Methodology definition for lattice structure simulation: from lattice to equivalent solid’s characteristics

Nowadays Engineering Industry is searching for new materials and manufacturing techniques to reduce weight and improve parts’ mechanical characteristics. In this scenario, Additive Manufacturing represents a central role. This technique differs from the traditional one because a part is realized by overlapping layer by layer, adding material only where necessary. This feature permits the creation of reticulated structures called lattice. Considering a structural analysis of lattice parts using FEM software requires many calculations power, and time, consequently elevating costs. These aspects are limitations in lattice structure applications. The thesis work focuses on defining a methodology helpful for simplifying and speeding the structural analysis of lattice structure. In particular, an equivalence stiffness matrix is defined for a rhombic dodecahedron unit cell lattice structure made by SS316L with the L-PBF process and attributed to a full component, avoiding considering many nodes and elements during the analysis, saving time and money. The thesis is composed of five chapters. The first one is dedicated to a brief introduction to the additive manufacturing and lattice world. The second one is divided into two subchapters: material research and state-of-the-art software approach to the lattice structure. Regarding material, the attention is put on metal ones, while the software approach is focused on the homogenization method. The third one represents the thesis’ core and contains a step-by-step strategy to reach the goal. In particular, a material software characterization is done, and a short explanation of the unit cell is provided. Many analyses are run on lattice structures to extrapolate elastic moduli and then attributed to an equivalence solid. Both lattice and equivalence parts are successfully stressed similarly, and displacements are compared to verify their coincidence. This chapter conducts a dedicated study on equivalence solid shape, constraints, and loads application scheme. In the fourth chapter, conclusions are stated, and the equivalence stiffness matrix is reported for the specific lattice structure. Moreover, the methodology steps are listed to apply to any lattice component. In the fifth one, future developments are depicted, and suggestions are provided to improve the thesis results.