Study on transient heat flux intensity factor with interaction integral

Abstract

Aim at determining of the heat flux intensity factor (HFIF) near a crack tip in structures under transient heat flux load, the transient JT integral is defined firstly and proved to be path-independent. Based on the path-independence of the transient JT integral, a transient interaction integral utilized to extract the transient HFIF is established by introducing a known auxiliary field. A singular isoparametric quadrilateral element with eight nodes, which is used to discretize the structure around the crack tip, by moving the midside nodes to one-fourth of the sides is presented. With this singular element, the 1/r singularity of heat flux near the crack tip can be exactly depicted. Numerical examples are carried out to verify the path-independence of the transient JT integral and the interaction integral method to extract the transient HFIF. Moreover, the transient HFIF in a structure with multiple cracks are numerically investigated by means of the presented method. The method proposed in this paper can be extended to investigate the thermo-mechanical problems.