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Finite element study of a shape memory alloy bone implant

Eshghinejad, Ahmadreza
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333726695

Abstract Details

2012, Master of Science, University of Toledo, Mechanical Engineering.
Shape memory alloys have been used in several biomedical devices in recent years. Their special thermo-mechanical behavior in recovering a certain shape upon heating and being able to tolerate large deformations without undergoing the plastic transformations make them a good choice for different applications. Biocompatibility of nitinol as a widely used shape memory alloy material is the other main property for biomedical devices. Osteoporosis is a common bone disease especially in elderly people. Bone degradation as the result of osteoporosis causes loosing of screws implanted in the bone during or after surgery. A new nitinol-based device which is designed to mitigate this adverse effect has been studied. This thesis analyzes the functionality of this novel nitinol-based expandable-retractable pedicle screw. The unique feature of this screw is that it is removable as needed. The functionality of the screw is verified by experiment and compared to the results of the numerical simulation in Abaqus. This simulation tool is the combination of the numerical implementation of shape memory alloy constitutive thermo-mechanical modeling into the Abaqus UMAT Fortran subroutine and the Abaqus finite element solver. The verification of this tool in several experiments has been carried out to establish validity of the numerical approach. The effect of the designed pedicle screw in mitigating the loosing effect has also been studied. Pullout test is a common way of evaluating a bone implant. The pullout force of a normal screw out of a normal bone was simulated with finite element in Abaqus. Consequently, performance of the new design in improving pull-out strength in osteoporosis bones has been studied. This thesis presents the design of the novel pedicle screw and paves the way of evaluating various medical devices with enhanced functionality.
Mohammad Elahinia, PhD (Committee Chair)
Douglas Oliver, PhD (Committee Member)
Lesley Berhan, PhD (Committee Member)
95 p.
Mechanical Engineering
Shape memory alloy; nitinol; pedicle screw; osteoporosis

Recommended Citations

Citations

  • Eshghinejad, A. (2012). Finite element study of a shape memory alloy bone implant [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333726695

    APA Style (7th edition)

  • Eshghinejad, Ahmadreza. Finite element study of a shape memory alloy bone implant. 2012. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333726695.

    MLA Style (8th edition)

  • Eshghinejad, Ahmadreza. "Finite element study of a shape memory alloy bone implant." Master's thesis, University of Toledo, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1333726695

    Chicago Manual of Style (17th edition)

toledo1333726695
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© 2012, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.