Creep Behavior of Symmetric Angle-Ply Laminates of CFRP at High Temperature and Numerical Simulation

Creep behavior of symmetric angle-ply laminates of T 800 H/3631 at high stress and high temperature has been examined. Constant-stress creep tests in tension are performed at 100°C on the plain coupon specimens of three types of angle-ply laminates: [±30]s, [±45]s, [±60]s. For each ply orientation, the creep tests are carried out at three different stress levels. Creep recovery tests are consecutively conducted also for five hours at the same temperature, after completely removing the creep stress for each of the five-hour creep. Creep responses are clearly observed in all kinds of angle-ply laminate. The creep strain rate of the angle-ply laminates tends to rapidly disappear as the creep strain increases. The transient creep is thus dominant for the system, regardless of ply orientation. The creep strain is not completely recovered with time after removing the creep stress. The classical laminated plate theory with a phenomenological viscoplasticity model for plies succeeds in favorably reproducing the creep behavior of the angle-ply CFRP laminates at high stress and high temperature. It is also demonstrated that a consideration of the relative rotation of plies results in better predictions.