydrogenated graphene by biaxial tensile strain: a computational study  

PubMed Central

Using density functional theory calculations, we have investigated the effects of biaxial tensile strain on the electronic and magnetic properties of partially hydrogenated graphene (PHG) structures. Our study demonstrates that PHG configuration with hexagon vacancies is more energetically favorable than several other types of PHG configurations. In addition, an appropriate biaxial tensile strain can effectively tune the band gap and magnetism of the hydrogenated graphene. The band gap and magnetism of such configurations can be continuously increased when the magnitude of the biaxial tensile strain is increased. This fact that both the band gap and magnetism of partially hydrogenated graphene can be tuned by applying biaxial tensile strain provides a new pathway for the applications of graphene to electronics and photonics.

2014-01-01

343

Tuning electronic and magnetic properties of partially hydrogenated graphene by biaxial tensile strain: a computational study  

NASA Astrophysics Data System (ADS)

Using density functional theory calculations, we have investigated the effects of biaxial tensile strain on the electronic and magnetic properties of partially hydrogenated graphene (PHG) structures. Our study demonstrates that PHG configuration with hexagon vacancies is more energetically favorable than several other types of PHG configurations. In addition, an appropriate biaxial tensile strain can effectively tune the band gap and magnetism of the hydrogenated graphene. The band gap and magnetism of such configurations can be continuously increased when the magnitude of the biaxial tensile strain is increased. This fact that both the band gap and magnetism of partially hydrogenated graphene can be tuned by applying biaxial tensile strain provides a new pathway for the applications of graphene to electronics and photonics.

Song, Er Hong; Ali, Ghafar; Yoo, Sung Ho; Jiang, Qing; Cho, Sung Oh

2014-09-01

344

Tensile testing on the mechanical properties of weld metal in dissimilar gage tailor-welded blanks  

Microsoft Academic Search

In this paper, tailor-welded blanks (TWBs) of three dissimilar gages for the automotive body inner side panel were analyzed. The basic mechanical properties were measured through the tensile test. Based on this, a method of ¿rule of mixtures¿ for measuring the properties of weld metal in TWBs was introduced. Moreover, the error between the calculated results and the measured data

Yu Tianming; Ma Wenxing; Wang Chunyan

2009-01-01

345

Effects of Microstructure on Tensile, Charpy Impact, and Crack Tip Opening Displacement Properties of Two API X80 Pipeline Steels  

NASA Astrophysics Data System (ADS)

The effects of microstructure on tensile, Charpy impact, and crack tip opening displacement (CTOD) properties of two API X80 pipeline steels were investigated in this study. Two API X80 pipeline steels consisting of acicular ferrite and granular bainite, and a small amount of hard phases such as martensite and secondary phases have elongated grains along the rolling direction, so that they show different mechanical properties as the specimens' directions change. The 90 deg specimens have high tensile strength due to the low stress concentration on the fine hard phases and the high loads for the deformation of the elongated grains. In contrast, the 30 deg specimens have less elongated grains and larger hard phases such as martensite, with the size of about 3 ?m, than the 90 deg specimens. Hence, the 30 deg specimens have low tensile strength because of the high stress concentration on the large hard phases and the low loads to deform grains. In the 90 deg specimen, brittle crack propagation surfaces are even since cracks propagate in a straight line along the elongated grain structure. In the 30 deg specimen, however, brittle crack propagation surfaces are uneven, and secondary cracks are observed, because of the zigzag brittle crack propagation path. In the CTOD properties, the 90 deg specimens have maximum forces of higher magnitude than the 30 deg specimens, because of the elongated grain structure. However, CTODs of the 90 deg specimens are lower than those of the 30 deg specimens because of the low plastic deformation areas by the elongated grains in the 90 deg specimens.

Shin, Sang Yong

2013-06-01

346

Reproducibility of the tensile properties of spider (Argiope trifasciata) silk obtained by forced silking.  

PubMed

A modified forced silking procedure was developed to allow an accurate study of the tensile properties of spider (Argiope trifasciata) silk, especially the characterization of the variability of the tensile properties of forcibly silked fibers. The procedure involves an immobilization technique that does not require anesthetization of the spider, a mode of collection that allows immediate access to any silk sample with a minimum manipulation, and a technique to measure the diameters of the spider silk fibers systematically. The forcibly silked fibers obtained by this procedure show reproducible tensile properties in terms of force-displacement curves as well as stress-strain curves. Furthermore, reproducibility also extends to forcibly silked fibers obtained from different spiders when stress-strain is considered. PMID:15612009

Guinea, Gustavo V; Elices, Manuel; Real, José Ignacio; Gutiérrez, Sara; Pérez-Rigueiro, José

2005-01-01

347

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

348

The variability and interdependence of spider viscid line tensile properties.  

PubMed

True stress-true strain curves of naturally spun viscid line fibres retrieved directly from the spiral of orb-webs built by Argiope trifasciata spiders were measured using a novel methodology. This new procedure combines a method for removing the aqueous coating of the fibres and a technique that allows the accurate measurement of their cross-sectional area. Comparison of the tensile behaviour of different samples indicated that naturally spun viscid lines show a large variability, comparable to that of other silks, such as major ampullate gland silk and silkworm silk. Nevertheless, application of a statistical analysis allowed the identification of two independent parameters that underlie the variability and characterize the observed range of true stress-true strain curves. The combination of this result with previous mechanical and microstructural data suggested the assignment of these two independent effects to the degree of alignment of the protein chains and to the local relative humidity, which, in turn, depends on the composition of the viscous coating and on the external environmental conditions. PMID:24072798

Perea, Gracia Belén; Plaza, Gustavo R; Guinea, Gustavo V; Elices, Manuel; Velasco, Beatriz; Pérez-Rigueiro, José

2013-12-15

349

Mechanical Properties of Polycrystalline Titanium Nitride Films Measured by XRD Tensile Testing  

NASA Astrophysics Data System (ADS)

This paper describes measurement of mechanical properties of micron-thin polycrystalline titanium nitride (TiN) films. We developed a novel tensile test technique that can directly measure lateral elastic strain of a microscale single/poly-crystalline specimen by means of X-ray diffraction (XRD), which enables evaluation of not only Young's modulus but also Poisson's ratio of TiN films. TiN films having thicknesses of 0.5 ?m to 1.6 ?m are deposited onto the top and bottom surfaces of a microscale single crystal silicon (Si) specimen. The deposition is carried out by r.f. reactive magnetron sputtering under Ar partial pressure ranging from 0.7 Pa to 1.0 Pa. Average values of Young's modulus and Poisson's ratio for the Si monolayer specimen are found to be 169 GPa and 0.35, respectively, which are in close agreement with analytical values. TiN films deposited under an Ar partial pressure of 0.7 Pa have average Young's modulus of 290 GPa and Poisson's ratio of 0.36. These values gradually decrease with increasing Ar partial pressure, but are independent of TiN film thickness. Fracture strength of a TiN/Si/TiN composite specimen shows dependence on film thickness, regardless of Ar partial pressure.

Namazu, Takahiro; Inoue, Shozo; Takemoto, Hideki; Koterazawa, Keiji

350

Elastic properties and fracture strength of quasi-isotropic graphite/epoxy composites  

NASA Technical Reports Server (NTRS)

A research program is described which was devised to determine experimentally the elastic properties in tension and bending of quasi-isotropic laminates made from high-modulus graphite fiber and epoxy. Four laminate configurations were investigated, and determinations were made of the tensile modulus, Poisson's ratio, bending stiffness, fracture strength, and fracture strain. The measured properties are compared with those predicted by laminate theory, reasons for scatter in the experimental data are discussed, and the effect of fiber misalignment on predicted elastic tensile properties is examined. The results strongly suggest that fiber misalignment in combination with variation in fiber volume content is responsible for the scatter in both elastic constants and fracture strength.

Sullivan, T. L.

1977-01-01

351

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

352

The change in tensile properties of wrought LCAC molybdenum irradiated with neutrons  

NASA Astrophysics Data System (ADS)

Molybdenum alloys are known to be most susceptible to neutron radiation damage at radiation temperatures <800 °C, a condition which has limited their broader use in nuclear applications. Manipulation of alloy microstructure through the optimization of carbon and oxygen contents, and mechanical working were investigated as means to mitigate the undesirable effects of irradiation. Low carbon arc cast (LCAC) molybdenum sheet specimens were irradiated in the high flux isotope reactor (HFIR) at temperatures ranging from 270 to 1100 °C and at neutron fluences between 10.5 and 64.4 × 10 24 n/m 2 ( E>0.1 MeV). Irradiation of LCAC molybdenum at nominal temperatures of 935-1100 °C produced only moderate changes in tensile strength, tensile elongation, and no change in the ductile to brittle transition temperature (DBTT) as inferred from tensile fracture surfaces. Irradiation of LCAC molybdenum at either 270 or 605 °C resulted in a significant increase in yield strength, a decrease in tensile elongation, and an increase in DBTT. This behavior is characteristic of that reported for pure molybdenum following irradiation at temperatures <800 °C. The use of arc-cast processing, a low oxygen content, and high carbon to oxygen ratio to produce the LCAC molybdenum used in this work results in strong grain boundaries that are not the preferred fracture path.

Cockeram, B. V.; Hollenbeck, J. L.; Snead, L. L.

2004-01-01

353

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

354

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

355

Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864  

NASA Astrophysics Data System (ADS)

Two large heats of V-4Cr-4Ti alloy were produced in the US in the past few years. The first, 832665, was a 500 kg heat procured by the US Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800°C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000°C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750°C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent - no brittle failures at temperatures above -150°C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented (H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 30th June 1998, DOE/ER-0313/24, p. 3; H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 31st December 1998, DOE/ER-0313/25, p. 3).

Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R.; Trester, P. W.

2000-12-01

356

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

357

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

358

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

359

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

360

Microstructures and Tensile Properties of Hot-Extruded Al Matrix Composites Containing Different Amounts of Al4Sr  

NASA Astrophysics Data System (ADS)

In this investigation, the effect of hot extrusion process has been studied on the microstructure and tensile properties of aluminum matrix composite containing different amounts (10, 15, and 20 wt pct) of Al4Sr intermetallic phase. Microstructural examinations assessed by scanning electron microscopy revealed that hot extrusion breaks large Al4Sr particles and reduces their length tremendously. It was also found that although the addition of Al4Sr content in the composite reduces ultimate tensile strength and elongation values, hot extrusion improves tensile results significantly. Remarkable result of this study was concerned with significant improvement in the toughness of hot-extruded Al-10 wt pct Al4Sr composite in which elongation values raised up to 22 pct. Therefore, optimum amount of Al4Sr intermetallic in the composite was found to be 10 wt pct. Fractographic examinations revealed that hot extrusion encourages ductile mode of fracture by introducing homogeneous distribution of fine dimples on the fracture surface of the composites.

Sharifian, K.; Emamy, M.; Tavighi, K.; Vaziri Yeganeh, S. E.

2014-08-01

361

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

362

Structural and Thermoelectric Properties of Nanocrystalline Bismuth Telluride Thin Films Under Compressive and Tensile Strain  

NASA Astrophysics Data System (ADS)

To investigate the effect of strain on bismuth telluride films, we applied different compressive and tensile strains to thin films by changing the bending radius of a flexible substrate so the strain ranged from -0.3% (compressive) to +0.3% (tensile). The structural properties of the strained thin films, composed of nanosized grains, were analyzed by x-ray diffraction and scanning electron microscopy. For all samples the main peak was the (015) diffraction peak; crystal orientation along the (015) growth direction was slightly enhanced by application of compressive strain. The thermoelectric properties of strained bismuth telluride thin films were evaluated by measurement of electrical conductivity, Seebeck coefficient, and power factor. The magnitude and direction of the applied strain did not significantly affect the power factor, because when the strain changed from compressive to tensile the electrical conductivity increased and the absolute Seebeck coefficient decreased.

Kusagaya, K.; Hagino, H.; Tanaka, S.; Miyazaki, K.; Takashiri, M.

2014-11-01

363

Effect of filler loading of nickel zinc ferrite on the tensile properties of PLA nanocomposites  

NASA Astrophysics Data System (ADS)

The mechanical strength of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90:10. The MPNC were prepared at constant mixing temperature at 180°C, mixing time of 15 min. and mixing speed of 100 rpm. In order to achieve a good dispersion of NiZn ferrite in the matrix, firstly an ultrasonic treatment had been employed to mix the LNR and NiZn ferrite for 1 hour. The MPNC of PLA/LNR/NiZn ferrite then were prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1-5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases the tensile strength also increases until an optimum value of filler loading was reached. The Young's modulus, tensile strength and elongation at break have also increased. The study proves that NiZn ferrite is excellent reinforcement filler in PLA matrix. Scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX) were meant to show the homogeneity dispersion of nanoparticles within the matrix and to confirm the elemental composition of NiZn ferrites-PLA/LNR nanocomposites respectively.

Shahdan, Dalila; Ahmad, Sahrim Hj

2013-05-01

364

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

365

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

366

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

367

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

368

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

369

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

370

77 to 1200 K tensile properties of several wrought superalloys after long-term 1093 K heat treatment in air and vacuum  

NASA Astrophysics Data System (ADS)

The 77 to 1200 K tensile properties of approximately 1.3 mm thick wrought sheet Co-base Haynes alloy 188 and Ni-base Haynes alloy 230 and Inconel 617 have been measured after heat treatment in air and vacuum for periods up to 22,500 h at 1093 K. Significant changes in structure were produced by prior exposures, including precipitation of second phases and, in the case of heat treatment in air, oxide scale and surface-connected grain boundary pits/oxides, as deep as 50 to 70 µm, in all three superalloys. Due to the geometry of the experiment, the vacuum-exposed samples were protected from loss of volatile elements by evaporation; hence, such specimens were simply given 1093 K anneals in an innocuous environment, which produced very little surface attack. Compared to the properties of as-received alloys, prior exposure tended to reduce both the yield strength and ultimate tensile strength, with the greatest reductions at 77 and 298 K. The most dramatic effect of heat treatment was found in the low-temperature residual tensile elongation, where decreases from 40 to 5% at 77 K were found. Ductility is the only property that was found to have a consistent dependency on environment, with air exposure always yielding less tensile elongation than vacuum exposure.

Whittenberger, J. D.

1994-02-01

371

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

372

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

373

Tensile and compressive properties of polymer laminates containing internal sensor cavities  

Microsoft Academic Search

This research paper presents an experimental study into the effect of introducing long, narrow interlaminar galleries on the tensile and compressive properties of aerospace carbon\\/epoxy laminates. Galleries are thin and long holes used for the installation of small measuring devices, such as structural health monitoring (SHM) sensors. The galleries considered in this study are similar to those used in a

A. Kousourakis; M. K. Bannister; A. P. Mouritz

2008-01-01

374

Tensile properties of short-glass-fiber- and short-carbon-fiber-reinforced polypropylene composites  

Microsoft Academic Search

Composites of polypropylene (PP) reinforced with short glass fibers (SGF) and short carbon fibers (SCF) were prepared with extrusion compounding and injection molding techniques. The tensile properties of these composites were investigated. It was noted that an increase in fiber volume fraction led to a decrease in mean fiber length as observed previously. The relationship between mean fiber length and

S.-Y Fu; B Lauke; E Mäder; C.-Y Yue; X Hu

2000-01-01

375

A Study of the Diameter Distribution and Tensile Property of Horse Tail Hair  

Microsoft Academic Search

The current research reviews a study of the variation in diameter along the Mongolian horse tail hair length, and its effect on tensile properties. Our results show that horse tail hair fibre has quite considerable changes in diameter from the root to the tip. There is a significant decrease in fibre diameter at the tip. A comparative study of single

Bazarsad Bolormaa; Jean Yves Drean; Dorj Enkhtuya

2008-01-01

376

Deep cryogenic treatment of AISI 302 stainless steel: Part I – Hardness and tensile properties  

Microsoft Academic Search

The effects of deep cryogenic treatment (DCT) on the static mechanical properties of the AISI 302 austenitic stainless steel were investigated through experimental testing. The results of the tensile and hardness tests are discussed and compared to data and microstructural observations from the DCT literature concerning the same class of steel. In addition, the influence of two important treatment parameters,

Paolo Baldissera

2010-01-01

377

Cure characteristics, tensile properties and swelling behaviour of recycled rubber powder-filled natural rubber compounds  

Microsoft Academic Search

The effect of recycled rubber powder (RRP) on cure characteristics, tensile properties and swelling behaviour of natural rubber (NR) compounds was investigated in the concentration range of 0 to 50 phr. Results indicate that the minimum torque and Mooney viscosity of the natural rubber compounds increase with increasing RRP loading whereas the scorch time and cure time exhibit a decreasing

H Ismail; R Nordin; A. M Noor

2002-01-01

378

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

379

Fatigue properties and failure characterization of spot welded high strength steel sheet  

Microsoft Academic Search

Fatigue properties and failure characterization of high strength spot welded steels, such as DP600 GI, TRIP600-bare and HSLA340Y GI, have been conducted. Tensile shear and coach peel samples have been used in this investigation. HSLA340Y GI samples were used as the baseline material for comparison. Microhardness was measured to study the hardness change across the weld nugget. Under low load

Xin Long; Sanjeev K. Khanna

2007-01-01

380

Effects of mechanical properties of adhesive resins on bond strength to dentin  

Microsoft Academic Search

Objectives: The purpose of this study was to evaluate the relationship between the micro-tensile bond strength to dentin and mechanical properties of the cured adhesive resins.Methods: Coronal dentin surfaces of extracted human teeth were treated with four commercial self-etching priming systems (Clearfil SE Bond; UniFil Bond; Tokuso Mac-Bond II; and Imperva Fluoro Bond) and bonded with a resin composite. After

A Takahashi; Y Sato; S Uno; P. N. R Pereira; H Sano

2002-01-01

381

Micromechanics models for predicting tensile properties of latex paint films  

Microsoft Academic Search

\\u000a The mechanical properties of latex paint films containing different volume fractions of TiO2, CaCO3 and kaolin were measured\\u000a in uniaxial tension over a broad range of temperatures and crosshead speeds. Young’s modulus results in the glassy region\\u000a are first compared with several micromechanics theories for particle-filled composites containing elastic phases. It was found\\u000a that the Mori-Tanaka theory [1, 2] slightly

Eric W. S. Hagan; Maria N. Charalambides; Christina R. T. Young; Thomas J. S. Learner; Stephen Hackney

382

Apparatus for measuring tensile and compressive properties of solid materials at cryogenic temperatures  

DOEpatents

An apparatus for evaluating the tensile and compressive properties of material samples at very low or cryogenic temperatures employs a stationary frame and a dewar mounted below the frame. A pair of coaxial cylindrical tubes extend downward towards the bottom of the dewar. A compressive or tensile load is generated hydraulically and is transmitted by the inner tube to the material sample. The material sample is located near the bottom of the dewar in a liquid refrigerant bath. The apparatus employs a displacement measuring device, such as a linear variable differential transformer, to measure the deformation of the material sample relative to the amount of compressive or tensile force applied to the sample. 7 figs.

Gonczy, J.D.; Markley, F.W.; McCaw, W.R.; Niemann, R.C.

1992-04-21

383

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

384

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

385

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

386

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

387

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

388

Development of India-specific RAFM steel through optimization of tungsten and tantalum contents for better combination of impact, tensile, low cycle fatigue and creep properties  

NASA Astrophysics Data System (ADS)

Effects of tungsten and tantalum contents on impact, tensile, low cycle fatigue and creep properties of Reduced Activation Ferritic-Martensitic (RAFM) steel were studied to develop India-specific RAFM steel. Four heats of the steel have been melted with tungsten and tantalum contents in the ranges 1-2 wt.% and 0.06-0.14 wt.% respectively. Increase in tungsten content increased the ductile-to-brittle transition temperature (DBTT), low cycle fatigue and creep strength of the steel, whereas the tensile strength was not changed significantly. Increase in tantalum content increased the DBTT and low cycle fatigue strength of the steel whereas the tensile and creep strength decreased. Detailed TEM investigations revealed enhanced microstructural stability of the steel against creep exposure on tungsten addition. The RAFM steel having 1.4 wt.% tungsten with 0.06 wt.% tantalum was found to possess optimum combination of impact, tensile, low cycle fatigue and creep properties and is considered for Indian-specific RAFM steel. Low temperature impact energy of the RAFM steel is quite sensitive to the contents of tungsten and tantalum. The DBTT increased with both the tungsten and tantalum contents. Tungsten and tantalum contents in the investigated ranges had no appreciable effect on the tensile properties of the RAFM steel. Low cycle fatigue life of the RAFM steel increased with the increase in tungsten and tantalum contents. The softening rate with cyclic exposure was lowest for tungsten content of 1.4 wt.%, further increase in tungsten led to an increase in softening rate. Creep deformation and rupture strength of the RAFM steel were found to be quite sensitive to the tungsten and tantalum contents. Creep strength of the steel increased with increase in tungsten content and decreased with increase in tantalum content. Based on the study, the chemical composition of India-specific RAFM steel has been established as 9Cr-1.4W-0.06Ta-V, having optimum combination of strength and toughness and is designated as Indian Reduced Activation Ferritic Martensitic (INRAFM) steel.

Laha, K.; Saroja, S.; Moitra, A.; Sandhya, R.; Mathew, M. D.; Jayakumar, T.; Rajendra Kumar, E.

2013-08-01

389

Microscale material testing of single crystalline silicon: process effects on surface morphology and tensile strength  

Microsoft Academic Search

The mechanical properties of single-crystalline silicon are measured by uniaxial tension tests from microscale beam specimens patterned by four different common silicon etchants — KOH, EDP, TMAH and XeF2. SOI wafers are used to prepare test samples, which are 3–5 ?m thick, 20–100 ?m wide, and 6 mm long beam specimens; these are monolithically mounted on a temporary frame. A

Taechung Yi; Lu Li; Chang-Jin Kim

2000-01-01

390

THE EFFECTS OF FAST REACTOR IRRADIATION CONDITIONS ON THE TENSILE PROPERTIES OF TWO FERRITIC/MARTENSITIC STEELS  

SciTech Connect

Tensile testing has been performed at 25 and at ~400°C on two ferritic/martensitic steels (JFMS and HT-9) after irradiation in FFTF to up to ~70 dpa at 373 to 433°C. As observed in previous studies, this range of irradiation temperatures has a significant effect on hardening. The percent increase in yield stress decreases with increasing irradiation temperature from 373 to 433ºC. The JFMS alloy, which has 0.7 wt. % silicon, exhibits approximately a factor of two increase in yield strength between tests at 427°C and at 373°C, and shows an increase in hardening with increasing dose. A comparison of the JFMS tensile properties to the properties of other ferritic/martensitic steels suggests that this hardening is due to precipitation of a Si-rich Laves phase in this alloy. The HT-9 alloy, which contains more chromium and more carbon but less silicon (0.2 wt. %), less molybdenum and less nickel, hardens during irradiation at 373°C, but shows less hardening for irradiations performed at 427ºC and no increase in yield stress with increasing dose beyond 10 dpa.

Maloy, Stuart A.; Toloczko, Mychailo B.; McClellan, K. J.; Romero, T. J.; Kohno, Y.; Garner, Francis A.; Kurtz, Richard J.; Kimura, Akihiko

2006-09-15

391

Effect of Tempering Time on Microstructure, Tensile Properties, and Deformation Behavior of a Ferritic Light-Weight Steel  

NASA Astrophysics Data System (ADS)

In the present study, a ferritic light-weight steel was tempered at 973 K (700 °C) for various tempering times, and tensile properties and deformation mechanisms were investigated and correlated to microstructure. ?-carbides precipitated in the tempered band-shaped martensite and ferrite matrix, and the tempered martensite became more decomposed with increasing tempering time. Tempering times for 3 days or longer led to the formation of austenite as irregular thick-film shapes mostly along boundaries between the tempered martensite and the ferrite matrix. Tensile tests of the 1-day-tempered specimen showed that deformation bands were homogeneously spread throughout the specimen, and that the fine carbides were sufficiently deformed inside these deformation bands resulting in high strength and ductility. The 3-day-tempered specimen showed a small amount of boundary austenite, which readily developed voids or cracks and became sites for fracture. This cracking at boundary austenites became more prominent in the 7- and 15-day-tempered specimens, as the volume fraction of boundary austenites increased with increasing tempering time. These findings suggested that, when the steel was tempered at 973 K (700 °C) for an appropriate time, i.e., 1 day, to sufficiently precipitate ?-carbides and to prevent the formation of boundary austenites, that the deformation occurred homogeneously, leading to overall higher mechanical properties.

Han, Seung Youb; Shin, Sang Yong; Lee, Byeong-Joo; Lee, Sunghak; Kim, Nack J.; Kwak, Jai-Hyun

2013-01-01

392

Effect of ultrasonic treatment on tensile properties of PLA/LNR/NiZn ferrite nanocomposite  

SciTech Connect

The influence of sonication treatment time on the morphological and mechanical properties of LNR/PLA composite impregnated with different filler loadings of NiZn ferrite nanoparticles was investigated. The nanocomposite was prepared using melt blending method with assistance of ultrasonic treatment of 0, 1 and 2 hrs. Structural characterization of the nanocomposites was examined using scanning electron microscopy (SEM) with their elemental composition being confirmed by energy dispersive X-ray spectroscopy (EDX). The tensile properties of LNR/PLA composite treated with different ultrasonication times have improved with increasing magnetic nanofiller signature in the nanocomposite. Further, the optimum sonication time of 1 hr was found to produce nanocomposite with maximum tensile properties.

Shahdan, Dalila; Ahmad, Sahrim Hj.; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2013-11-27

393

Tensile and fracture properties of type 316 stainless steel after creep  

NASA Astrophysics Data System (ADS)

The effects of creep on the mechanical properties of type 316 stainless steel were studied. Tensile and Charpy specimens were machined from the oversize specimens crept at 750 °C and 103 MPa. The ambient fracture energy was found to deteriorate rapidly after creep. The ambient yield stress was increased moderately, but the tensile ductility was severely reduced. The effects of intergranular carbides alone on mechanical properties were studied with specimens thermal aged without load. These carbides were shown to cause a moderate reduction in fracture energy and tensile ductility but had little effect on yield stress. Extensive grain boundary separations were observed on the fracture surfaces. SEM studies showed that these grain boundaries were covered with micro voids initiated by the dense intergranular carbides. Frequently, large dimples on grain boundary joined up and initiated shear fracture into the grain. In the crept specimens additional microstructural changes in the form of intragranular carbides and subgrain boundaries were observed. Both are responsible for the increase in yield stress and the further reduction in tensile ductility and fracture energy. The intragranular carbides also modified the size and density of the dimples on the fracture surfaces.

Gan, D.

1982-12-01

394

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

395

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

396

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

397

Microstructure and tensile properties of iron parts fabricated by selective laser melting  

NASA Astrophysics Data System (ADS)

Iron, as the basic industry material was extensively studied in the past, but it could still offer extended possibilities with the use of new processing techniques such as selective laser melting (SLM). In this work, the manufacturing of iron parts using SLM technology was investigated. The effect of processing parameters on density of the iron parts was studied. Fully dense iron parts have been fabricated at the laser power of 100 W using different laser scanning speeds. By means of metallographic observation and TEM characterization, it can be found that the grains size decreased with increasing scanning speed and high dislocation density was observed. Tensile specimens were fabricated using optimal parameters and mechanical tests allowed observing an ultimate tensile strength of 412 MPa and the yield strength of 305 MPa. Multiple self-strengthening mechanisms during SLM process are proposed to explain this high mechanical strength. The grain refinement seems to be the most significant strengthening mechanism, followed by work hardening arising from the high cooling rate.

Song, Bo; Dong, Shujuan; Deng, Sihao; Liao, Hanlin; Coddet, Christian

2014-03-01

398

Effect of Specimen Diameter on Tensile Properties of Austenitic Stainless Steels in Liquid Hydrogen and Gaseous Helium at 20K  

SciTech Connect

Tensile tests using round bar type specimens of 3, 5 and 7 mm in diameter were conducted at 20K in liquid hydrogen and also in gaseous helium at the same temperature for three major austenitic stainless steels, JIS SUS304L, 316L and 316LN, extensively used for cryogenic applications including liquid hydrogen transportation and storage vessels. Stress-strain curves were considerably different between circumstances and also specimen diameter, resulting in differences of strength and ductility. In liquid hydrogen, serrated deformation appeared after considerable work hardening and more active in specimens with larger diameter. Meanwhile serrated deformation was observed from the early stage of plastic deformation in gaseous helium at 20 K and serration was more frequent in specimens with smaller diameter. The serrated deformation behaviors were numerically simulated for 304L steel with taking thermal properties such as thermal conductivity, specific heat, heat transfer from specimens to cryogenic media into account, and some agreement with the experiments was obtained.

Fujii, H.; Ohmiya, S. [Steel Research Labs., Nippon Steel Corporation, Futtsu, Chiba, 293-8511 (Japan); Shibata, K.; Ogata, T. [National Institute for Materials Science, Tsukuba, Ibaraki, 305-0047 (Japan)

2006-03-31

399

Effect of Specimen Diameter on Tensile Properties of Austenitic Stainless Steels in Liquid Hydrogen and Gaseous Helium at 20K  

NASA Astrophysics Data System (ADS)

Tensile tests using round bar type specimens of 3, 5 and 7 mm in diameter were conducted at 20K in liquid hydrogen and also in gaseous helium at the same temperature for three major austenitic stainless steels, JIS SUS304L, 316L and 316LN, extensively used for cryogenic applications including liquid hydrogen transportation and storage vessels. Stress-strain curves were considerably different between circumstances and also specimen diameter, resulting in differences of strength and ductility. In liquid hydrogen, serrated deformation appeared after considerable work hardening and more active in specimens with larger diameter. Meanwhile serrated deformation was observed from the early stage of plastic deformation in gaseous helium at 20 K and serration was more frequent in specimens with smaller diameter. The serrated deformation behaviors were numerically simulated for 304L steel with taking thermal properties such as thermal conductivity, specific heat, heat transfer from specimens to cryogenic media into account, and some agreement with the experiments was obtained.

Fujii, H.; Ohmiya, S.; Shibata, K.; Ogata, T.

2006-03-01

400

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

401

Tensile and creep properties of an oxide dispersion-strengthened ferritic steel  

NASA Astrophysics Data System (ADS)

The tensile and creep properties of two oxide dispersion-strengthened (ODS) steels with nominal compositions of Fe-12Cr-0.25Y 2O 3 (designated 12Y1) and Fe-12Cr-2.5W-0.4Ti-0.25Y 2O 3 (12YWT) were investigated. Optical microscopy, transmission electron microscopy, and atom probe field ion microscopy studies indicated that the 12YWT contained a high density of extremely fine Y-Ti-O clusters, compared to the much larger oxide particles in the 12Y1. The fine dispersion of particles gave the 12YWT better tensile and creep properties compared to commercial ODS alloys and ferritic/martensitic steels that would be replaced by the new ODS steel.

Klueh, R. L.; Maziasz, P. J.; Kim, I. S.; Heatherly, L.; Hoelzer, D. T.; Hashimoto, N.; Kenik, E. A.; Miyahara, K.

2002-12-01

402

Transverse tensile and stress rupture properties of gamma/gamma prime-delta directionally solidified eutectic  

NASA Technical Reports Server (NTRS)

Tensile and stress rupture properties were determined primarily at 760 C for specimens oriented at various angles (0 deg, 10 deg, 45 deg, and 90 deg) from the solidification direction of bars and/or slabs of the Ni-20Cb-6Cr-2.5A (gamma/gamma prime-delta) eutectic. Threaded-head specimens yielded longer rupture lives with significantly less scatter than did tapered-head specimens. Miniature specimens are suitable for determining traverse tensile and rupture properties of 1.2 centimeter diameter bar stock. The 300 hour rupture stress at 760 C for specimens oriented at 10 deg from the solidification direction was reduced from 740 to 460 MPa, and to 230 MPa for material oriented at either 45 deg or 90 deg.

Gray, H. H.

1976-01-01

403

Determination of tensile, flexural properties and microstructural characterization of calcium carbonate filler reinforced polypropylene matrix composites  

Microsoft Academic Search

Calcium carbonate is one of the commonly used inorganic filler reinforcements in polypropylene matrix. In this research work,\\u000a granules of chicken egg shell containing natural organic calcium carbonate resource has been introduced to reinforce in the\\u000a polypropylene base material. The aim of this experimental study is to determine the tensile, flexural properties and to characterize\\u000a the microstructures of granular chicken

Sivarao; T. R. Vijayaram

2009-01-01

404

Elasticity and Tensile Properties of Human Hair. II. Light Radiation Effects  

Microsoft Academic Search

Synopsis--The effects on the TENSILE PROPERTIES of HAIR by LIGHT RADIATION in the form of ULTRAVIOLET and SUNLIGHT are reported. These effects are inter- preted from the stress-strain measurements made on single fiber tests and the indcx used is the force at 15% elongation. The ultraviolet light effects were studied by exposing hair samples to a carbon-arc lamp for increasing

RICHARD BEYAK; G. S. KASS; C. F. MEYER

405

Tensile and impact properties changes of HASTELLOY X after exposure in high-temperature helium environment  

Microsoft Academic Search

Experimental results are presented on the changes in mechanical properties of HASTELLOY X* after being used in the liner tube\\u000a of HENDEL hot gas duct under high temperature helium gas for about 6000 hours. In both room and elevated-temperature tensile\\u000a tests, 0.2 pct proof stress and total elongation were significantly decreased after exposure in high temperature helium. Room-temperature\\u000a impact toughness

Yasuo Kondo; Kiyoshi Fukaya; Kazuhiko Kunitomi; Yoshiaki Miyamoto

1988-01-01

406

Tensile properties of HVOF sprayed Inconel 625 coatings subjected aqueous corrosion  

Microsoft Academic Search

Purpose – To examine the tensile properties of high velocity oxy-fuel (HVOF) sprayed Inconel 625 coating of steel substrate before and after the aqueous corrosion. Design\\/methodology\\/approach – Workpieces were cut from steel sheets. After chemical and ultrasonic cleaning, workpiece surfaces were sand blasted and HVOF sprayed Inconel 625 coated. The coated and un-coated surfaces were subjected to the aqueous corrosion

A. Boudi; M. S. J. Hashmi; B. S. Yilbas

2006-01-01

407

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

Microsoft Academic Search

The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile\\u000a properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite\\u000a and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in

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

2011-01-01

408

Tensile properties of latex paint films with TiO 2  pigment  

Microsoft Academic Search

The tensile properties of latex paint films containing TiO2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments\\u000a was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature\\u000a of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence

Eric W. S. Hagan; Maria N. Charalambides; Christina T. Young; Thomas J. S. Learner; Stephen Hackney

2009-01-01

409

Tensile properties of latex paint films with TiO2 pigment  

Microsoft Academic Search

The tensile properties of latex paint films containing TiO2 pigment were studied with respect to temperature, strain-rate and moisture content. The purpose of performing these experiments was to assist museums in defining safe conditions for modern paintings held in collections. The glass transition temperature of latex paint binders is in close proximity to ambient temperature, resulting in high strain-rate dependence

Eric W. S. Hagan; Maria N. Charalambides; Christina T. Young; Thomas J. S. Learner; Stephen Hackney

2009-01-01

410

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

411

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

412

[The deformation-strength properties of the vertebral and common carotid arteries in fetuses and newborn infants].  

PubMed

General carotid and vertebral arteries of 51 corpses of foetuses and newborns with 28-40 weeks gestation were studied. The entire material was divided into 3 groups: 28-32 weeks, 33-36 weeks and 37-40 weeks. The thickness of the wall and its certain layers and connective tissue fibres architectonics were studied. General tensile strength, its limit, maximum relative deformation and the arterial wall Junge module were studied at longitudinal tension on ZM-40 tension machine. General carotid artery wall of foetuses and newborns is more tensile and has greater strength and less rigidity than that of the vertebral artery. The wall of the arteries studied has tensility reserve, safe for its structure in account of its fibroarchitectonics peculiarities. All the tensile strength parameters of the vessels investigated, with the exception of general carotid artery relative deformation, significantly change with the gestation increase. Tensile strength properties change depending on gestation term and body weight of foetuses and newborns may be approximated with linear function Y = A + B x X + C x Z (X--gestation term, Z--body weight). PMID:7550910

Kalmin, O V

1995-01-01

413

Effects of Friction Stir Processing Parameters and In Situ Passes on Microstructure and Tensile Properties of Al-Si-Mg Casting  

NASA Astrophysics Data System (ADS)

Friction stir processing (FSP) was applied to modify the microstructure of an as-cast A356 alloy. The effects of rotation rate, travel speed, in situ FSP pass, FSP direction, and artificial aging on microstructures and tensile properties were investigated. FSP broke up the coarse eutectic Si phase into 2.5 to 3.5 ?m particles and distributed them homogeneously, and resulted in the dissolution of the coarse Mg2Si particles and the elimination of porosity, thereby improving both the strength and the ductility of the casting. Increasing the rotation rate was beneficial to breaking up and dissolving the particles, but it contributed little to eliminating the porosity. The travel speed did not affect the size of the particles apparently, but lower speed was beneficial to eliminating the porosity. 2-pass FSP showed an obvious advantage in the microstructure modification and tensile properties compared with the single-pass. However, a further increase of FSP passes only resulted in slight improvement. The FSP direction of the following pass did not show distinct effect on the microstructure and tensile properties. After post-FSP artificial aging, the strengthening phase (??-Mg2Si) precipitated, which increased the strength and decreased the ductility of the FSP samples.

Cui, G. R.; Ni, D. R.; Ma, Z. Y.; Li, S. X.

2014-11-01

414

Tensile and tribological properties of high-crystallinity radiation crosslinked UHMWPE.  

PubMed

Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in acetabular cups of total hip replacement prostheses. A drawback of radiation crosslinking is that it leads to a crosslinked PE (or XPE) with lower mechanical properties compared with uncrosslinked PE. In contrast, high-crystallinity PEs are known to have several mechanical properties higher than conventional PE. In this study, we hypothesized that increasing the crystallinity of radiation crosslinked and remelted XPE would result in an increase in tensile properties without compromising wear resistance. High-pressure crystallization was performed on PE and XPE and analyzed for the resulting morphological alterations using differential scanning calorimeter, low voltage scanning electron microscopy, and ultrasmall angle X-ray scattering. Uniaxial tensile tests showed that high-pressure crystallization increased the tensile modulus and yield stress in both PE and XPE, decreased the ultimate strain and ultimate stress in PE but had no significant effect on ultimate strain or ultimate stress in XPE. Multidirectional wear tests demonstrated that high-pressure crystallization decreased the wear resistance of PE but had no effect on the wear resistance of XPE. In conclusion, this study shows that high-pressure crystallization can be effectively used to increase the crystallinity and modulus of XPE without compromising its superior wear resistance compared with PE. PMID:18985795

Bistolfi, Alessandro; Turell, Mary Beth; Lee, Ying-Lung; Bellare, Anuj

2009-07-01

415

Tensile and tribological properties of high-crystallinity radiation crosslinked UHMWPE  

SciTech Connect

Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in acetabular cups of total hip replacement prostheses. A drawback of radiation crosslinking is that it leads to a crosslinked PE (or XPE) with lower mechanical properties compared with uncrosslinked PE. In contrast, high-crystallinity PEs are known to have several mechanical properties higher than conventional PE. In this study, we hypothesized that increasing the crystallinity of radiation crosslinked and remelted XPE would result in an increase in tensile properties without compromising wear resistance. High-pressure crystallization was performed on PE and XPE and analyzed for the resulting morphological alterations using differential scanning calorimeter, low voltage scanning electron microscopy, and ultrasmall angle X-ray scattering. Uniaxial tensile tests showed that high-pressure crystallization increased the tensile modulus and yield stress in both PE and XPE, decreased the ultimate strain and ultimate stress in PE but had no significant effect on ultimate strain or ultimate stress in XPE. Multidirectional wear tests demonstrated that high-pressure crystallization decreased the wear resistance of PE but had no effect on the wear resistance of XPE. In conclusion, this study shows that high-pressure crystallization can be effectively used to increase the crystallinity and modulus of XPE without compromising its superior wear resistance compared with PE.

Bistolfi, Alessandro; Turell, Mary Beth; Lee, Ying-Lung; Bellare, Anuj; (BWH)

2009-09-02

416

Effect of processing parameter and filler content on tensile properties of multi-walled carbon nanotubes reinforced polylactic acid nanocomposite  

NASA Astrophysics Data System (ADS)

Polymer nanocomposite of multi-walled carbon nanotubes (MWCNT) nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer were prepared via melt blending method using the Haake Rheomix internal mixer. In order to obtain the optimal processing parameter, the nanocomposite with 89 wt % of PLA was blended with 10 wt % of LNR and 1 wt % of MWCNTs were mixed with various mixing parameter condition; mixing temperature, mixing speed and mixing time. The optimum processing parameter of the composites was obtained at temperature of 190°C, rotation speed of 90 rpm and mixing time of 14 min. Next, the effect of MWCNTs loading on the tensile properties of nanocomposites was investigated. The nanocomposites were melt blended using the optimal processing parameter with MWCNTs loading of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4 wt %. The result showed that the sample with 3.5 wt % of MWCNTs gave higher tensile strength and Young's modulus. The SEM micrographs confirmed the effect of good dispersion of MWCNTs and their interfacial bonding in PLA nanocomposites. However, the elongation at break decreased with increasing the percentage of MWCNTs.

Ali, Adilah Mat; Ahmad, Sahrim Hj.

2013-05-01

417

Tensile properties and deformation - induced martensitic transformation at cryogenic temperatures in Fe-Cr-Ni-Mn-N alloys  

SciTech Connect

The tensile properties and changes in microstructures during tensile deformation in Fe-Cr-Ni-Mn-N alloys with a variation of C and N contents have been investigated over the temperature range of 293-4.2 K. It was found that with decreasing temperature the deformation-induced martensitic transformation started at 173 K in the process of {gamma}{r_arrow}{epsilon}{r_arrow}{alpha}{prime}; the amount of {alpha}{prime} martensite formed with maximum uniform strain was greater at 77 K than at 173 or 4.2 K. For the formation of {alpha}{prime} martensite a critical strain was required, and the amount of {alpha}{prime} martensite increased with increasing deformation strain. With the increase in the contents of C and N, the critical strain and the tendency for the increase in the amount of {alpha}{prime} martensite with strain decreased. The results show that both C and N can lead to some increase in the yield and ultimate strengths and a decrease in the elongation, while the deformation-induced martensitic transformation is strongly restrained by the increase in C or N content.

Li, D.F.; Fan, C.G.; Li, Y.Y.; Cheng, H.M. [Institute of Metal Research, Shenyang (China)

1997-06-01

418

A comparison of tensile properties of polyester composites reinforced with pineapple leaf fiber and pineapple peduncle fiber  

NASA Astrophysics Data System (ADS)

Pineapple fiber which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. This research presents a study of the tensile properties of pineapple leaf fiber and pineapple peduncle fiber reinforced polyester composites. Composites were fabricated using leaf fiber and peduncle fiber with varying fiber length and fiber loading. Both fibers were mixed with polyester composites the various fiber volume fractions of 4, 8 and 12% and with three different fiber lengths of 10, 20 and 30 mm. The composites panels were fabricated using hand lay-out technique. The tensile test was carried out in accordance to ASTM D638. The result showed that pineapple peduncle fiber with 4% fiber volume fraction and fiber length of 30 mm give highest tensile properties. From the overall results, pineapple peduncle fiber shown the higher tensile properties compared to pineapple leaf fiber. It is found that by increasing the fiber volume fraction the tensile properties has significantly decreased but by increasing the fiber length, the tensile properties will be increased proportionally. Minitab software is used to perform the two-way ANOVA analysis to measure the significant. From the analysis done, there is a significant effect of fiber volume fraction and fiber length on the tensile properties.

Juraidi, J. M.; Shuhairul, N.; Syed Azuan, S. A.; Intan Saffinaz Anuar, Noor

2013-12-01

419

Nanocrystalline structures and tensile properties of stainless steels processed by severe plastic deformation  

NASA Astrophysics Data System (ADS)

The development of nanocrystalline structures in austenitic stainless steels during large strain cold rolling and their tensile behavior were studied. The cold rolling to total equivalent strains above 2 was accompanied by the evolution of nanocrystalline structures with the transverse grain size of about 100 nm. The development of deformation twinning and martensitic transformation during cold working promoted the fast kinetics of structural changes. The development of nanocrystalline structures resulted in significant strengthening. More than fourfold increase in the yield strength was achieved. The strengthening of nanocrystalline steels after severe plastic deformation was considered as a concurrent operation of two strengthening mechanisms, which were attributed to grain size and internal stress. The contribution of internal stresses to the yield strength is comparable with that from grain size strengthening.

Belyakov, A.; Odnobokova, M.; Kipelova, A.; Tsuzaki, K.; Kaibyshev, R.

2014-08-01

420

The tensile property of commercial Bi2223 tapes: a report on the international round-robin test  

NASA Astrophysics Data System (ADS)

In order to establish the test method of mechanical properties of oxide composite superconductors, an international round-robin test (RRT) has been carried out under the programme of VAMAS activity, for which eight research groups participated. The present RRT made the following guideline clear for assessing the mechanical property of Ag/Bi2223 multifilamentary tapes. Owing to the constitution of the brittle superconductive oxide layer embedded in the ductile metal matrix, the stress-percentage extension (R-A) curve shows a three-stage behaviour, that is, the true elastic region is very narrow and is followed by the quasi-elastic region before reaching the macroscopic plastic region. For assessing the elastic constant, it is recommended to look for the maximum slope carefully by enlarging the initial part of the R-A curve. The following three quantities, elastic constant, yield strength and tensile strength, can be reasonably determined with good accuracy by the procedure reported in this paper. The percentage extension after fracture is, however, excluded from the standard procedure, because it scatters to a great extent owing to the nature of the test sample as well as the experimental limitation.

Osamura, K.; Sugano, M.; Nyilas, A.; Shin, H. S.; Weijers, H.; Hampshire, D. P.; Morley, N.; Morley, K.; Keys, S.; Leghissa, M.; Herkert, W.; Katagiri, K.; Ogata, T.

2002-06-01

421

Effects of Long-Term Thermal Exposure on Commercially Pure Titanium Grade 2 Elevated-Temperature Tensile Properties  

NASA Technical Reports Server (NTRS)

Elevated-temperature tensile testing of commercially pure titanium (CP Ti) Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K (531 and 711 F) for times up to 5000 h. The tensile testing revealed some statistical differences between the 11 thermal treatments, but most thermal treatments were statistically equivalent. Previous data from room temperature tensile testing was combined with the new data to allow regression and development of mathematical models relating tensile properties to temperature and thermal exposure. The results indicate that thermal exposure temperature has a very small effect, whereas the thermal exposure duration has no statistically significant effects on the tensile properties. These results indicate that CP Ti Grade 2 will be thermally stable and suitable for long-duration space missions.

Ellis, David L.

2012-01-01

422

Tensile properties and flow behavior analysis of modified 9Cr-1Mo steel clad tube material  

NASA Astrophysics Data System (ADS)

The tensile properties and flow behavior of modified 9Cr-1Mo steel clad tube have been investigated in the framework of various constitutive equations for a wide range of temperatures (300-923 K) and strain rates (3 × 10-3 s-1, 3 × 10-4 s-1 and 3 × 10-5 s-1). The tensile flow behavior of modified 9Cr-1Mo steel clad tube was most accurately described by Voce equation. The variation of instantaneous work hardening rate (? = d?/d?) and ?? with stress (?) indicated two stage behavior characterized by rapid decrease at low stresses (transient stage) followed by a gradual decrease in high stresses (Stage III). The variation of work hardening parameters and work hardening rate in terms of ? vs. ? and ?? vs. ? with temperature exhibited three distinct regimes. Rapid decrease in flow stress and work hardening parameters and rapid shift of ? vs. ? and ?? vs. ? towards low stresses with increase in temperature indicated dynamic recovery at high temperatures. Tensile properties of the material have been best predicted from Voce equation.

Singh, Kanwarjeet; Latha, S.; Nandagopal, M.; Mathew, M. D.; Laha, K.; Jayakumar, T.

2014-11-01

423

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

424

Low-energy electron effects on tensile modulus and infrared transmission properties of a polypyromellitimide film  

NASA Technical Reports Server (NTRS)

Infrared (IR) spectroscopy and tensile modulus testing were used to evaluate the importance of experimental procedure on changes in properties of pyromellitic dianhydride-p,p prime-oxydianiline film exposed to electron radiation. The radiation exposures were accelerated, approximate equivalents to the total dose expected for a 30 year mission in geosynchronous Earth orbit. The change in the tensile modulus depends more on the dose rate and the time interval between exposure and testing than on total dose. The IR data vary with both total dose and dose rate. A threshold dose rate exists below which reversible radiation effects on the IR spectra occur. Above the threshold dose rate, irreversible effects occur with the appearance of a new band. Post-irradiation and in situ IR absorption bands are significantly different. It is suggested that the electron radiation induced metastable, excites molecular states.

Ferl, J. E.; Long, E. R., Jr.

1981-01-01

425

Tensile properties of austenitic stainless steels irradiated at SINQ target 3  

NASA Astrophysics Data System (ADS)

The beam window of the spallation target will be subjected to proton/neutron irradiation. It is important to know the irradiation effect on structural materials to facilitate the facility design and the lifetime evaluation. The SINQ target irradiation program (STIP) at the Paul Scherrer Institute (PSI) began to obtain high-energy proton irradiation data. JAERI joined this program and shares the post irradiation experimental (PIE) work. The JAERI specimens were irradiated at 90-380 °C and dpa ranged from 3.5 to 11.8 dpa. Tensile tests were done in air at RT and 250 °C. The results on JPCA-SA and 316F-SA indicate that the irradiation caused considerable hardening and degradation of ductility. However, no drastic change of tensile properties was shown in comparison with specimens irradiated in fission reactors. Fracture surfaces were observed by microscope and their morphology revealed fracture in a ductile manner.

Saito, S.; Kikuchi, K.; Usami, K.; Ishikawa, A.; Nishino, Y.; Kawai, M.; Dai, Y.

2005-08-01

426

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 ­100 °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

427

Effects of temperature and strain rate on tensile properties and activation energy for dynamic strain aging in alloy 625  

NASA Astrophysics Data System (ADS)

Alloy 625 ammonia cracker tubes were service exposed for 60,000 hours at 873 K. These were then subjected to a solution-annealing treatment at 1473 K for 0.5 hours. The effects of temperature and strain rate on the tensile properties of the solution-annealed alloy were examined in the temperature range of 300 to 1023 K, employing the strain rates in the range of 3×10-5 s-1 to 3×10-3 s-1. At intermediate temperatures (523 to 923 K), various manifestations of dynamic strain aging (DSA) such as serrated flow, peaks, and plateaus in the variations of yield strength (YS) and ultimate tensile strength (UTS) and work-hardening rate with temperature were observed. The activation energy for serrated flow ( Q) was determined by employing various methodologies for T<823 K, where a normal Portevien-Le Chatelier effect (PLE) was observed. The value of Q was found to be independent of the method employed. The average Q value of 98 kJ/mol was found to be in agreement with that for Mo migration in a Ni matrix. At elevated temperatures ( T?823 K), type-C serrations and an inverse PLE was noticed. The decrease in uniform elongation beyond 873 K for 3×10-5 s-1 and 3×10-3 s-1 and beyond 923 K for 3×10-4 s-1 strain rates seen in this alloy has been ascribed to reduction in ductility due to precipitation of carbides and ? phase on the grain boundaries.

Shankar, Vani; Valsan, M.; Rao, K. Bhanu Sankara; Mannan, S. L.

2004-10-01

428

Correlation between strength properties in standard test specimens and molded phenolic parts  

NASA Technical Reports Server (NTRS)

This report describes an investigation of the tensile, flexural, and impact properties of 10 selected types of phenolic molding materials. The materials were studied to see in what ways and to what extent their properties satisfy some assumptions on which the theory of strength of materials is based: namely, (a) isotropy, (b) linear stress-strain relationship for small strains, and (c) homogeneity. The effect of changing the dimensions of tensile and flexural specimens and the span-depth ratio in flexural tests were studied. The strengths of molded boxes and flexural specimens cut from the boxes were compared with results of tests on standard test specimens molded from the respective materials. The nonuniformity of a material, which is indicated by the coefficient of variation, affects the results of tests made with specimens of different sizes and tests with different methods of loading. The strength values were found to depend on the relationship between size and shape of the molded specimen and size and shape of the fillers. The most significant variations observed within a diversified group of materials were found to depend on the orientation of fibrous fillers. Of secondary importance was the dependence of the variability of test results on the pieces of filler incorporated into the molding powder as well as on the size of the piece. Static breaking strength tests on boxes molded from six representative phenolic materials correlated well with falling-ball impact tests on specimens cut from molded flat sheets. Good correlation was obtained with Izod impact tests on standard test specimens prepared from the molding materials. The static breaking strengths of the boxes do not correlate with the results of tensile or flexural tests on standard specimens.

Turner, P S; Thomason, R H

1946-01-01

429

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

430

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

431

Influence of thermo-mechanical treatment on the tensile properties of a modified 14Cr-15Ni stainless steel  

NASA Astrophysics Data System (ADS)

The titanium modified 14Cr-15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 × 10-4 s-1 over a temperature range of 298-1073 K. The yield stress and the ultimate tensile strength of the steel increased with increase in solution treatment temperature and this has been attributed to the fine and higher density of Ti(C,N) precipitate. Tensile flow behaviour of the steel has been analysed using Ludwigson and Voce constitutive equations. The steel heat treated at higher solution temperature exhibited earlier onset of cross slip during tensile deformation. The rate of recovery at higher test temperatures was also influenced by variations in solution heat treatment temperature. In addition, dynamic recrystallization during tensile deformation at higher temperatures was profound for steel solution heat-treated at lower temperature. The differences in flow behaviour and softening mechanisms during tensile testing of the steel after different heat treated conditions have been attributed to the nature of Ti(C,N) precipitation.

Vijayanand, V. D.; Laha, K.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.

2014-10-01

432

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

433

Tensile properties of the medial patellofemoral ligament: The effect of specimen orientation  

PubMed Central

For recurrent patellar dislocation, reconstruction of the medial patellofemoral ligament (MPFL) with replacement autografts has often been performed but with only little data on the tensile properties of the MPFL to guide graft selection. With its complex anatomy and geometry, these properties are difficult to obtain. In this study, we showed how the orientation of the femur-MPFL-patella complex (FMPC) during uniaxial tensile testing can have a significant effect on its structural properties. Twenty two FMPCs were isolated from porcine stifle joints and randomly assigned to two groups of 11 each. For the first group, the specimens were loaded to failure with the patella oriented 30 degrees away from the direction of the applied load to mimic its orientation in situ, called natural orientation. In the second group, the patella was aligned in the direction of the tensile load, called non-natural orientation. The stiffness for the natural orientation group was 65 ± 13 N/mm, 32% higher than that for the non-natural orientation group (50 ± 17 N/mm; p < 0.05). The ultimate loads were 438 ± 128 N and 386 ± 136 N, respectively (p > 0.05). Ten out of 11 specimens in the natural orientation group failed at the femoral attachment (the narrowest portion of the MPFL) compared to 6 out of 11 in the non-natural orientation group. Our findings suggest that the specimen orientation that mimics the in-situ loading conditions of the MPFL should be used to obtain more representative data for the structural properties of the FMPC. PMID:24332616

Kim, Kwang E.; Hsu, Shan-Ling; Woo, Savio L-Y.

2014-01-01

434

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

435

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

436

Tensile properties of a ZnS nanowire determined with a nano-manipulator and force sensor  

NASA Astrophysics Data System (ADS)

Tensile tests of an individual ZnS nanowire with a cubic structure were performed with a nano-manipulator inside a scanning electron microscope (SEM). To perform the tensile test of ZnS nanowires, a mechanical testing system was installed in the SEM. A nano-manipulator was set up in the SEM, and a cantilever force sensor was mounted on the nano-manipulator. The force sensor could be controlled with the nano-manipulator. The ZnS nanowires were dispersed on the transmission electron microscope (TEM) grid; then, the ends of the ZnS nanowires were welded to the TEM grid and the tip of force sensor by exposing them to the E-beam of the SEM. The tensile tests of the ZnS nanowires were performed by controlling the nano-manipulator in the SEM. The load response during the tensile tests was obtained with a force sensor. The strain-stress curve was obtained from the tensile load-displacement curve after the tensile test. The tensile strengths for nanowires 1, 2, and 3 were 364.7 ± 5.2, 146.2 ± 5.2, and 234.4 ± 5.2 MPa, respectively, and the elastic moduli for nanowires 1, 2, and 3 were 39 ± 5.2, 33.4 ± 5.2, and 37.4 ± 5.2 GPa, respectively.

Jang, Hoon-Sik; Nahm, Seung Hoon; Lee, Hak Joo; Kim, Jung Han; Oh, Kyu Hwan

2012-08-01

437

Predictions of the Mechanical Properties and Microstructure Evolution of High Strength Steel in Hot Stamping  

NASA Astrophysics Data System (ADS)

Hot stamping is an innovative operation in metal-forming processes which virtually avoids the cracking and wrinkling of high strength steel (HSS) sheets. Examining the phase transformation and mechanical properties of HSS by means of experiments is challenging. In this article, a numerical model of the hot stamping process including forming, quenching, and air cooling was developed to reveal the microstructure evolution and to predict the final mechanical properties of hot-stamped components after multi-process cycles. The effects of the number of process cycles and the holding times on the temperature of HSS were examined using the model. The microstructure evolution of HSS under variable holding times is illustrated. The mechanical properties, particularly hardness and tensile strength, were predicted. It was found that the martensitic content increased with increasing holding time, and the martensitic content of the formed component at the flange and end was higher than for the sidewall, and lowest for the bottom. The hardness trend was consistent with the martensitic content. After six process cycles, the predictive errors of the model for hardness and tensile strength were acceptable for practical applications in engineering. Comparison between the predicted results and the experiment results showed that the developed model was reliable.

Cui, Junjia; Lei, Chengxi; Xing, Zhongwen; Li, Chunfeng; Ma, Shumei

2012-11-01

438

A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials  

NASA Astrophysics Data System (ADS)

In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

2014-06-01

439

A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials.  

PubMed

In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument. PMID:24985848

Wang, Shupeng; Zhang, Zhi