Modelling of Process-Induced Deformation for Composite Parts Considering Tool-Part Interaction

Residual stresses are generated by tool-part interaction due to the large difference in the coefficients of thermal expansion (CTE) between the tool and the composite part, resulting in more process-induced part deformation. In this paper, a 3-D numerical model considering the influence of tool-part interaction is proposed to predict the deformation in complex-shape composite parts. In this numerical model, the existing path-dependent model is improved to consider the effect of tool-part interaction by adding the residual stress generated by tool-part interaction, and a simplified self-consistent micromechanics model is selected to predict the composite mechanical properties in the viscous and rubbery stages. The predicted and experimental spring-in angles of L- and U-shaped parts are compared. A good agreement shows the validity of the proposed numerical model. A parametric study is performed and the influence of part structural parameters on the spring-in angle is analyzed quantitatively. The results show that the spring-in angles caused by chemical shrinkage and tool-part interaction decrease with the increase of part thickness, but that caused by thermal contraction is almost constant.