ABSTRACT
The material subjected to dynamic loading shows higher strength than the static strength of the material. The dynamic increase factor (DIF) gives the relationship of the dynamic to the static strength of the material. DIF's definition is based on the assumption that the strength of the material increases with increasing strain rate. This assumption over-predicts the strength of the material at a higher strain rate. The numerical solution obtained by taking the DIF definition cannot predict the correct behavior of the material under blast and impact loading. Thus, the strain rate-dependent material model has been developed under dynamic loading. The physical mechanism has been considered while defining the dependency of strain rate in the material model. Therefore, the constitutive equation is defined in terms of the viscosity parameter, damage rate and damage. The strain rate-dependent failure surface is defined and the size of the failure surface is limited using the ultimate value. Thus, the accurate dynamic strength of the material can be predicted. The failure surface is defined in terms of load angle to predict the behavior of the material at low and high hydrostatic pressure. The validation of the model is done for the experimental impact results available in the literature. It is observed that the proposed model is capable of predicting the material and mechanical behavior of the material accurately. The split Hopkinson pressure bar (SHPB) analysis is carried out to predict the damage mechanism of the material at a high strain rate.
