Abstract : Abstract
This work investigates the effect of cyclic loading upon periodic elasto-plastic porous materials. The aim is to understand the evolution of the underlying microstructure, described here with a single void embedded in a cubic unit-cell. Periodic finite element (FEM) calculations are carried out under a finite strain deformation process keeping the absolute value of the stress triaxiality and the Lode angle constant during the cycle. As a result of the applied loading conditions, the void geometry, both volume and shape, change significantly leading to porosity and void shape ratcheting. The void shape becomes non-spherical from the very first cycle leading to a markedly asymmetric cyclic response of the material. This, in turn, results in an observed maximum stress as a function of the number of cycles. In addition, even though the average applied strains are relatively small, the local strains near the void surface increase significantly inducing a significant localization of the deformation. Finally, several initial void shape configurations are also considered. In the majority of the cases studied, the void evolves into a crack-type shape in the direction of the minimum absolute stress. This, in turn, is consistent with a configuration corresponding to a crack subjected to a mode I cyclic loading.
https://hal-polytechnique.archives-ouvertes.fr/hal-01219714 Contributor : Andrei ConstantinescuConnect in order to contact the contributor Submitted on : Monday, February 24, 2020 - 7:16:22 PM Last modification on : Wednesday, November 17, 2021 - 12:29:25 PM
A. Mbiakop, A. Constantinescu, Kostas Danas. On void shape effects of periodic elasto-plastic materials subjected to cyclic loading. European Journal of Mechanics - A/Solids, Elsevier, 2015, 49, pp.481-499. ⟨10.1016/j.euromechsol.2014.09.001⟩. ⟨hal-01219714⟩