Quantitative Non-Destructive Testing of Metallic Foam Based on Direct Current Potential Drop Method

To detect cavity defects in metallic foam and to predict its size, a quantitative nondestructive testing (NDT) method based on the direct current potential drop (DCPD) technique was proposed and validated in this study. At first, an efficient forward analysis scheme was introduced to simulate the DCPD signals. In order to obtain measured signals for defect reconstruction, specimens of practical aluminum metal foam with defects of different sizes were fabricated and inspected then by using a DCPD testing system. Third, an inverse analysis scheme in model based optimization category was proposed and implemented for sizing cavity defects in the metal foam. Through inversion of both simulated and measured DCPD signals, the validity of both the forward and the inverse analysis schemes was demonstrated for the quantitative DCPD evaluation of the metallic foam.