Size effect of thermal shock crack patterns in ceramics: Insights from a nonlocal numerical approach

Abstract

A new weakly coupled thermoelastic ordinary state-based peridynamic (SB-PD) model considering strain-softening characteristics is developed to investigate the size effect on thermal shock crack patterns of ceramic slabs in water quenching tests. In the new weakly coupled thermoelastic ordinary (SB-PD) model, the general SB-PD model is derived by considering thermal effects. The new microscopic thermal conductivity that establishes the relationship between the microscopic geometries and macroscopic geometric conditions is derived from the analytical temperature distributions. Moreover, the new general form of the critical stretch takes the peridynamic state into consideration and is presented based on an equivalent energy relationship in which the softening tensile parts are taken into consideration. The numerically predicted thermal shock crack patterns are in good agreement with previous experimental observations, which demonstrates that the new nonlocal model is effective in capturing thermal shock crack patterns in cold quenching tests. Moreover, differences from the effects of the brittle ceramic specimen size and the water quenching temperature that affect the energy evolution and crack propagation speed during thermal shock fracturing processes are investigated.