A methodology to design and fabricate a smart brace using low-cost additive manufacturing

ABSTRACT

Ankle braces typically restrict the functional range of motion. Braces should preferably allow a free functional range of motion during sport while protecting the foot at high-risk positions beyond that range. This could be achieved with 3D printed metamaterial structures that could have varying properties throughout an individual’s ankle range of motion. This paper aims to illustrate an exploratory methodology of using an affordable Fused Deposition Modelling 3D printing technology to develop an ankle brace using metamaterial structures. It also showcases the design, manufacturing processes and testing of 3D printed customised ankle brace prototype designs that incorporated metamaterial structures. Initial tests showed that as designed, the prototype braces maintained the full range of motion for plantar flexion angles. Results also showed that the prototypes required one of the lowest moments during functional range of motion while achieving almost twice to thrice the moment required beyond the functional range of motion.

KEYWORDS:

• Ankle sprain
• metamaterial structures
• biomimetic
• anisotropic material properties
• tensile testing

Acknowledgements

The authors would like to thank Chan Jinhao for his preliminary test results using the ‘square grid’ structures. A Patent Application (Singapore Patent Application no.: 10201803671X and US Patent Application no.: 17/052,506) incorporating parts of this paper has been filed.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Institute for Sports Research, Innovation Development Grant [grant number S11-1191-IDS].

Notes on contributors

P.S.P. Teng

Dr Phillis Teng is a senior research fellow at the Nanyang Technological University, Singapore (NTU), with the passion in biomechanics research, especially in injury risk reduction. She has a diverse background in biomechanics research and mechanical engineering, with 6.5 years of industry experience as an Engineer at Hewlett-Packard Singapore. She obtained her PhD in NTU in 2015 and her PhD research on ‘Investigation of Foot Landing Techniques and Muscle Activation during Single-Leg Drop Landings: Implications for Non-Contact Anterior Cruciate Ligament Injuries’ has produced 4 journal and 4 conference papers. Her past 10 years in research included areas in sport injury risk reduction; human perception in comfort and fit; mechanical shoe testing; 3D printed brace development using metamaterial structures; and biomechanics study of customised 3D printed insoles. She is now with the Rehabilitation Research Institute of Singapore, studying knee osteoarthritis risks and exploring the possibility for an early biomechanics intervention.

K.F. Leong

A/P Kah Fai Leong is an associate professor in the School of Mechanical and Aerospace Engineering, Nanyang Technological University. He obtained his B.Eng. (Mech.) with Honours from the National University of Singapore in 1981 and M.Sc. degrees in Engineering Product Design and Mechanical Engineering, from Stanford University in 1987. Prior to joining NTU, he worked for several years as a product development engineer and designer in the Singapore electronics industries. He was awarded the Merit Award in 1994 and Distinguished Award in 1997 for his contributions to the national standardisation program. His research interests are in Additive Manufacturing for biomedical applications, particularly in tissue engineering; sports technology; sports science; polymer matrix composites; design science; and design education. He has co-authored five books, published more than ten book chapters and more than 200 papers in international journals, conferences, and seminars in these areas. He has been invited as a keynote speaker for a number of premier conferences and has acted as reviewers for several journals, including Materials and Design, Virtual and Physical Prototyping; Additive Manufacturing; Materials Today, Trends in Biotechnology, Biomaterials, Acta Biomaterials, Journal of the Mechanical Behavior of Biomedical Materials, amongst others.

P.W. Kong

A/P Pui Wah (Veni) Kong is the Associate Dean for Research Grants Management and an Associate Professor at the National Institute of Education, Nanyang Technological University, Singapore. Her research interests are sports and clinical biomechanics, with applications in human performance, injury prevention and rehabilitation. Dr Kong has led research projects on high-performance sports, gait, footwear, foot health, low back pain, massage, and sports injuries. She conducted laboratory experiments and field tests on athletes, school children, older adults, firefighters, paramedics, military personnel, and patients with various musculoskeletal health conditions. She worked closely with hospitals, clinics, government agencies and industrial partners to conduct interdisciplinary research that can impact the society. She was the recipient of the Fellow of International Society of Biomechanics in Sports (FISBS) in 2020, among other presentation awards from the International Sports Engineering Association, British Association of Sport and Exercise Sciences, Asian Society of Sport Biomechanics and Sports Medicine Association Singapore.

B.H. Er

Mr Er Bin Hao created the template for ankle brace development as part of his final year engineering project and is currently a UX designer, working on designing digital products that help to solve the sustainability challenge. Having graduated from Nanyang Technological University, Singapore with a Bachelor in Mechanical Engineering, he has since pivoted to a career in user experience and design, working with companies to deliver visual solutions and data driven metrics in order to help in energy management and carbon net zero.

Z.Y. Chew

Mr Chew Zhi Yuan graduated from Nanyang Technological University in 2021 and obtained a degree in Mechanical Engineering. For his final year engineering project, he re-designed the existing metamaterial structure to improve its tensile properties and used simulation in his design iterations. He also explored the use of printing on cloth to enhance the ankle brace comfort levels.

P.S. Tan

Ms Tan Phei Shien graduated from Nanyang Technological University in 2021 and obtained a degree in Mechanical Engineering with a specialisation in Design. She has worked on various design projects throughout her undergraduate course and her work on utilising metamaterials in an ankle brace was her first research related project. She also designed and developed the newer test jig to allow for ankle brace testing and competitive analysis.

C.H. Tee

Mr Chor Hiong Tee (Frankie) is a Project Officer at the Rehabilitation Research Institute of Singapore, Nanyang Technology University, Singapore. His research interests include product aesthetics, human-centered design and design strategies. Frankie has more than a decade of design and research experience in the multimedia, advertising and industrial design industries. Since graduating with a Bachelor of Fine Art in Product Design from Nanyang Technological University (NTU), he has managed numerous research projects in academia and industrial collaborations with commercial partners. As an industrial designer/design researcher, Frankie is instrumental in developing various consumer products, ranging from home service robots for the elderly, intelligent wearables for lifestyle needs, gears and equipment for sports and medical rehabilitation applications. His collaboration with the Badminton World Federation (BWF) to develop an outdoor shuttlecock solution has led to a successful commercial launch of a new outdoor game called Air Badminton. In addition, Frankie has written a book chapter and helped edit manuscripts for a collaborative book project on Digital Manufacturing for the HP-NTU Corporate Laboratory in NTU.