Research On The Cavitation In Elastoplastic Materials Under Thermal Shocks

During processing, lots of initial imperfections will be produced in the metal. The initial imperfections will lead to crack or damage when the material is under thermal shocks. The main aim of this paper is to solve the transient response and the growth of a spherical micro-void in thermal elastoplastic material under thermal or mechanical loads. The problem is discussed from the coupled thermal stress and instability of materials separately.The thermoelastotransient response in a hollow sphere under different thermal shocks is analyzed. Coupled thermal stress and non-Fourier heat conduction are considered in the mathematic model. The systems of heat and motion equations are successfully uncoupled before Laplace transformation, and an analytic solution is given. By means of numerical Laplace inversion, the temperature and stress distributions are presented. From the numerical results from different thermal shocks, the influence of the impact speed to the coupled thermal stress problems can be observed. A comparison of temperature and stress distribution is given between the coupled thermal stress problems and static thermoelastic problems.The growth of preexisting of spherical micro-void in an infinite elastic body under thermal loads is analyzed. Based on the large deformation, a similarity transformation results is given. By giving a transformation, partial differential equation including inertia term is transformed to an ordinary differential equation. The analytic solution of displacement and stress distribution around the micro-void is given.The growth of preexisting spherical micro-void in an infinite elastoplastic body under thermal load is analyzed. Based on the geometrical nonlinearity with large deformation and the yield criterion of perfect plasticity, a mathematical model of the problem is presented. The Lagrangian and Euler coordinate systems are introduced to describe the thermal expansion deformation. By the elastoplastic analysis, the distributions of the stresses near the cavity are obtained. When the initial radius of a preexisting micro-void tends to be infinitely small, the critical temperature of cavitation can be calculated. The instability of the micro-void inside the infinite body is discussed. The results of numeric computation indicate that the radius of the cavity and the radius of the plastic zone would rapidly grow when the remote temperature increases and approaches the critical temperature.