Dynamic Performance Of Metal Foam Impact Study

Because of its unique structures, foams metal has a lot of excellent properties such as exceed-light in weighty, high strength rates, sound -absorption, sound-insulation, heating-insulation, heating-scattering, fire retardant,vibration-reducing, impact energy absorbing and electromagnetion shield and so on. In some fields such as aerospace, automobile and building, foams metal has broad application prospect. So the investigation on the properties of foams metal, especially the investigation on the impact dynamics properties when they are used as safeguard material, has important theory signification and application value.This paper is engaged in research as follows:1. The research results on static mechanical properties of foams metal in recent years are summarized,including the static mechanical properties, the influencing factors and the static constitutive relations of foams metal .2. The research results on dynamics properties of foams metal in recent years are summarized. The influencing factors analyzed could be divided into two types, external factor and the internal one. The external factor included the strain rate and effect of aging treatment, the internal one included the matrix properties and relative density and so on.3. By using the FEM software LS-DYNA and the Power Lawer model , numerical simulation of deformation process of cell model with circinal hole or cubic hole are made separately under impact load,the influencing factors of impact dynamics properties,include hole structure, relative density and impact velocity are dicussed.Conclusions obtained as follows:1,Hole structure is important to deformation mechanism of foam metal.When the strain is small ,plastic yield is the main deformation to the circinal structure, elastic bend is the main deformation to the cubic one;when the strain is big enough,to the circinal hole, collapse happened,and to the cubic one,buckling happened.2,Obvious asymmetric phenomenon appeared in the deformation process of foam metal with circinal hole or cubic hole,average stress and macroscopical average strain near the contact surface is higer than that of whole level.3,Transmition of wave in the impact course is ignored ,energy which was translated into kinetic energy of foam metal played an import role in the process of energy absorption.4,Beside hole structure, relative density also affects the stability of foam metal,when the relative density is lower than 0.3, bucking happened easily.5,Aluminum foam has strain-rate sensitivity,it's yield stress is enhanced when the impact velocity is increased.