Study On Testing And Analyzing Of Details Of The Defects In The Composites

This thesis is about a detective method towards the structures of composite by comparing and analyzing the characters of the defects in the actual structures.This method that involves Infrared imaging technology and ESSPI is about testing and analysis of the details of defects.In this paper, it discusses the related theories,dynamic Thermal excitation,how to resolve the given graphic image and confirms the resolutions above are true.Researches indicate that: ESSPI is a much effective method to find the sub-surface debonding-defects in metal alloy composite and double-layer non-metallic composite structures . Through qualitative and quantitative analysis on the processed defective images,the position and the size of defect can be found ,the laboratory result and the theoretical are identical.Unfortunately, the method is useless for the water defects in the structures.Infrared imaging technology can effectively detect the water defects. The positions and the sizes of defect can be determined by observing the temperature-graph.The drawback of the method is that it can not detect the sub-surface debonding-defects.For improving the quality and precision of the detection in practice, polytype fusion-arithmetics are investigated in this thesis.The results, based on Infrared image and visible-light image, come from the most popular arithmetics,including Wavelet Transform,Laplace Pyramid and Gradient Laplace Pyramid.The results show that method of Image-Fusion could effectively slove the problem,the irregularity of emissivity of the surface, and eliminate the partiality in the Infrared Nondestructive Testing.