Product development of an ankle brace using 3D printing

• Main Author: Chew, Zhi Yuan
• Other Authors: Leong Kah Fai
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/150899
• Institution: Nanyang Technological University

One of the greatest fears that all athletes face is getting injured. A serious injury could potentially destroy an athlete’s career or even hinder the progress towards his or her goal. Amongst all these injuries, ankle sprains are one of the most common injuries. Manufacturers have developed different types of ankle braces to help with the prevention and recovery from ankle sprains. They have created ankle braces to restrict the range of motion such that ankle inversion is avoided. Though these braces have can be effective, there are nevertheless shortcomings. These ankle braces are overly stiff that it hinders the functional range of motion of the wearer which causes discomfort and degradation in athletic performance. Hence, utilising the technology of 3D printing, coupled with the study on metamaterials, this project aims to create an ankle brace with a great level of mobility within the functional range of motion while maintaining adequate support during an ankle inversion. Previous work had been done to investigate the use of patented diamond-like metamaterial to restrict ankle inversion. The previous prototype, made of two different metamaterial designs (Diamond-like metamaterial and Square Grid metamaterial) was able to retain full range of motion in common sporting motions and provided ankle support at critical angles of inversion. However, the geometric misfit of two different metamaterial designs deteriorated the integrity of the structure. Thus, this study also aims to improve the previous prototype in terms of structural integrity and performance with the use of only Square Grid metamaterial. Multiple tests were done at each iteration to test for key indicators such as young modulus at different ranges of motion and Young’s modulus at 30°. With our final iteration, we were able to achieve low Young’s modulus at the functional range of motion and high Young’s modulus at critical angles of ankle inversion. This was evident in the moment test, with the prototype having the highest moment ratio of 2.94 which is 40% higher than the average moment ratio of current braces. Also, the prototype performed well in the plantar flexion test by retaining full 50° range of motion. However, the prototype provided less support at critical angles of inversion as compared to other semi-rigid braces, which were almost two times stronger.