With advancements in the 3D printing technology, many industrial sectors are transitioning from traditional production methods, such as cutting processing, and casting, to utilizing 3D printers for manufacturing. For instance, in the automotive industry, the production of vehicle upright knuckle parts typically involves casting followed by machining processes, such as turning and milling, to achieve dimensional accuracy. However, this approach is associated with high processing costs and longer lead times. This study focuses on the production of vehicle upright knuckle parts using a selective laser melting (SLM)-type 3D printer, with SUS 630 as the material. To evaluate the feasibility of utilizing this method in industrial vehicles, this study conducts static and modal analyses, along with topology optimization. Additionally, experimental test drives are performed with the parts installed in KSAE BAJA vehicles, and modal frequency experiments are conducted. The objective of these analyses and experiments is to assess the performance, reliability, and applicability of utilizing SLM-based 3D printing for manufacturing vehicle upright knuckle parts by optimizing the design through topology optimization and evaluating the results through experiments and analysis.

Effective elastic constants of biomimetic multilayer structures with hierarchical structures are evaluated based on the potential energy balance method. The effective anisotropic elastic constants are used in analyzing low-velocity impact of biomimetic multilayer structures consisting of mineral and protein. It is shown that displacements of biomimetic multilayer structures strongly depend on the volume fraction of mineral and hierarchical level. The effect of the volume fraction of mineral and hierarchical level on the contact force and stresses at the impact point are also discussed.