Mechanical Performance of Lightweight-Designed Honeycomb Structures Fabricated Using Multijet Fusion Additive Manufacturing Technology

Aamer Nazir; Ahmad Bin Arshad; Shang-Chih Lin; Jeng-Ywan Jeng

doi:10.1089/3dp.2021.0004

Mechanical Performance of Lightweight-Designed Honeycomb Structures Fabricated Using Multijet Fusion Additive Manufacturing Technology

3D Print Addit Manuf. 2022 Aug 1;9(4):311-325. doi: 10.1089/3dp.2021.0004. Epub 2022 Aug 3.

Authors

Aamer Nazir^{1

2}, Ahmad Bin Arshad^{1

3}, Shang-Chih Lin^{1

4}, Jeng-Ywan Jeng^{1

3

5}

Affiliations

¹ High Speed 3D Printing Research Center, National Taiwan University of Science and Technology, Taipei, Taiwan, Republic of China.
² Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, SAR, China.
³ Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, Republic of China.
⁴ Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, Republic of China.
⁵ President Office, LungHwa University of Science and Technology, Taoyuan, Taiwan, Republic of China.

Abstract

Cellular structures including three-dimensional lattices and two-dimensional honeycombs have significant benefits in achieving optimal mechanical performance with light weighting. Recently developed design techniques integrated with additive manufacturing (AM) technologies have enhanced the possibility of fabricating intricate geometries such as honeycomb structures. Generally, failure initiates from the sharp edges in honeycomb structures, which leads to a reduction in stiffness and energy absorption performance. By material quantity, these hinges account for a large amount of material in cells. Therefore, redesigning of honeycomb structures is needed, which can improve aforementioned characteristics. However, this increases the design complexity of honeycombs, such that novel manufacturing techniques such as AM has to be employed. This research attempts to investigate the optimal material distribution of three different topologies of honeycomb structures (hexagonal, triangular, and square) with nine different design configurations. To achieve this, higher amount of material was distributed at nodes in the form of fillets while keeping overall weight of the structure constant. Furthermore, these design configurations were analyzed in terms of stiffness, energy absorption, and the failure behavior by performing finite element analysis and experimental tests on the samples manufactured using Multijet fusion AM technology. It was found that adding material to the edges can improve the mechanical properties of honeycombs such as stiffness and energy absorption efficiency. Furthermore, the failure mechanism is changed due to redistribution of material in the structure. The design configurations without fillets suffer from brittle failure at the start of the plastic deformation, whereas the configurations with increased material proportion at the nodes have larger plastic deformation zones, which improves the energy absorption efficiency.

Keywords: additive manufacturing; design for AM; energy absorption efficiency; fillets; honeycomb structure; optimal material distribution; stiffness.