Development of a finite element model of a transtibial socket liner--an initial study

A number of computer models of limb loading by lower limb prostheses have been developed to date, however their accuracy and clinical usefulness is somewhat debatable. This paper is the first in a series describing investigations into the behaviour of a transtibial socket under compressive loading. The work focuses upon the socket liner and its role in reducing and redistributing stresses within the socket. This initial study used non-linear finite element analysis to replicate the effect of pressure loading on a polyurethane socket liner in the region of a bony prominence. It is a first step in understanding the load transfer between the residual limb, socket liner and socket of a transtibial prosthesis. The Mooney Rivlin material model [1] was used to simulate the polyurethane socket liner and compression tests in accordance with BS903 [2] were performed to gain the necessary data to calculate the Mooney Rivlin constants. Experimental validation showed that a very accurate, large-strain representation of the material was achieved. Future work will model more complex, three-dimensional geometries.