Non-Destructive Inspection of TCPs Using Pulse-Echo Ultrasound and X-Ray Microcomputed Tomography Techniques

Abstract

Thermoplastic composite pipes (TCPs) have potential applications in offshore oil and gas industries because of their strength, lack of corrosion, and flexibility. Designed for fluid transportation in high-pressure and high-temperature environments, manufacturing defects and operational loads can compromise their performance. However, their material composition and thickness make conventional non-destructive testing (NDT) methods ineffective, highlighting a gap in the literature on suitable inspection techniques. This study aims to evaluate the effectiveness of the pulse-echo ultrasound technique and X-ray microtomography (micro-CT) in detecting defects in TCPs. Two samples were analyzed, each consisting of two outer layers of PVDF and an inner layer of carbon fiber-reinforced PVDF. The layer thicknesses, from outer to inner, measured 5.74, 18.86, and 4.48 mm. Based on the evaluated samples and the results obtained, the pulse-echo technique proved effective in detecting defects at depths of up to 18 mm, as well as their corresponding locations in the samples. Micro-CT provided a three-dimensional representation of the discontinuities, offering detailed insights into the spatial distribution and connectivity of structural delaminations. The combination of the analyses conducted using these two non-destructive techniques becomes a valuable tool for evaluating their impact on the mechanical performance of TCPs.