Moisture absorption/desorption effects on flexural properties of GFRP laminates

Abstract:

To investigate the influence of moisture absorption/desorption on the flexural property degradation of glass fiber reinforced polymer (GFRP) laminates under hot/wet aging environments, three-point bending tests were carried out. The flexural properties of specimens were compared under dry, unsaturated, and saturated water absorption conditions at test temperatures 20 ℃ and 40 ℃. A moisture absorption-desorption process was considered as a cycle to investigate the mechanical degradation and permanent damage of GFRP laminates induced by moisture diffusion. Experimental results show that the combination effects of moisture and temperature reduced the flexural strength and elastic modulus of GFRP laminates, and the reduction rate of flexural strength was much larger than that of elastic modulus. At the test temperature of 40 ℃, unrecoverable losses of elastic modulus (15.0%) and flexural strength (16.4%) occurred for GFRP laminates experiencing one cycle of moisture absorption-desorption process, which was not evident at the test temperature of 20 ℃.Moreover,a coupled hygro-mechanical finite element (FE) model was developed to characterize the mechanical behaviors of GFRP laminates at different moisture absorption/desorption stages, and was subsequently validated with flexural test results.