Fracture Mechanics Based Life Prediction of High Temperature Composite Joints

An important aspect in the design of aircraft structure and aeropropulsion components made of high temperature composite materials is damage tolerance and life prediction. Many components contain joints between composites and metals. There is a need to develop methods for predicting life of such components and then implementing the methods in software for design calculations on computers. The proposed research addresses this need. Specifically, Phase I has the objective of assessing the feasibility of a model formulated by AdTech to perdict crack growth rates associated with fabrication or service induced cracks within joints. A combined mechanics of composites, interface fracture mechanics and experimental approach is proposed. Experiments will be performed using joints of a titanium matrix composite. If found feasible, Phase II will involve data base generation, further validation and implementation of the model in a general design and life prediction methodology which may involve a probabilistic framework. The methodology will be implemented in a user friendly software package.