INTERFACIAL STRESS IN A CARBON-TO-METAL BOND JOINT UNDER THERMAL-SHOCK LOADING

The duplex bond joint consisting of a metallic substrate armored with carbon-base materials is a promising candidate configuration for appli cation to high heat flux operations. When a bond joint is subjected to thermal loadings, significant thermal stresses may develop due to mis match of the thermal expansion coefficients, Stress intensification oc curs near the free surface edge of the interface, sometimes showing si ngularity, The singular stress fields are critical for understanding t he loading nature of the bond interface in a joint system. In this pap er, thermal stresses in the bond interface of a carbon-to-molybdenum j oint element were investigated, A high heat flux (HHF) pulse was assum ed as the reference load history to simulate the thermal shock conditi on. The thermomechanical behavior was described quantitatively in term s of the stress intensity factor. The stress solutions of the singular field computed by the theoretical approach showed a good agreement wi th the numerical results of the finite element analysis. The stress in tensity factor of the singular stress fields near the free surface edg e of the interface showed a time variation similar to that of the bulk stress, The temperature gradient induced by the transient HBF load af fected the overall interfacial stress only slightly.