OS1301-376 対称アングルプライCFRP積層板の高温におけるサイクル軟化挙動

Abstract

Strain-controlled cyclic behavior of angle-ply CFRP laminates [±θ] at high temperature has been studied. Strain-controlled symmetric tension-compression cyclic tests for different strain amplitudes were carried out on coupon specimens with different fiber orientations (θ = 30°, 35° and 45°), respectively. On the basis of the cyclic tests, the changes of stress amplitude, mean stress, non-elastic strain amplitude, maximum and minimum stress levels and loading and unloading tangent moduli with cyclic straining are examined. The experimental results showed that hysteretic stress-strain response to cyclic straining appears, regardless of the fiber orientation. The stress amplitude decreased with increasing number of cycles, and accordingly the non-elastic strain amplitude increased with cyclic straining. These observations reveal that the cyclic softening occurs in the angle-ply CFRP laminates tested in this study. The cyclic softening terminates rapidly in a small number of cycles, and a cyclic saturation stage is reached in all the strain-controlled cyclic tests, except some cases of large strain amplitude or small fiber orientation angle.