Finite Element-Based Modeling of Stress Distribution in 3D-Printed Lattice Structures

Abstract

Additive manufacturing, or AM in short, is sweeping the design and fabrication of lattice structures into a new era, yielding lightweight components with high mechanical performance tailored to specific aerospace, biomedical, and engineering applications. One of the most competent production processes within various AM technologies for manufacturing precise metallic lattices with a well defined microarchitecture is the Selective Laser Melting (SLM). However, their geometrical complexity and process induced anisotropy make the mechanical behavior of such structures, specifically, stress distribution under operational loads inadequately understood. In this work we develop a complete finite element method (FEM) based modeling framework to study stress distribution in 3D printed lattice structures that are based on Body-Centered Cubic (BCC), Face-Centered Cubic (FCC) and Triply Periodic Minimal Surface (TPMS) designs. Coupled FEM simulations were carried out in both axial compression and torsional loading conditions to reveal critical stress zones, to investigate deformation patterns, and to examine the effect of geometrical topology on structural response. Material properties for AlSi10Mg are considered, and realistic boundary conditions are assumed to ensure accuracy of results. To validate the proposed analytical fits, strain gauge instrumentation and uniaxial compression tests were performed on SLM fabricated samples, and the results exhibit good agreement with FEM predictions and a maximum deviation less than 8.5%. These show that the TPMS-based structures have a better capacity for both stress distribution and load sharing over traditional strut based geometries. The developed methodology provides a robust means of mechanical evaluation and design optimization of lattice structures, which is beneficial to the development of next generation of lightweight and load bearing components in critical engineering disciplines.