Showing papers on "Tensile testing published in 1985"
TL;DR: In this paper, the tensile mechanical properties and fracture toughness of a Bisphenol-A type difunctional epoxy resin, cured with different amounts of metaphenylene diamine, using two cure cycles, were determined over a range of temperature.
Abstract: The tensile mechanical properties and fracture toughness of a Bisphenol-A type difunctional epoxy resin, cured with different amounts of metaphenylene diamine, using two cure cycles, were determined over a range of temperature. The tensile modulus in the glassy state was seen to be predominantly related to intermolecular packing, while in the rubbery state crosslink density was the important factor. Yielding appeared to be due to an increase in free volume as a result of dilatation during the tensile test and was related to a critical shear stress. The large strain properties like tensile strength, elongation-to-break, and toughness showed a more complex dependence on chemical structure, molecular architecture, intermolecular packing, and crosslink density. The roles played by the relaxation processes in determining mechanical properties are highlighted.
193 citations
TL;DR: In this article, changes in the morphology of the Ni-Al-Mo-Ta superalloy precipitate were examined during creep and tensile testing at temperatures between 927 and 1038 °C in [001]-oriented single crystals of a model NMT super alloy.
Abstract: Changes in the morphology of the γ′ precipitate were examined during creep and tensile testing at temperatures between 927 and 1038 °C in [001]-oriented single crystals of a model Ni-Al-Mo-Ta superalloy. In this alloy, the γ′ particles link together to form lamellae, or rafts, which are aligned with their broad faces perpendicular to the applied tensile axis. The dimensions of the γ and γ′ phases were measured as the lamellar structure developed and were related to time and strain in an attempt to trace the changing γ-γ′ morphology. The results showed that directional coarsening of γ′ began during primary creep, and the attainment of a fully developed lamellar structure did not appear to be directly related to the onset of steady-state creep. The rate of directional coarsening during creep increased as the temperature was raised and also increased as the stress level was raised at a given testing temperature. The raft thickness remained equal to the initial γ′ size from the start of the creep test up through the onset of tertiary creep for all testing conditions. It was found that extensive rafts did not develop during the shorter testing times of the tensile tests, and that tensile testing of pre-rafted structures did not alter the morphology of the rafts. The overall behavior of the alloy was a clear indication of the stability of the finely-spaced γ-γ′ lamellar structure.
122 citations
TL;DR: New methods, based on porous foam technology, for tensile testing of fresh/frozen trabecular bone specimens, show that isotropic bovine trabECular bone exhibits significantly lower strengths in tension than in compression.
93 citations
TL;DR: In this article, the deformation and ultimate properties of gelatin and agarose gels were investigated, in simple tension, as a necessary preliminary to an examination of mixed bipolymer gel systems.
89 citations
01 Jan 1985
TL;DR: The tensile fracture of concrete is as a rule regarded as brittle as discussed by the authors, which causes the fracture process zone in front of a growing crack to be of the order of 100-200 mm or even longer.
Abstract: The tensile fracture of concrete is as a rule regarded as brittle. Concrete has no yield behaviour of the type found in metals. Its tensile stress-strain diagram is nearly linear up to the maximum point, whereupon it immediately starts to descend. In spite of this concrete however can be said to have a considerable toughness. This toughness causes the fracture process zone in front of a growing crack to be of the order of 100–200 mm or even longer [1], i.e. much longer than what is normally found for metals. Because of these long fracture process zones linear elastic fracture mechanics (LEFM) can as a rule not be applied to concrete. On the other hand those methods which have been developed to take into account yielding within the non-linear zone for metals cannot be applied directly to concrete, as concrete does not yield in the way metals do. The toughness of concrete has to do with the softening, i.e. the existence of a descending branch in the stress-deformation diagram. This chapter describes the possibility of analysing the tensile fracture and fracture mechanics of concrete by means of methods based on the softening behaviour. The starting point will therefore be the softening properties of concrete in a simple tension test.
87 citations
TL;DR: In this article, a tensile test for the combined Mode I (crack opening) and Mode II (forward shearing) fracture behavior of unidirectional T300/1034C graphite/epoxy and graphite-reinforced APC-1 polyetheretherketone is described.
86 citations
TL;DR: In this article, the tensile behavior of polypropylene (PP) filled with calcium carbonate particles has been studied using a tensile test, in particular, the effect of strain rate, filler content, and filler size upon the elastic modulus, yield stress, and strain of surface-modified and unmodified particles-filled PP were investigated.
Abstract: The tensile behavior of polypropylene (PP) filled with calcium carbonate particles has been studied using a tensile test. In particular, the effect of strain rate, filler content, and filler size upon the elastic modulus, yield stress, and strain of surface-modified and unmodified particles-filled PP were investigated. The results indicated that the elastic modulus and yield stress of an unmodified system were increased with an increase of strain rate and filler content, and with a decrease of filler size. The yield strain was decreased with an increase of filler content, and with a decrease of filler size, but did not depend on the strain rate. Although the dependence of elastic modulus on the filler size was maintained even by the surface-modified fillers, that dependence on the strain rate and filler content was decreased by such fillers. This may be because the modifier is present at the interface of filler and polymer matrix.
69 citations
TL;DR: An isotropic formulation of the viscoplasticity theory for small strain and based on overstress with a differential growth law for the equilibrium stress is introduced in this paper, where the four material constants and the two material functions of the theory are determined from uniaxial tensile tests involving strain-rate changes at room temperature and performed on a 6061 T6 Aluminum Alloy.
69 citations
TL;DR: In this article, a fractional constitutive relation with a quadratic denominator is derived by the method of the theory of non-linear elasticity, which exhibits an excellent agreement with the experimental results.
Abstract: Uniaxial tensile tests of unidirectional carbon-epoxy coupons are conducted in the longitudinal direction. It is observed that the longitudinal modulus increases with axial stress or strain up to the intermediate level of tension. A fractional constitutive relation with a quadratic denominator is derived by the method of the theory of non-linear elasticity. This equation adopting the estimated higher-order compliance coefficients exhibits an excellent agreement with the experimental results. An empirical strain-based equation is also proposed as a simpler alternative. Averaging formulae for both types of relation are provided for a practical application. The present phenomenon includes the behaviour in a low-stress region discovered by some early work. The consideration of the present non-linear behaviour improves the correlation between theory and experiments in stress-strain relationships of fabric composites with carbon fibres.
55 citations
TL;DR: In this article, a tensile test method which permits the in situ measurement of the mechanical properties of a solidifying shell is described, where the tensile stress is applied in a direction which is perpendicular to the growth axis of the columnar crystals so that, when alloys are tested, the mechanical behaviour of the mushy zone can be studied, as well as its contribution to the mechanical strength of the shell.
53 citations
TL;DR: In this article, mixed gels of agarose and gelatin were prepared, and their mechanical behaviour in tensile tests was determined, up to failure, using four decades of (constant) strain rate.
TL;DR: In this paper, the tensile and impact properties were measured of a heterogeneous polymer blend system, consisting of nylon 6 and a chemically modified polyolefin, DuPont CXA3095, which is an ethylene-based multifunctional polymer.
Abstract: Both tensile and impact properties were measured of a heterogeneous polymer blend system, consisting of nylon 6 and a chemically modified polyolefin, DuPont CXA3095, which is an ethylene-based multifunctional polymer. It was found, from the tensile testing, that the blends exhibited no signs of necking, and the addition of a soft resin (CXA3095) reduced the modulus and the tensile strength of nylon 6, whereas the percent elongation at break went through a minimum. When 20 wt % of CXA3095 was added to nylon 6, the impact strength was increased approximately three times. When the factors describing the interfacial adhesion were incorporated, the existing models for predicting the tensile modulus of blends were found to describe the experimental data rather well. In order to help explain the mechanical behavior observed, photomicrographs were taken of the fracture surfaces, using a scanning electron microscope.
Journal Article•
TL;DR: Fracture mechanics studies of non-yielding materials are presented in this paper, which are based on theoretical models for the macroscopical mechanical behaviour of materials during tensile stress induced fracture.
Abstract: Fracture mechanics studies of non-yielding materials are presented. The studies are based on theoretical models for the macroscopical mechanical behaviour of materials during tensile stress induced fracture. A number of applied numercal analysis are indicated. Fracture models and strength relations are discussed also from a few more general and fundamental points of view. A number of comparisons are made to test results from literature. The applications concern materials such as concrete, reinforced concrete, mortar and wood. Most numerical calculations are carried out by means of finite element methods. The fracture mechanics model called the fictitious crack model is emphasized. This model gives a.description of gradual and localized fracture-softening in a single discrete tensile fracture process region. 0ther models dealt with: linear elastic fracture mechanics, Weibull-model, un-limited plasticity, conventional maximum stress theory and a few more special models. Specimens dealt with during numerical calculations: beams in bending, fracture mechanics tests specimens, tensile test specimens, pipes in bending and crushing, specimens with a re-entrant corner and longitudinally reinforced concrete beams in shear. According to the results obtained, it seems to be theoretically consistent and often of great practical importance to take into account the gradual and localized fracture-softening during strength analysis of specimens and structural elements. (Less)
TL;DR: In this article, a comparison of the tensile properties determined with these different specimens was made by testing cold-worked and solution-annealed Type 316 stainless steel sheet and rod at room temperature, 300°C and 600°C.
TL;DR: In this paper, an explosively welded interface between aluminum and steel is shown to be devoid of intermetallic formation and maintain integrity with heat exposures of up to 8 h at 550 °C.
Abstract: Waveless, explosively welded interfaces between aluminum and steel are seen to be devoid of intermetallic formation and maintain integrity with heat exposures of up to 8 h at 550 °C. Microhardness determinations as well as tensile testing of the samples indicate the interface to be a zone of higher hardness than the weaker of the bonded materials (Al‐1100) and of extremely high adhesion strength. The hardness profiles taken were utilized to determine the difference in the energy deposited at the wavy and waveless interface as well as the presence of extraneous byproducts of these energies in the respective interfaces. The study conclusively shows the superior characteristics of the waveless interface for this weld and its resistance to intermetallic formation that would lead to the consequential deterioration of the associated adhesion properties of these transition joints.
TL;DR: In this article, the tensile behavior of polycarbonate and polyglass bead composites has been investigated by tensile testing with simultaneous volume change measurements, and the effect of the bead size and the degree of interfacial adhesion on the composites behavior has been studied.
Abstract: The tensile behavior at 20°C of unfilled polycarbonate and polycarbonate–glass bead composites (90/10 vol %) has been investigated by tensile testing with simultaneous volume change measurements. Both the effect of the bead size and the degree of interfacial adhesion on the tensile behavior of the composites has been studied. A simple model has been applied to obtain quantitative information on the separate contributions of several possible deformation mechanisms to the total deformation. For unfilled polycarbonate and the polycarbonate–glass bead composites with excellent interfacial adhesion, shear deformation is found to be the only significant non-Hookean deformation mechanism. By means of strain recovery experiments it is shown that the shear deformation is highly elastic in character. For the composites with poor interfacial adhesion, besides shear deformation also dewetting cavitation contributes to the non-Hookean deformation. The differences in tensile behavior between the composites with excellent and poor interfacial adhesion are explained by the different mechanisms for shear band formation at excellently and poorly adhering glass beads.
TL;DR: In this paper, an extrometer was designed to record simultaneously the extension and rotation over a predetermined gauge length of a wire rope strand with polyester resin and silica filler in conical end grips which are capable of full end fixity, partial restraint, or zero torsional resistance.
Abstract: Experimental tests are reported on wire rope strands subjected to static axial loads. The wire rope strands are held with a polyester resin and silica filler in conical end grips which are capable of full end fixity, partial restraint, or zero torsional resistance (free ends). Strain gauge load cells monitor the tensile load and the associated twisting moment developed in a strand which is restrained at both ends. A new instrument (‘extrometer’) was designed to record simultaneously the extension and rotation over a predetermined gauge length. Strain gauges are used to measure the surface strains on the wires in the outer layer of the strand.Preliminary tests on seven-wire strands demonstrate that the extrometer instrument provides reliable results. The extension and rotation characteristics recorded on a seven-wire strand under tensile load agree reasonably well with the corresponding theoretical predictions, but the wire surface strains reveal an unequal load sharing between nominally identical ...
TL;DR: In this paper, the superplastic behavior of δ-ferrite/austenite duplex stainless steels has been studied by means of isothermal hot tensile test at temperatures (T) from 700 to 1100°C at initial strain rates (e) from 10-4 to 10-1 s-1 in relation to microstructural aspects prior to and during deformation.
Abstract: Superplastic behavior of δ-ferrite/austenite duplex stainless steels has been studied by means of isothermal hot tensile test at temperatures (T)from 700 to 1100°C at initial strain rates (e) from 10-4 to 10-1 s-1 in relation to microstructural aspects prior to and during deformation. Superpiastic elongations were observed in wide ranges of T and e. The maximum elongation greater than 2500% was obtained under the condition where c phase precipitation occurred during deformation. The elongation depended on the precipitation rate of c phase especially in the lower temperature deformation as well as on the prior microstructure. The most suitable microstructure obtained for superplasticity was fine grained δ-ferrite matrix with fine dispersion of γ particles. In the deformation of the specimens with such optimun microstructure, elongations greater than 200% were obtained at T≅1000°C even at e_??_10-1s-1. During superplastic flow, the large microstructural changes were observed. At above 1000°C γ phase was separated and was refined into spherical particles within the δ-ferrite matrix and at temperature below 1000°C, a γ/σ mixed structure was formed by the eutectoid decomposition of δ-ferrite, resulting finally in the stable equiaxed micro-duplex structures with δ/γ and γ/σ, respectively. Such microstructural changes can play an important role for the superplastic behavior in addition to the effect of m-value.
01 Mar 1985
TL;DR: In this article, a mechanical framework on the transformation-induced plasticity (TRIP) is presented, which can explain the remarkable increase in elongation at a certain range of temperature in the uniaxial tensile tests and the effect of the residual austenite.
Abstract: A mechanical framework on the transformation-induced plasticity (TRIP) is presented. Numerical illustration of the theory can well explain such phenomena in TRIP as a remarkable increase in elongation at a certain range of temperature in the uniaxial tensile tests and the effect of the residual austenite.
TL;DR: In this paper, a procedure is presented which converts standard specimen test data to a true stress-strain relation postulated as valid for higher strains, and a series of finite element test specimen simulations demonstrates the correction algorithm rationale for HY100 steel.
TL;DR: In this paper, a simplified numerical analysis of the tensile test for sheet metal specimens is presented with particular emphasis on the relationship between plastic flow parameters and tensile ductility, based on a one-dimensional, "long wavelength" approximation in which the stress state is assumed to be uniaxial throughout the deformation.
Abstract: A simplified numerical analysis of the tensile test for sheet metal specimens is presented with particular emphasis on the relationship between plastic flow parameters and tensile ductility. This analysis is based on a one-dimensional, “long wavelength” approximation in which the stress state is assumed to be uniaxial throughout the deformation. To account for the influence of necking and triaxiality on the flow behavior, however, an extended Bridgman correction for sheet specimens deformed under conditions of plane stress is employed. The governing equilibrium equation and boundary conditions are discretized to obtain computer solutions. Engineering stress-strain curves and strain distributions in deformed tensile specimens are compared to results from a more complex formulation previously published in the technical literature and show good agreement with it.
TL;DR: Three commercial palladium alloys were melted and cast in graphite and ceramic crucibles in order to introduce small, but different levels of carbon impurities in the alloys, and scanning electron microscopy revealed that carbon caused increased destabilization of this alloy.
TL;DR: In this paper, a non-uniform residual stress distribution is proposed to account for the elastic-plastic behaviour of as-extruded films and the subsequent extensive fibrillization during tensile testing or tension heat treatment.
Abstract: The stress-strain behaviour and morphological features of PBT films before and after heat treatment are reported. PBT films possess extraordinary mechanical properties comparable to those of the fibres. A non-uniform residual stress distribution is proposed to account for the elastic-plastic behaviour of as-extruded films and the subsequent extensive fibrillization during tensile testing or tension heat treatment. Tension heat treatment results in significant axial modulus and tensile strength increase by improving overall sample orientation and lateral crystallite size with concomitant straightening of buckled regions in the film.
TL;DR: In this article, the effects of grain size and specimen thickness on the mechanical properties (0.2% proof stress, ultimate strength, total elongation and work hardening exponent) of specimens of type 316 austenitic stainless steels have been investigated by tensile testing at room temperature.
TL;DR: In this article, the tension properties of various rapidly solidified and ingot-based aluminum alloys were examined and correlated with their notched tensile properties, and it was shown that there is a weaker correlation between the ductility and the notch yield ratio.
TL;DR: In this paper, a dislocation model for the σ-ϵ behavior of f.c. metals at low temperatures is proposed and a new theory of dynamic recovery is proposed.
TL;DR: In this article, Fe-6Al-4V sheets were explosively welded to mild steel base plates with an attachment zone that approximates a straight, waveless interface devoid of vorticity and thus the attendant formation of the Fe-Ti intermetallics.
Abstract: Ti–6Al–4V sheets were explosively welded to mild steel base plates with an attachment zone that approximates a straight, waveless interface devoid of vorticity and thus the attendant formation of the Fe–Ti intermetallics. The welded interface is seen to be harder than either of the bi‐alloys joined and the attachment strength, measured in terms of shear stress required for fracture of the weld zone, is seen to be stronger than the weaker of the materials (mild steel) joined. Stress relief treatments given at 525 °C is seen to induce ductility to the brittle interface without the introduction of recrystallization and/or the formation of Fe–Ti intermetallics at the weld zone. Approximate energy calculations indicate that explosively induced welds that comprise a nearly straight interface make efficient use of the detonation introduced energy, and thus the plastic straining of the alloys adjacent to the weld are minimal as confirmed by the microhardness and tensile test data obtained on the as‐welded and stress relieved samples.
TL;DR: In this paper, the standard procedure for determining the tensile strength and Young's modulus of single-filament ceramic fibers (outlined in ASTM test method D-3379-75) was modified for accurate determination of Youngs modulus, especially for fibers with larger diameters.
Abstract: The standard procedure for determining the tensile strength and Young's modulus of single-filament ceramic fibers (outlined in ASTM test method D-3379-75) was modified for accurate determination of Young's modulus, especially for fibers with larger diameters. An improved plotting method to determine the system compliance factor was developed; this method allows for variations in fiber diameter and produces more accurate Young's moduli.
TL;DR: In this article, an analysis of the uniaxial tensile test which includes the effects of heat generation and transfer on flow behavior is presented based on the solution of modified versions of the onedimensional force equilibrium and heat conduction equations, subject to the appropriate boundary conditions.
Abstract: An analysis of the uniaxial tensile test which includes the effects of heat generation and transfer on flow behavior is presented. The analysis is based on the solution of modified versions of the onedimensional force equilibrium and heat conduction equations, subject to the appropriate boundary conditions. The stress biaxiality or triaxiality developed during necking is taken into account by including a Bridgman correction in the equilibrium expression. In order to obtain solutions of the coupled deformation-heat transfer problem, the governing equations were discretized to enable numerical calculations using a finite-difference scheme. The accuracy of the analysis was confirmed by comparison of model predictions with experimental data from nonisothermal tensile tests on 1008 aluminum-killed sheet steel. These and other simulations lead to the conclusion that temperature effects are most important following the onset of necking. The development of temperature gradients during necking can substantially decrease the tensile elongation and mitigate the stabilizing influence of positive strain rate sensitivity.
TL;DR: In this paper, the highly stressed volume (HSV) approach is considered for relating tensile strength of concrete as determined by a range of test methods and a variety of loading configurations with various sizes of specimen.
Abstract: Synopsis The highly stressed volume (HSV) approach is considered for relating tensile strength of concrete as determined by a range of test methods and a range of loading configurations with various sizes of specimen. The paper demonstrates that the approach explains the effect of specimen size of geometrically similar specimens upon tensile strength as determined by a given method. However, the HSV approach alone does not correlate the different values of tensile strength as yielded by various methods of test.