Document Type
Thesis
Date of Award
5-31-1987
Degree Name
Master of Science in Mechanical Engineering - (M.S.)
Department
Mechanical Engineering
First Advisor
Michael Pappas
Second Advisor
Harry Herman
Third Advisor
Frederick F. Buechel
Fourth Advisor
Bernard Koplik
Abstract
A three-dimensional finite element model is used to examine the stresses of the femoral hip stem prosthesis and surrounding bone, specifically at the interface between the stem and the bone. Using General Electric's GEOMOD modelling program, 3-dimensional models of the hip stem prosthesis, and both the cortical and cancellous bone, are generated. Due to the complexity of the individual models, General Electric's SUPERTAB modelling program is required to merge the three separate models into one complete model. The model is then broken down into finite elements for analysis. The model assumes isotropic properties to cortical bone and cancellous bone. Several different loading conditions, simulating loading conditions associated with normal activity are studied. The stresses on the various components at specific nodal points are computed, using General Electric's SUPERB analysis program.
The computer package available to N.J.I.T. at the time of this work is incapable of calculating the stresses on the bone and the stem. Using the finite element models generated herein, one may be able to optimize the porous coating configuration for a particular hip stem design.
In order to generate some results, an axisymmetrical element model of a femoral resurfacing cup is created. Maximum principle, shear and Von Mises stresses are generated, along with maximum displacements, for four loading conditions which occur at 2%, 9%, 41% and 52% of the walking cycle.
The results that are obtained give a good estimation of stresses in the bone/porous coating interface. However, stresses at the base of the model are not valid because, in the natural femur, there would be a distribution of these stresses along the entire length of the femur. Therefore, the stresses present in the lower section of the finite element model are ignored.
Recommended Citation
Buechel, Mark C., "Finite element stress analysis of the femoral hip stem prosthesis - bone interface" (1987). Theses. 3053.
https://digitalcommons.njit.edu/theses/3053
