Numerical modelling and full-field measurement of composite laminates under blast load

The dynamic response of Fibre Reinforced Polymers (FRP) under blast loads is actively studied due to the increasing use of these materials and the arising risks of being subjected to accidental and intentional explosions. In the context of material identification by means of mixed numerical/experimental technics, the repeatability of the tests and the accurate modelling of the boundary and initial experimental conditions are key factors. The discussion of these two factors is the main topic of this paper. The results of a series of blast tests on fully clamped square glass fibre reinforced epoxy panels are presented. An explosive driven shock tube (EDST) is used to generate uniform blast loadings with different pressure-impulse combinations. First, experiments are performed on an assumed rigid target provided with pressure transducers to measure the pressure history and distribution which, also, allows assessing the planarity and repeatability of the loading. Then, the dynamic responses of the specimens are measured with a high-speed 3D-DIC system and the failure modes are described. The laminates are modelled in LS-Dyna using Belytschko-Tsay four-node shell elements and the loading is modelled with a pressure history distribution fitted from experimental measurements. The experimental measurements are compared to the numerical results for three material models with different failure criteria.