Simulation and experimental research on nonlinear ultrasonic testing of composite material porosity

Abstract

Porosity is related to the composite material performance and affects the product quality. It is very necessary to detect the porosity. Due to the lack of precision of the linear ultrasonic testing for small pores, the nonlinear ultrasonic testing of composite porosity is simulated and tested in this paper. The random pore model is introduced to perform nonlinear ultrasonic simulation in order to consider the randomness of pore size, morphology, and distribution characteristics. Different pore length, pore width and porosity models were created to investigate the relations of the ultrasonic propagation characteristic with pore parameters. And the real porous graphite composite materials are performed nonlinear ultrasonic simulation and experimental study. The results show that the relative nonlinear coefficient increases with the increasing pore length and decreases with the increasing pore width. The simulation and experimental results show that relative nonlinear coefficient increase with the increase of porosity. This paper provides a reference for nonlinear ultrasonic technology to detect the porosity of composite materials.