Experiments Method Design Applied to Optimization of Patch Repairs for Cracked Plates

The optimization of the patch shape of bonded composite repair in aircraft structures is an efficient way to improve the repair performance. In this study the three-dimensional nonlinear finite element method is used to determine the J integral variation along the front of repaired crack with bonded composite patch in aircraft structures. The experimental design method was applied to optimize the patch shape and size in order to determine the most influencing dimension on the repair efficiency.

Fatigue Life Prediction for Cord-Rubber Composite Tires Using a Global-Local Finite Element Method

A failure analysis, based on fracture mechanics, may be useful for predicting the lifetime of a cord-reinforced rubber composite pneumatic tire. This paper presents a new three-dimensional Finite Element (FE) local model to calculate the energy release rate at the belt edge region. The new local model uses a three-dimensional (3D) Finite Element Modeling (FEM) fracture analysis based on a steady-state rolling assumption, in conjunction with a global-local technique in ABAQUS. Within the local model, a J-integral variation study is performed in the crack region. This consists of a prediction of the crack propagation direction and a mesh density analysis of the crack model. Furthermore, the study is used to determine the crack growth rate analysis. This study assumes that a flaw exists inside the tire, in the local model, due to a mechanical inhomogeneity introduced in the manufacturing of the tire. This paper also considers how different driving conditions, such as free-rolling, braking and traction, contribute to the detrimental effects of belt separation in tire failure.