Pulsed Infrared Non-destructive Quantitative Analysis Of Finite Element Simulation And Depth Of Defect Detection

The infrared thermal wave imaging technology, as a new non-destructive method, has developed rapidly in recent years. According to the material of sample, structure and type of defects and testing conditions, this technology design different heat sources with different characteristics. Computer and special software were used to control the thermal excitation system to heat samples with various heat source, such as periodical heating and pulsed heating. The infrared camera can collect and record the real time thermal wave signals. Then the recorded signals were processed and analyzed by special computer software and different algorithms. By In practical applications, the quantitative measurement of defect depth and size can realized by establishing heat conduction models and analyzing the change of sample surface temperature to obtain thermal parameters of internal defects and damages (such as foreign body, porosity and delamination).ANSYS is a kind of large-scale element software, which is combined with structural, thermal, fluid, electromagnetic and acoustic. The thermal analysis model in this software can solve many kinds of thermal problems. By combining ANSYS with infrared Nondestructive testing (NDT) technology, ANSYS can simulation testing, which the simulation results provide reference data for actual testing. Adjustment detect scheme, according to this reference data, can shorten the test time and optimize the detection process. The depths of defects were obtained by processing simulation data with different calculation methods.This thesis introduces the basic theory of pulsed infrared nondestructive testing and ANSYS software briefly. The theoretical model of thermal wave in one single medium was derived to get the relation of defect depth and surface temperature peak time. And based on the relation, the defects depth of aluminum, stainless steel and glass fiber reinforced plastics (GFRP) were obtained by method peak second derivative of the temperature decay curve in the log scale (PSDT) and absolute peak slope time (APST). Using ANSYS finite element software simulate the pulse thermography of three samples on the above, and then process this simulated data by the method of PSDT and APST. The results of ANSYS and pulsed infrared nondestructive testing were compared and analyzed, which indicated that ANSYS can be used for defect quantitative measurement. And then discuss the influence of defect size on depth quantitative measurement. ANSYS not only has sure auxiliary function to testing, but also can lay the foundation for quantitative measurement of defects depth. Expect broking through the limits of specific problems in practice, ANSYS can set different parameters of experiment to find the most suitable test scheme and improve the defect quantitative measurement accuracy.