The control of process-induced deformations in composite structures is important for cost-effective manufacturing. In recent years, significant advances have been made in predicting the average deformation behaviour, but little work has been done in predicting the variability, which results from uncertainties in both the raw material properties and the manufacturing process conditions. A probability-based approach is presented in this paper for predicting the variability of process-induced deformations. A two-dimensional finite element code, which deterministically simulates the various physical phenomena during processing of composite structures, is integrated with a first-order reliability analysis method to calculate the probability of the deformations exceeding a specified allowable tolerance. The methodology is demonstrated through two case studies. In the first study, a probabilistic description of the process-induced spring-in of a channel section is achieved and the effect of variability in material properties on the final channel angle is studied. In the second study, the optimal tool-shape for the channel section is determined by coupling reliability analysis with a simple cost model of the manufacturing process.
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