Analysis of Deformation and Residual Stresses in Composites Processed on a Carbon Foam Tooling

Carbon foam is a low cost, durable, light-weight material with a low coefficient of thermal expansion (CTE) and it has cure process compatibility with aerospace composites. Therefore, carbon foam is being investigated as an alternative to traditional composite tooling material for aerospace applications. However, the dramatic differences in properties between traditional tooling materials and carbon foam makes it difficult to fully predict the performance of this novel material as a tooling alternative. This article is a comparative analytical study of the effects of processing of composite geometries on a carbon foam tooling vs. conventional tooling materials. Simulation is carried out on graphite-epoxy composite system using a carbon foam tooling and the stresses and the resulting deformations are predicted for three different geometric features of composites. The results show that both the lower CTE and modulus of the carbon foam tooling can contribute to a reduction of residual stresses in the part and the tooling; however, the mechanical strength of the foam needs to be considered in the tooling design.