Optimisation of wheelchairs for Paralympic athletes: design of a flexible carbon fibre backrest

Abstract

The research lab ICA is working on a global project of designing a wheelchair for a Paralympic badminton athlete. Because this athlete has no abdominal muscles, the backrest of this wheelchair requires elastic bands to support the athlete’s back. The goal of this master’s thesis is to investigate if the elastic bands could be replicated with thin carbon fibre sheets with a variable rigidity.

There are three objectives in the design of such a sheet. Firstly, the relationship between the design of the sheet and the deformation is unknown. The rigidity varies depending on the position on the sheet. Therefore, a method to calculate the deformation characteristic in function of the position is developed. Secondly, the impact of varying a design parameter on the deformation is investigated. Thirdly, the desired deformation is converted to a sheet design and prototype.

To investigate the deformation, various designs for the section of the sheet are made, for each of which a mathematical model is developed. After selecting the preferred model, the deformation in function of the position is calculated. By varying design parameters, the impact on the deformation characteristic is found. Subsequently, the desired deformation can be converted by varying the design parameters of the model, resulting in a final sheet design. Finally, the results of finite element analyses (FEA) on the design are discussed and physical tests are prepared. The linear and non-linear FEA show that the proposed design is feasible for a limited charge.