Damping Optimization of 3D Printed Thermoplastic Structures for Mass Reduction
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Authors
McKenzie, Adam
Date
Type
thesis
Language
eng
Keyword
3D Printing , Thermoplastic , Viscoelastic Properties , Damping Optimization , FEA , Mass Reduction
Alternative Title
Abstract
Aerospace, automotive, and marine industries all have structures that are subject to vibrations. These vibrations can stem from aero-structural interactions on aircraft, road noise for automotives, wave impacts on marine vessels and engines in all cases. If sufficient vibrational energy is not removed from the structure through damping, there can be damage to on board structures or electronics.
Typical methods of damping a structure include the addition of fasteners or a viscoelastic material layer. These methods are widely used in industry but increase the total mass of the structure. Current damping optimizations have redistributed viscoelastic material on a metallic structure to strategically add damping. These damping optimizations use the widely accepted Modal Strain Energy (MSE) method to quantify damping using the quality factor (Q factor). However, this method is only applicable in cases that have a structural material which provides stiffness with insignificant damping, and a separate material which provides the damping with negligible stiffness. Thermoplastics have significant stiffness and damping properties which presents the possibility to use one material as both the structural material and the damping material. Additionally, in previous optimizations, users manually assigned a weight to each mode's Q factor. However, when using a single material, the natural frequencies may shift during optimization making it infeasible to manually assign these weights.
This work first presents an Improved Modal Strain Energy (IMSE) method which expands the capabilities of the MSE method to quantify the damping performance for any application. The work then presents a novel weighting method that uses kinetic energy to assign each frequency a weight which allows for shifting natural frequencies during the optimization.
The methodology developed for this thesis was applied to the PEEKbot lunar rover which is a university led project mentored by the Canadian Space Agency. The base panel of the rover was optimized to achieve a 20% damping improvement in the first mode with a 9% mass reduction. The full rover achieved a 15% damping improvement in the second mode with an 11% mass reduction.
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Attribution 4.0 International
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.