Showing papers in "Mechanics of Materials in 1998"

TL;DR: In this article, the energy converted to heat during high strain rate plastic deformation is measured directly using an infra-red method for Ta−2.5% W alloy and, indirectly, using UCSD's recovery Hopkinson bar technique for the same alloy, as well as for commercially pure Ti, 1018 steel, 6061 Al and OFHC Cu.

TL;DR: In this paper, the authors illustrate three advantages of infrared thermography as a non-destructive, real-time and non-contact technique, which allows first observation of the physical processes of damage and failure in metals, and in particular, automotive components subjected to fatigue loading, second detection of the occurrence of intrinsic dissipation, and third evaluation of the fatigue strength in a very short time.

TL;DR: In this article, a large-amplitude, nonlinear wave-profile measurements which manifest the shock strength and equation-of-state properties of brittle solids has been performed.

TL;DR: In this article, the influence of strain rate on the superelastic properties of TiNi shape memory alloy was investigated and it was shown that the martensitic transformation stress and the dissipated work increased with an increase in strain rate.

TL;DR: In this paper, the piezoresistive behavior of a conductive short fiber/elastomer matrix composite was analyzed by applying a percolation model to the composite system with the aim of predicting the relation between the applied finite strain and fiber reorientation.

TL;DR: In this article, the behavior of aluminum oxide under compressive loading is investigated over a wide range in strain rate and degrees of confinement, and it is shown that plastic flow can be generated in Al 2 O 3 at all strain rates if confinement is sufficient to prevent premature failure via microfracture.

TL;DR: In this article, the authors investigated the densification of powders by initial stage sintering through computer simulations, where every particle center is represented by a node and every contact between neighboring particles by a discrete element.

TL;DR: In this paper, an analytical model of the stress field caused by sliding microindentation of brittle materials is developed, where the complete stress field is treated as the superposition of applied normal and tangential forces with a sliding blister approximation of the localized inelastic deformation occurring just underneath the indenter.

TL;DR: In this article, the authors used finite element models to identify the driving mechanisms which lead to internal crack growth and failure in the thermally sprayed coatings and found that the energy release rate of large cracks can reach close to fracture toughness of ceramic coatings.

TL;DR: In this paper, a numerical study of the mechanical properties of low-density open-cell polymer foams subjected to large deformations is presented, where the foams are modelled as three-dimensional frameworks of slender struts.

TL;DR: In this paper, a model for the poroelastic behavior of brittle materials exhibiting induced anisotropic damage is proposed, based on a thermodynamics potential and some principles of fracture mechanics.

TL;DR: In this paper, a single internal state variable constitutive model is presented to represent the deformation behavior of metals that exhibit flow softening caused by the competing hardening and recovery processes and heat generation during plastic deformation.

TL;DR: In this article, an asymptotic approach for modeling of adhesive joints in a layered structure is presented for the case when two elastic layers are bonded together by a thin and soft layer of glue and differential equations for the displacements (including the displacement jump across the thin interface layer) in a compound thin beam are derived.

TL;DR: In this article, an elasto-dynamic finite element simulation of the particle-impact experiment was carried out to study the threshold conditions for dynamic fragmentation of brittle materials, and illustrates some of the issues involved in the application of cohesive zone models to problems involving impact and dynamic fragmentation in brittle materials.

TL;DR: Nemat-Nasser et al. as discussed by the authors proposed a physically based, rate and temperature-dependent constitutive model for fcc single crystals using the Taylor averaging method and numerical calculations are performed to simulate the experimental results for polycrystalline OFHC copper.

TL;DR: In this paper, microstructural changes during shear deformation in two natural sands and one artificial assembly of oval rods are investigated with special interest in the micromechanisms leading to the generation of shear bands.

TL;DR: In this article, the authors studied the toughening of alumina ceramics with dispersed silicon carbide nano-particles and identified three mechanisms: switching from the intergranular cracking to the transgranular one by nanoparticles along the grain boundaries, fracture surface roughening by zigzag crack path perturbed by the internal stresses of nano particles within the grains, and shielding by clinched rough surfaces near the crack tip.

TL;DR: In this article, a variational approach is taken to estimate the stresses in the region between transverse cracks, and these are found to be accurate away from the crack planes when comparison is made with finite element computations.

TL;DR: In this paper, a model for the dynamic finite element analysis of large-strain, high strain rate deformation behavior of materials is presented, where a total Lagrangian formulation is used in the derivation of discrete equations of motion.

TL;DR: In this paper, an integral transform solution is developed to reduce the solution of the problem to a Fredholm integral equation of the second kind with a symmetrical kernel depending on the boundary conditions (frictionless/bonded) in the areas of contact.

TL;DR: In this article, the deformation of an assembly of particles is examined using a discrete element method (DEM) numerical model, where the particles are modeled as random-sized, rough, inelastic, circular two-dimensional disks.

TL;DR: In this paper, the influence of thermal residual stress on the deformation behavior of a composite has been analyzed with a new micromechanical method based on secant moduli approximation and a new homogenized effective stress to characterize the plastic state of the matrix.

TL;DR: In this paper, a system of singular integral equations for the unknown temperature discontinuity defined on crack faces is developed to study the interaction between crack and elliptic hole, and numerical results are presented to elucidate the effects of crack orientation on stress and electric displacement (SED) intensity factors.

TL;DR: In this paper, a two-dimensional sliding crack model is applied to examine the response of brittle materials to compressive loads, and the problem is treated numerically by means of a boundary element method (BEM) solving a singular integral equation for the dislocation density along the crack contour.

TL;DR: In this paper, microheterogeneity resulting from dislocation substructure evolution is introduced into polycrystal elastoviscoplasticity through a second rank tensorial internal state variable.

TL;DR: In this article, a general time-dependent constitutive model for rubber materials has been developed, based on combination of the general rubber hyperelastic theory and the microstructure alteration theory.

TL;DR: In this article, two numerical approaches were used to simulate the wind-driven motion of fractured ice in a wedge-shaped channel, one is a discrete-element method, in which the ice blocks (or floes) are simulated as random-sized disks floating on the water surface, driven by the wind force and interacting with each other through normal and friction forces.

TL;DR: In this paper, a numerical simulation method is proposed for the growth of interacting non-collinear cracks in a finite, heterogeneous, and two-dimensional elastic solid, which is based on a step-by-step finite element method using the method of superposition of analytical and finite-element solutions accompanied by the quadtree automatic mesh generation algorithm.

TL;DR: In this article, a rational set of conditions that must be satisfied by all intensive (material) parameters and, therefore, by the damage parameter as well is formulated, and the brittle response of materials with inferior cohesive strength on three different scales is considered.

TL;DR: In this article, the authors derived upper and lower bounds for the eAective piezoelectric moduli by applying the Fourier transform to the Green's functions of an unbounded homogeneous body.