功能梯度涂层III型界面裂纹的动应力强度因子

Research is conducted to investigate the moving crack on the interface between the functionally graded coating and infinite substrate structure with free boundary in this paper. Using the bonding conditions of the interface between different media, all the quantities in our question have been represented with a single unknown function, and the dual integral equation of moving crack problem is obtained through Fourier transform with the help of the exponent model of the shear modulus and density. The displacement is expanded into series form using Jacobi Polynomial by Schmidt method, then the semi-analytic and numerical solutions of dynamic stress intensity factor are derived. The influences of parameters such as crack velocity, graded parameter and coating height on dynamic stress intensity factor are also studied. The results show that the stress at the crack tip is of singularity; dynamic stress intensity factors decrease with the increasing graded parameter and coating height, increase with increasing of crack propagation rate for the problems of interface moving crack. Increasing graded parameter and coating height can be used to reduce the stress concentration and raise material security, so we can adjust dynamic stress intensity factor by changing the graded parameter and coating height.