PSI - Issue 28

Fuzuli Ağrı Akçay et al. / Procedia Structural Integrity 28 (2020) 1399– 1406

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Author name / Structural Integrity Procedia 00 (2019) 000–000

Fig. 3. 2D finite element model of decuple lattice, i.e., ID #3 of cubic vertex centroid lattice

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(b)

Fig. 4. (a) Shear bands captured in 2D finite element simulations of decuple lattice, i.e., ID #3 of cubic vertex centroid lattice, (b) An example of typical shear crack in compressive test of micro lattice.

4.2. 3D Finite Element Simulations As two-dimensional finite element models do not provide consistent results with the experiments, contribution of “shear effect” on this inconsistency is investigated. The investigation is conducted using a simple case, a circular cylindrical rod with a fixed end and a free end, where the force is applied. The limit analysis for this straightforward case results in a collapse load of � � �� � � ⁄3 . Here, a rod length of 1.732 mm with a circular cross section of a radius of 0.2 mm is utilized. These dimensions are chosen to be consistent with ID #3 of cubic vertex centroid configuration which has a strut length of � 1.732 mm and a circular cross section of a radius of � 0.2 mm. The analytical result as well as 2D and 3D finite element results are presented in Table 6. Numerical collapse loads correspond to experienced force values at 0.5 mm vertical free-end displacement. As can be seen from the table, analytical result is in agreement with 2D finite element result, which is expected, since analytical model is a two dimensional model as well. However, 3D finite element result differs significantly from both the analytical result and 2D finite element result, and this outcome suggests the use of three dimensional finite element models to accurately represent the experimental cases. 3D simulations are conducted for single lattice and double lattice models for ID #3 of cubic vertex centroid configuration and further simulations are underway.