J. Biomedical Science and Engineering, 2011, 4, 762-768 doi:10.4236/jbise.2011.412094 Published Online December 2011 (http://www.SciRP.org/journal/jbise/ JBiSE ). Published Online December 2011 in SciRes. http://www.scirp.org/journal/JBiSE Analysis of trans tibial prosthetic socket materials using finite element method Prasanna Kumar Lenka 1 , Amit Roy Choudhury 2 1 Department of Rehab Engineering, NIOH, Kolkata, India; 2 Department of Applied Mechanics, BESU, Shibpur, India. Email: lenka_pk@yahoo.co.uk , arc.bec@gmail.com Received 24 August 2011; revised 19 October 2011; accepted 14 November 2011. ABSTRACT The objective of this work was to analyze in a para- metric study for optimum design solution of pros- thetic socket material by finite element method. A realistic three-dimensional finite element model of the PTB socket was developed to find out the stress distribution pattern under physiologically relevant loading condition during normal walking. The CAD model of the rectified socket was collected from a CMET 250 non-tactile high accuracy (0.06 mm) white light scanner and analyses were carried out using finite element Method in ANSYS®. All struc- tural materials used in the analysis were assumed to be linearly elastic, homogeneous and isotropic. Dif- ferent materials were used for socket and only poly- propylene was used for socket adopter. Analysis was prepared at 2 mm, 3 mm, 4 mm, 5 mm & 6 mm thickness of socket in different materials commonly used in developing countries. The bottom line of socket was made to zero displacement constraints and vertical loads in relation to stance phase of gait cycle were applied under static condition at the pa- tella tendon brim. The 3 mm laminated composite sockets was found to be optimum in terms of strength, weight and factor of safety. Keywords: Finite Element Method; Transtibial Prosthe- sis; Socket; Polymer 1. INTRODUCTION The major contribution towards successful fitment of prosthesis may be obtained by comprehensible under- standing the biomechanical structure of socket and its material, weight, thickness in particular to fulfill the de- sirable load distribution in soft tissues and bone of re- sidual limb. One most commonly used socket design in developing countries, that has shown success in balanc- ing the biomechanical principles and load bearing fac- tors of the residual limb anatomy for persons with tran- stibial amputation (TTA) is the patellar tendon bearing (PTB) socket, developed following the World War II at the University of California, Berkeley in the late 1950 s [1,2]. The Finite Element Method (FEM) has been used widely in biomechanics to predict stress and strain in complicated systems and have been identified as a useful tool in understanding load transfer in prosthesis [3]. The FEA Models have been used to study the effects of the inertial loads and contact conditions on the interface between prosthetic socket and residual limb of an ampu- tee during the gait [4,5]. The FEA has also been used as a tool for parametric study and evaluation of prosthetic components [6,7]. Most of the previous studies have attempted to investigate socket interface pressure meas- urement, friction-related phenomena, computational modeling, and real-time patient specific internal stress at the residuum [8-23]. The biomechanical understanding of stresses at the residual limb and development of ad- vanced manufacturing process like CAD/CAM has im- proved socket design in developed countries. However, the requirements sockets for TTA in developing coun- tries are different. Often financial resources are quite limited and the functional demands on prosthetic sockets are extreme. It has been reported that the basic factors which should be considered in developing countries when selecting socket materials are function, durability, stability, cost, availability, sustainability, climatic condi- tions, and ease of maintenance [24]. In a survey of ten years (1994-2004) follow up and repair records of TTA fitted in one of the national Institutes in India, it was observed that 66% of total replacement/repair of pros- thesis occurred due to socket breakage, material failure and deformation [25]. In a follow up study of HDPE Jaipur Prosthetic technology, Jensen (2004) et al., re- ported 50% cases need replacement due to failure of components [26]. Hence, a further study is required to analyze structural topology, compliance and biome- chanics of the socket to predict critical stress zones in