Stress projection procedure for the form-finding analysis of membrane structures

Abstract

This study examines the form-finding analysis of membrane structures and presents a new general method for determining prestress called stress projection. This method addresses several deficiencies while performing the form-finding analysis, especially in the case of conical membrane structures. A key feature of the proposed stress projection procedure is the adoption of a generally oriented projection plane, where finite elements are projected onto, and the determination of their stress states, which allows for a smooth adaptation of stresses over the membrane structures. Deformation gradients are then evaluated with respect to this projection plane, as opposed to the inertial reference frame used for the computation of stress tensors in subsequent form-finding processes.The proposed stress projection procedure efficiently modifies the stresses over the structures and significantly addresses intrinsic element distortion problems within the form-finding analysis. Thus, the proposed method allows for the maintenance of regularized finite element shapes and the smooth changing of stress states throughout form-finding iteration processes, especially for conical membrane shapes. Numerical experiments demonstrate the efficiency of the implemented stress projection scheme compared with two well-known stress adaptation schemes.