Comparative study by FEM of different liners of a transfemoral amputated lower limb

Abstract

The mechanical behavior of prosthetic liners significantly influences stress distribution, soft tissue protection, and the overall efficiency of the prosthetic. While extensive research has been conducted on liner materials, the impact of liner thickness (2 mm, 4 mm, and 6 mm) on biomechanical response remains underexplored. This study utilizes finite element analysis in Abaqus to investigate how liner material (Gel vs. Silicone) and thickness affect contact pressure (CPRESS), maximum principal strain (Le. Max), shear stress (CSHEAR1), and vertical displacement (U3) at the residual limb-liner interface. A three-dimensional numerical model was developed to simulate stress transmission and displacement behavior under physiological loading conditions. The results demonstrate that liner thickness plays a critical role in modulating pressure distribution and mechanical stability, with Gel providing superior flexibility and shock absorption, whereas Silicone offers enhanced structural integrity. At a thickness of 2 mm, the highest pressure of 0.4656 MPa is recorded. When the thickness is increased to 4 mm, the pressure decreases to 0.4153 MPa, reflecting a reduction of approximately 10.8%. Further increasing the thickness to 6 mm results in a pressure drop of 0.3825 MPa, corresponding to a total reduction of 17.9%. These findings provide quantitative insights into stress attenuation mechanisms, contributing to the optimization of prosthetic liner design for improved clinical outcomes in lower-limb amputees.

Keywords: Contact pressure; Displacement; Finite element analysis; Prosthetic liner; Shear stress.

Fig. 1

Final finite element (FE) model representation.

Fig. 2

Design variations of prosthetic liners based on thickness parameters.

Fig. 3

Finite element mesh distribution for the model components: (a) bone, (b) muscle, (c) liner, and (d) socket.

Fig. 4

Mesh convergence curve for CPRESS analysis.

Fig. 5

Representation of the boundary and loading conditions.

Fig. 6

Contact Pressure (CPRESS) contour for different liner thicknesses.

Fig. 7

Histograms comparing Contact Pressure (CPRESS) values for each material and coating thickness.

Fig. 8

Maximum Principal Strain (Le. Max) for different liner thicknesses.

Fig. 9

Histograms comparing maximum principal strain (Le. Max) values for each material and liner thickness.

Fig. 10

Shear Stress (CSHEAR1) contour plot for different liner thicknesses.

Fig. 11

Histograms comparing Shear Stress (CSHEAR1) values for each material and liner thickness.

Fig. 12

Vertical Displacement (U3) contour plot for different liner thicknesses.

Fig. 13

Histograms comparing Maximum Vertical Displacement (U3) values for each material and liner thickness.