The effect of hydrogen on the tensile properties of palladium
Hydrogen content effect on annealed and work hardened palladium wire tensile properties, determining yield/tensile stress and elongation
Otterson, D. A.↗
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Stored energy function of rubberlike materials derived from simple tensile data.
An explicit formulation is developed to obtain the stored energy function, based on the Valanis-Landel separable symmetric stored energy function. This formulation is applicable to any multiaxial stress state, from simple tensile data alone, for those cases in which the stored energy function is a separable function of the stretch ratios. By direct comparison, it is also shown that styrene butadiene rubber, at least over a specific range, follows this postulated separable form.
Peng, T. J.↗
A comparative study of tensile fracture mechanisms.
Identification of the failure mechanism characteristic for the more widely used carbon fibers in epoxy matrices under tensile loads as an aid toward improvements and more reliable predictions of the performance of these composites. The presented results pertain to high-strength, high-modulus, and low-modulus fibers in unmodified and modified epoxy novolac matrices.
Mullin, J. V.↗
Effect of nitrogen on tensile properties and structures of T-111 (tantalum, 8 percent tungsten, 2 percent hafnium) tubing
The effect of controlled nitrogen additions was evaluated on the mechanical properties of T-111 (Ta-8W-2Hf) fuel pin cladding material proposed for use in a lithium-cooled nuclear reactor concept. Additions of 80 to 1125 ppm nitrogen resulted in increased strengthening of T-111 tubular section test specimens at temperatures of 25 to 1200 C. Homogeneous distributions of up to 500 ppm nitrogen did not seriously decrease tensile ductility. Both single and two-phase microstructures, with hafnium nitride as the second phase, were evaluated in this study.
Buzzard, R. J.↗
Tensile properties of PRD-49 fiber in epoxy matrix.
Recently a high-modulus and high-strength organic fiber, identified as PRD-49-III by the manufacturer, became commercially available. To assess the fiber performance and its potential as a reinforcement for fiber composites, the tensile properties of the fiber in an epoxy matrix were determined. During this study over 6000 fiber/epoxy strands were made using the filament winding process; these strands were representative samples taken from over 60 lb of single-end fiber. The fiber uniformity, its strength distribution at room and LN2 temperature, stress-strain characteristics, and the strain rate effect on the fiber strength were evaluated.
Chiao, T. T.↗
Tensile fracture of unidirectional B-Al composite.
Fracture studies on unidirectional boron filament/aluminum matrix composite under axial tension were conducted using scanning electron microscopy, microradiography, and an acoustic emission technique. The combination of these analysis techniques has allowed the description and microstructural characterization of a new noncumulative fracture mode which involves filament break propagation. This fracture mode was found to severely limit the tensile strength of the composite, since the initiation of break propagation leads immediately to catastrophic failure at filament stress levels above a critical value. This critical filament stress was found to be 170,000 psi, and it appeared to be independent of filament diameter, number of filament layers, and the type of matrix alloy.
Steele, J. H.↗
Exploratory study of elevated-temperature tensile properties of alloys based on the intermetallic compound TiNi
The tensile properties and oxygen contamination behavior of TiNi alloyed with aluminum, chromium, and silicon were investigated in the temperature range between 800 and 1000 K (980 and 1340 F). The alloys were significantly stronger than unalloyed TiNi and less susceptible to embrittlement than the Ti-6242 alloy.
Garfinkle, M.↗
Tensile properties from room temperature to 1315 C of tungsten-lined tantalum-alloy (T-111) tubing fabricated by hot isostatic pressing
The effects were studied of a thin tungsten liner on the tensile properties of T-111 tubing considered for fuel cladding in a space power nuclear reactor concept. The results indicate that the metallurgically bonded liner had no appreciable effects on the properties of the T-111 tubing. A hot isostatic pressing method used to apply the liners is described along with a means for overcoming the possible embrittling effects of hydrogen contamination.
Buzzard, R. J.↗
Effect of service usage on tensile, fatigue, and fracture properties of 7075-T6 and 7178-T6 aluminum alloys
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.↗
Comparison of fracture mechanisms for carbon-epoxy composites under tensile loading
The effects of oxidative surface treatments and differences in resin crack sensitivity on the tensile properties of carbon-epoxy composites have been investigated. A comparison of the fracture mechanisms for two different fiber batches was made in both model and engineering composites, using unmodified and modified epoxy resin. It has been observed that two distinct characteristics occur in the fracture surfaces of most engineering composites; first, fibers which fracture at the surface result in cleavage failure and, second, those which have fractured elsewhere and pulled out. A detailed discussion of these observations is contained in this paper.
Mazzio, V. F.↗
Tensile viscosities of non-Newtonian fluids
Tubeless siphon technique offers practical viscosity parameter for accurately determining non-Newtonian liquid tensile viscosity.
Landel, R. F.↗
Stochastic models for the tensile strength, fatigue
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.↗
Tensile and creep rupture properties of (16) uncoated and (2) coated engineering alloys at elevated temperatures
Sixteen test materials were supplied by NASA-Lewis Research Center as wrought bar or cast remelt stock. The cast remelt stock was cast into test blanks with two such materials being also evaluated after Jocoat coating was applied. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, creep properties and creep rupture strength. Tests were conducted at temperatures applicable to the service temperature of the various alloys. This range extended from room temperature to 1000 C.
Fritz, L. J.↗
A Weibull characterization for tensile fracture of multicomponent brittle fibers
A statistical characterization for multicomponent brittle fibers in presented. The method, which is an extension of usual Weibull distribution procedures, statistically considers the components making up a fiber (e.g., substrate, sheath, and surface) as separate entities and taken together as in a fiber. Tensile data for silicon carbide fiber and for an experimental carbon-boron alloy fiber are evaluated in terms of the proposed multicomponent Weibull characterization.
Barrows, R. G.↗
Tensile stress-strain behavior of boron/aluminum laminates
The tensile stress-strain behavior of five types of boron/aluminum laminates was investigated. Longitudinal and transverse stress-strain curves were obtained for monotonic loading to failure and for three cycles of loading to successively higher load levels. The laminate strengths predicted by assuming that the zero deg plies failed first correlated well with the experimental results. The stress-strain curves for all the boron/aluminum laminates were nonlinear except at very small strains. Within the small linear regions, elastic constants calculated from laminate theory corresponded to those obtained experimentally to within 10 to 20 percent. A limited amount of cyclic loading did not affect the ultimate strength and strain for the boron/aluminum laminates. The laminates, however, exhibited a permanent strain on unloading. The Ramberg-Osgood equation was fitted to the stress-strain curves to obtain average curves for the various laminates.
Sova, J. A.↗
An experimental investigation on the tensile moduli and strengths of graphite/epoxy laminates
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.↗
Influence of residual stresses on the tensile strength of composite-metal sandwich laminates
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.↗
A Weibull characterization for tensile fracture of multicomponent brittle fibers
Necessary to the development and understanding of brittle fiber reinforced composites is a means to statistically describe fiber strength and strain-to-failure behavior. A statistical characterization for multicomponent brittle fibers is presented. The method, which is an extension of usual Weibull distribution procedures, statistically considers the components making up a fiber (e.g., substrate, sheath, and surface) as separate entities and taken together as in a fiber. Tensile data for silicon carbide fiber and for an experimental carbon-boron alloy fiber are evaluated in terms of the proposed multicomponent Weibull characterization.
Barrows, R. G.↗