Effect of the transitional gradient of material property on the mechanical behavior of a non-homogeneous interlayer

The main idea of this paper is to study the effects of the transitional gradient of material property at interface on the mechanical behavior of a bi-interface structure with a sandwiched non-homogeneous interlayer. Four different types of transitional functions of material property are put forward and their influences are analyzed by the finite element method. It is indicated that, to diminish the value of the gradient of Young’s modulus at interface is beneficial to decreasing the stress concentration at interface. Under the mode-I loading, among all the mode-I and mode-II stress intensity factors at both interfaces, the dominant one is always the mode-I stress intensity factor at the more rigid interface. With the gradient of Young’s modulus at interface decreasing, the SIFs corresponding to the two different interfaces vary inversely, however, the dominant stress intensity factor decreases. To reduce the gradient of material property at interfaces, i.e., to reduce the weak-discontinuity of interfaces, will be beneficial to enhancing the ability of bi-interface structure against fracture.