Bi-layered materials are a reduced weight derivative of the sandwich structure and are comprised of one thin skin face reinforced by a thick layer of low density material. Bi-layered materials are characterized by high flexural stiffness and are a viable alternative to conventional sandwich materials in applications where the functional requirements can be met without the second face sheet of the sandwich. For structural applications bi-layered materials are required to have oil canning and buckling resistance. This work addresses the buckling of shallow bi-layered arches using numerical and analytical approaches. A numerical, finite element model is developed to simulate the buckling phenomenon and the results were compared with known experimental data. An analytical model was developed using the energy method analysis and the buckling load was predicted from the minimum energy criterion. Comparison of the numerical and analytical results yielded fairly good agreement. An imperfection analysis conducted by means of the numerical model indicated that the load carrying capacity of bi-layered structures is reduced by up to 40% due to the presence of material and geometric imperfections. A parametric study conducted using the analytical model has been described to setup design guidelines for shallow bi-layered arches. It was found that the use of bi-layered structures can result in weight reduction of around 70% when compared with equivalent single layered structure.
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