Modeling of a Cartwheel Flexural Pivot

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Bi Shusheng ◽  
Zhao Hongzhe ◽  
Yu Jingjun
Keyword(s):  
Parametric Design ◽  
Bending Moment ◽  
Equivalent Model ◽  
Vertical Force ◽  
Element Analysis ◽  
Rotational Angle ◽  
Single Beam ◽  
Primary Motion ◽  
Center Shift ◽  
Parasitic Motion

A cartwheel flexural pivot has a small center shift as a function of loading and ease of manufacturing. This paper addresses an accurate model that includes the loading cases of a bending moment combined with both a horizontal force and a vertical force. First, a triangle flexural pivot is modeled as a single beam. Then, the model of cartwheel flexural pivot based on an equivalent model is developed by utilizing the results of the triangle pivot. The expressions for rotational displacement and center shift are derived to evaluate the primary motion and the parasitic motion; the maximum rotational angle is simply formulated to predicate the range of motion. Finally, the model is verified by finite element analysis. The relative error of the primary motion is less than 1.1% for various loading cases even if the rotational angle reaches ±20 deg, and the predicted errors for the two center shift components are less than 15.4% and 7.1%. The result shows that the model is accurate enough for designers to use for initial parametric design studies, such as for conceptual design.

The Accurate Modeling and Performance Analysis of Cross-Spring Pivot as a Flexure Module

2008 ◽  
Author(s):  
Hongzhe Zhao ◽  
Shusheng Bi ◽  
Jingjun Yu ◽  
Guanghua Zong
Keyword(s):  
Compliant Mechanisms ◽  
Bending Moment ◽  
Element Analysis ◽  
Rotational Angle ◽  
Rotational Displacement ◽  
Center Shift ◽  
Rotational Element ◽  
Displacement Behavior ◽  
And Performance ◽  
Relative Errors

The load-displacement behavior of a cross-spring pivot as a kind of rotational element or module in compliant mechanisms is a subject of keen interest for many researchers. The model allowing not only quick design but also characteristics capture is pursued. This paper addresses some accurate closed-form results via approximations. These expressions are simple for a designer to understand the parameters without resorting to a tedious iterative procedure. The rotational displacement and center shift of the pivot are analyzed both qualitatively and quantitatively, with a general-purposed load applied including bending moment, horizontal and vertical forces. Meanwhile, a concise expression for center shift without approximations is proposed. The validity of the model is verified by finite element analysis (FEA). The relative error of the rotational displacement is less than 1.8% even if the rotational angle reaches ±20° the relative errors for the two components of center shift are less than 6% and 4% respectively, in the case of typical but general configurations and loads.

Analytical Modeling and Analysis of an Annulus-Shaped Flexural Pivot

2012 ◽  
Author(s):  
Yanbin Yao ◽  
Shusheng Bi ◽  
Hongzhe Zhao
Keyword(s):  
Analytical Modeling ◽  
Compliant Mechanisms ◽  
Bending Moment ◽  
Vertical Force ◽  
Rotational Stiffness ◽  
Element Analysis ◽  
Rotational Angle ◽  
Modeling And Analysis ◽  
The Finite Element Analysis ◽  
Constraint Model

Annulus-shaped flexural pivots (ASFP), composed of three or more identical leaves that are symmetrically arrayed in an annulus, can be used widely in compliant mechanisms for their excellent performances. This paper proposes the accurate load-rotation models of ASFP with three straight leaves, which include the load cases of bending moment combined with horizontal force and vertical force. Firstly, the load-rotation models of ASFP are derived based on the Beam Constraint Model (BCM). Then, the rotational stiffness and buckling characteristics are analyzed based on the derived models. Finally, the accuracy of the models is validated by the finite element analysis (FEA). The relative error of the load-rotation models is within 7% for various load cases even if the rotational angle reaches 0.07 (4°). The results show that the models are accurate enough to be used for initial parametric designing of ASFP.

scholarly journals Finite Element Analysis and Parametric Study of Spudcan Footing Geometries Penetrating Clay Near Existing Footprints

2019 ◽  
Vol 7 (6) ◽  
pp. 175 ◽  
Author(s):  
Long Yu ◽  
Heyue Zhang ◽  
Jing Li ◽  
Xian Wang
Keyword(s):  
Bending Moment ◽  
Vertical Force ◽  
Leg Length ◽  
Element Analysis ◽  
Centrifuge Tests ◽  
Flat Base ◽  
Key Factor ◽  
The Stability ◽  
Resultant Forces ◽  
Theoretical Analyses

Most existing research on the stability of spudcans during reinstallation nearing footprints is based on centrifuge tests and theoretical analyses. In this study, the reinstallation of the flat base footing, fusimform spudcan footing and skirted footing near existing footprints are simulated using the coupled Eulerian–Lagrangian (CEL) method. The effects of footprints’ geometry, reinstallation eccentricity (0.25D–2.0D) and the roughness between spudcan and soil on the profiles of the vertical force, horizontal force and bending moment are discussed. The results show that the friction condition of the soil–footing interface has a significant effect on H profile but much less effect on M profile. The eccentricity ratio is a key factor to evaluate the H and M. The results show that the geometry shape of the footing also has certain effects on the V, H, and M profiles. The flat base footing gives the lowest peak value in H but largest in M, and the performances of the fusiform spudcan footing and the skirted footing are similar. From the view of the resultant forces, the skirted footing shows a certain potential in resisting the damage during reinstallation near existing footprints by comparing with commonly used fusiform spudcan footings. The bending moments on the leg–hull connection section of different leg length at certain offset distances are discussed.

scholarly journals Modeling Stray Capacitances of High-Voltage Capacitive Dividers for Conventional Measurement Setups

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1262
Author(s):  
Alessandro Mingotti ◽  
Federica Costa ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli ◽  
Paolo Mazza
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Equivalent Circuit ◽  
High Voltage ◽  
Equivalent Model ◽  
Simulation Environment ◽  
Element Analysis ◽  
Ratio Error ◽  
Complicated Geometries

Stray capacitances (SCs) are a serious issue in high-voltage (HV) applications. Their presence can alter the circuit or the operation of a device, resulting in wrong or even disastrous consequences. To this purpose, in this work, we describe the modeling of SCs in HV capacitive dividers. Such modeling does not rely on finite element analysis or complicated geometries; instead, it starts from an equivalent circuit of a conventional measurement setup described by the standard IEC 61869-11. Once the equivalent model including the SCs is found, closed expressions of the SCs are derived starting from the ratio error definition. Afterwards, they are validated in a simulation environment by implementing various circuit configurations. The results demonstrate the expressions applicability and effectiveness; hence, thanks to their simplicity, they can be implemented by system operators, researchers, and manufacturers avoiding the use of complicated methods and technologies.

Character Analysis of Balance and Imbalance of Varying Rigidity of Rigid Pile Composite Foundation under Seismic Load

2014 ◽  
Vol 1065-1069 ◽  
pp. 19-22
Author(s):  
Zhen Feng Wang ◽  
Ke Sheng Ma
Keyword(s):  
Finite Element ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Composite Foundation ◽  
Seismic Load ◽  
Seismic Loads ◽  
Element Analysis ◽  
Rigid Pile ◽  
Rigid Pile Composite Foundation

Based on ABAQUS finite element analysis software simulation, the finite element model for dynamic analysis of rigid pile composite foundation and superstructure interaction system is established, which selects the two kinds of models, by simulating the soil dynamic constitutive model, selecting appropriate artificial boundary.The influence of rigid pile composite foundation on balance and imbalance of varying rigidity is analyzed under seismic loads. The result shows that the maximum bending moment and the horizontal displacement of the long pile is much greater than that of the short pile under seismic loads, the long pile of bending moment is larger in the position of stiffness change. By constrast, under the same economic condition, the aseismic performance of of rigid pile composite foundation on balance of varying rigidity is better than that of rigid pile composite foundation on imbalance of varying rigidity.

Preliminary Parametric Assessment of a Bolted Endplate Joint under Combined Axial Force and Cyclic Bending Moment

2011 ◽  
Vol 255-260 ◽  
pp. 718-721
Author(s):  
Z.Y. Wang ◽  
Q.Y. Wang
Keyword(s):  
Finite Element Analysis ◽  
Axial Force ◽  
Seismic Design ◽  
Axial Load ◽  
Failure Modes ◽  
Bending Moment ◽  
Element Analysis ◽  
Cyclic Behaviour ◽  
Joint Behaviour ◽  
Steel Joints

Problems regarding the combined axial force and bending moment for the behaviour of semi-rigid steel joints under service loading have been recognized in recent studies. As an extended research on the cyclic behaviour of a bolted endplate joint, this study is performed relating to the contribution of column axial force on the cyclic behaviour of the joint. Using finite element analysis, the deteriorations of the joint performance have been evaluated. The preliminary parametric study of the joint is conducted with the consideration of flexibility of the column flange. The column axial force was observed to significantly influence the joint behaviour when the bending of the column flange dominates the failure modes. The reductions of moment resistance predicted by numerical analysis have been compared with codified suggestions. Comments have been made for further consideration of the influence of column axial load in seismic design of bolted endplate joints.

The Study of CAD/CAE Integrated Technology in Network Environment

2010 ◽  
Vol 145 ◽  
pp. 567-572
Author(s):  
Hua Ding ◽  
Zhao Jian Yang ◽  
Xue Wen Wang ◽  
Zhi Yong Ding
Keyword(s):  
Parametric Design ◽  
Parametric Modeling ◽  
Component Technology ◽  
Secondary Development ◽  
Element Analysis ◽  
Development Tool ◽  
Database Technology ◽  
Remote Design ◽  
Parametric Finite Element Analysis ◽  
Analysis Platform

Based on the concept of parametric design, this paper realizes the parametric modeling and parametric finite element analysis by utilizing UG/OPEN secondary development tool and APDL module of ANSYS software respectively. This paper also achieves data sharing of CAD/CAE through compiling interface program between UG6.0 and ANSYS10.0. In addition, the remote design and analysis platform has been built by using ASP.NET technology, component technology, and database technology. We take piston-piston rod part of coal mining machine’s cutting unit as an example to verify the system. Meanwhile, it proves system can effectively shorten design and analysis cycle time, and reduce workload of designer. Therefore, this software has potential application value in engineering.

ANALYSIS OF AN INTERNAL FIXATION OF A LONG BONE FRACTURE

2005 ◽  
Vol 05 (01) ◽  
pp. 89-103 ◽  
Author(s):  
K. RAMAKRISHNA ◽  
I. SRIDHAR ◽  
S. SIVASHANKER ◽  
V. K. GANESH ◽  
D. N. GHISTA
Keyword(s):  
Stress Shielding ◽  
Axial Loading ◽  
Bending Moment ◽  
Fracture Site ◽  
Long Bone ◽  
Radius Of Curvature ◽  
Element Analysis ◽  
Long Bone Fracture ◽  
Fracture Interface ◽  
Tensile Surface

A major concern when a fractured bone is fastened by stiff-plates to the bone on its tensile surface is excessive stress shielding of the bone. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays bone healing. Likewise, the tensile stress shielding of the healed bone underneath the plate also does not enable it to recover its tensile strength. Initially, the effect of a uniaxial load and a bending moment on the assembly of bone and plate is investigated analytically. The calculations showed that the screws near the fracture site transfers more load than the screws away from the fracture site in axial loading and it is found that less force is required when the screw is placed near to fracture site than the screw placed away from the fracture site to make the bone and plate bend with same radius of curvature when subjected to bending moment. Finally, the viability of using a stiffness graded bone-plate as a fixator is studied using finite element analysis (FEA): the stiffness-graded plate cause less stress-shielding than stainless steel plate.

Simulations on Hydrodynamic Coefficients of Stationary Cactus-Shaped Cylinders at a Low Reynolds Number

2018 ◽  
Author(s):  
J. Wang ◽  
C. Shi ◽  
Y. Liu ◽  
X. Bao
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Bending Moment ◽  
Hydrodynamic Coefficients ◽  
Rotational Angle ◽  
Desert Region ◽  
Helical Strakes ◽  
Wind Velocities ◽  
Low Reynolds ◽  
Very High

Flexible cylinders, such as marine risers, often experience sustained vortex-induced vibration (VIV). Both helical strakes and fairings are demonstrated to be effective in suppressing VIV, while, helical strakes result in large drag, which increases the rotational angle and bending moment at the riser hang-off location and, fairings are cumbersome in term of storage, installation and maintenance. This study was inspired by the giant Saguaro Cacti which grow in desert region. Saguaro Cacti have shallow root system, but can grow up to fifty feet in height and can withstand very high wind velocities. In this study, numerical simulations of flow past a stationary cactus-shaped cylinder are performed in two-dimensional field at a low Reynolds number of 200. The hydrodynamic coefficients and the vortex-shedding patterns of a cactus-shaped cylinder are compared with those of a circular cylinder. In addition, a set of two cactus-shaped cylinders of tandem arrangement are also studied to investigate the effects of wake. Results showed that a cactus-shaped cylinder can reduce the drag, lift, and Strouhal number, which suggests its potential as an alternative technology to suppress VIV of a riser.

scholarly journals Fatigue life prediction of upper arm suspension using strain life approach

2019 ◽  
Vol 17 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Hafida Kahoul ◽  
Samira Belhour ◽  
Ahmed Bellaouar ◽  
Jean Paul Dron
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Aluminium Alloys ◽  
Fatigue Analysis ◽  
Vertical Force ◽  
Upper Arm ◽  
Element Analysis ◽  
Content Type ◽  
Critical Location

Purpose This paper aims to present the fatigue life behaviour of upper arm suspension. The main objectives are to predict the fatigue life of the component and to identify the critical location. In this analysis, three aluminium alloys were used for the suspension, and their fatigue life was compared to select the suitable material for the suspension arm. Design/methodology/approach CAD model was prepared using Solid Works software, and finite element analysis was done using ANSYS 14.0 software by importing the Parasolid file to ANSYS. The model is subjected to loading and boundary conditions; the authors consider a vertical force with constant amplitude applied at the bushing that connected to the tire, the others two bushing that connected to the body of the car are constraint. Tetrahedral elements given enhanced results as compared to other types of elements; therefore, the elements (TET 10) are used. The maximum principal stress was considered in the linear static analysis, and fatigue analysis was done using strain life approach. Findings Life and damage are evaluated and the critical location was considered at node 63,754. From the fatigue analysis, aluminium alloys 7175-T73 (Al 90%-Zn 5.6%-Mg 2.5% -… …) and 2014-T6 (Al 93.5%-Cu 4.4%-Mg 0.5%… …) present a similar behaviour as compared to 6061-T6 (Al 97.9%-Mg 1.0%-Si 0.6%… … .); in this case of study, these lather are considered to be the materials of choice to manufacture the suspension arms; but 7175-T73 aluminium alloys remain the material with a better resistance to fatigue. Originality/value By the finite element analysis method and assistance of ANSYS software, it is able to analyse the different car components from varied aspects such as fatigue, and consequently save time and cost. For further research, the experimental works under controlled laboratory conditions should be done to determine the validation of the result from the software analysis.

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