一方向 CFRP の非主軸クリープ回復挙動とその負荷履歴依存性

抄録

Effect of loading history on off-axis creep recovery behavior of a unidirectional carbon/epoxy composite has been examined. Off-axis creep recovery tests after a single loading up to a certain stress level are first performed on off-axis specimens with different fiber orientations at high temperature. Then, repeated off-axis recovery tests performed for different number of cycles as well as for different stress levels of poor loading. It is observed that the creep strain after complete unloading of prior stress recovers when the stress level for prior loading is small, while it does not completely recover for the case of a lager prior stress. The amount of creep strain recovery tends to increase with increasing number of loading-unloading cycle, suggesting the history dependence of creep recovery. The test results suggest that the total strain developed with loading consists of the elastic stain, the recoverable creep strain and the unrecoverable plastic strain. It is also observed that the amount of creep strain recovery is proportional to the total strain accumulated.