A low cost thermographic NDT system based on long pulse excitation - Development and Evaluation

摘要

A new low-cost thermographic system making use of a miniature ThermoVision A10T microbolometer camera from FLIR Systems and employing long pulse (typically seconds) heating excitation has been developed. Its performance in defect detection has been evaluated using carbon fibre reinforced plastic (CFRP) test pieces containing a range of real and artificial defects. Finite difference modelling has been used to simulate the long pulse excitation technique and to make comparisons with the more widely used short pulse (typically 2 ms) excitation technique. The performance of the new system has been compared with that of the TWI Inc. ThermoScope short pulse excitation system. The defect detectability of both systems has been found to be surprisingly similar using raw unprocessed image data. This is despite the new system camera having a significantly lower thermal sensitivity and lower spatial resolution than the camera used in the ThermoScope system.