A Novel Family of Leaf-Type Compliant Joints: Combination of Two Isosceles-Trapezoidal Flexural Pivots

2009 ◽  
Vol 1 (2) ◽  
Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Guanghua Zong ◽  
Shusheng Bi ◽  
Yida Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Range Of Motion ◽  
Rigid Bodies ◽  
The Other ◽  
Element Analysis ◽  
Leaf Type ◽  
Center Shift ◽  
Compliant Joints ◽  
Finite Element Analysis Result

The leaf-type isosceles-trapezoidal flexural (LITF) pivot consists of two compliant beams and two rigid bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of two LITF pivots. Base on the pseudorigid-body (PRB) model of a LITF pivot, a method to construct the double-LITF pivots is presented by regarding a single LITF pivot as a the configurable flexure module. The trends of the center-shift are mainly considered by using this method with the combination of two LIFT pivots. Eight types of double-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. Two of the double-LITF pivots are selected as the examples to explain the proposed method. The comparison between PRB model and finite element analysis result shows the validity and effectiveness of the method.

A Family of Butterfly Flexural Joints: Q-LITF Pivots

2011 ◽  
Author(s):  
Xu Pei ◽  
Jingjun Yu ◽  
Shusheng Bi ◽  
Guanghua Zong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rigid Body ◽  
Rigid Bodies ◽  
The Other ◽  
Element Analysis ◽  
Leaf Type ◽  
Center Shift ◽  
Body Model ◽  
Rigid Body Model

The Leaf-type Isosceles-Trapezoidal Flexural (LITF) pivot consists of two compliant beams and two rigid-bodies. For a single LITF pivot, the range of motion is small while the center-shift is relatively large. The capability of performance can be improved greatly by the combination of four LITF pivots. Base on the pseudo-rigid-body model (PRBM) of a LITF pivot, a method to construct the Quadri-LITF pivots is presented by regarding a single LITF pivot (or double-LITF pivot) as a the configurable flexure module. Ten types of Q-LITF pivots are synthesized. Compared with the single LIFT pivot, the stroke becomes larger, and stiffness becomes smaller. Four of them have the increased center-shift. The other four have the decreased center-shift. One of the quadruple LITF pivots is selected as the examples to explain the proposed method. The comparison between PRBM and Finite Element Analysis (FEA) result shows the validity and effectiveness of the method.

Study on the Thermal Field Distribution of Steel Claws for Anode in Aluminium Electrolysis Cell

2015 ◽  
Vol 1120-1121 ◽  
pp. 1089-1092
Author(s):  
Qing Dong Qin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Field Distribution ◽  
Thermal Field ◽  
Voltage Drop ◽  
The Other ◽  
Electrolysis Cell ◽  
Aluminium Electrolysis ◽  
Element Analysis ◽  
Anode Carbon

The electricity consuming of aluminium electrolysis cell is affected by the voltage drop of anode steel claws during the aluminium electrolysis course. The resistivity of anode steel claws is affected by the temperature. In the present study, the thermal field distribution of anode steel claws was studied by finite element analysis. The results show that the thermal energy of anode steel claws come from anode carbon blocks and environment. The temperature of steel claws less than 1/3 height is affected by anode carbon blocks, and the other part is affected by surrounding temperature. According the results, the principle of the new anode steel claw design is proposed.

Biomechanics of a posture-controlling cervical artificial disc: mechanical, in vitro, and finite-element analysis

2010 ◽  
Vol 28 (6) ◽  
pp. E11 ◽  
Author(s):  
Neil R. Crawford ◽  
Jeffery D. Arnett ◽  
Joshua A. Butters ◽  
Lisa A. Ferrara ◽  
Nikhil Kulkarni ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
Postural Control ◽  
Range Of Motion ◽  
Computer Modeling ◽  
Mechanical Testing ◽  
Artificial Disc ◽  
Element Analysis

Different methods have been described by numerous investigators for experimentally assessing the kinematics of cervical artificial discs. However, in addition to understanding how artificial discs affect range of motion, it is also clinically relevant to understand how artificial discs affect segmental posture. The purpose of this paper is to describe novel considerations and methods for experimentally assessing cervical spine postural control in the laboratory. These methods, which include mechanical testing, cadaveric testing, and computer modeling studies, are applied in comparing postural biomechanics of a novel postural control arthroplasty (PCA) device versus standard ball-and-socket (BS) and ball-in-trough (BT) arthroplasty devices. The overall body of evidence from this group of tests supports the conclusion that the PCA device does control posture to a particular lordotic position, whereas BS and BT devices move freely through their ranges of motion.

A Non-Prismatic Beam Element for the Optimization of Flexure Mechanisms

2020 ◽  
Author(s):  
Koen Dwarshuis ◽  
Ronald Aarts ◽  
Marcel Ellenbroek ◽  
Dannis Brouwer
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Range Of Motion ◽  
Beam Element ◽  
Precision Engineering ◽  
Element Analysis ◽  
Leaf Springs ◽  
Prismatic Beam ◽  
The Common ◽  
Flexure Joints

Abstract Flexure joints are rapidly gaining ground in precision engineering because of their predictable behavior. However the range of motion of flexure joints is limited due to loss of support stiffness in deformed configurations. Most of the common flexure joints consist of prismatic leaf springs. This paper presents a simple non-prismatic beam formulation that can be used for the efficient modelling of non-prismatic leaf springs. The resulting stiffness and stress computed by the non-prismatic beam element are compared to the results of a finite element analysis. The paper shows that the support stiffness of two typical flexure joints can be increased up to a factor of 1.9 by using non-prismatic instead of prismatic leaf springs.

Finite-Element Analysis and Reliability Test of Power Steering Gear on the Fatigue Performance

2012 ◽  
Vol 271-272 ◽  
pp. 927-931
Author(s):  
Ying Wu ◽  
Jun Li ◽  
Wen Hao Lu ◽  
Shi Yuan Xiong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Developed Countries ◽  
The Other ◽  
Fatigue Properties ◽  
Reliability Test ◽  
Element Analysis ◽  
Input Shaft ◽  
Power Steering ◽  
Fea Model

The study on power steering gear is less than other auto parts at home or abroad. Compared with developed countries, the independent design and manufacture of power steering starts late, and lacks practical and effective evaluation standards. The combination of the theoretical analysis, numerical calculation and experimental verification is the key technology to optimize the design or test to evaluate the power steering gear’s function and performance. In this paper, the power steering gear’s finite element analysis(FEA) model was built to analyse the fatigue stress and fatigue life of the power steering gear’s components, such as housing, input shaft and output shaft. and the fatigue test of the power steering gear was also designed and implemented. Research showed that, the power steering gear fatigue properties of FEA and reliability test have the same results. The total damage of 4 A-B-C event cycles is less than 1, the steering gear system is judged safe after 4 event cycles per design requirements. Each component of the power steering gear has different maximum average stress. The stress of the sector shaft, the piston and the screws is very close to the yield stress, which is much larger than the other components, and needed to be treated with caution The maximum stresses of the gear housing are a little over the yield strengths at the stress of 6,118 lbs, which is more dangerous than the other components, and great attention should be paid to it.

Workspace Comparison Between 3-PRR and 3-RPR Micro-Manipulator

2012 ◽  
Author(s):  
Yi Dong ◽  
Feng Gao ◽  
Yi Yue ◽  
Jin Feng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
The Other ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Structural Differences ◽  
Micro Manipulator

This paper presents two compliant micro-manipulators with different structures. One uses 3-PRR mechanism while the other one adopts 3-RPR mechanism. Both of the two micro-manipulators have two translational degrees of freedom (DOF) and one rotational DOF. But the properties, such as workspace, of the two micro-manipulators are not the same. In this paper, the workspaces are studied and compared. First, the structural differences are presented. Then, the stiffness derivations of the two micro-manipulators are given and the workspaces are calculated considering the properties of piezoelectric (PZT) actuators. Finally the finite element analysis and prototype experiments are performed to validate the obtained results.

scholarly journals ANALYSIS OF SPOT WELDING ELECTRODE

2013 ◽  
pp. 263-268
Author(s):  
RAJANARENDER REDDY PINGILI
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
The Other ◽  
Element Analysis ◽  
Resistance Spot ◽  
Electrode Shape ◽  
The Finite Element Analysis ◽  
Welding Electrode

Electric resistance spot welding has been extensively used for many years in the automotive and aerospace industry for joining body sheet components. Compared to other welding processes such as arc welding process, resistance spot welding is fast, easily automated and easily maintained. Accurate thermal analysis of spot welding electrode could permit critical design parameters to be identified for improved electrode life. It is a complex process where coupled interactions exist between electrical, thermal and mechanical phenomena. On the other hand, finite element method (FEM), which can deal with nonlinear behaviors and complex boundary conditions, provides a powerful tool for studying these interactions and has become the most important method for the analysis of resistance spot welding. In this study, a 2-D finite element model has been developed to predict the transient thermal behavior of spot welding electrodes. The model included heat transfer analysis, electrical field analysis and phase change during melting or solidification and temperature dependant material properties, and also their inter-dependence. The contacts at faying surface and at electrode – work interface, with temperature dependant contact resistances were modeled. Three types of electrode shapes – flat, pointed and dome nose were analyzed. Temperature distribution on each electrode shape was obtained from the finite element analysis. Maximum temperature of 2876 ºC was observed in dome nose electrode in 0.2 seconds of welding time. Dome nose electrode requires a minimum weld time of all the other electrode shapes to get the required nugget size, resulting in the least power consumption. Nugget size was predicted for each electrode shape. Experimental results obtained were in good agreement with the finite element analysis results.

Contact Between Elastic Bodies With an Elliptic Contact Interface in Torsion

1997 ◽  
Vol 64 (1) ◽  
pp. 144-148 ◽  
Author(s):  
J. F. Cuttino ◽  
T. A. Dow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
The Other ◽  
Contact Interface ◽  
Element Analysis ◽  
Elastic Bodies ◽  
Torque Generation ◽  
Elliptical Contact ◽  
Elliptic Contact

When two elastic three-dimensional bodies of specified radii come into contact, Hertzian forces at the interface result in the formation of an elliptical contact area. The rotation of one body relative to the other about an axis normal to the contact induces a nonlinear torque due to the progression of sliding in the contact interface. Using finite element analysis, a relationship describing torsional compliance with slip is presented for two elastic bodies with an elliptic contact interface under pure twist. The effect of changing material and geometric parameters is studied, and the relationships between torque generation and angle are defined with respect to these nondimensionalized parameters.

Finite Element Modeling in Musculoskeletal Biomechanics

2004 ◽  
Vol 20 (4) ◽  
pp. 336-366 ◽  
Author(s):  
Thomas D. Brown
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Approximation ◽  
The Other ◽  
Finite Element Models ◽  
Element Analysis ◽  
Femoral Head Osteonecrosis ◽  
Implant Dislocation ◽  
Technical Considerations

Numerical approximation of the solutions to continuum mechanics boundary value problems, by means of finite element analysis, has proven to be of incalculable benefit to the field of musculoskeletal biomechanics. This article briefly outlines the conceptual basis of finite element analysis and discusses a number of the key technical considerations involved, specifically from the standpoint of effective modeling of musculoskeletal structures. The process of conceiving, developing, validating, parametrically exercising, and interpreting the results of musculoskeletal finite element models is described. Pertinent case study examples are presented from two series of finite element models, one involving total hip implant dislocation and the other involving femoral head osteonecrosis.

scholarly journals Preliminary Finite Element Analysis of Locomotive Crashworthy Components

2011 ◽  
Author(s):  
Patricia Llana ◽  
Richard Stringfellow
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Management ◽  
New Technologies ◽  
The Other ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Passenger Trains ◽  
Deformation Modes

The Office of Research and Development of the Federal Railroad Administration (FRA) and the Volpe Center are continuing to evaluate new technologies for increasing the safety of passengers and operators in rail equipment. In recognition of the importance of override prevention in train-to-train collisions in which one of the vehicles is a locomotive, and in light of the success of crash energy management technologies in cab car-led passenger trains, the Volpe Center seeks to evaluate the effectiveness of components that could be integrated into the end structure of a locomotive that are specifically designed to mitigate the effects of a collision and, in particular, to prevent override of one of the lead vehicles onto the other. A research program is being conducted that aims to develop, fabricate and test two crashworthy components for the forward end of a locomotive: (1) a deformable anti-climber, and (2) a push-back coupler. Preliminary designs for these components have been developed. This paper provides details on the finite element models of the crashworthy components and how the component designs behave in the finite element analyses. The component designs will be evaluated to determine if the requirements have been met, such as the energy absorption capability, deformation modes, and force/crush characteristics.

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