The Study And Application Of Pulsed Excitation-device With Flashing Lamps Array Based On Infrared Thermal Wave Nondestructive Testing System

In recent years, Infrared Thermal Waves Imaging(TWI) has emerged as a widely used method for Nondestructive Testing(NDT). Using the technology we can inspect the sample which is excited by exterior energy with flashing lamps, the subsequent change of surface temperature of the sample is monitored by an infrared camera, then sequence of thermal wave signal and data acquisition are processed using the computer,at last, real-time image signal processing and the analysis are carried on by the software. Not only can it perform non-contact,wide area detection of subsurface defects, but also it can measure thickness of paint.Heat excitation technology is the key to inspect. In this thesis,the setup of infrared thermal wave system and the new heat excitation-device will be presented,the key technology is the heat excitation-device which is made of the Neon Lamps as synchronization heating excitation source and is developed independently by the author. In order to improve the heating device, effective and new heating excited method is prerequisite.Some qualities of the technology like simple structure, lower power, portable, lower expenses and costs, and so on,make the device novel and effective. Especially, the much narrowed pulse width can separate the weak signal better from the submerged saturation signal when heating. Using the advantages of the device to study and analyze these folium materials,such as paint layer,membrane materials, characterized by the large area coating with the depth in one millimeter order, etc. Two typical samples are taken as research object, which are covered with different thickness paint layers on the surface of aluminum. Analyzing the experimental thermal curve which were based on the thermography of the samples according to the thermal wave theory, we can detect the homogeneity of thin layer object and measure the layer thickness quantitatively.The experimental results shows that the new heat excitation-device can measure the sample with thin thickness in both micron and millimeter order quantitatively. At the same time,measurement result can be shown by thermography.It is important for the excitation-device to be applied in the industry and the military research field.