This master thesis report relates the process leading toward the volume optimization of a composite patch repairing a through thickness crack in a metallic plate using the Finite Element software ANSYS. First, two-dimension and three-dimension models are build using ANSYS. Then, validation of the numerical model are done by calculation of the stress intensity factor K of the crack tip, both through the analytical solution and the Anisotropic Elastic Plate – Hwu’s software. The value of the stress intensity factor and the y component of the stress ahead of the crack tip are linked: when the stress decreases, so does the stress intensity factor. Thus, in order to save computational time, the optimization of the repair is conducted such as decreasing the y component of the stress ahead of the crack tip. Different approaches of optimization process are tested. One procedure involves the length, width, thickness and fiber orientation of the composite patch. Another sets the number of layers of composite and leaves the other input value as variables that will change throughout the optimization process. At the end, the final K obtained on the optimal configuration is computed and compared with the initial one to prove the efficiency of the repair.

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