MEEN 475 Project Presentation

1. Improving the Lifetime of a
Headband
Thomas Addison-Smith, Caitlin Carroll, Elaine Eberhardt, Neil Doran, McKenzie Sweeney
MEEN 475 - 501 : Team H
Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References
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2. Underlying Physics & Mechanics
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Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References
● Material: ABS Plastic
● Manufacturing Process: Injection Molding
● Motion: Opening to fit around head
● Concerns: Repeated stress leads to
snapping
● Environmental: Broken headbands
contribute to plastic waste
Two Main Issues:
1. Plastic headbands snap
2. Elastic headbands slip
R
PP
θ

3. Merit Index Derivations
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Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References

4. Materials Choices
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Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References
Material Fracture Toughness Elastic Modulus
Polycarbonate 2.2 2.39
Polystyrene 0.8 2.72
Aluminum Alloy 24 76.2
Steel Alloy 50 200
Titanium Alloy 55 114
PMMA 1.2 2.4
Carbon Carbon Composite 3.3 35.9

5. Results of Optimization: AHP Process
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Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References
Material Weighted
KIC
Weighted
E
Score
Steel Alloy 0.36630 0.46124 1.65508
Titanium Alloy 0.40293 0.26291 1.33168
Aluminum Alloy 0.17582 0.17573 0.7031
Carbon Carbon
Composite
0.02418 0.08279 0.21394
Polycarbonate 0.01612 0.00551 0.04326
PMMA 0.00879 0.00553 0.02864
Polystyrene 0.00586 0.00627 0.02426
KIC E
KIC 1 1/3
E 3 1
KIC E Average Weight Consistency
Measure
KIC .25 .25 .25 2
E .75 .75 .75 2
KIC and E for AHP Method
AHP Process Results
AHP Weight Calculation Results

6. References
[1] Conair Corporation. “Our New Comfy Flexible Headband.” Scünci Hair Accessories, Conair Corporation, 2015,
www.scunci.com/comfy-flexible-headband/. Accessed 3 Dec. 2017.
[2] Stratasys. “Tooling + Injection Molding Materials.” Stratasys Direct Manufacturing, Stratasys Direct, Inc., 2017,
www.stratasysdirect.com/materials/tooling-molding/. Accessed 3 Dec. 2017.
[3] Shapeways, Inc. “Strong & Flexible Plastic 3D Printing Material Information.” Shapeways.com, Shapeways, Inc.,
2017, www.shapeways.com/materials/strong-and-flexible-plastic. Accessed 3 Dec. 2017.
[4] University of Cambridge. “Toughness - Young´s Modulus Selection Map.” TLP Library Optimization of Materials
Properties in Living Systems, University of Cambridge, 2015, www.doitpoms.ac.uk/tlplib/optimisation-
biomaterials/toughness_modulus.php. Accessed 3 Dec. 2017.
[5] Minick, Moet, and J Minick. Fracture Toughness of Carbon/Carbon Composites. Office of Naval Research, Arlington,
1991, Fracture Toughness of Carbon/Carbon Composites.
[6] Suni, Ian I. “Chapter 9 Failure Mechanics.” ES 260: Materials Science and Engineering I: Fall 2012, Clarkson
University, 2012, people.clarkson.edu/~isuni/course260.htm. Accessed 3 Dec. 2017.
[7] MatWeb, LLC. "MatWeb." MatWeb Material Property Data. MatWeb, LLC, 2017. Web. 03 Dec. 2017.
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Underlying Physics & Mechanics - Merit Index Derivations - Material Choices - Results - References