Inelastic Buckling of Prestressed Sandwich or Homogeneous Arches

Abstract

Inelastic buckling of prestressed homogeneous and sandwich arches is studied using a nonlinear finite element model. Prestressed arches are made by intentional buckling of thin struts into elastica shapes. In the case of sandwich construction, each layer is first buckled into shape, then the prebuckled layers are connected to form a composite section. The fabrication process is modeled by a special algorithm that accounts for the change in element type from three single-layer homogeneous elements into a single three-layer sandwich beam element. A corotational formulation is used for the large displacement, large rotation analysis of an elastic, linear strain-hardening material. Shear deformations and membrane and flexural rigidities of all layers are included. A parametric study is carried out to include the effects of plastic tangent modulus, relative thickness of the core layer, and the ratio of prestress to the yield stress of the material. Symmetrical and asymmetrical buckling modes are both considered. The results indicate that plastification of the facings could reduce the buckling loads by as much as 55% compared to the linear elastic buckling loads.