Influence of variable-stiffness layup configuration on curing deformation of curved-surface structures

Accurate prediction the curing-induced deformation is the key to the fabrication of high-quality composite structures. Aiming at controlling shape distortion of curved-surface parts during curing process, a layup optimization strategy is proposed based on a variable stiffness (VS) placement method, which uses geodesic curves as fiber-tow paths. Taking an offset parabolic antenna reflector (PAR) for example, chemical shrinkage and thermal deformation of curved-surface composites during the curing process and after demolding are modeled. By combining Fourier heat conduction theory, curing kinetics, and generalized Maxwell viscoelastic model, the interactions between chemical cross-link reaction, heat transfer, and mechanical deformation are taken into account. By comparing the deformation characteristics of VS and traditional constant stiffness structures, the proposed simulation strategy of curing process for composites can predict the factors that influence the curing deformation of VS structures are analyzed. The results show that the maximum of VS PAR decreases by 11.02%, and the average magnitude decreases by 32.35%.