Compression characteristics of AlSi10Mg functionally graded gyroid and primitive lattice structures

• Main Author: Ong, Benny Jun Hao
• Other Authors: Zhou Kun
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/150911
• Institution: Nanyang Technological University

Additive manufacturing is a revolutionary manufacturing method that opens the doors to many potential applications due to its ability to fabricate complex structures such as lattices. In this project, two different types of Triply Periodic Minimal Surfaces (TPMS) lattices were investigated based on their compression characteristics, namely the gyroid and the primitive. The lattices were successfully fabricated using Selective Laser Melting (SLM) and subjected to compression testing by the Shimadzu AG-X plus compression testing machine. The uniform relative density gyroids exhibited diagonal shearing when under compression and according to the force-displacement curve obtained, shows very good capability in energy absorption applications. For the functionally graded gyroid, it exhibited a better energy absorption characteristic in comparison to its uniform relative density counterpart. Additionally, it can reach a substantially higher peak strength than the 30% uniform relative density gyroid despite weighing lesser than it. The uniform relative density primitives exhibited not just diagonal shearing when under compression, but also a variation, namely a “V shape” shearing. According to the force-displacement curve, it exhibited high stiffness with increasing brittleness as relative density increases, thus finding value in high stiffness applications, but with detrimental results once the force exceeds its peak strength. For the functionally graded primitive, it can avoid a catastrophic collapse like that exhibited by the uniform 40% relative density primitive upon reaching its peak strength. It avoids this by collapsing layer-by-layer, which is due to its increasing relative density. From the results obtained from this project, it aims to provide a better understanding on the compression characteristics of two different TPMS lattice structures, thus enabling one to make a more informed choice when picking the right lattice topology for the right application.