The Study On Infrared Thermal Wave Nondestructive Testing Technology For Interface Debond

With the advance of science and technology, adhesive structure is widely applied in Aviation, petrochemical and other defense and civil fields. Nondestructive Testing technology that with the background of felting quality has become the subjects direction that people pay attention at and study. As currently the relatively mature nondestructive testing technology applied in the interface debond, ultrasonic testing have mad a lot of achievements in this field. But when adhesive layer is very thin or the multi-layer bonding structure has obvious differences at acoustic properties, the ultrasonic signal of interface debond defect will become very weak and hard to distinguish. As an emerging discipline, ultrasonic infrared thermal wave technique has a broad application prospect in multiple interface debonding detection because of its directness ,rapid,large area detection and distance detection, etc.In infrared thermal wave nondestructive testing, the choice of thermal excitation method will directly influence defect detectability, and actual test results.This paper primarily takes steel and rubber multilayer bonding structure as research subject and study the method of thermal excitation in the multiple interface thin adhesive layer debonding detection. Through constructing multiple interface debond defect model, the paper do simulation calculation for different thermal excitation infrared debond NDT by using finite element analysis software COMSOL and then research the relationship between the thermal excitation method and the detection sensitivity. The study provides numerical basis for making accurate infrared detection experiment scheme. Then according to the simulation computation result,complete experiment for debond specimen is done with the light phase lock thermal excitation system and the thermal infrared imager which is used to collect continuous infrared image sequences. Finally the paper research the algorithm that extracted from phase lock infrared signals and finish the following data processing algorithm to extract the signal corresponding to the thermal excitation phase-locked frequency in order to realize the effective debond defects detection.Numerical simulation result and experimental result show that the light phase lock infrared thermal wave nondestructive testing method is feasible to detect multiple interface thin adhesive layer debond. The data processing result shows that the extraction algorithm is effective for detect signal.