QIU Xu1，ZHONG Shun-cong1，2，3，ZHU Zhi-bin4，5，FU Xi-bin5

（1. School of Mechanical Engineering and Automation，Fuzhou University，Fuzhou 350108，China；

2. Fujian Key Laboratory of Medical Instrument and Pharmaceutical Technology，Fuzhou 350002，China；

3. Key Laboratory of Safety Science of Pressurized System of Ministry of Education，East China University

of Science and Technology，Shanghai 200237，China；

4. School of Chemical Engineering，Fuzhou University，Fuzhou 350108，China；

5. Xiamen Special Equipment Inspection Institute，Xiamen 361000，China）

Abstract：Aiming at defect detection of polyethylene（PE）pipes，finite element method was used to simulate transient heat transfer in PE Pipes. In the computational model，constant heat flux boundary condition was applied to the internal surface of the PE pipes. The internal defects would affect the temperature distributions on the external surface of PE pipes and，therefore the relationships between the by an electrical heating bar，was built for the verification of the FE model for defect detection of PE pipes. A high speed infrared camera

with high sensitivity was employed as a detector. The temperature curves at the positions of defects with different dimensions were obtained and compared. The FE simulation results well agreed with the one obtained from the infrared imaging experiments. The results indicate that finite element numerical method can be an effective method to analyze infrared imaging，it can provide the numerical model for thermal imaging based defect detection and precise theoretical foundations of using infrared thermography in non-destructive testing.

Key words：polyethylene（PE） pipes；internal defect；infrared thermography；finite element simulation；nondestructive testing and

evaluation