Quantitative Estimation of Crack Position and Dimension in a Plate Using Lamb Waves: Numerical Simulation.

Quantitative assessment of the crack position and dimension in metallic structures is critical to nondestructive testing and evaluation. Finite-difference time-domain method was used to simulate the propagation of Lamb waves in a plate and its interaction with cracks. The corresponding reflection and transmission coefficients and power spectral densities were used as the training data for direct search and an artificial neural network model. The estimation accuracy was compared with each other at varied detection thresholds. In addition, detecting multiple cracks was also possible by considering each crack individually, if the echoes from each crack can be separated in the time domain. [ABSTRACT FROM AUTHOR]