Stability and Bifurcation Analysis of an Asymmetrically Electrostatically Actuated Microbeam

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Hadi Madinei ◽  
Ghader Rezazadeh ◽  
Saber Azizi
Keyword(s):  
Applied Voltage ◽  
Equilibrium Points ◽  
Pitchfork Bifurcation ◽  
Spring Model ◽  
Electrostatically Actuated ◽  
Proposed Model ◽  
Mass Spring Model ◽  
The Stability ◽  
Mass Spring ◽  
Two Degree Of Freedom

This paper deals with the study of bifurcational behavior of a capacitive microbeam actuated by asymmetrically located electrodes in the upper and lower sides of the microbeam. A distributed and a modified two degree of freedom (DOF) mass–spring model have been implemented for the analysis of the microbeam behavior. Fixed or equilibrium points of the microbeam have been obtained and have been shown that with variation of the applied voltage as a control parameter the number of equilibrium points is changed. The stability of the fixed points has been investigated by Jacobian matrix of system in the two DOF mass–spring model. Pull-in or critical values of the applied voltage leading to qualitative changes in the microbeam behavior have been obtained and has been shown that the proposed model has a tendency to a static instability by undergoing a pitchfork bifurcation whereas classic capacitive microbeams cease to have stability by undergoing to a saddle node bifurcation.

Deformation Analysis of a Compliant Underactuated Finger Grasping a Soft Object

2018 ◽  
Author(s):  
Nicolas Mouazé ◽  
Lionel Birglen
Keyword(s):  
Deformation Analysis ◽  
Spring Model ◽  
Rigid Objects ◽  
Proposed Model ◽  
Mass Spring Model ◽  
Soft Objects ◽  
Simple Mass ◽  
Computationally Intensive ◽  
Mass Spring ◽  
Soft Object

In the literature, many models of compliant fingers grasping rigid objects have been extensively discussed. However, when the objects are themselves deformable, as in many practical cases, the effect of compliant underactuated fingers onto these soft objects is generally not addressed due to the complexity of the model required for accurate results. This paper aims at addressing this issue by proposing to simulate deformations using a simple mass-spring model. This model discretizes the object similarly to how a pseudo-rigid body technique usually approximates the compliant finger. Comparisons between simulations using the proposed model and finite element analyses demonstrate that for a significant range of deformations our approach offers an efficient and accurate approximation while less computationally intensive.

A Simple Dynamic Model for Beams Subjected to Blast Loads

2012 ◽  
Vol 479-481 ◽  
pp. 1763-1767
Author(s):  
Z.N. Yin
Keyword(s):  
Dynamic Response ◽  
Deformation Behavior ◽  
Spring Model ◽  
Blast Loads ◽  
Lumped Mass ◽  
Proposed Model ◽  
Mass Spring Model ◽  
Three Degree Of Freedom ◽  
Mass Spring ◽  
The Relationship

A three Degree-of-Freedom (DoF) mass-spring model is proposed to predict the dynamic response of clamped supported beams subjected to blast loads at the mid-span of the beam. The stiffness of inelastic spring is defined from the relationship between force and mid-span displacement of beams subjected to blast loads. The lumped mass is calculated from the equivalency between the model and beam based on the fundamental frequency. Clamped supported solid beams and T-beams are taken as typical examples to verify the proposed model. And the influence of geometric parameters on deformation behavior is discussed in details.

scholarly journals Review on the 3-D simulation for weft knitted fabric

2021 ◽  
Vol 16 ◽  
pp. 155892502110125
Author(s):  
Sha Sha ◽  
Anqi Geng ◽  
Yuqin Gao ◽  
Bin Li ◽  
Xuewei Jiang ◽  
...  
Keyword(s):  
Physical Models ◽  
Spring Model ◽  
Finite Element Analyses ◽  
Knitted Fabrics ◽  
Piecewise Function ◽  
Fabric Structure ◽  
Weft Knitted Fabric ◽  
Mass Spring Model ◽  
Virtual Display ◽  
Mass Spring

There are different kinds of geometrical models and physical models used to simulate weft knitted fabrics nowadays, such as loop models based on Pierce, piecewise function, spline curve, mass-spring model, and finite element analyses (FEA). Weft knitting simulation technology, including modeling and yarn reality, has been widely adopted in fabric structure designing for the manufacturer. The technology has great potentials in both industries and dynamic virtual display. The present article is aimed to review the current development of 3-D simulation technique for weft knitted fabrics.

Microstructure-dependent dynamic stability analysis of torsional NEMS scanner in van der Waals regime

2016 ◽  
Vol 30 (18) ◽  
pp. 1650109 ◽  
Author(s):  
Javad Abdi ◽  
Maryam Keivani ◽  
Mohamadreza Abadyan
Keyword(s):  
Phase Portrait ◽  
Applied Voltage ◽  
Dynamic Instability ◽  
Equilibrium Points ◽  
Van Der Waals ◽  
Continuum Theory ◽  
Pitchfork Bifurcation ◽  
Strain Gradient Theory ◽  
Gradient Theory ◽  
Microstructure Parameters

The physico-mechanical behavior of nanoscale devices might be microstructure dependent. However, the classical continuum theory cannot correctly predict the microstructure dependency. In this paper, the strain gradient theory is employed to examine the instability characteristics of a nanoscanner with circular geometry. The governing equation of the scanner is derived incorporating the Coulomb and van der Waals (vdW) forces. The influences of applied voltage, squeeze damping and microstructure parameters on the dynamic instability of equilibrium points are studied by plotting the phase portrait and bifurcation diagrams. In the presence of the applied voltage, the phase portrait shows the saddle-node bifurcation while for freestanding scanner a subcritical pitchfork bifurcation is observed. It is concluded that the microstructure parameter enhances the torsional stability.

scholarly journals Effect of time complexities and variation of mass spring model parameters on surgical simulation

2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Salina Sulaiman ◽  
Tan Sing Yee ◽  
Abdullah Bade
Keyword(s):  
Soft Tissue ◽  
Human Liver ◽  
Soft Tissues ◽  
Surgical Simulation ◽  
Model Parameters ◽  
Spring Model ◽  
Surgical Simulator ◽  
Tissue Model ◽  
Mass Spring Model ◽  
Mass Spring

Physically based models assimilate organ-specific material properties, thus they are suitable in developing a surgical simulation. This study uses mass spring model (MSM) to represent the human liver because MSM is a discrete model that is potentially more realistic than the finite element model (FEM). For a high-end computer aided medical technology such as the surgical simulator, the most important issues are to fulfil the basic requirement of a surgical simulator. Novice and experienced surgeons use surgical simulator for surgery training and planning. Therefore, surgical simulation must provide a realistic and fast responding virtual environment. This study focuses on fulfilling the time complexity and realistic of the surgical simulator. In order to have a fast responding simulation, the choice of numerical integration method is crucial. This study shows that MATLAB ode45 is the fastest method compared to 2nd ordered Euler, MATLAB ode113, MATLAB ode23s and MATLAB ode23t. However, the major issue is human liver consists of soft tissues. In modelling a soft tissue model, we need to understand the mechanical response of soft tissues to surgical manipulation. Any interaction between haptic device and the liver model may causes large deformation and topology change in the soft tissue model. Thus, this study investigates and presents the effect of varying mass, damping, stiffness coefficient on the nonlinear liver mass spring model. MATLAB performs and shows simulation results for each of the experiment. Additionally, the observed optimal dataset of liver behaviour is applied in SOFA (Simulation Open Framework Architecture) to visualize the major effect.

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