COMPRESSIVE FAILURE ANALYSIS AND EXPERIMENTAL RESULTS FOR A CARBON/EPOXY COMPOSITE CURED AT DIFFERENT ISOTHERMAL TEMPERATURES

摘要

This paper presents compressive failure analysis and experimental results for a commercial carbon fiber prepreg (977-2 UD) cured at different isothermal cure temperatures. To obtain mechanical properties, compressive strength, and also stress-strain curves, Combined Loading Compression (CLC) test was performed on coupons cut from five panels laid up in 0/90/90/0 order and cured at different isothermal temperatures. Different failure criteria including maximum stress, maximum strain and Tsai-Wu criteria were studied to investigate how well these criteria describe the failure of the material based on the experimental results. The theoretical compressive stress-strain curves, obtained by Classical Laminate Theory (CLT), were compared with the experimental data for specimens cured at different isothermal cure temperatures. It was observed that, for relatively wide range of isothermal cure temperature, the final compressive strength of 977-2 specimens showed no significant variation by changing the curing temperature up to a certain level. Also, it was found that the predicted strength was in good agreement with the experimental failure results. Nonlinearity was observed in the stress-strain curves obtained by CLC test. However, the experimental curves were in satisfactory agreement with the ones obtained using classical laminate theory.