Date of Award

10-5-2017

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

First Advisor

Altenhof, William

Keywords

axial cutting, blade, crashworthiness, deformation, deploy, impact

Abstract

A circular cutting device, referred to as the quadrotor, that adaptively changes configuration to either 4, 6, or 8 equally spaced blades and endures axially cutting through a 3.175 mm thick AA6061-T6 aluminum extrusion under impact has been developed to a manufacture-ready stage. The device comprises a pair of uniquely shaped 3-bladed cutters and 4-bladed cutters. Finite element simulations of both cutters during deployment as well as during dynamic axial cutting were generated to evaluate the device performance. Virtually, all the parts during the deployment stage of either cutter have negligible stresses. During cutting, the device was found to endure 36,000 cycles, which should equate to decades of testing. A simplified apparatus which replicates each cutter deployment was also constructed to validate the numerical models of each cutter’s deployment dynamics. As was assumed in the simulations, the neodymium magnet was necessary to catch the blade upon impact with the end stop. Also, compared to the simulations, the angular rotation of the 3-bladed cutter and 4-bladed cutter geometries with respect to time had acceptable validation metrics of 0.78 and 0.70, respectively. Friction associated with the experimental setup was more significant than expected and caused both cutters to deploy slightly slower than predicted. Nonetheless, the apparatus demonstrated a successful deployment of both cutters. The slower cutter had a total response time of 47 ms, allowing the electronic system that controls the device configuration to trigger when the impacting entity is still within close range, which is desirable. Overall, based on the findings of this thesis, the complete quadrotor is worth constructing to perform dynamic axial cutting experiments in the future.

Available for download on Wednesday, October 17, 2018

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