Page 72 - MSAM-3-3

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Design criteria and energy absorption prediction

empirical rule for deformation-induced
densification of gradient porous materials

Yi Chao and Che-Nan Kuo*

Department of Materials and Optoelectronic Science, College of Engineering, National Sun Yat-Sen
University, Kaohsiung, Taiwan

Abstract

Additive manufacturing is an excellent process for complex shapes, porous
structures, and bionic structures. Recently, Ti-6Al-4V alloy has been used to
fabricate these porous structures and perform well in terms of mechanical
properties. In addition, compared with single porosity materials, functionally
graded cellular materials have attracted increasing attention due to their good
mechanical properties. Compared with single porosity materials, deformation
causes the gradient porous materials to be densified layer by layer, leading to
better specific energy absorption. However, not all of the gradient porosity
materials present the deformation-induced densification phenomenon. Hence,
the design criteria for deformation-induced densification of gradient porosity
materials must be explored for further application. To explore the design
*Corresponding author: criteria for deformation-induced densification and establish an empirical rule
Che-Nan Kuo
(cnkuo@mail.nsysu.edu.tw) for estimating energy absorption, two types of porous/bionic structures, Schon-
Gyroid sheet and Schwarz-Diamond sheet, were investigated in this study. The
Citation: Chao Y, Kuo C. Design
criteria and energy absorption tendency of the deformation-induced densification phenomenon was evaluated
prediction empirical rule for using porous materials with two layers (two porosity changes), and the empirical
deformation-induced densification rule for estimating energy absorption was developed with porous materials
of gradient porous materials. Mater
Sci Add Manuf. 2024;3(3):4234 doi: with three layers (three porosity changes). As a result, the energy absorption of
10.36922/msam.4234 gradient porosity materials can be estimated through the mechanical properties
Received: July 12, 2024 of single porosity materials with the same porous structure. The energy absorption
of the gradient porosity materials with different designs can be predicted by the
Accepted: August 20, 2024
empirical rule, and the difference between calculated and experimental energy
Published Online: September 25, 2024 absorption is only 1 – 2%. In the empirical rule, the porosity, aspect ratio, and yield
Copyright: © 2024 Author(s). stress are designed as changeable values. Other factors, such as material’s nature,
This is an Open-Access article surface issues, and unit cell design, can be corrected by C value. Furthermore,
distributed under the terms of the
Creative Commons Attribution the deformation-induced densification can be applied by following two design
License, permitting distribution, criteria: (1) the aspect ratio of the layers should be <1; and (2) the yield stress of
and reproduction in any medium, the lower-porosity layer should be 9.8% higher than the maximum stress of the
provided the original work is
properly cited. higher-porosity layer.
Publisher’s Note: AccScience
Publishing remains neutral with Keywords: Gradient porosity materials; Laser powder bed fusion; Energy absorption;
regard to jurisdictional claims in
published maps and institutional Design criteria; Empirical rule
affiliations.

Volume 3 Issue 3 (2024) 1 doi: 10.36922/msam.4234