Structural Optimization of a Composite Plate Subjected to a Small Mass Impact

This paper presents the optimization of a composite plate subjected to a small mass impact under a mode II delamination constraint, considering impact response and delamination threshold load predicted by closed form solutions. These solutions are inexpensive from a computational point of view and have good agreement with experimental data. Therefore, this approach can be very interesting when working with optimization methods that require a large number of iterations to converge. On other hand, the closed form solutions have implicit limitations. An example is the plate and impactor masses ratio that must be within a defined range, otherwise the impact model does not apply. Consequently, the plate optimization problem must be well stated and constrained in order to provide results comprised in the closed form solutions validity. In this work, the optimization problem and solution are stated and discussed. The optimization method employed is the simulated annealing, together with appropriate optimization heuristics. Final optimization results are validated by finite element analysis with the capability of predicting damage by mixed-mode delamination in composites under impact. The results obtained using the proposed optimization procedures agree remarkably well with the finite element predictions.