Dual-phase-lag heat conduction and associate fracture mechanics of a ceramic fiber/matrix composite cylinder

This paper studies a ceramic fiber/matrix composite cylinder subjected to a fast heating shock on its surface, which may have its root application for future thermal protection system of space vehicles. Theoretical model of the thermoelasticity field is established under the framework of dual-phase-lag (DPL) heat conduction. It is found that the intensity of the thermal wave described by DPL model increases with the heating rate. However the classic Fourier model scarcely embodies the effect of the heating rate on the thermoelasticity response. In addition, a comparison of the thermal stresses is made when investigating the fiber/matrix composite cylinder and the monolithic matrix cylinder. The fiber increases the compression stress of the matrix and decreases the tension stress due to the high modulus of the fiber. And the tension stress in the fiber is much higher than that in the matrix. Thus the thermal shock fracture behavior of the fiber/matrix composite cylinder with a center crack is studied. There is an optimal volume content for the fiber/matrix composite cylinder so that the peak value of the thermal stress intensity factor is minimized. This study may be useful for designs of fiber reinforced composites under severe heating.