Discrete element method for elastoplastic buckling analysis of single-layer reticulated shells

This paper presents a discrete element plastic zone method which could be recognized as an exact solution compared with the discrete element plastic hinge method. In the method, the contact cross section between two arbitrary adjacent particles is divided into a finite number of monitored subsections, while the spread of plasticity over the cross section is captured by tracing the stress state of each subsection. The incremental section strain formula in the member Discrete Element Method (DEM) is derived first, then the space elastoplastic constitutive equation, the loading and unloading criterion as well as the integral formula of section internal force are established in turn. Either discrete element force control method or the displacement control method for tracing elastic buckling behavior can be employed directly in elastoplastic buckling analysis. Finally, the calculation flowchart of elastoplastic buckling analysis process in DEM is obtained and an object-oriented computer program is compiled by Fortran Language. The computer program is used to investigate the elastoplastic buckling behaviors of several single-layer reticulated shells. The comparisons made have verified the correctness and applicability of the proposed discrete element plastic zone method. Additionally, the application range of DEM in structural engineering is extended and a novel approach for structural analysis is provided.