Engineering, 2013, 5, 518-521
http://dx.doi.org/10.4236/eng.2013.510B106 Published Online October 2013 (http://www.scirp.org/journal/eng)
Copyright © 2013 SciRes. ENG
Comparative Finite Element Analysis of Jaipur Foot
and Polyurethane Foot
Priya Sharma, Shubhda Sharma, S. Vidhya, M. K. Mathur
Centre for Biomedical Research, VIT University Vellore, Tamilnadu Jaipur, India
Email: priya_vit2009@yahoo.in, shubhda.vit@gmail.com, vidhyavalentina@gmail.com, drmk1@yahoo.com
Received 2013
ABSTRACT
FEA is amongst best methods that help us e rs to solve complex problems. There are fixed number of nodes in each ele-
ment of the model that define the element boundaries to which boundary condition and loads can be applied. The geo-
metry of the structure, the lo ad applications, stress and displacement gradients can be approximated in a accurate man-
ner, if the mesh is finer. The problem with the foot was unusual cracks in JP Foot and early breakage of PU Foot due to
crack propagation [1]. To solve this problem we modelled the foot using SolidWorks and performed FEA Analysis for
single leg below knee amputee patients. After analysis, it has been concluded that JP Foot as compared to PU Foot has
more stress bearing capacity but has less displacement threshold due to its material properties [2]. This work will lead to
optimization of both the feet thus enhancing the durability of foot.
Keywords: Load Applications; Crack Propagation; Durability; Solid Works; Stress; Displacement
1. Introduction
A Finite element analysis usually consists of three prin-
cipal steps:
1) Pre-processing: The user constructs a model on which
analysis needs to be done and its geometry gets divided
into multiple number of discrete elements, or sub regions,
which forms nodes while connecting at discrete poin ts [3].
2) Analysis: The user s elects restraints and proper
loads needed to be applied on the model and optimizes
the limits for stress, tolerance and factor of safety ac-
cordingly.
3) Post processing: Reports with stress and displace-
ment tables as well as plots are generated for a particular
loading condition applied on the model. FEA provides a
solution by predicting failure of designed model due to
unperceived stress by repr esenting problem areas in used
material and allowing analyst to analyse all the specula-
tive stresses within. This designing and testing of Foot
can be successfully done using SolidWorks 2008 software.
• COSMOSXp r ess is a simulation technique of solid-
works which performs FEA of solid models. It en-
sures the performance and quality of the design be-
fore it reaches to production stage. Comprehensive
analysis tools perform digital model testing for in-
sight at early stage in the process of designing [3]. It
is suitable for stress analysis of simple parts, provid-
ing the ability to simulate effect of force or pressure
loads on those parts. Thus it helps in determining
various methods to reduce material costs and weight,
to improve manufacturability and durability, to opti-
mize boundaries, and finally to compare design alter-
natives best suited to customer requirements. A 3d
model of Foot size 6 was designed using Solid Works
and FEA analysis has been performed.
2. Materials and Methodology
Materials Required for Jaipur Foot are Microcellular
rubber compound, Cosmetic rubber, Cushion rubber, and
Tread rubber. Materials Required for Polyurethane Foot
are Polyurethane foam made up of (polyol + isocynate)
and Polyurethane elastomer [2]. Physical (Density), me-
chanical (Elastic Modulus, Shear Modulus, Poisson Ratio,
Tensile Strength and Yield Strength) and thermal proper-
ties (Thermal Expansion and Thermal Conductivity) [2]
values were taken for both the foot and according to that
the material was finalized. Properties were given as an
input to software as material property before analysis.
2.1. Software Required
Software used for modelling is SOLID WORKS 2008.
Software used fo r FEA is COSMOSXp r es s Analysis
Wiz ard (A simulation Technology of Solid Works 2 008)
2.2. Data Collection
Data collection regarding the weights of the patients suf-