A computational model for monolimb design

Monolimb refers to a kind of trans-tibial prosthesis having the socket and the shank molded into one piece of thermoplastic material. It has a characteristic that the shank could deform during walking. Positive feedbacks were gained including better comfort and improved gait efficiency from patients using prostheses with deformable shanks (Valenti, 1991; Coleman et al., 2001). By proper use of material and structural design, the shank flexibility could be raised which might further improve comfort and gait. However, structural integrity should be remained which resists buckling of the prosthesis. Finite element (FE) analysis has been used in lower limb prosthetics in the past two decades. The advantages of using FE analysis are that stress, strain and motion in any parts of the model can be predicted and parametric analyses can be done easily. In previous FE models, focus was put at the socket-limb interface. In this investigation, FE analysis was applied to study the stress distribution at the residual limb and monolimb. Prediction of interface stress, shank flexibility and possible failure could be made in this model. Once validated, different parameters will be input for design optimization.