Transient growth of a micro-void in an infinite medium under thermal load with modified Zerilli–Armstrong model

Abstract

In this paper, the transient growth of a spherical micro-void under remote thermal load in an infinite medium is investigated. After developing the governing equations in the problem domain, the coupled nonlinear set of equations is solved through a numerical scheme. It is shown that a small cavity can grow rapidly as the temperature increases in a remote distance and may damage the material containing preexisting micro-voids. Conducting a transient thermal analysis simultaneously with a structural one reveals that the material may experience a peak in the radial stress distribution, which is five times larger compared to the steady-state one, and shows the importance of employing a time-dependent approach in this problem. Furthermore, utilizing a sensible yield criterion, i.e., the modified Zerilli–Armstrong model, discloses that there is a large discrepancy in the results assuming perfectly plastic constitutive model. It is verified that the obtained results do not violate the proportional loading conditions that is the basis for development of the governing formulation in this work. The monotonic alteration of the plastic strain components versus time proves that we do not encounter any elastic unloading during the void growth, which is a basic assumption in the present work. Some numerical examples are also presented to investigate the features of the presented model.