Quantitative validation of finite element models of fibre metal laminate thermo-forming

Finite element modelling has been used to study the forming mechanism of thermoplastic fibre metal laminates (FMLs) at elevated temperatures. Experiments on thermoplastic FMLs with the same settings as the model have been performed, whilst for the first-time digital image correlation (DIC) strain measurements were carried out on the edge of the specimens during the thermoforming process. The finite element model was validated by comparing its outputs with the DIC data using the orthogonal decomposition approach. The shape of the curved tip and the damage on the cohesive bonding surface were measured and compared to model results. A comprehensive understanding was acquired of the forming mechanism of FMLs. The validated model demonstrated good predictions of strain field evolution, interlayer damage, and curved tip radius of specimens at different temperatures. The development of validated models may contribute to the industrial application of FMLs by enabling manufacturers to confidently optimise forming quality whilst maintaining low operating costs.