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Model of geometry of micro-lattice structures for finite element method
Javorský, Dominik ; Maňas, Pavel (referee) ; Červinek, Ondřej (advisor)
The growing availability of additive manufacturing technology, such as SLM, enables the creation of innovative structural designs. An example of these are complex lattice structures which are used because of their excellent mechanical properties relative to weight. One significant challenge lies in production tolerances. These are not crucial for the majority of components. However, when dealing with lattice structures and their thin-walled geometry, manufacturing tolerances lead to substantial deviations in mechanical properties. The process of designing such structures and achieving results comparable to the experiment requires the use of non-standard methods. These methods are time-consuming and costly for obtaining real geometry. The real geometry is then used for numerical simulations based on the FEM principle. This thesis focuses on the impact of geometric imperfections occurring in BCC-type structures made of stainless steel 316L. During the solution, the real geometry was obtained through optical digitization using the ATOS Triple Scan scanner. Dynamic drop-weight tests were also conducted, and the obtained results were used to modify the geometry model in combination with the acquired real geometry. The aim was to minimize the deviation between experimental and numerical simulation results below 5%. The knowledge gained from this process was then applied in simulations investigating the impact of geometric imperfections. Deviations up to 30% were observed in simulations investigating the impact of geometric imperfections. These deviations can be minimized by incorporating the knowledge of real geometry into the design. The results also help determine the diameter range within which including geometric imperfections in the design is irrelevant. Furthermore, a significant impact of the node geometry on the results of numerical simulations was observed. This knowledge brought the values closer to the experimental data. Another important contribution of this work is the simplified geometry model. This model will enable the study of the impact of additional imperfections in a range that was previously unattainable.
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