The capacity of a sandwich material to adsorb, dissipate and store energy has always been important in problems of low-velocity impact or dynamic loading. In a bi-linear elastic regime, core materials that behave as elastic foundations supporting the face sheets of the sandwich are viscoelastic in the primary elastic regime and elasto-visco-plastic the secondary elastic regime. This paper expands the current derivations of stress in the bi-linear quasi-elastic regime to the response of the material to higher strain rate of input load. A new constitutive equation has been derived which explicitly includes the physical constant, α , the modulus of residual stiffness which characterizes the core material bounded by the face sheets. The results of this equation are presented in this paper for test and predicted data. This includes the correlation of very low strain rate to predicted results at secondary yield, the prediction of design limit curves and specific modulus of residual stiffness and data for Sea State 5 to predict a potential failure regime for high speed US Navy Patrol Vessels. The results of this calculation for stress due to higher strain rate will make it possible to design faster high-speed trains, lighter aircraft structural components and more durable marine vessels operating in a seaway.
展开▼
