Mass and stiffness deviation effect on micro ring with thermoelastic damping

다국어 초록 (Multilingual Abstract)

Vibration characteristics are an important factor for the stability of structures. Up to now, a ring model is used as a typical model for structures, and then irregularity of point mass distribution has been a main issue for the research works. And rotational speed has been an additional consideration due to the effects of the centrifugal and Coriolis Forces. In this paper, in-plane vibration of thermo-elastic micro ring structures with finite sized imperfection is to investigate. Then, in-extensionality of the model is assumed, and multiple local deviations in structure are to be represented by Heaviside step functions. Fourier's one-dimensional heat conduction equation is to analyze, and Laplace transform method is used to solve the governing equations to obtain analytical solution. Rotational speed is additionally considered and compared with previous results. In order to determine Quality factor (Q-factor) of ring model, primarily, the split of the natural frequencies are discussed with the irregularity of mass and stiffness. Furthermore, variation of Q-factor from rotating effect is researched and compared with prior results. And the mode shapes are compared between perfect and imperfect ring models.

목차 (Table of Contents)

• Abstract ‥‥‥‥‥‥‥‥‥‥‥‥ i
• Contents ‥‥‥‥‥‥‥‥‥‥‥‥ ii
• List of Tables and Figures ‥‥‥‥‥‥‥‥‥‥‥‥ iii
• List of Nomenclature ‥‥‥‥‥‥‥‥‥‥‥‥ iv
• 1. Introduction ‥‥‥‥‥‥‥‥‥‥‥‥ 1
• 2.1 Ring model ‥‥‥‥‥‥‥‥‥‥‥‥ 4
• 2.1 Ring model ‥‥‥‥‥‥‥‥‥‥‥‥ 4
• 2.2 Heat Conduction Equation ‥‥‥‥‥‥‥‥‥‥‥‥ 7
• 2.3 Boundary conditions ‥‥‥‥‥‥‥‥‥‥‥‥ 8
• 2.4 Natural frequency ‥‥‥‥‥‥‥‥‥‥‥‥ 9
• 2.5 Q-factor with rotating effect ‥‥‥‥‥‥‥‥‥‥‥‥ 11
• 3. Numerical Results ‥‥‥‥‥‥‥‥‥‥‥‥ 14
• 3.1 Code Verification ‥‥‥‥‥‥‥‥‥‥‥‥ 14
• 3.2 Numerical results ‥‥‥‥‥‥‥‥‥‥‥‥ 14
• 3.2.1 Mass and stiffness effect ‥‥‥‥‥‥‥‥‥‥‥‥ 14
• 3.2.2 Rotating effect ‥‥‥‥‥‥‥‥‥‥‥‥ 15
• 4. Conclusions and Future works ‥‥‥‥‥‥‥‥‥‥‥‥ 18
• References ‥‥‥‥‥‥‥‥‥‥‥‥ 20
• 국문 초록 ‥‥‥‥‥‥‥‥‥‥‥‥ 40