Page 102 - MSAM-3-4

Materials Science in

Additive Manufacturing

ORIGINAL RESEARCH ARTICLE
Investigation of reversibility and bi-stability of

3D-printed compliant structures with double
curved beams

1
1
Changlang Wu , Chenxi Peng 2,3 , Phuong Tran * , and Erich Rutz 2,3,4,5,6,7 *
1 RMIT Centre for Additive Manufacturing, School of Engineering, RMIT University, Melbourne,
Victoria 3000, Australia
2 Department of Paediatrics, The University of Melbourne, Parkville, Victoria 3052, Australia
3 Murdoch Children’s Research Institute, Parkville, Victoria 3052, Australia
4 The Royal Children’s Hospital Melbourne, Parkville, Victoria 3052, Australia
5 The Hugh Williamson Gait Analysis Laboratory, The Royal Children’s Hospital Melbourne, Parkville,
Victoria 3052, Australia
6 School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria 3083, Australia
7 Medical Faculty, The University of Basel, Basel 4001, Switzerland

*Corresponding authors: Abstract
Phuong Tran
(jonathan.tran@rmit.edu.au) Compliant mechanisms have been widely found in nature. Instead of using rigid
Erich Rutz
(erich.rutz@rch.org.au) joints in conventional mechanisms, compliant mechanisms transfer motions through
their flexible members. This work employs the buckling of double curved beam
Citation: Wu C, Peng C, Tran P, element to design compliant structures. Three groups of structures were proposed
Rutz E. Investigation of reversibility
and bi-stability of 3D printed to investigate the influence of three different design parameters on their compliant
compliant structures with double behaviors under quasi-static compression: h’ (the ratio of beam apex height to beam
curved beams. Mater Sci Add thickness), l’ (the ratio of beam span length to thickness), and g’ (the ratio of membrane
Manuf. 2024;3(4):4960.
doi: 10.36922/msam.4960 length to thickness). The proposed structures were fabricated by fused filament
fabrication with a composite material. Experimental data, numerical simulations,
Received: September 26, 2024
and analytical results were compared and evaluated. It was demonstrated that the
1st revised: October 24, 2024 positive structural stiffness and peak force were correlated to the design parameter
2nd revised: November 29, 2024 l’. The higher h’ value resulted in a more pronounced negative stiffness phase. In
addition, the larger g’ could provide the beams with more constraint of buckling
Accepted: November 29, 2024
Mode 2 by transferring the rotational motion of either beam center to the axial
Published Online: December 19, motion of the other beam more effectively. The discrepancies between theoretical
2024 predictions and experimental results demonstrate the importance of fixed-end
Copyright: © 2024 Author(s). boundary conditions in achieving bi-stability. The transitions from reversibility to
This is an Open-Access article bi-stability by varying different design parameters provide insight into the design
distributed under the terms of the
Creative Commons Attribution of compliant mechanisms. Herein, two approaches are evident to be effective in
License, permitting distribution, increasing the bi-stability of the curved beams with manufacturing defects and
and reproduction in any medium, under undesired boundary conditions: (i) designing with a higher ‘g’’ value and (ii)
provided the original work is
properly cited. increasing the number of coupling beams.
Publisher’s Note: AccScience
Publishing remains neutral with Keywords: Compliant structure; Double curved beams; Negative stiffness; Additive
regard to jurisdictional claims in
published maps and institutional manufacturing; Reversibility; Bi-stability
affiliations.

Volume 3 Issue 4 (2024) 1 doi: 10.36922/msam.4960