Large, plastic deformation behavior of lattice structure in compression

Lattice structures have garnered significant attention in industrial applications due to their exceptional mechanical properties and superior energy absorption capabilities. The nonlinear response of these structures under extreme loading conditions can critically influence their mechanical performance and safety. However, existing research mostly focuses on their properties in the elastic range, and only limited studies have been conducted on the large, plastic deformation behavior of lattice structures. This work provides a comprehensive investigation of the complete large plastic deformation process, including the stabilization effects of strain hardening and its influence on collapse mechanisms. In this study, their large, plastic deformation behaviour was studied experimentally and theoretically. Steel BCC lattice structures were fabricated by using selective laser melting (SLM) and tested in compression. Also, an analytical framework was developed based on an idealized deformation mechanism, incorporating two material constitutive models: a rigid-perfectly plastic model and a rigid-linear hardening model. For the linear hardening model, a characteristic length parameter (λd) was introduced to represent the extended plastic deformation zone. The analytical model was validated through finite element (FE) analysis and experimental methods. Applicability of the proposed model to lattice structures was thoroughly discussed by considering different geometrical parameters.