Experiments in vibro-impact beam dynamics and a system exhibiting a landau-zener quantum effect

Mane, Mercedes

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https://hdl.handle.net/2142/18326 Copy

Description

Title

Experiments in vibro-impact beam dynamics and a system exhibiting a landau-zener quantum effect

Author(s)

Mane, Mercedes

Issue Date

2011-01-14T22:46:19Z

Director of Research (if dissertation) or Advisor (if thesis)

Bergman, Lawrence A.

Department of Study

Aerospace Engineering

Discipline

Aerospace Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Vibro-Impacts
• Landau-Zener Tunneling
• Cantilever beam

Abstract

This report describes the model of a system comprised of a cantilever beam bilaterally constrained at the tip where the spacing between the beam and the stop was varied. The purpose of this work was to model the system, simulate it, and validate the numerical results with experimental data. It is important to mention that it is not the purpose of this work to obtain point-wise correspondence between the two systems, model and physical, but to obtain an algorithm that can be easily modified to study key parameters, such as clearance between beam and stop, impact stiffness and energy dissipation. To verify the piecewise-smooth simulation algorithm, three stop cases are considered. With each kind of stop, different information is obtained about the system. With the first setup, wherein transducers were used as stops, it was possible to measure the exact time of impact and how the impacts evolved over time. In the second arrangement the stops are heavy stainless steel blocks. In this setup the dynamics of the stops are minimized. In the third setup, thin aluminum plates are used as stops. Here, the plates flex during impact, and more complicated dynamics that are not modeled are introduced into the system. The position of the forcing as well as the kind of forcing are studied to try to understand how the system behaves. The best agreement between the model and experiment was obtained with the heavy stainless steel stop setup. In this case the dynamics of the system were limited, and the model of the stop as a spring-damper was a reasonable approximation of the system. Overall, the model and the algorithm used to detect the impacts successfully predict the impacts and thus the code can be used to further investigate ways to identify systems with vibro-impact characteristics. This report also includes the setup for a Landau-Zener Tunneling experiment involving two pendulums, one with fixed length and one with variable length. The experimental setup and tools used will be described, and some experimental results showing agreement with analytical data will be shown. It is important to understand that the theoretical and analytical research for this part of the thesis was fully developed by Manevitch et al., and only experimental validation was performed by the author.

Graduation Semester

2010-12

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http://hdl.handle.net/2142/18326

Copyright and License Information

Copyright 2010 Mercedes Mane

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