Time and Temperature Dependent Stress-strain Behavior of Unidirectional Carbon Fiber/Polyimide Composites Under On-axis and Off-axis Tensile Loading

摘要

Phenylethynyl terminated polyimide “TriA-X” developed in Japan AerospaceExploration Agency (JAXA) exhibits excellent mechanical properties with high glasstransition temperature (> 350 °C), therefore it is suitable as matrix resin of hightemperature composites. However, the time and temperature dependent mechanicalproperties have not been investigated. This study examined the mechanical behavior ofunidirectional (UD) carbon fiber (CF)/ TriA-X polyimide composites by off-axismonotonic tensile tests and off-axis tensile creep tests. As results, it was revealed thatone parameter plasticity model by Sun and Chen was effective to represent the nonlinearstress-strain behavior of UD-CF/ TriA-X composites. Furthermore, linear viscoelasticbehavior was observed from the off-axis tensile creep tests of UD-CF/ TriA-Xcomposites. On the other hand, residual strain was observed in creep recovery curvesafter unloading, which suggested that the creep and creep recovery behaviors of UDCF/TriA-X composites are not affected only by viscoelastic and plastic deformation,but also by viscoplastic deformation.