An experimental method to measure the layer thickness and wave velocity of copper–steel composite board without interface echo

Abstract

Thickness of each medium layer and velocity of ultrasonic wave propagation in each medium layer of the two-layer composite medium were measured simultaneously based on the method to collect phase information from continuous echo signals on front surface and undersurface. Such measurement was implemented under no interface echo and fixed total thickness of the testpiece. The method can be applied to any two kinds of two-layer composite medium. The paper only used a 35mm thick copper–steel composite board as an experimental example. Calculated results demonstrated that measuring errors of both thickness and velocity of ultrasonic wave propagation are smaller than 0.2%, indicating the effectiveness of the proposed measurement method.