Date of Thesis

5-5-2017

Thesis Type

Masters Thesis

Degree Type

Master of Science in Mechanical Engineering

Department

Mechanical Engineering

First Advisor

Charles J. Kim

Abstract

Adolescent idiopathic scoliosis is a deformity of the spine that affects 2-3% of the population and often requires treatment in the form of a brace. Most successful braces consist of a rigid plastic shell that can be uncomfortable and limit the patient's ability to perform activities of daily living. The greatest cause of treatment failure is patient unwillingness to wear the brace for the prescribed amount of time, up to 23 hours each day. Other flexible braces have been designed to overcome this obstacle, but they have a lower success rate and other drawbacks. It was proposed in this thesis that compliant mechanisms can provide the lateral stiffness required for correction combined with compliance in other directions since they naturally offer relativestiffness and compliance directions. Throughout the process of designing the brace, multiple valuable contributions were generated for various fields of study. The development of the kinematic profile of the spine included determining the locations of the three primary spinal motions and specific axes of rotation for each motion. A corrective force paradigm was used for design rather than the standard displacement paradigm, therefore, requiring a complete understanding of the force profile applied by the brace, which is not found in literature. The force system was determined through an integration of the pressure applied to the torso by a brace. In order to design in 3-dimensions, the Building Block Approach for compliant mechanism synthesis was expanded. This method was used to design the overall mechanism topology. Finally, an iteration of the brace was designed, produced, and tested. Overall, the tools necessary to design a compliant scoliosis brace were developed and can now be easily used to iterate through designs.

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