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dc.contributor.authorRyan, Steven Francisen_US
dc.date.accessioned2014-03-14T20:37:51Z
dc.date.available2014-03-14T20:37:51Z
dc.date.issued2006-05-09en_US
dc.identifier.otheretd-05212006-225655en_US
dc.identifier.urihttp://hdl.handle.net/10919/33067
dc.description.abstractFinite element modeling has become a powerful tool in orthopedic biomechanics, allowing simulations with complex geometries. Current fatigue behavior simulations are unable to accurately predict the cycles to failure, creep, and damage or modulus loss even when applied to a bending model. It is thought that the inhomogeneity of the models may be the source of the problem. It has also been suggested that the volume size of the element will affect the fatigue behavior. This is called a stressed volume effect. In this thesis non-homogeneous finite element models were used to examine the effects of â sizing factorsâ on damage laws in fatigue simulations.

Non-homogeneous finite element models were created from micro computed tomography (CT) images of dumbbell shaped fatigue samples. An automatic voxel meshing technique was used which converted the CT data directly into mesh geometry and material properties.

My results showed that including these sizing factors improved the accuracy of the fatigue simulations on the non-homogeneous models. Using the Nelder-Mead optimization routine, I optimized the sizing factors for a group of 5 models. When these optimized sizing factors were applied to other models they improved the accuracy of the simulations but not as much as for the original models, but they improved the results more than with no sizing factors at all. I found that in our fatigue simulations we could account for the effects of stressed volume and inhomogeneity by including sizing factors in the life and damaging laws.

en_US
dc.publisherVirginia Techen_US
dc.relation.haspartStevenRyan.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectstressed volumeen_US
dc.subjectfatigue simulationsen_US
dc.subjectfinite element modelingen_US
dc.subjectboneen_US
dc.subjectnon-homogeneous finite element modelsen_US
dc.subjectdamageen_US
dc.subjectsizing factorsen_US
dc.titleFatigue Simulation of Human Cortical Bone using Non-Homogeneous Finite Element Models to Examine the Importance of Sizing Factors on Damage Lawsen_US
dc.typeThesisen_US
dc.contributor.departmentEngineering Mechanicsen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineEngineering Mechanicsen_US
dc.contributor.committeechairCotton, John R.en_US
dc.contributor.committeememberDowling, Norman E.en_US
dc.contributor.committeememberGrant, John Wallaceen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05212006-225655/en_US
dc.date.sdate2006-05-21en_US
dc.date.rdate2006-07-06
dc.date.adate2006-07-06en_US


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