Toward customized flexural properties of additively manufactured architected lattice beams via grading struts cross-section and targeted designed unit cell distributions

Abstract

Purpose The purpose of this paper is the study of flexural properties of architected lattice beams composed of modified body-centered cubic (BCC) structures when such are additively manufactured with the liquid crystal display method. The BCC topology was modified by grading the dimensions of the cross-sections of the struts that compose them and their targeted distribution within the lattice beam. Design/methodology/approach Six gradations of strut cross-sections were proposed, and their effective stiffness was evaluated in compression finite element (FE) simulations. These were compared and categorized according to their stiffness. Then, these were distributed and arranged in a targeted manner, following two approaches: longitudinal and transversal. Experimental three-point bending tests and FE simulations were performed to characterize their effective flexural properties. The properties of targeted distributions were contrasted with those of uniform distributions. Findings Although the structures with longitudinal and transverse distribution presented the same relative density, they demonstrated different stiffness and strength. Beams with longitudinal distribution were 77% stiffer than those with transverse distribution. The method proposed here demonstrates how the effective mechanical properties and failure modes can be tailored by modifying the material arrangement in engineered structures while keeping the amount of material used constant. Originality/value The flexural properties of lattice beams with two types of grading and unit cell arrangements were studied. The literature has not deeply studied such a double degree of matter distribution and arrangement in structures.