scholarly journals Design of a Monolithic Double-Slider Based Compliant Gripper with Large Displacement and Anti-Buckling Ability

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 665 ◽  
Author(s):  
Hao ◽  
Zhu
Keyword(s):  
Virtual Work ◽  
Large Displacement ◽  
Amplification Coefficient ◽  
Element Analysis ◽  
Virtual Work Principle ◽  
Manipulation System ◽  
The Finite Element Analysis ◽  
Rigid Body Model ◽  
Analytical Relations ◽  
Kinematic Mechanism

In a micro-manipulation system, the compliant gripper is used for gripping, handling and assembling of objects. Large displacement and anti-buckling characteristics are desired in the design of the gripper. In this paper, a compliant gripper with these two characteristics is proposed, modelled and verified. The large displacement is enabled by using distributed compliance in a double-slider kinematic mechanism. An inverted flexure arrangement enables the anti-buckling of the gripper when closing the two jaws. A pseudo-rigid-body model (PRBM) method with the help of virtual work principle is employed to obtain several desired analytical relations including the amplification coefficient and kinetostatics. The results of the finite element analysis (FEA) are shown to be consistent with the results of the derived analytical model. An experimental test was carried out through a milling machined aluminium alloy prototype, the results of which verify the good performance of the compliant gripper.

Force-Displacement Model of the FlexSuRe™ Spinal Implant

2010 ◽  
Author(s):  
Eric Stratton ◽  
Larry Howell ◽  
Anton Bowden
Keyword(s):  
Rigid Body ◽  
Virtual Work ◽  
Implant Design ◽  
Element Analysis ◽  
Spinal Implant ◽  
Body Model ◽  
Flexion Extension ◽  
Rigid Body Model ◽  
Displacement Model ◽  
Force Displacement

This paper presents modeling of a novel compliant spinal implant designed to reduce back pain and restore function to degenerate spinal disc tissues as well as provide a mechanical environment conducive to healing of the tissues. Modeling was done through the use of the pseudo-rigid-body model. The pseudo-rigid-body model is a 3 DOF mechanism for flexion-extension (forward-backward bending) and a 5 DOF mechanism for lateral bending (side-to-side). These models were analyzed using the principle of virtual work to obtain the force-deflection response of the device. The model showed good correlation to finite element analysis and experimental results. The implant may be particularly useful in the early phases of implant design and when designing for particular biological parameters.

LARGE DISPLACEMENT BEAM MODEL FOR CREEP BUCKLING ANALYSIS OF FRAMED STRUCTURES

2009 ◽  
Vol 09 (01) ◽  
pp. 61-83 ◽  
Author(s):  
GORAN TURKALJ ◽  
DOMAGOJ LANC ◽  
JOSIP BRNIC
Keyword(s):  
Virtual Work ◽  
Buckling Analysis ◽  
Large Displacement ◽  
Isotropic Hardening ◽  
Beam Model ◽  
Inelastic Behavior ◽  
Equilibrium Equations ◽  
Virtual Work Principle ◽  
Framed Structures ◽  
Spatial Beam

In this work, a one-dimensional beam model for buckling analysis of framed structures under large displacement creep regimes is presented. The equilibrium equations of a prismatic and straight spatial beam element are formulated in the framework of corotational description, using the virtual work principle. Although the translations and rotations of the element are allowed to be large, the strains are assumed to be small. The material of a framed structure is assumed to be homogenous and isotropic. The bilinear elastic–plastic model with isotropic hardening and the power creep law are adopted for describing the inelastic behavior of the material. The numerical algorithm is implemented in a computer program called BMCA and its reliability is validated through test examples.

scholarly journals Simplified PRBMs of spatial compliant multi-beam modules for planar motion

2013 ◽  
Vol 4 (2) ◽  
pp. 311-318 ◽  
Author(s):  
G. Hao
Keyword(s):  
Rigid Body ◽  
Compliant Mechanisms ◽  
Virtual Work ◽  
Planar Motion ◽  
Nonlinear Constraint ◽  
Element Analysis ◽  
Virtual Work Principle ◽  
Slender Beams ◽  
Cross Axis ◽  
Stiffening Effect

Abstract. PRBMs (pseudo-rigid-body models) have been becoming important engineering technologies/methods in the field of compliant mechanisms to simplify the design and analysis through the use of the knowledge body of rigid-body mechanisms coupling with springs. This article addresses the PRBMs of spatial multi-beam modules for planar motion, which are composed of three or more symmetrical wire/slender beams parallel to each other where the planar twisting DOF (degree of freedom) is assumed to be very small for specific applications/loading conditions. Simplified PRBMs are firstly proposed through replacing each beam in spatial multi-beam module with a rigid-body link plus two identical spherical joints at its two ends. The characteristics factor, bending stiffness and twisting stiffness for the spherical joint are determined. Load-displacement equations are then derived for a class of spatial multi-beam modules and general spatial multi-beam modules using the virtual work principle and kinematic relationships. Finally, nonlinear FEA (finite element analysis) is employed with comparisons with the PRBMs. The present PRBMs have shown the ability to predict the primary nonlinear constraint characteristics such as load-stiffening effect, cross-axis coupling in the two primary translational directions and buckling load.

Finite Element Analysis of Pressurized Fabric Beams With Material Nonlinearity

2006 ◽  
Author(s):  
Hui Zhang ◽  
William G. Davids ◽  
Michael L. Peterson ◽  
Adam Turner ◽  
Christopher Malm
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Virtual Work ◽  
Material Nonlinearity ◽  
Woven Fabric ◽  
Nonlinear Material ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Bend Tests ◽  
Point Bend

This paper presents a finite element analysis of inflated fabric beams that considers nonlinear material response and shear deformations. Applying the principle of virtual work, we obtain the FEM formulation for inflated fabric beams with material nonlinearity. Comparisons between 4-point bend tests of inflated woven fabric beams and finite element results indicate that the finite element analysis provides good estimates of deflections, and that it is important to incorporate the effects of shear deformation and pressure when predicting inflated fabric beam response.

A two degrees of freedom comb capacitive-type accelerometer with low cross-axis sensitivity

2019 ◽  
Vol 13 (3) ◽  
pp. 5334-5346
Author(s):  
M. N. Nguyen ◽  
L. Q. Nguyen ◽  
H. M. Chu ◽  
H. N. Vu
Keyword(s):  
Degrees Of Freedom ◽  
Proof Mass ◽  
Vibration Modes ◽  
Electrode Structure ◽  
Element Analysis ◽  
Mechanical Coupling ◽  
Fully Differential ◽  
Mode Effects ◽  
The Finite Element Analysis ◽  
Cross Axis

In this paper, we report on a SOI-based comb capacitive-type accelerometer that senses acceleration in two lateral directions. The structure of the accelerometer was designed using a proof mass connected by four folded-beam springs, which are compliant to inertial displacement causing by attached acceleration in the two lateral directions. At the same time, the folded-beam springs enabled to suppress cross-talk causing by mechanical coupling from parasitic vibration modes. The differential capacitor sense structure was employed to eliminate common mode effects. The design of gap between comb fingers was also analyzed to find an optimally sensing comb electrode structure. The design of the accelerometer was carried out using the finite element analysis. The fabrication of the device was based on SOI-micromachining. The characteristics of the accelerometer have been investigated by a fully differential capacitive bridge interface using a sub-fF switched-capacitor integrator circuit. The sensitivities of the accelerometer in the two lateral directions were determined to be 6 and 5.5 fF/g, respectively. The cross-axis sensitivities of the accelerometer were less than 5%, which shows that the accelerometer can be used for measuring precisely acceleration in the two lateral directions. The accelerometer operates linearly in the range of investigated acceleration from 0 to 4g. The proposed accelerometer is expected for low-g applications.

Tread Depth Effects on Tire Rolling Resistance

2001 ◽  
Vol 29 (3) ◽  
pp. 134-154 ◽  
Author(s):  
J. R. Luchini ◽  
M. M. Motil ◽  
W. V. Mars
Keyword(s):  
Finite Element Analysis ◽  
Common Knowledge ◽  
Rolling Resistance ◽  
Test Method ◽  
Tire Model ◽  
Element Analysis ◽  
Truck Tires ◽  
The Finite Element Analysis ◽  
Equilibrium Test ◽  
Depth Effects

Abstract This paper discusses the measurement and modeling of tire rolling resistance for a group of radial medium truck tires. The tires were subjected to tread depth modifications by “buffing” the tread surface. The experimental work used the equilibrium test method of SAE J-1269. The finite element analysis (FEA) tire model for tire rolling resistance has been previously presented. The results of the testing showed changes in rolling resistance as a function of tread depth that were inconsistent between tires. Several observations were also inconsistent with published information and common knowledge. Several mechanisms were proposed to explain the results. Additional experiments and models were used to evaluate the mechanisms. Mechanisms that were examined included tire age, surface texture, and tire shape. An explanation based on buffed tread radius, and the resulting changes in footprint stresses, is proposed that explains the observed experimental changes in rolling resistance with tread depth.

Interactive Graphics for the Analysis of Tires

1985 ◽  
Vol 13 (3) ◽  
pp. 127-146 ◽  
Author(s):  
R. Prabhakaran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Approximate Solutions ◽  
Interactive Graphics ◽  
Element Analysis ◽  
Analysis Process ◽  
Physical Problems ◽  
The Finite Element Analysis ◽  
Analysis Computer ◽  
Discretization Technique

Abstract The finite element method, which is a numerical discretization technique for obtaining approximate solutions to complex physical problems, is accepted in many industries as the primary tool for structural analysis. Computer graphics is an essential ingredient of the finite element analysis process. The use of interactive graphics techniques for analysis of tires is discussed in this presentation. The features and capabilities of the program used for pre- and post-processing for finite element analysis at GenCorp are included.

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