Constrained Stochastic Imperfection Modal Method for Nonlinear Buckling Analysis of Single-Layer Reticulated Shells

Abstract

Single-layer reticulated shells (SLRSs) are highly sensitive to initial geometric imperfections (IGIs) with respect to their nonlinear buckling behavior. However, the traditional random imperfection modal method assumes the joint deviations to be independent, which leads to the member length deviations always exceeding the manufacturing error limit given by design codes, i.e., the IGIs are unrealistic, and the nonlinear buckling load must be inaccurate. This paper proposes a simple and efficient method to generate stochastic IGIs for SLRSs considering topology constraints. By applying nonlinear heuristically perturbed virtual interaction forces to the joints, the joint coordinates can be updated using the iterative forward Euler method, aiming to generate realistic stochastic IGIs. Numerical experiments show that all the members in the IGIs generated by the proposed method satisfy the topology constraint, resulting in more significant out-of-plane joint deviations. Moreover, compared with the traditional method, the proposed method has better potential to search for the lower boundary of the nonlinear buckling load of SLRSs.