DEVELOPMENT OF FLAW DETECTING SYSTEM BY INFRARED THERMOGRAPHY

（1）针对构件内部的裂纹缺陷，研究了不同的加热或冷却方法。高频涡流加热是最合适的方法。(2)大于2.0mm的疲劳裂纹可以通过带放大镜的红外热成像检测到。(3)开发了一个图像处理专家系统，以获得清晰的裂纹图像。(4)由于检测到蜂窝夹层结构中的缺陷，已经检查了用于加热或冷却试样的各种方法。用带有蓄热器的硅橡胶加热器加热是最合适的方法。(5)已证实，该方法是有用的，以检测各种缺陷的蜂窝夹层结构，可以在各自的制造过程中造成的。(6)可以检测出尺寸大于蜂窝芯尺寸的缺陷。(7)开发的图像处理方法揭示了蜂窝状结构和不清晰的缺陷。(8)本文编制了一个三维有限元程序，对结构墙体的缺陷进行了热传导分析。

In this research project, the following results have been gotten :(1) Due to a detection of cracks embedded in the structural members, various methods for heating or cooling the specimen have been examined. Heating by high-frequency eddy current is the best suited method.(2) More than 2.0mm fatigue cracks can be detected by an infrared thermography with a magnifying glass.(3) An image-processing expert system has been developed to obtain definite images of the cracks.(4) Due to a detection of flaws in honeycomb sandwich constructions, various methods for heating or cooling the specimen have been examined. Heating by a silicone rubber heater with a heat accumulator is the best suited method.(5) It has been confirmed that this method is useful to detect of various flaws in honeycomb sandwich constructions which can be caused in the respective manufacturing process.(6) Flaws of which sizes are larger than the honeycomb core size can be detected.(7) The developed image-processing method reveals the honeycomb structure and unclear flaws.(8) A three-dimensional finite element method program has been developed to carry out the heat conduction for the detection of flaws in a structural wall.