PSI - Issue 34

Guilherme Guimarães et al. / Procedia Structural Integrity 34 (2021) 26–31 Guilherme Guimarães/ Structural Integrity Procedia 00 (2021) 000 – 000

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1. Introduction Additive manufacturing technologies are increasingly developing in the industrial scenario. Due to geometric freedom of the process complex design oriented to behavior can be implemented. One of the structures enabled by additive manufacturing is the gyroid structure, a triply periodic minimal surface structure with high stiffness and strength being suitable for automotive and aerospace industries [1]. Besides the application of lattice structures, the mechanical behavior of these structures still needs to the studied. Shrestha et al. [2] conducted a first studied on the mechanical behavior of parts subjected to tensile stress. However, due to the geometry of the gyroid structures, the compressive behavior also needs to be studied [3]. The previous studies on the lattice compressive don't consider a standard to enable the comparison with laminated material. Therefore, this study uses the ASTM E9 [4] sample enabling the comparison of the gyroid with commonly used materials.

2. Materials and Method

2.1 Study Design The study’s objective is to analyze the compressive behavior of 20MnCr5 gyroid samples manufactured by selective laser melting and compare numerical and experimental results from a compressive test. Therefore the sample format was based on the ASTM E9 Standard [4], using an aspect ratio of 2. With the nTopology Lattice Tool the Gyroid structure was applied to the solid sample, creating a group of samples varying the cell size and maintaining constant both thickness and bias, Figure 1.

Figure 1: Sample size and lattice cells

2.2 Numerical model The numerical model was developed using the Ansys Discovery Live software. To analyze the model the first step consists in converting the .stl file into a solid part, this procedure was carried out by the SpaceClaim software, where it was also used the repair tools to proceed with the treatment of both mesh and solid files. Therefore, it achieved a coherent solid which can be processed numerically. The second step consists in applying the material properties to the solid. It was used in this step properties previously found in the literature, being the E = 205 GPa and v=0.3 for the elastic behavior, and the plasticity values are displayed in Table1.