Experimental Verification of Rarefied Gas Squeezed-Film Damping Models Used in MEMS

2006 ◽  
Author(s):  
Lukas Mol ◽  
Luis A. Rocha ◽  
Edmond Cretu ◽  
Reinoud F. Wolffenbuttel
Keyword(s):  
Experimental Verification ◽  
Parallel Plate ◽  
Rarefied Gas ◽  
Experimental Results ◽  
Squeeze Film ◽  
Border Effects ◽  
Knudsen Numbers ◽  
Electrostatic Mems ◽  
Simulation Errors

Existing compact parallel-plate squeeze-film models including rarefaction and border effects are verified using the experimental results of a new electrostatic MEMS actuation technique that enables full gap positioning. Measurements at high Knudsen numbers ranging from 0.03 to 0.18 are performed and results compared to the models. The simulation errors are confirmed to be lower than 20%. The experiments also indicate that both gas rarefaction and border effects have to be included in any model.

A Comparative Study of Thin-Film and Reynolds Equation Simulation Models for Squeeze Film Damping in MEMS Plate Structures

2011 ◽  
Vol 403-408 ◽  
pp. 4580-4587
Author(s):  
Wei Guo Liu ◽  
Wei Wang ◽  
Shou Jun Peng
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Knudsen Number ◽  
Parallel Plate ◽  
Reynolds Equation ◽  
Perforated Plate ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Knudsen Numbers ◽  
Viscosity Modification

Squeeze film damping effect of MEMS parallel plate structure was analyzed based on thin film and Reynolds Equation in ANSYS under the different Knudsen numbers. Perforation effect of parallel plate with certain size and operating frequency was achieved under the different Knudsen numbers, the simulation results of two methods are very close. For unperforated plate, when Knudsen number is below 0.01, the discrepancy of two simulations is nonsignificant, and it grows up with Knudsen number. But gas rarefaction effects related with Knudsen number was considered in heat transfer analogy theory and used viscosity modification according to Veijola model, two simulations get the same result. For perforated plate, the simulation discrepancy of two methods will be great because of channel flow's effect and also grow up with Knudsen number, it can't be avoided even if the channel flow's effect and viscosity modification were concerned in heat transfer analogy theory.

Transition Process From Contact to Floating State in a Squeeze Air Film

1998 ◽  
Vol 120 (1) ◽  
pp. 60-68 ◽  
Author(s):  
K. Kajiwara ◽  
Y. Harayama ◽  
R. Ueda ◽  
T. Sonoda
Keyword(s):  
Parallel Plate ◽  
Direct Detection ◽  
Transition Process ◽  
Experimental Results ◽  
Experimental Result ◽  
Test Material ◽  
Squeeze Film ◽  
The Time Domain ◽  
Dc Current ◽  
Air Film

This paper presents a series of trials of direct detection of the transition process of a squeeze film, from the contacting state into the floating one. The material was initially placed on the surface of a vibrator constituting a squeeze air film. Three electrical trials were performed to certify whether the material could be elevated after the vibrator was excited. When this is done, clearance is expected between the surfaces of the test material and the vibrator. This may be regarded as the equivalent of a change in electrical resistance from almost zero to infinity, with a kind of parallel-plate capacitor being formed. First, detection through DC current was carried out. The experimental result, however, reveals that the resistance never does become infinite, although the equivalent contacting area calculated from this value is very small. Second, detection through DC voltage was performed by terminating the clearance with parallel resistance. The experimental results verify the appearance of the floating state. Third, the average clearance could be detected by regarding it as a parallel-plate type capacitor. Here a Langevin type piezoelectric transducer was used as the vibrator. Through these experimental results an important fact was observed: the waveform of the voltage applied to the transducer is closely related to the movement of the clearance in the time domain.

Investigation of the Squeeze Film Dynamics Underneath a Microstructure With Large Oscillation Amplitudes and Inertia Effects

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Nadim A. Diab ◽  
Issam A. Lakkis
Keyword(s):  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Squeeze Film ◽  
Dsmc Method ◽  
Inertia Effects ◽  
Flow Parameters ◽  
Fluid Behavior ◽  
Dimensionless Groups ◽  
Simulation Monte Carlo ◽  
The Impact

This paper presents direct simulation Monte Carlo (DSMC) numerical investigation of the dynamic behavior of a gas film in a microbeam. The microbeam undergoes large amplitude harmonic motion between its equilibrium position and the fixed substrate underneath. Unlike previous work in literature, the beam undergoes large displacements throughout the film gap thickness and the behavior of the gas film along with its impact on the moving microstructure (force exerted by gas on the beam's front and back faces) is discussed. Since the gas film thickness is of the order of few microns (i.e., 0.01 < Kn < 1), the rarefied gas exists in the noncontinuum regime and, as such, the DSMC method is used to simulate the fluid behavior. The impact of the squeeze film on the beam is investigated over a range of frequencies and velocity amplitudes, corresponding to ranges of dimensionless flow parameters such as the Reynolds, Strouhal, and Mach numbers on the gas film behavior. Moreover, the behavior of compressibility pressure waves as a function of these dimensionless groups is discussed for different simulation case studies.

Stresses in compact end closures for cylindrical pressure vessels

1969 ◽  
Vol 4 (1) ◽  
pp. 57-64
Author(s):  
R W T Preater
Keyword(s):  
Cylindrical Shell ◽  
Rigid Body ◽  
Optimum Design ◽  
Cross Section ◽  
Experimental Verification ◽  
Pressure Vessels ◽  
Rigid Body Motion ◽  
Experimental Results ◽  
Body Motion ◽  
Annular Ring

Three different assumptions are made for the behaviour of the junction between the cylindrical shell and the end closure. Comparisons of analytical and experimental results show that the inclusion of a ‘rigid’ annular ring beam at the junction of the cylider and the closure best represents the shell behaviour for a ratio of cylinder mean radius to thickness of 3–7, and enables a prediction of an optimum vessel configuration to be made. Experimental verification of this optimum design confirms the predictions. (The special use of the term ‘rigid’ is taken in this context to refer to a ring beam for which deformations of the cross-section are ignored but rigid body motion is permitted.)

EXPERIMENTAL VERIFICATION OF PYRAGAS’S CHAOS CONTROL METHOD APPLIED TO CHUA’S CIRCUIT

1994 ◽  
Vol 04 (06) ◽  
pp. 1703-1706 ◽  
Author(s):  
P. CELKA
Keyword(s):  
Periodic Orbits ◽  
Experimental Verification ◽  
Chaos Control ◽  
Control Method ◽  
Experimental Results ◽  
Experimental Setup ◽  
Chua’S Circuit ◽  
Unstable Periodic Orbits ◽  
Chua's Circuit

We have built an experimental setup to apply Pyragas’s [1992, 1993] control method in order to stabilize unstable periodic orbits (UPO) in Chua’s circuit. We have been able to control low period UPO embedded in the double scroll attractor. However, experimental results show that the control method is useful under some restrictions we will discuss.

A hybrid linear actuator based on screw clamp operation principle: Design and experimental verification

2021 ◽  
pp. 1045389X2110643
Author(s):  
Yunlai Shi ◽  
Haichao Sun ◽  
Dingji Cheng ◽  
Jun Zhang ◽  
Yuyang Lin ◽  
...  
Keyword(s):  
Experimental Verification ◽  
Peak Power ◽  
Piezoelectric Element ◽  
Experimental Results ◽  
Linear Actuator ◽  
Electromagnetic Torque ◽  
Feed Screw ◽  
Piezoelectric Stacks ◽  
Maximum Thrust

This paper presents a hybrid linear actuator using screw clamp operation principle. The actuator mainly consists of a hollow electromagnetic torque motor located between two clamping nuts, two hollow cylindrical shaped piezoelectric stacks symmetrically configured at two ends of the actuator and a feed-screw (also considered as the mover of the actuator) assembled throughout all the parts. The torque motor is symmetrically connected to two clamping nuts via two torsion coupling springs located at either end of the motor spindle. Two piezoelectric stacks can work independently to propel the opposing loads, which effectively take advantage of the anti-compression and non-tensile characteristics of piezoelectric element. The special feature of the actuator is the screw clamp mechanism, the operation of which involves intermittent rotation of two nuts (driven by the torque motor) on a feed-screw to achieve the bi-direction piezoelectric motion accumulation. Furthermore, the application of feed-screw could decrease the actuator’s sensitivity to wear, in order to realize a rigid self-locking and thus ensure the actuator’s holding capacity. A prototype was fabricated and the experimental results show that the no-load speed, maximum thrust, and peak power of the actuator were 20 mm/s, 280 N, and 1.54 W, respectively.

Currents induced in a model of a rat exposed to EMP in a parallel-plate line: Calculations and experimental results

1992 ◽  
Vol 13 (5) ◽  
pp. 439-443 ◽  
Author(s):  
Ben-Qing Gao ◽  
Om P. Gandhi ◽  
Satnam Mathur ◽  
Frank Bates ◽  
Howard Bassen
Keyword(s):  
Parallel Plate ◽  
Experimental Results

Experimental verification and validation of nonlocal peridynamic approach for simulating guided Lamb wave propagation and damage interaction

2019 ◽  
Vol 18 (5-6) ◽  
pp. 1789-1802 ◽  
Author(s):  
Subir Patra ◽  
Hossain Ahmed ◽  
Mohammadsadegh Saadatzi ◽  
Sourav Banerjee
Keyword(s):  
Wave Propagation ◽  
Structural Health Monitoring ◽  
Nondestructive Evaluation ◽  
Health Monitoring ◽  
Experimental Verification ◽  
Lamb Wave ◽  
Verification And Validation ◽  
Experimental Results ◽  
Lamb Wave Propagation ◽  
Wave Modes

In this article, experimental verification and validation of a peridynamics-based simulation technique, called peri-elastodynamics, are presented while simulating the guided Lamb wave propagation and wave–damage interaction for ultrasonic nondestructive evaluation and structural health monitoring applications. Peri-elastodynamics is a recently developed elastodynamic computation tool where material particles are assumed to interact with the neighboring particles nonlocally, distributed within an influence zone. First, in this article, peri-elastodynamics was used to simulate the Lamb wave modes and their interactions with the damages in a three-dimensional plate-like structure, while the accuracy and the efficacy of the method were verified using the finite element simulation method (FEM). Next, the peri-elastodynamics results were validated with the experimental results, which showed that the newly developed method is more accurate and computationally cheaper than the FEM to be used for computational nondestructive evaluation and structural health monitoring. Specifically, in this work, peri-elastodynamics was used to accurately simulate the in-plane and out-of-plane symmetric and anti-symmetric guided Lamb wave modes in a pristine plate and was extended to investigate the wave–damage interaction with damage (e.g. a crack) in the plate. Experiments were designed keeping all the simulation parameters consistent. The accuracy of the proposed technique is confirmed by performing error analysis on symmetric and anti-symmetric Lamb wave modes compared to the experimental results for pristine and damaged plates.

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