Ultrasonic Inspection for aging monitoring of GFRP composites

Abstract

The use of composite materials has been an option increasingly used in various industry sectors. However, the degradation process by which these materials are subjected due to operational conditions is a reality that makes monitoring a challenge. In this work, conventional ultrasonic technique was used to analyse the behaviour of GFRP pipes under different aging conditions (temperature and pressure). The pipes were submitted to aging for 2, 6 and 18 months and acoustic measurements were performed in certain areas of each pipe in order to monitor the relevant locations, both in circumference and in length. The gathering of these signals was carried out periodically throughout the aging process. Through the methodology presented in this work regarding ultrasonic inspection, it was possible to correlate the acoustic properties obtained with the mechanical properties of the material during aging. Additionally, after the end of the aging process and occasional failures, some samples were extracted to perform tensile tests, which were able to indicate residual Young Modulus in the axial direction. Sound testing for mechanical characterization were also performed and their results were compared to the ones calculated by ultrasonic results. Microstructure of the material and its manufacturing process were also found to be important parameters that must be considered. The experimental database obtained were analysed using statistical tools to evaluate the feasibility of a trend model in the behaviour of material properties during aging.