Page 60 - MSAM-2-1

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Energy absorption and recoverability of Moore

space-filling thin-walled structures

Changlang Wu, Vuong Nguyen-Van, and Phuong Tran*
School of Engineering, RMIT University, Melbourne, VIC 3000, Australia

Abstract

This paper proposes novel thin-walled structures inspired by Moore space-filling
curves. Nine designs, featuring three fractal hierarchies (1 , 2 , and 3 orders) with
st
nd
rd
three different relative densities (20%, 30%, and 40%), were used as cross-sectional
configurations of the thin-walled structures. Specimens were manufactured using
a material extrusion additive manufacturing technique, fused filament fabrication,
with a carbon fiber-reinforced composite. Quasi-static compression tests from
in-plane direction were conducted to investigate the influences of fractal hierarchy
and relative density on the energy absorption capacity. Finite element models were
developed to compare with the experiments and to further explore the 4 order
th
structures. A certain level of compliance and snap-in instability were observed
in all the structures. These properties show great potential for such thin-walled
structures to absorb more energy by enduring large strain. Among them, the
2 order structures exhibited the best energy absorption capacity. Furthermore,
nd
loading and unloading compression tests were performed on the 2 and 3 order
rd
nd
structures (relative density of 20%) to evaluate their resilience toward displacement
and damages. The residual strain and dissipated energy ratio demonstrated that the
*Corresponding author: 2 order structure outperformed the 3 order structure owing to its less compliant
nd
rd
Phuong Tran
(jonathan.tran@rmit.edu.au) feature. The integration of Moore curves with thin-walled structures contributes
to great compliance and snap-in instability, offering a new approach to designing
Citation: Wu C, Nguyen-Van V,
Tran P, 2023, Energy absorption lightweight energy absorption structures.
and recoverability of Moore space-
filling thin-walled structures. Mater
Sci Add Manuf, 2(1): 53. Keywords: Fractal; Compliant structures; Snap-in instability; Energy absorption; Additive
https://doi.org/10.36922/msam.53 manufacturing
Received: February 20, 2023
Accepted: March 7, 2023
Published Online: March 24, 2023 1. Introduction
Copyright: © 2023 Author(s). Energy absorption has always been one of the design objectives to provide protection to
This is an Open Access article
distributed under the terms of the humans and structures during dynamic or impact events, such as high specific energy
Creative Commons Attribution absorption (SEA) [1-4] , lightweight [5-8] , low cost [5,9,10] , and easy installation [11,12] . Among
License, permitting distribution, various types of structures, thin-walled structures have been widely used as effective
and reproduction in any medium,
provided the original work is energy absorbers in civil engineering, automobile engineering, aerospace engineering,
properly cited. etc., considering its excellent energy absorbing capacity and lightweight features .
[13]
Publisher’s Note: AccScience Over the past decades, designing lightweight thin-walled structures without sacrificing
Publishing remains neutral with their energy absorption or crashworthiness has become a hot research topic. It has been
regard to jurisdictional claims in
published maps and institutional demonstrated that the energy absorption capacity of thin-walled structures is influenced
affiliations. by various factors, such as structural configuration, material selection, and trigger

Volume 2 Issue 1 (2023) 1 https://doi.org/10.36922/msam.53