Evaluation of Static and Fatigue Properties of Regular Lattice and Trabecular Cellular Structures

Abstract

Laser-based Powder Based Fusion (LPBF) being one of the most widely used additive manufacturing (AM) process has not only impacted the design of components in aeronautical and automobile industries but also in development of porous components. The properties of these lattice structures can be tailored according to the structural and compatibility requirements depending on the application. Therefore, understanding the behavior of cellular structures under static and fatigue loading becomes necessary. The factors that influence their behavior include relative density, cell topology, cell geometry and microstructure of the material.In this current study, titanium alloy Ti6Al4V cellular structures with four different geometries (Cubic, Star-shaped, X-shaped and Trabecular) manufactured using LPBF are considered. The mechanical performances of the samples, designed in order to have an overall porosity of 70-75%, have been evaluated with static tests under tensile and compressive loading, and with compression-compression fatigue test (R=0.1). The results indicate a clear decrease in the mechanical properties with increase in the bending dominated behavior of the cell types. However, Cubic structures displayed a catastrophic fracture behaviour, while the other structures were more resilient. Furthermore, despite the facts being bending dominated and with the lowest number of struts per node, the Trabecular structures showed good fatigue resistance thanks to the presence of struts in all the directions.