The mechanical properties and fatigue responses of fiber metal nanocomposite laminates with double-edged cracks

Abstract

ABSTRACT The fiber metal laminates (FMLs) of hybrid Ti/APC-2 neat and nanocomposite laminates were fabricated. Geometrically symmetric and anti-symmetric double-edged cracks were cut in FMLs. From tensile tests, we received the load vs. displacement curves, stress intensity factors of mixed mode and mechanical properties. From cyclic tests, the load vs. cycles (P–N) curves, residual life and failure mechanisms were obtained. The mechanical properties of symmetrically cracked specimens were slightly lower than those of anti-symmetrically cracked counterparts. As the crack length increases and inclination angle decreases, the fatigue life decreases. The enhancement of nanopowder improved the ultimate load and fatigue life. The local stress intensity at the crack tip dominates the fatigue responses. The piece of elliptical part was observed from cyclic tests at failure. Although the attraction of two crack tips accelerated the crack growth towards each other, the delay to failure was caused by two crack tips circling around and forming a small piece of ellipse centrally.