Inline Measurement of Acoustoelastic Coefficient in Conductive Sheet Material With Electromagnetic Loading System

In ultrasonic non-destructive testing technology, the method to detect the stress of metal plates using longitudinal critically refracted waves (LCR) is increasingly developing, in which the calculation of acoustoelastic coefficient of the metal plate is indispensable. However, due to the influence of the metallic material's in-service environment on acoustoelastic coefficient, the existing calculation method of the acoustoelastic coefficient cannot meet the engineering requirements. Therefore, an inline measurement method based on electromagnetic loading is proposed in this paper. The calculation formula for the inline measurement of acoustoelastic coefficient is derived. An electromagnetic loading experimental platform is designed, including an electromagnetic loading module, an ultrasonic detecting module, and a delay control module. The loading test of a 1060 aluminum plate is carried out using the designed platform. The flight time of LCR waves is measured experimentally and used in the calculation formula of acoustoelastic coefficient. The experimental results of acoustoelastic coefficient meet the accuracy requirement of less than 5%, which can be used for stress measurement. So, the inline measurement method of acoustoelastic coefficient proposed in this paper is feasible.