A large displacement orthotropic viscoelastic model for manufacturing-induced distortions in Fibre Metal Laminates

Distortions and residual stresses are predicted in Fibre Metal Laminates (FMLs) under large deformations. A new modelling procedure is presented for small and large deformation analysis of thermo-viscoelastic problems of orthotropic materials. The material model is implemented in a finite element package which can be used for cure and/or temperature dependent response of composites undergoing large rotations but with small strains.Temperature-dependent and viscoelastic responses are characterised for GLARE, as the mostly used type of FMLs. The geometrically nonlinear thermo-viscoelastic model is used to predict the manufacturing-induced warpage of panels. The curing stresses are calculated from a previously developed model accounting for chemical shrinkage and stiffness evolution of the prepreg layers during cure. The shape deviation of some non-symmetric GLARE panels are predicted and compared to the real measurement of fabricated laminates. The accuracy of the model is verified which can be used in further studies to improve the precision of manufacturing and assembly and also to have better prediction of the fatigue life and residual strength.