Evaluation of manufacturing deviations of composite materials

Manufacturing induced imperfections in composites lead to a reduction in the performance of the structure. In order to carry out repairs only when they are really necessary, evaluation capabilities to determine the strength reduction are required. Two methods of evaluation are presented: a finite element based and a Peridynamic based approach, respectively. The finite element based process is used to evaluate stiffness and strength reduction. This processes currently doesn't include progressive failure analysis. Hence, the peridynamics process serves among other things to verify the prediction by the finite element model. Because, the correspondence formulation is used, integral Cauchy stresses are obtained for the laminate and can be verified. Progressive failure analysis is then used to evaluate whether the first ply failure approach used in the finite element model is accurate enough to ensure strength reduction values.