Hydrostatic stress

About: Hydrostatic stress is a research topic. Over the lifetime, 1568 publications have been published within this topic receiving 37773 citations.

Global material constraints and their associated reactive stresses

Abstract: The stress field in a material subject to a global material constraint is composed of a reactive stress and an active stress The active stress is determined by the deformation while the reactive stress arises because of the constraint The static equilibrium equations can be reduced to equations involving only the active stress The resulting equations may then be solved to determine the deformation Although the reactive stress is not needed in order to find the deformation, it is needed to satisfy traction boundary conditions Rod, shell, and finite element theories can therefore be developed in an unambiguous way As an example, one can calculate explicitly a reactive stress in a rod-like body subjected to a compressive end load

Investigation of Triaxial Stress State in Retained Austenite during Quenching of a Low Alloy Steel by In Situ X-Ray Diffraction

Abstract: In situ XRD measurements were performed at ESRF, Grenoble, France (ID11) during quenching of a ball bearing steel AISI 52100 (100Cr6) with varying carbon content in solution. The evolution of austenite lattice parameter during cooling is nearly linear until Ms is reached and then, a divergent behavior can be observed. Assuming that the extrapolation of the linear range to room temperature gives the stress-free lattice spacing, an increasing compressive hydrostatic stress state is resulting. A strong effect of the carbon content was found. These results were confirmed by theoretical calculations based on data from the literature.

The Elastic-Plastic Finite-Element Method

Abstract: The rigid-plastic and viscoplastic finite-element techniques described in the previous chapters are useful approaches to the modelling of metal deformation when the elastic component of strain may reasonably be ignored. This is often the case, for example, for hot working conditions. In other situations, it is important to take into account the elastic as well as the plastic deformation of the material, and it is vital to do so if the unloading behaviour is to be predicted.

Multi-physics-based FEM analysis for post-voiding analysis of electromigration failure effects

Abstract: In this paper, we propose a new multi-physics finite element method (FEM) based analysis method for void growth simulation of confined copper interconnects. This new method for the first time considers three important physics simultaneously in the EM failure process and their time-varying interactions: the hydrostatic stress in the confined interconnect wire, the current density and Joule heating induced temperature. As a result, we end up with solving a set of coupled partial differential equations which consist of the stress diffusion equation (Korhonen's equation), the phase field equation (for modeling void boundary move), the Laplace equation for current density and the heat diffusion equation for Joule heating and wire temperature. In the new method, we show that each of the physics will have different physical domains and differential boundary conditions, and how such coupled multi-physics transient analysis was carried out based on FEM and different time scales are properly handled. Experiment results show that by considering all three coupled physics - the stress, current density, and temperature - and their transient behaviors, the proposed FEM EM solver can predict the unique transient wire resistance change pattern for copper interconnect wires, which were well observed by the published experiment data. We also show that the simulated void growth speed is less conservative than recently proposed compact EM model.