Wave propagation in glass fibre-reinforced polymer (GFRP) bars subjected to progressive damage-Experimental and numerical results

Glass fibre reinforced polymer (GFRP) is a material of increasing interest in civil engineering applications. It is used as internal reinforcement for concrete structures (especially in extremely corrosive environments), as well as structural profiles, plates, and gratings. However, estimating the life of GFRP structures represents a challenge for the construction industry. To address this challenge, a numerical model of elastic wave propagation in GFRP bars is presented in this paper so that it can be used to reduce the number of physical testing required to estimate the degradation of GFRP bars in the field. The proposed numerical model is designed to assist the application of ultrasonic non-destructive testing (NDT) techniques and develop a framework for the evaluation of progressive damage of GFRP bars due to a highly alkaline environment. The proposed methodology consists of: (i) development and calibration of a numerical model of elastic wave propagation in GFRP bars in Abaqus, (ii) simulation of deterioration of the bars, and (iii) comparison of experimental, large and low strain tests (shear test and ultrasonic evaluation) with results of numerical simulations. The results show that the model (low strain properties) correctly captures the deterioration rates seen in the shear strength test (large strains). The model is used to study ultrasonic features and demonstrates that low strain measurements (e.g. wave dispersion, wave amplitude) can be used to estimate the effect of progressive damage on large strain properties in GFRP bars, which can result in a decreased number of required destructive tests.