抄録
Repair with bonded fiber-reinforced polymer composite patches has been recognized as an efficient and cost-effective method to extend the service life of aging aircraft. In this paper, a two-dimensional three-layered finite element model consisting of layers of composite patch, adhesive and cracked structural panel is made to analyze the stresses in cracked rectangular structural panels repaired with a bonded circular composite patch. The composite patch and structural panel are modeled as separate layers which are covered with Mindlin plate elements, whereas the adhesive is modeled as a thin elastic layer. The modified crack closure method is used to obtain stress intensity factors at the crack tip. First, by calculating the stress intensity factors, the effects of the diameter and thickness of the circular composite patch on the patching efficiency are examined. The stress intensity factors are also calculated at various hygrothermal conditions and the effect of the environment on the patching efficiency is clarified. Finally, the diagram of patching efficiency is presented to evaluate easily the patching efficiency at hygrothermal conditions.
