Investigating the potential of piezoelectric actuator patches for the reduction of fatigue crack propagation in aluminum panels

Fatigue cracks in light weight shell or panel structures may lead to major failures when used for sealing or load carrying purposes. This article investigates the potential of piezoelectric actuator patches that are applied on the surface of an already cracked thin aluminum panel to actively reduce fatigue crack propagation by inducing compression forces near the crack tip. With active reduction of the fatigue crack propagation, uncertainties in the cracked structure's strength, which always remain present even when the structure is used under damage tolerance conditions, e.g. airplane fuselages, will be lowered. The main idea is to lower the cyclic stress intensity factor near the crack tip with actively induced mechanical compression forces by thin piezoelectric actuator patches applied on the panel's surface. This paper discusses the proper placement and alignment of thin piezoelectric actuator patches to induce the compression near the crack tip by numerical simulations