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.

The self-similarity theory of high pressure torsion.

Abstract: By analyzing the problem of high pressure torsion (HPT) in the rigid plastic formulation, we show that the power hardening law of plastically deformed materials leads to self-similarity of HPT, admitting a simple mathematical description of the process. The analysis shows that the main parameters of HPT are proportional to β q , with β being the angle of the anvil rotation. The meaning of the parameter q is: q = 0 for velocity and strain rate, q = 1 for shear strain and von Mises strain, q = n for stress, pressure and torque (n is the exponent of a power hardening law). We conclude that if the hardening law is a power law in a rotation interval β, self-similar regimes can emerge in HPT if the friction with the lateral wall of the die is not too high. In these intervals a simple mathematical description can be applied based on self-similarity. Outside these ranges, the plasticity problem still has to be solved for each value of β. The results obtained have important practical implications for the proper design and analysis of HPT experiments.

Quantitative stress/strain mapping during micropillar compression

Abstract: Micropillar compression is increasingly used as a method to examine small length-scale mechanical properties since it minimises the strain gradients that are unavoidable during nanoindentation into a flat surface. It also simplifies the data analysis since it is assumed that the compression is uniaxial. But how valid is this assumption when misalignments in the microscale setup are generally unavoidable? In order to investigate this, the stress and strain tensors of the micropillar should be measured during the compression. To accomplish this, electron backscatter diffraction (EBSD) mappings were obtained before, during and after consecutive compressions of a GaAs micropillar inside of a high-resolution scanning electron microscope. Elastic strain and the corresponding stress tensors were determined from the EBSD measurements using a cross-correlation technique. The results show that the von Mises stress compares well to the engineering stress determined from the nanoindenter load–displacement data. Even ...