Thermoelastic analysis and 3 dimensional failure analysis of Carbon/Carbon brake disk were done in this research. A brake disk problem, defined as a thermoelastic non-linear contact problem, was solved using a commercial finite element package and user-defined linkage subroutines. The governing is linear static in elasticity and steady state in heat problem. With the axisymmetric assumption of 3 dimensional Carbon/Carbon brake disk, thermoelastic stress analysis was performed. Elastic contact condition was imposed on the brake contact surface by joining or separating the normal displacements of upper surface nodes and lower surface nodes depending upon the sign of the normal stress to the contact surface. Until elastic contact condition was satisfied, the elastic iterations were continued.
Using the result of axisymmetric analysis, 3 dimensional failure analysis was performed. Temperature, surface pressure, and friction force distributions on the contact surface were imposed on the 3 dimensional composite solid element and then the failure was analyzed using Tsai-Wu failure criterion. Cyclic symmetry condition was imposed on a brake disk to reduce the total d.o.f. of the problem. Layup sequence used in the analysis was quasi-isotropic $[0/±45/90]_s$. The effecs of notch shape and notch radius on the failure were studied.
