Finite element design of a mechanical testing method for polymer composite femoral stems

Bibliographic Details
Main Author: Heiner, Anneliese Dorothy
Language:English
Published: Case Western Reserve University School of Graduate Studies / OhioLINK 1995
Subjects:
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=case1058203976
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-case10582039762021-08-03T05:31:04Z Finite element design of a mechanical testing method for polymer composite femoral stems Heiner, Anneliese Dorothy Finite element design mechanical testing method polymer composite femoral stems Polymer composite femoral stems do not have a standardized in vitro mechanical testing method. The testing device for metallic stems, which simulates proximal resorption of the femur, is inappropriate for composite stems, which they are expected to reduce or prevent proximal resorption. The objective of this study was to determine a mechanical testing method for pressfit composite stems, using finite element analysis (FEA). The goal was to reproduce the strains of the stem implanted in a femur. Three simplified models used for preliminary studies were beam-on-elastic-foundation, two-dimensional plus sideplates FEA, and axisymmetric FEA. These models showed that stem stresses were affected by design changes to the testing device, and gave some results equivalent to those found with the more complex models. The effects on the composite stem of varying the testing device were studied using full 3-D FEA models. The stem strains were affected by design changes to the testing device. The maximum normal and interlaminar shear strains of the composite stem in the testing device were either lower than or about equal to the maximum strains of the composite stem in the femur. A single-material testing device made of birchwood was chosen as the b est testing device from the parametric study. Birchwood is an orthotropic material with a longitudinal stiffness in the range of bone. This testing device improved the stem strains which lead to composite interlaminar failure, relative to the other testing devices studied. The viability of the testing device, as measured by stresses on the bone cement or testing device and by interface motion, was also affected by changes to the testing device and stem material. Changing from a metallic stem to a composite stem increased the bone cement stresses by about twofold. Some testing device configurations had cement stresses that were close to or above static cement strengths. The birchwood testing device had high interface motion. Other stem materials were compared to the composite stem. The strains on a metallic stem and the composite stem were not always affected in the same way by changes to the testing device. An isotropic stem was a better simplification of the composite stem than was a transversely isotropic stem. 1995 English text Case Western Reserve University School of Graduate Studies / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=case1058203976 http://rave.ohiolink.edu/etdc/view?acc_num=case1058203976 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Finite element design
mechanical testing method
polymer composite
femoral stems
spellingShingle Finite element design
mechanical testing method
polymer composite
femoral stems
Heiner, Anneliese Dorothy
Finite element design of a mechanical testing method for polymer composite femoral stems
author Heiner, Anneliese Dorothy
author_facet Heiner, Anneliese Dorothy
author_sort Heiner, Anneliese Dorothy
title Finite element design of a mechanical testing method for polymer composite femoral stems
title_short Finite element design of a mechanical testing method for polymer composite femoral stems
title_full Finite element design of a mechanical testing method for polymer composite femoral stems
title_fullStr Finite element design of a mechanical testing method for polymer composite femoral stems
title_full_unstemmed Finite element design of a mechanical testing method for polymer composite femoral stems
title_sort finite element design of a mechanical testing method for polymer composite femoral stems
publisher Case Western Reserve University School of Graduate Studies / OhioLINK
publishDate 1995
url http://rave.ohiolink.edu/etdc/view?acc_num=case1058203976
work_keys_str_mv AT heineranneliesedorothy finiteelementdesignofamechanicaltestingmethodforpolymercompositefemoralstems
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