A Preliminary Study On Multiscale Simulation Method For Surface Interaction Of Foamed Aluminum

Wider and wider applications of foamed materials are swelling the requirement of precise calculation of surfaces interaction problems.Surfaces interaction problems are not only classical mechanical problems that should be handled in macro-scale,but also physical problems produced by interaction of atoms in micro-scale.The method of multi-scale numerical simulation of surfaces interaction problems of foamed materials was investigated here.The microstructure of a foamed material was numerically modeled corresponding to its different preparation processes.Multi-scale simulation calculations should be based on these accurate numerical models of material histology.Specifically,MC methods corresponding to frothing method and investment casting method were designed and numerically specimens of formed aluminum were obtained through MC simulations.From virtual tests of a number of specimens,the characteristics of dispersion of such mechanical property as elastic modulus of the material were obtained.Based on the thoughts of RVE and FMG methods,huge-atom multiscale connecting method was used with predigested physics potential describing the interactions among huge-atoms to develop a multi-scale simulation method of atom-huge-atom-FE.Based on the microstructure models of material histology obtained by MC simulation,using an elastic FEM program generated by IFEPG,and using GID as pre- and post- processors,an example of multi-scale numerical calculation of pure elastic contact problem of the foamed aluminum was carried out.The results show that the stress concentration occurs on the contact surface of the foamed material,but this condition is not notably related to the deformation of atom and huge-atom scales,it is closely related to the macro-scale holes in the formed material.By using an elastic-plastic FEM program generated by IFEPG,related calculation was performed on the same numerical model in which the plastic deformation was considered only in the macro-scale of FE.The results represented the trend that the max shear stress decreased and the change of shear stress in space was smaller than that in pure elastic simulation because of the plastic zones being in existence.But the programs of elastic-plastic multi-scale simulation are not efficient with this kind of problems and the method of elastic-plastic multi-scale simulation needs to be modified.