INFLUENCE OF WATER ABSORPTION ON FLEXURAL FATIGUE STRENGTH FOR CFRP LAMINATES WITH DIFFERENT WEAVE STRUCTURE

摘要

Our proposed accelerated testing methodology for the long-term durability of polymer composites is based on the time-temperature superposition principle to be held for the viscoelasticity of polymer matrix. This paper is concerned with the influence of water absorption on the time-temperature dependent flexural fatigue strength of two kinds of CFRP laminates, flat yarn plain-woven carbon fiber/vinylester resin (T700/VE:F) and multi-axial knitted fabric carbon fiber/vinylester resin (T700/VE:K). These CFRP laminates were treated under the three conditions, Dry, Wet, and Wet+Dry. The three-point bending constant strain-rate (CSR) and fatigue tests for these specimens were carried out under various loading rates and temperatures. It is cleared that the flexural CSR and fatigue strengths for these CFRP laminates strongly depends on water absorption as well as time and temperature, and that the time-temperature superposition principle for viscoelastic behavior of VE resin holds for these flexural strengths under water absorption condition.