THERMOELASTICITY: The use of thermoelastic stress analysis to identify defects in polymeric materials

Author: Calvert Geoff   Smith Gordon   Thomson Barry  

Publisher: The British Institute of Non-Destructive Testing

ISSN: 1354-2575

Source: Insight - Non-Destructive Testing and Condition Monitoring, Vol.46, Iss.9, 2004-09, pp. : 550-553

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The work described here emerged from an EPSRC-funded programme investigating the thermomechanical ageing of selected engineering plastics used in the offshore oil & gas industry. The polymers investigated are PEEK and PEK, materials of the polyaryletherketone family. The latest infrared array thermoelastic camera, coupled with an innovative five-times magnification zoom lens, was used to identify and quantify sub-surface defects in the materials, which had been aged in high pressure gas environments at elevated temperatures. The results were subsequently verified using a scanning electron microscope. The work demonstrates that Thermoelastic Stress Analysis (TSA) is a powerful technique, capable of identifying defects of less than 100 microns in size. The observed defects arise from so-called explosive decompression (ED) damage; here absorbed pressurised gas can cause swelling, blistering and fracturing of non-metallic materials when the external pressure is rapidly reduced. ED is a significant industry issue for sealing elastomers, meaning that thermoplastics receive relatively little research attention.

Related content