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An explicit 3D Finite Element (FE) model was developed in the LS-Dyna code to simulate the laser shock paint stripping on aircraft aluminum substrates. The main objective of the model is to explain the physical mechanisms of the laser shock stripping process in terms of shock wave propagation, stress and strain evolution and stripping shape and size and to evaluate the effects of laser and material parameters on the stripping pattern. To simulate the behavior of aluminum, the Johnson–Cook plasticity model and the Gruneisen equation of state were applied. To simulate stripping, the cohesive zone modeling method was applied. The FE model was compared successfully against experiments in terms of back-face velocity profiles. The parameters considered in the study are the aluminum thickness, the epoxy paint thickness, the laser spot diameter, the fracture toughness of the aluminum/epoxy interface and the maximum applied pressure. In all cases, a circular solid or hollow stripping pattern was predicted, which agrees with the experimental findings. All parameters were found to affect the stripping pattern. The numerical results could be used for the design of selective laser shock stripping tests.

This paper presents an innovative methodology of material characterization under high strain rate (order of 107s-1) laser shock loading coupled with microstructural and mechanical material features. To that scope, experimental and simulation analyses have been conducted for Al alloys (AA7075-T6 and AA2017-T4) and dissimilar Friction Stir Welded (FSWed) AA7075-AA2017 joint, under shock pressure of 4.5 GPa (laser power density of 3.5 GW/cm2). In order to perform proper in-depth material model simulation of these alloys and dissimilar pairs, Johnson–Cook (J-C) material model has been coupled with Grüneisen equation of state using the non-linear explicit code LS-DYNA. For the first time, we provided a way to differentiate between material behaviour in the cross-section and the in-plane rolling and welding direction. What is more, we have provided the link between microstructural features and mechanical properties such as microhardness, residual stresses and the identified material parameters. By achieving this goal, the bigger difference between studied planes was confirmed for strain hardening modulus, strain hardening exponent and strain rate sensitivity parameters. Obtained results and proposed methodology indicate high potential to predict material properties and behaviour of dynamically stressed parts and at the same time can be used for optimization of LSP process.