Mechanical Properties in Notched AS-4/PEEK APC-2 Composite Laminates at Elevated Temperature

Abstract

The response of centrally notched AS-4/PEEK APC-2 composite laminates at elevated temperatures is investigated empirically and systematically. The failure mechanism and mechanical properties in notched cross-ply and quasi-isotropic laminates are perceived. First, the ultimate strength decreases seriously as the hole diameter increases, whereas the longitudinal stiffness changes irregularly. Next, combined with the effect of temperature elevation, the ultimate strength is accelerated to decay while the longitudinal stiffness is reduced slowly. Neglecting the increase in longitudinal stiffness, the worst case of both lay-ups as expected with the largest hole diameter and at the highest temperature still sustains at least 60% of ultimate strength. However, the reduction of strength in cross-ply laminates is more serious than that in quasi-isotropic laminates. Finally, a modified predictive model was proposed and found satisfactorily acceptable. It is also highlighted as a reliable, general, and simple model.