Simulating thermal NDT of bonded structures by FEM

摘要

Characteristics of heat transfer and signal evolution in thermal nondestructive testing (TNDT) in aluminum adhesively-bonded structures were studied by computer simulation based on the finite element method (FEM). TheTNDT mathematical model of bonded structures was constructed in cylindrical coordinates. The evolutions of TNDTinformative parameters versus defect size and depth were simulated by using the FEM analysis software ANSYS. Somesimple regression expressions were obtained for the relations between the informative parameters and the defectparameters. It is shown that, at a fixed defect depth, the four informative parameters including the maximum differentialtemperature, maximum contrast, differential temperature peak time and best observation time, are linearly proportionalto defect radius respectively. However, if defect radius is fixed, the maximum differential temperature and maximumcontrast become a non-linear function of defect depth, and the differential temperature peak time and best observationtime are linearly proportional to defect depth. It is believed that the obtained results may be of help in developing aninspection strategy for aviation aluminum panels.