Modeling and Experimental Validation of Actuating a Bistable Buckled Beam Via Moment Input

2015 ◽  
Vol 82 (5) ◽  
Author(s):  
Jonathon Cleary ◽  
Hai-Jun Su
Keyword(s):  
Theoretical Model ◽  
Experimental Test ◽  
Experimental Validation ◽  
Stable Equilibrium ◽  
Compliant Mechanisms ◽  
Computational Tool ◽  
Specific Mechanism ◽  
Test Setup ◽  
Buckled Beams ◽  
Buckled Beam

Bistable mechanisms have two stable equilibrium positions separated by a higher energy unstable equilibrium position. They are well suited for microswitches, microrelays, and many other macro- and micro-applications. This paper discusses a bistable buckled beam actuated by a moment input. A theoretical model is developed for predicting the necessary input moment. A novel experimental test setup was created for experimental verification of the model. The results show that the theoretical model is able to predict the maximum necessary input moment within 2.53%. This theoretical model provides a guideline to design bistable compliant mechanisms and actuators. It is also a computational tool to size the dimensions of buckled beams for actuating a specific mechanism.

Design of a Dielectric Elastomer Cylindrical Actuator With Quasi-Constant Available Thrust: Modeling Procedure and Experimental Validation

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Giovanni Berselli ◽  
Giovanni Scirè Mammano ◽  
Eugenio Dragoni
Keyword(s):  
Experimental Validation ◽  
Large Deflection ◽  
Analytical Procedure ◽  
Compliant Mechanisms ◽  
Elastic Beam ◽  
Dielectric Elastomer ◽  
Fe Analysis ◽  
Buckled Beam ◽  
Slender Beams ◽  
Novel Design

A novel design for a dielectric elastomer (DE) actuator is presented. The actuator is obtained by coupling a cylindrical DE film with a series of slender beams axially loaded beyond their buckling limit. Similar to previous published solutions, where different actuator geometries were coupled with compliant mechanisms of various topologies, the elastic beams are designed so as to provide a suitable compensating force that allows obtaining a quasi-constant available thrust along the entire actuator stroke. Whilst the elastic beam are sized on the basis of an analytical procedure, the overall system performance is evaluated by means of multiphysics finite element (FE) analysis, accounting for the large deflection of the buckled-beam springs (BBSs) and for the DE material hyperelasticity. Numerical and experimental results are finally provided, which demonstrate the prediction capabilities of the proposed modeling method and confirm that well-behaved cylindrical actuators can be conceived and produced.

scholarly journals A Class of Methods for the Analysis of Blade Tip Timing Data from Bladed Assemblies Undergoing Simultaneous Resonances—Part II: Experimental Validation

2007 ◽  
Vol 2007 ◽  
pp. 1-10 ◽  
Author(s):  
J. Gallego-Garrido ◽  
G. Dimitriadis ◽  
I. B. Carrington ◽  
J. R. Wright
Keyword(s):  
Experimental Test ◽  
Experimental Validation ◽  
Test Rig ◽  
New Techniques ◽  
Analysis Techniques ◽  
Simultaneous Resonances ◽  
Timing Data ◽  
Blade Tip ◽  
Using Data ◽  
Double Resonances

Blade tip timing is a technique for the measurement of vibrations in rotating bladed assemblies. In Part I of this work a class of methods for the analysis of blade tip timing data from bladed assemblies undergoing two simultaneous synchronous resonances was developed. The approaches were demonstrated using data from a mathematical simulation of tip timing data. In Part II the methods are validated on an experimental test rig. First, the construction and characteristics of the rig will be discussed. Then, the performance of the analysis techniques when applied to data from the rig will be compared and analysed. It is shown that accurate frequency estimates are obtained by all the methods for both single and double resonances. Furthermore, the recovered frequencies are used to calculate the amplitudes of the blade tip responses. The presence of mistuning in the bladed assembly does not affect the performance of the new techniques.

scholarly journals Social Ties and the Job Search of Recent Immigrants

ILR Review ◽  
2017 ◽  
Vol 72 (2) ◽  
pp. 355-381 ◽  
Author(s):  
Deepti Goel ◽  
Kevin Lang
Keyword(s):  
Social Networks ◽  
Theoretical Model ◽  
Job Search ◽  
Social Ties ◽  
Wage Distribution ◽  
Specific Mechanism ◽  
Recent Immigrants ◽  
The Difference

This article highlights a specific mechanism through which social networks help in job search. The authors characterize the strength of a network by its likelihood of providing a job offer. Using a theoretical model, they show that the difference between wages in jobs found using networks versus those found using formal channels decreases as the network becomes stronger. The authors verify this result for recent immigrants to Canada for whom a strong network is captured by the presence of a “close tie.” Furthermore, structural estimates confirm that the presence of a close tie operates by increasing the likelihood of generating a job offer from the network rather than by altering the network wage distribution.

A Theoretical Model for RF Ablation of Kidney Tissue and Its Experimental Validation

2010 ◽  
pp. 119-129 ◽  
Author(s):  
Mihaela Pop ◽  
Sean R. H. Davidson ◽  
Mark Gertner ◽  
Michael A. S. Jewett ◽  
Michael D. Sherar ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Experimental Validation ◽  
Kidney Tissue ◽  
Rf Ablation

Synthesizing Precompressed Beams As Bistable Compliant Mechanisms

2017 ◽  
Author(s):  
Mohammed Abdullah Maaz Siddiqui ◽  
Hong Zhou
Keyword(s):  
Rigid Body ◽  
Axial Compression ◽  
Stable Equilibrium ◽  
Compliant Mechanisms ◽  
Input Power ◽  
Elastic Deformations ◽  
Buckling Instability ◽  
Beam Thickness ◽  
Fixed End ◽  
Input Torque

Bistable mechanisms provide two stable positions. Input power is not needed to maintain any of the two stable positions. To switch from one stable position to another, input power is required. Bistable mechanisms have many applications including valves, closures, switches and various other devices. Unlike conventional rigid-body bistable mechanisms that rely on relative motions of kinematic joints, bistable compliant mechanisms take advantage of elastic deformations of flexible members to achieve two stable positions. There are two symmetric buckled shapes in a precompressed beam that has one fixed end and one pinned end. The two buckled shapes match the two stable equilibrium positions of bistable compliant mechanisms. The precompressed beam can be rotationally actuated at the pinned end to snap from one buckled shape to another. Synthesizing precompressed beams as bistable mechanisms is challenging because of buckling instability and integrated force and deflection characteristics. In this paper, the buckled shape is derived for a precompressed beam with fixed and pinned ends. The input torque at the pinned end is analyzed for a precompressed beam to snap between its two symmetric buckled shapes. Precompressed beams are synthesized as bistable compliant mechanisms through axial compression and beam thickness in this paper.

An Experimental Test Setup for Advanced Estimation and Control of an AirborneWind Energy System

2013 ◽  
pp. 459-471 ◽  
Author(s):  
Kurt Geebelen ◽  
Milan Vukov ◽  
Mario Zanon ◽  
Sébastien Gros ◽  
Andrew Wagner ◽  
...  
Keyword(s):  
Experimental Test ◽  
Energy System ◽  
Test Setup ◽  
Estimation And Control ◽  
And Control

Investigation on Free Vibration of Buckled Beams

2012 ◽  
Vol 433-440 ◽  
pp. 41-44 ◽  
Author(s):  
Ming Hsu Tsai ◽  
Wen Yi Lin ◽  
Kuo Mo Hsiao ◽  
Fu Mio Fujii
Keyword(s):  
Free Vibration ◽  
Virtual Work ◽  
Beam Theory ◽  
Taylor Series Expansion ◽  
Element Formulation ◽  
Governing Equations ◽  
Nonlinear Beam ◽  
Buckled Beams ◽  
Buckled Beam ◽  
D’Alembert Principle

The objective of this study is to investigate the deformed configuration and free vibration around the deformed configuration of clamped buckled beams by co-rotational finite element formulation. The principle of virtual work, d'Alembert principle and the consistent second order linearization of the nonlinear beam theory are used to derive the element equations in current element coordinates. The governing equations for linear vibration are obtained by the first order Taylor series expansion of the equation of motion at the static equilibrium position of the buckled beam. Numerical examples are studied to investigate the natural frequencies of clamped buckled beams with different slenderness ratios under different axial compression.

Experimental Validation of a Piezoceramic Annular Plate Theoretical Model

1996 ◽  
pp. 451-457 ◽  
Author(s):  
A. Iula ◽  
F. R. Montero de Espinosa ◽  
N. Lamberti ◽  
M. Pappalardo
Keyword(s):  
Theoretical Model ◽  
Experimental Validation ◽  
Annular Plate
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