Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 37 for “"Pull-in"”.
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Calculation of Unbalanced Magnetic Pull in Cage Induction Machines
If the rotor of an induction motor is not concentric with the stator then an electromagnetic force is generated in a direction that will increase the eccentricity. This is called unbalanced magnetic pull (UMP). The first part of the work presented in this dissertation develops theoretical models …
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Effect of noise on the pull-in dynamics of an electrostatic microswitch
The goal of this research is to investigate the effects of noise on the pull-in dynamics of a micro-electromechanical switch. We take into account thermal noise and noise present in the voltage source. Thermal noise is modeled as white noise. First, we study its effect on the linear response of the …
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Comparative study of knowledge transfer during technology pull in complex production environments
Thesis (S.M.M.O.T.)--Massachusetts Institute of Technology, Sloan School of Management, 1998.
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Electrostatic pull-in test structure design for in-situ mechanical property measurements of microelectromechanical systems (MEMS)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Analysis by Meshless Local Petrov-Galerkin Method of Material Discontinuities, Pull-in Instability in MEMS, Vibrations of Cracked Beams, and Finite Deformations of Rubberlike Materials
The Meshless Local Petrov-Galerkin (MLPG) method has been employed to analyze the following linear and nonlinear solid mechanics problems: free and forced vibrations of a segmented bar and a cracked beam, pull-in instability of an electrostatically actuated microbeam, and plane strain deformations …
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Achieving large stable vertical displacement in surface-micromachined microelectromechanical systems (MEMS)
… and mechanical design features for realizing large planar analog vertical travel in an electrostatically actuated diffractive mid-infrared optical device, which is robust, both to manufacture, and against pull-in during use. This device, called the Polychromator, is fabricated by …
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Nonlinear Dynamics of Circular Plates under Electrical Loadings for Capacitive Micromachined Ultrasonic Transducers (CMUTs)
… an electrically actuated circular plate with an in-plane residual stress for applications in capacitive micromachined ultrasonic transducers (CMUTs). After establishing the equations governing the plate, we discretized the system by using a Galerkin approach. The distributed-parameter equations …
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Instabilities in Multiphysics Problems: Micro- and Nano-electromechanical Systems, and Heat-Conducting Thermoelastoviscoplastic Solids
We investigate (i) pull-in instabilities in a microelectromechanical (MEM) beam due to the Coulomb force and in MEM membranes due to the Coulomb and the Casimir forces, and (ii) thermomechanical instability in a heat-conducting thermoelastoviscoplastic solid due to thermal softening overcoming …
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Optimization studies of thermal bimorph cantilevers, electrostatic torsion actuators and variable capacitors
In this dissertation, theoretical analyses and optimization studies are given for three kinds of MEMS devices: thermal bimorph cantilevers, electrostatic torsion actuators, and variable capacitors. Calculation, simulation, and experimental data are used to confirm the device behavior and …
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Electrostatic zipping actuators and their applications to MEMS
… most common and well-developed method of generating motion on the micro scale. To overcome the challenge of providing both high force and large displacement, electrostatic zipping actuators have been developed and applied to various devices. As device thicknesses increase, however, conventional …
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Rough Surface Interactions of Micro/nano-Scale Contact Systems
In this work, three major issues of miniature systems in regards to contact behavior have been studied. First, nanomechanical properties of ultra-thin carbon films such as hardness and elastic modulus have been investigated using a newly developed nanoindentation technique and custom-built …
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Applications of Non-linearities in RF MEMS Switches and Resonators
The 21st century is emerging into an era of wireless ubiquity. To support this trend, the RF (Radio Frequency) front end must be capable of processing a range of wireless signals (cellular phone, data connectivity, broadcast TV, GPS positioning, etc.) spanning a total bandwidth of nearly 6 GHz. …
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Modeling and Simulation of Microelectromechanical Systems in Multi-Physics Fields
… simulate microelectromechanical systems (MEMS) in multi-physics fields. These include electric actuation (AC and DC), squeeze-film damping, thermoelastic damping, and structural forces. The second objective is to investigate MEMS phenomena, such as squeeze-film damping and dynamic pull-in, and …
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Design of curved electrodes to enable large stroke -- low voltage micro actuators
Electrostatic actuators are common in many MicroElectroMechanical Systems (MEMS) devices. These actuators tend to be fabricated as two parallel planar structures, which works well for applications where the motion and electrode spacing are small. To achieve larger displacements, very large voltages …
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Electrostatic micro actuators for mirror and other applications
… based electrostatic micro actuators are becoming important building blocks for innovations in optical signal processing and computing systems due to their inherently small size, high density, high speed and low power consumption. Generally, the principle of operation in these systems can be …
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Suspended Gate Silicon Nanodot Memory
… memory market has been driven by Flash memory since its invention more than three decades ago. Today, this non-volatile memory is used in a wide variety of devices and systems from pen drives, mp3 players to cars, planes and satellites. However,the conventional floating gate memory technology in …
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EXTREME VERTICAL DISPLACEMENT, HIGH FORCE, SILICON MICROSTAGE ZIPPER ACTUATORS
… high force microactuators are desired in MEMS for a variety of applications. This thesis details a novel large-displacement electrostatic "zipper" microactuator capable of achieving hundreds of microns of out-of-plane deflection and delivering high forces, fabricated entirely from SOI …
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Quasistatisch auslenkbarer Kippspiegel zur Ablenkung von Licht
… torsional mirror's for optical applications. The intended main area of application is the use as switch in optical network's, replacing the conventional optical-electro-optical conversation. With these actuator's a new concept of electrostatic actuation has been realised. While the drive …
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Design and implementation of MEMS biomechanical sensors for real-life measurements of gait parameters
Foot clearance above the ground during walking is an important clinical and rehabilitation gait analysis parameter. Current bulky and laboratory environment based instruments are not suitable for measurement in the natural environment such as in the outdoors. This research analyses three promising …
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Microelectromechanical (MEMS) structures for thin film property measurement
Microelectromechanical systems (MEMS) are becoming the bases for an important industry with potential applications in numerous fields. The current study explores the use of MEMS-based, electrically-actuated structures to determine thin film mechanical properties, including intrinsic stresses of …
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