nonlinear deformation analysis and modeling of composite with aluminum layers

fiber metal laminates (fmls) are new composite materials consisting of thin metal layers and high strength composite layers. arall (aramid aluminum laminate) is a family of the fml that consists of thin aluminum sheets along with kevlar/epoxy composite layers. this material has many advantages such as light weight, excellent corrosion, fatigue and impact resistance. since, arall is a new material, therefore presentation of a model for nonlinear behavior analysis is important. this paper presents the elastic– plastic behavior of arall under in- plane tensile loading. for this purpose, the orthotropic plasticity theory and modified classical laminated plate theory are used. in the orthotropic plasticity model, a three parameter plastic potential function is used. in the second theory, the kevlar/epoxy composite layers and aluminum sheets are assumed to be linearly elastic and orthotropic elastic– plastic solids, respectively. good agreement is obtained between results of two models. the results show that the case study behavior is almost bilinear under tensile loading and it has more strength in longitudinal direction in comparison to transverse direction. variation of the poisson’s ratio is considered in longitudinal and transverse loading too.