Damage occurrence under dynamic loading for strain rate sensitive materials

To predict damage evolution occurring under dynamic loading, a damage model is implemented inside the explicit finite element framework. The damage model is based on the description of the growth, the nucleation and the coalescence of the microvoids. The microvoid growth is related to the plastic incompressibility relation. The microvoid nucleation is either controlled by the plastic strain or by the stress. The microvoid coalescence is described by a specific function. This damage process leads to the progressive loss of the stress carrying capacity of the structure. The ductile fracture occurs when the stress carrying capacity of the structure vanishes. The sensitivity of damage volution under dynamic loading in the case of porous strain rate sensitive material is analysed using single tensile tests. The dynamic bending test of a cantilever beam with a U-cross-section is performed. The influence of the strain rate on the deformed shape and on the loss of the structure's stress carrying capacity is shown.