von Mises yield criterion

About: von Mises yield criterion is a research topic. Over the lifetime, 4374 publications have been published within this topic receiving 82642 citations. The topic is also known as: Von Mises stress.

An explicit, direct approach to obtaining multiaxial elastic potentials that exactly match data of four benchmark tests for rubbery materials—part 1: incompressible deformations

Abstract: An explicit, direct approach is proposed to obtain multiaxial elastic potentials that exactly match finite strain data of four benchmark tests for incompressible rubberlike materials, including uniaxial, biaxial, plane-strain compression and simple shear tests. This approach is composed of three direct procedures. At first, we utilize a usual interpolating method for single-variable functions to obtain one-dimensional stress–strain relations matching data of uniaxial test and simple shear test, separately, and then obtain two one-dimensional elastic potentials via directly integrating the stress power. After that, we introduce a multiaxial bridging method based on certain invariants of Hencky strain and extend the foregoing two one-dimensional potentials to two potentials for multiaxial cases. Then, we further introduce a multiaxial matching method based also on Hencky invariants and combine the just-mentioned two independent multiaxial potentials to obtain a unified form of multiaxial potential. With two universal relations first disclosed here between the four tests, eventually we demonstrate that each such unified multiaxial potential exactly matches data of four benchmark tests. In particular, we apply the proposed explicit approach with a simple form of rational interpolating function for uniaxial stress–strain relation with two poles and directly from uniaxial stress–strain relation to obtain a new, simple form of multiaxial elastic potential with a limit for strain. It is found that this limit for strain is just a counterpart of the well-known von Mises limit for stress in the theory of elastoplasticity. Also, it is shown that this simple potential accurately matches data of four benchmark tests over the whole range from small to large deformations.

A Model Study of Thermal Stress-Induced Voiding in Electronic Packages

Abstract: Thin film metallizations are one of the most important interconnects in large-scale integrated circuits They are covered by substrates and passivation films Large hydrostatic (mean) tension develops due to the constraint and thermal mismatch, and voiding is identified as the failure mechanism This phenomenon of rapid nucleation and growth of voids is called cavitation instability and it can lead to the failure of ductile components in electronic packages such as metallizations A micromechanics model is developed to provide the critical mean stress level that will trigger the cavitation instability It is found that this critical mean stress level the cavitation stress, not only depends on the material properties but also is very sensitive to defects in the material For example, the cavitation stress decreases drastically as the void volume fraction increases The stress-based design criterion for ductile components in electronic packages should then be: (1) Von Mises effective stress < yield stress; and (2) mean stress < cavitation stress, which is particularly important to the constrained ductile components in electronic packages such as vias and conductive adhesives An analytical expression of cavitation stress for elastic-perfectly plastic solids is obtained, and numerical results for elastic-power law hardening solids are presented

Determination of Ductile Damage Parameters by Local Deformation Fields: Measurement and Simulation

Abstract: This work comprises the development, implementation and application of methods for the parameter identification of damage mechanical constitutive laws. Ductile damage is described on a continuum mechanical basis by extension of the von Mises yield condition with the Gurson–Tvergaard–Needleman as well as with the Rousselier model. The classical Rousselier model is complemented by accelerated void growth and void nucleation. The non-linear boundary and initial value problem is solved by the finite element system SPC–PMHP, which was developed in the frame of the special research program SFB393 for parallel computers. The material parameters are identified by locally measured displacement fields and measured force–displacement curves. For the material parameter identification a non-linear optimization algorithm is used, which renders the objective function to a minimum by means of a gradient based method. A useful strategy to identify the material parameters was found by careful numerical studies. Finally, using the object grating method the local displacement fields as well as the force–displacement curves are measured at notched flat bar tension specimens made of StE 690 and the parameters of the material are identified.