Finite element simulation of impulsive drawing of square cups

摘要

A FE model is developed to simulate the impulsive deep drawing of a brass square cup. In practice, the loading of the assembly is achieved by the detonation of a high explosive, under water. Direct energy transfer to the brass plate gives rise to material instability and material failure resulting in non-uniform material thickness over the formed region. To remedy this, a lead plug is incorporated to slow down the forming process by acting as a reservoir for the kinetic energy. As the deformation progresses, kinetic energy in the plug is transferred to the plate and the prolonged time scale of the operation enables the system to approach to a quasi static forming process. The temporal loading profile is diminishing, as: p(t) =P{sub}(max) exp(-t/θ)(1) where P{sub}(max) and θ are dependant constants as defined in the load definition section. The effects of the medium impedance, wave reflection and refraction are considered to be negligible in order to achieve a relatively simple modelling procedure.