Using Stress Shielding in Hip Implants  as a Case Study to Teach Loading of Composite Beams

Blake M. Ashby; Wendy S. Reffeor

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Conference: 2016 ASEE Annual Conference & Exposition
Location: New Orleans, Louisiana
Publication Date: June 26, 2016
Start Date: June 26, 2016
End Date: June 29, 2016
ISBN: 978-0-692-68565-5
ISSN: 2153-5965
Conference Session: Teaching Methods in Mechancial Engineering
Tagged Division: Mechanical Engineering
Page Count: 14
DOI: 10.18260/p.27164
Permanent URL: https://strategy.asee.org/27164
Download Count: 880

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Paper Authors

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Blake M. Ashby P.E. Grand Valley State University

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Blake M. Ashby is an Assistant Professor of Mechanical Engineering in the School of Engineering at Grand Valley State University. His research and teaching interests include the areas of dynamics, kinematics, solid mechanics, movement biomechanics, injury biomechanics, and accident reconstruction. Prior to joining to Grand Valley State, he worked for several years as a consulting engineer with Woolley Engineering Research Corporation and Exponent Failure Analysis Associates. He received a B.S. degree in Mechanical Engineering from Utah State University and M.S. and Ph.D. degrees in Mechanical Engineering from Stanford University. He is a registered Professional Engineer.

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Wendy S. Reffeor Grand Valley State University

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Wendy Reffeor is an Associate Professor of Mechanical Engineering in the Padnos College of Engineering and Computing at Grand Valley State University. She earned her Bachelors from GMI Engineering & Management Institute, Masters from Purdue University and Doctorate from Michigan State University. Her industrial experience includes designing quality systems for Allison Engine Company in Indianapolis. Since joining GVSU, she has focused on introducing design and build projects in traditionally analytical courses in the Engineering Mechanics sequence.

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Abstract

A laboratory activity was developed in which the students modeled and analyzed the femoral portion of an artificial hip replacement as a composite beam. A historical challenge with artificial hip replacements has been that the stiffer artificial femoral component shields the surrounding bone from stresses during physiological activities. This phenomenon, known as “stress shielding,” results in bone resorption that can lead to implant failure. In this activity, the students investigated the extent of stress shielding for femoral implants of varying sizes and material properties for different loading conditions. The students discovered that making the femoral component smaller and of more compliant material minimizes the detrimental effects of stress shielding in hip replacements.

The effectiveness of this hip implant activity was studied by comparing it with the traditional laboratory in which the students were tasked with designing a composite beam out of various materials to satisfy rigidity and cost constraints. Students from two laboratory sections completed the traditional composite beams exercise, and students from two laboratory sections completed the hip implant case study. The students from both groups were surveyed before and after the laboratory exercises to determine their confidence in the course material, their interest in the course, and their perception of the real-world relevance of the course.

In the post-exercise survey, students were asked all of the questions from the pre-exercise survey as well as questions to determine the effectiveness of the exercise as a teaching tool and the adequacy of the instruction they received. Students consistently felt the hip implant activity was more effective as a teaching tool for the material and were more interested in biomedical engineering than those completing the traditional exercise. The students who completed the hip implant activity expressed greater confidence in their abilities to interpret the results for bending calculations and to design a machine using bending. Overall, the results of the student perception surveys indicate that the hip replacement activity was a better tool for teaching the composite beam theory and had the added benefit of introducing students to biomedical engineering applications of fundamental mechanics principles.

Citation
Format

Ashby, B. M., & Reffeor, W. S. (2016, June), Using Stress Shielding in Hip Implants as a Case Study to Teach Loading of Composite Beams Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.27164

TY - CPAPER
AB - A laboratory activity was developed in which the students modeled and analyzed the femoral portion of an artificial hip replacement as a composite beam. A historical challenge with artificial hip replacements has been that the stiffer artificial femoral component shields the surrounding bone from stresses during physiological activities. This phenomenon, known as “stress shielding,” results in bone resorption that can lead to implant failure. In this activity, the students investigated the extent of stress shielding for femoral implants of varying sizes and material properties for different loading conditions. The students discovered that making the femoral component smaller and of more compliant material minimizes the detrimental effects of stress shielding in hip replacements.

The effectiveness of this hip implant activity was studied by comparing it with the traditional laboratory in which the students were tasked with designing a composite beam out of various materials to satisfy rigidity and cost constraints. Students from two laboratory sections completed the traditional composite beams exercise, and students from two laboratory sections completed the hip implant case study. The students from both groups were surveyed before and after the laboratory exercises to determine their confidence in the course material, their interest in the course, and their perception of the real-world relevance of the course.

In the post-exercise survey, students were asked all of the questions from the pre-exercise survey as well as questions to determine the effectiveness of the exercise as a teaching tool and the adequacy of the instruction they received. Students consistently felt the hip implant activity was more effective as a teaching tool for the material and were more interested in biomedical engineering than those completing the traditional exercise. The students who completed the hip implant activity expressed greater confidence in their abilities to interpret the results for bending calculations and to design a machine using bending. Overall, the results of the student perception surveys indicate that the hip replacement activity was a better tool for teaching the composite beam theory and had the added benefit of introducing students to biomedical engineering applications of fundamental mechanics principles.

AU - Blake M. Ashby P.E.
AU - Wendy S. Reffeor
CY - New Orleans, Louisiana
DA - 2016/06/26
PB - ASEE Conferences
TI - Using Stress Shielding in Hip Implants as a Case Study to Teach Loading of Composite Beams
UR - https://strategy.asee.org/27164
DO - 10.18260/p.27164
ER -