Experimental investigation and computer simulation of wheelchair cushions

This project aims to investigate the properties of 4 types of commonly used wheelchair cushions --- the Honeycomb (polymer), Roho (air), Jay (gel) and high density foam --- with regards to their capability in pressure distribution and postural support from the biomechanical point of view. These are possibly the 2 most important characteristics of wheelchair cushions for wheelchair users. Presence of a cushion cover and type of support structure the cushion is placed on are the variables that will be investigated. Displacement of the cushion surface over a series of loads comparable to human masses was measured. Displacement of the cushion surface was measured using a 3-D digitizer (Minolta Vivid 900) and computer software Rapidform 2001. Simulation of cushion properties was then carried out using software CosmosWorks 2005. Results indicate that the foam cushion exhibits the best pressure distribution characteristic, while cushion covers tend to decrease deformation and increase pressure on bone protrusions. Simulations also indicated that a symmetrical cushion appeals not to be ideal for users with asymmetrical weight distribution.