Detection and size estimation of crack in plate based on guided wave propagation

Abstract

The paper presents results of the comprehensive theoretical and experimental investigation of crack detection in metallic plate using guided wave propagation. The main aim of the paper is to develop the novel method which would allow for linear crack size estimation with the use of minimal number of the transducers. In general, there exists the relation between length of the propagation path and the wave amplitude value. However, we have shown that the amplitude value can be also influenced by the interaction with the damage. The meaningful differences in the amplitudes of waves reflected from various damage zones (the end and middle point) have become the foundation of the novel algorithm of line-crack detection. All stages of the algorithm have been described in detail and then the experimental tests were conducted. The experimental investigation involved crack detection and its size estimation for four different configurations of piezo transducers. Each configuration consisted of one actuator and three sensors, what which so far was the minimum number of sensors for point damage detection. The damage maps created on the basis of the collected time-domain signals visualized the exact crack orientation in each case. It has been revealed that the developed algorithm allows also for determining the crack size when the configuration of the transducers is designed properly.