Detection of failures in plastic composites using thermography

Composite materials can show their advantages effectively only when material and structure have no failure. To ensure the quality of products, non-destructive testing (NDT) must be executed. Usually non-contact NDT-methods are preferred, and possible methods are thermography, radiography and holography. The most common contact method is ultrasonic. This paper presents results of detecting sub-surface defects from plastic composites using thermography. We have examined glass-fiber reinforced composites, which have several flaws occurring during manufacture. The results of thermography have been verified by using ultrasound or by cutting the specimen. Experimental results show that flaws can be detected if the wall thickness of the object is small enough and delamination-like failure is bigger than wall thickness.