Design, static analysis and development of a new three-legged shake table

2021 ◽  
pp. 095440622110184
Author(s):  
Ganesh Mangavu ◽  
Anjan Kumar Dash
Keyword(s):  
Vertical Motion ◽  
Torsional Stiffness ◽  
Shake Table ◽  
Lateral Motion ◽  
Sinusoidal Motion ◽  
Gravity Load ◽  
Simulation Results ◽  
Electromechanical Actuation ◽  
Translational Stiffness ◽  
Earthquake Data

In this paper, an alternative design is proposed based on a family of three-legged manipulators. Such manipulators have two actuators (one vertical and one horizontal) in each leg, unlike the standard UP̅S Stewart platform, which has one actuator in each leg. The arrangement of the two actuators is such a way that, to have vertical motion of the shake table only the Vertical Motion Actuators (VMA) are actuated and for longitudinal or lateral motion, the Horizontal Motion Actuators (HMA) alone are moved. Due to its inherent features such as simplified kinematics, control and distributed loading, a study is carried out to determine the performance of such three-legged manipulators as a shake table. Sinusoidal motion and white noise motions are given to the actuators and shown that the VMA forces have linear relationship with the platform forces. The translational stiffness and the torsional stiffness are studied separately for the manipulators. In the dynamic analysis, it is highlighted that the gravity load of the legs is borne by the Vertical actuators, irrespective of the motion being spatial or planar. Hence, this topology provides scope for lighter electromechanical actuation. The performance analysis of the 3 legged configuration is accomplished using simulation results, in comparison to a 7-UP̅S configuration of shake table. A prototype of the shake table is fabricated and tested with earthquake data of El Centro.

Reduction of Torsional Vibration in Resonance Phenomena for Tractor Power Take-Off Drivelines Using Torsional Damper

2021 ◽  
Vol 64 (2) ◽  
pp. 365-376
Author(s):  
Da-Vin Ahn ◽  
In-Kyung Shin ◽  
Jooseon Oh ◽  
Woo-Jin Chung ◽  
Hyun-Woo Han ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Torsional Vibration ◽  
Simulation Software ◽  
Drive Shaft ◽  
Torsional Stiffness ◽  
List Type ◽  
Two Stage ◽  
Mass Moment ◽  
Simulation Results ◽  
Agricultural Tractors

HighlightsRattling of tractor power take-off drivelines can be detrimental to operators.A novel driveline model, which includes a torsional damper, was constructed.The behavior of the model was validated against that of an actual tractor driveline.The validated model was used to determine the optimal torsional damper parameters.These optimal parameters were validated by laboratory tests.Abstract. Rattle noise and high levels of vibration in agricultural tractors lower the productivity of the operators and may cause serious health issues in them. This study examined a method for preventing resonance and reducing the torsional vibration that causes rattling in tractor power take-off (PTO) drivelines in the idle state using a two-stage torsional damper. The PTO driveline was simplified to a 6-DOF model based on the principle of equivalent mass moment of inertia using commercial simulation software. The variations in the angular velocity of the PTO drive shaft in an actual tractor were measured and compared to the simulation results using a single-stage torsional damper to validate the model. Using this validated PTO driveline model, the pre spring of a two-stage torsional damper was investigated to determine its optimal torsional stiffness to minimize torsional vibration. The simulation results showed that the variations in the angular velocity of the PTO drive shaft decreased as the torsional stiffness of the pre spring decreased; accordingly, an appropriate torsional stiffness reduced the variation in the angular velocity delivered to the PTO drive shaft. The optimal torsional stiffness of the pre spring was determined by considering the manufacturing limitations of the torsional damper and the magnitude of the input engine torque. A pre spring with this optimal torsional stiffness was installed on an actual PTO driveline to measure the angular velocity transmissibility, which was the ratio of the variation in the angular velocity of the engine flywheel to the variation in the angular velocity of the PTO drive shaft, and the results were compared with those of the simulation. When the angular velocity of the engine was 850 rpm, the angular velocity transmissibility of the PTO drive shaft was 0.4 in the actual test, similar to the value of 0.29 obtained using the simulation. Thus, the simulation-optimized pre spring was able to avoid the resonance domain, while considerably reducing the torsional vibration that leads to rattling. The results of this study support the safe operation of agricultural tractors and guide the evaluation of torsional damper configurations of different vehicles. Keywords: PTO driveline, Resonance, Simulation model, Torsional damper, Torsional vibration, Tractor rattle.

scholarly journals Design and fabrication of a twist fixture to measure torsional stiffness of a pick up chassis

2018 ◽  
Vol 159 ◽  
pp. 02030 ◽  
Author(s):  
Ojo Kurdi ◽  
Mohd Shukri Yob ◽  
Awisqarni Haji Ishamuddin ◽  
Agus Suprihanto ◽  
Susilo Adi Widyanto ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Early Stage ◽  
Torsional Stiffness ◽  
Stage Design ◽  
Handling Performance ◽  
Simulation Results ◽  
Early Stage Design ◽  
Measured Displacement ◽  
Dial Indicator

Torsional stiffness is important parameter of chassis that affect the handling performance of chassis. Torsional stiffness can be determined using Finite Element Method (FEM) in early stage design of its. In order to validate the FEM result, experimental work needs to be done. The fixture has been design in simpler stucture, flexible for any kind of chassis and using a simple measurement’s equipment such as dial indicator and load cell. Twist fixture has been designed for measuring of torsional stiffness of TATA cab chassis indirectly. The fixture measured the deflection caused by torsion subjected to the chassis. The torsional stiffness was calculated based on measured displacement of chassis. The result of comparison shows that the experimental results in agreement with the simulation results. Therefore, the simulation results of TATA cab chassis model are valid.

Dispersion of Particles on Liquid Surfaces

2011 ◽  
Author(s):  
Shriram B. Pillapakkam ◽  
Pushpendra Singh
Keyword(s):  
Numerical Simulation ◽  
Particle Size ◽  
Vertical Motion ◽  
Liquid Interface ◽  
Water Interface ◽  
Small Particles ◽  
Air Water Interface ◽  
Large Velocity ◽  
Simulation Results ◽  
Air Liquid Interface

In a recent study we have shown that when small particles, e.g., flour, pollen, glass, etc., contact an air-liquid interface, they disperse rapidly as if they were in an explosion. The rapid dispersion is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a large velocity. The vertical motion of a particle during its adsorption causes a radially-outward lateral (secondary) flow on the interface that causes nearby particles to move away. We present direct numerical simulation results for the adsorption of particles and show that the inertia of a particle plays an important role in its motion in the direction normal to a fluid-liquid interface. Although the importance of inertia diminishes with decreasing particle size, on an air-water interface the inertia continues to be important even when the size is as small as a few nanometers.

scholarly journals Parametric Investigation of Dual-Mass Flywheel Based on Driveline Start-Up Torsional Vibration Control

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Liupeng He ◽  
Changgao Xia ◽  
Sida Chen ◽  
Jiwei Guo ◽  
Yi Liu
Keyword(s):  
Torsional Vibration ◽  
Torsion Angle ◽  
Torsional Stiffness ◽  
Rotary Inertia ◽  
Research Model ◽  
Attenuation Effect ◽  
Start Up ◽  
Design Requirements ◽  
Simulation Results ◽  
Engine Start

This paper is aimed to investigate the influence of dual-mass flywheel (DMF) kinetic parameters on driveline torsional vibration in engine start-up process, which prescribes the design requirements under start-up condition for DMF matching. On the basis of driveline excitation analysis during engine start-up, the analytical model of DMF driveline torsional vibration system is built and simulated. The vehicle start-up test is conducted and compared with the simulation results. On account of the partial nonstationary characteristic of driveline during start-up, the start-up process is separated into 3 phases for discussing the influence of DMF rotary inertia ratio, hysteresis torque, and nonlinear torsional stiffness on attenuation effect. The test and simulation results show that the DMF undergoes severe oscillation when driveline passes through resonance zone, and the research model is verified to be valid. The DMF design requirements under start-up condition are obtained: the appropriate rotary inertia ratio (the 1st flywheel rotary inertia-to-the 2nd flywheel rotary inertia ratio) is 0.7∼1.1; the interval of DMF small torsion angle should be designed as being with small damping, while large damping is demanded in the interval of large torsion angle; DMF should be equipped with low torsional stiffness when working in start-up process.

scholarly journals Modeling and performance evaluation of a robotic treatment couch for tumor tracking

2016 ◽  
Vol 61 (5) ◽  
Author(s):  
Alexander Jöhl ◽  
Stephanie Lang ◽  
Stefanie Ehrbar ◽  
Matthias Guckenberger ◽  
Stephan Klöck ◽  
...  
Keyword(s):  
Vertical Motion ◽  
Longitudinal Direction ◽  
Lateral Motion ◽  
Tumor Motion ◽  
Unknown Parameters ◽  
One Dimensional ◽  
Tumor Tracking ◽  
Chirp Signals ◽  
And Performance ◽  
Lateral Axis

AbstractTumor motion during radiation therapy increases the irradiation of healthy tissue. However, this problem may be mitigated by moving the patient via the treatment couch such that the tumor motion relative to the beam is minimized. The treatment couch poses limitations to the potential mitigation, thus the performance of the Protura (CIVCO) treatment couch was characterized and numerically modeled. The unknown parameters were identified using chirp signals and verified with one-dimensional tumor tracking. The Protura tracked chirp signals well up to 0.2 Hz in both longitudinal and vertical directions. If only the vertical or only the longitudinal direction was tracked, the Protura tracked well up to 0.3 Hz. However, there was unintentional yet substantial lateral motion in the former case. And during vertical motion, the extension caused rotation of the Protura around the lateral axis. The numerical model matched the Protura up to 0.3 Hz. Even though the Protura was designed for static positioning, it was able to reduce the tumor motion by 69% (median). The correlation coefficient between the tumor motion reductions of the Protura and the model was 0.99. Therefore, the model allows tumor-tracking results of the Protura to be predicted.

Why Is (111) Silicon a Better Mechanical Material for MEMS: Torsion Case

2003 ◽  
Author(s):  
Donghun Kwak ◽  
Jongpal Kim ◽  
Sangjun Park ◽  
Hyoungho Ko ◽  
Dong-Il Cho
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Silicon Wafers ◽  
Torsional Stiffness ◽  
Rotational Inertia ◽  
The Finite Element Method ◽  
Element Type ◽  
Simulation Results

This paper shows that using the Finite Element Method (FEM), the torsional stiffness of silicon varies by the least amount on silicon (111) with respect to crystallographic directions, when compared to silicon (100) and (110). The used simulator is ANSYS 5.7 with the element type of Solid 64. As a simulation model, we use a simple torsion system, in which a rotational inertia is attached to the center of clamped-clamped beam with a rectangular cross-section. From the results of the modal analysis, the torsional stiffness is derived using the formula between the natural frequency and the torsional stiffness. Simulation results show that the maximum variations of the torsional stiffness on silicon (111), (100) and (110) are 2.3%, 26.5%, and 31.2%, respectively. This implies that on <100> and <110> silicon wafers, substantially different physical dimensions are necessary for devices with the same torsional characteristics, but with different orientations. Therefore, <111> silicon wafers represent a more suitable substrate to design and fabricate torsional micro and nano systems.

Functional Analysis of Bushing in Four-Link Suspension on K&C Characteristics Using Multibody Dynamics Method

2012 ◽  
Author(s):  
Kang Song ◽  
Xiao-kai Chen ◽  
Yi Lin ◽  
Zheng-Dong Ma
Keyword(s):  
Vehicle Dynamics ◽  
Torsional Stiffness ◽  
Main Function ◽  
Displacement Method ◽  
Force Method ◽  
Acceptable Range ◽  
Loading Tests ◽  
Dynamics Method ◽  
Translational Stiffness ◽  
Numerical Calculation Result

The link of multilink suspension usually has bushings at both body connection and wheel carrier connection. These bushings are designed subjected to the function of link. In the studies of vehicle dynamics, bushing could be represented by three translational stiffness and three torsional stiffness as well as corresponding damping. Due to specific location and orientation of each bushing, usually only one of these six stiffness plays an important role. In this paper, effect of bushing on suspension K&C characteristics was investigated with a four-link suspension. Through virtual loading tests, force distribution of suspension bushing was studied to find the relation between bushing stiffness and K&C characteristics. In order to quantitatively measure effect of bushing stiffness on parasitic rate, an “equivalent force” method based on energy conservation was proposed. Similarly, an “equivalent displacement” method was proposed to measure effect of bushing stiffness on suspension compliance. According to theoretical analysis and numerical calculation result, six stiffness of a bushing could be classified into three categories: main function stiffness closely related to suspension behavior, sub-function stiffness affecting parasitic rate or subjected to large load and non-function stiffness to be controlled within an acceptable range.

Stiffness Modeling and Sensitivity Analysis for Worm Geared Transmission

2014 ◽  
Vol 989-994 ◽  
pp. 3328-3330
Author(s):  
Lin Han ◽  
Hou Jun Qi
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tools ◽  
Torsional Stiffness ◽  
Axial Stiffness ◽  
Static Stiffness ◽  
Meshing Stiffness ◽  
Stiffness Modeling ◽  
Transmission Chain ◽  
Stiffness Model ◽  
Simulation Results

The worm geared transmission chain is widely employed in rotary feeding table of machine tools. This article proposes a static stiffness model and conducts sensitivity analysis of the transmission chain. Firstly, a unified static stiffness model is established, considering meshing stiffness, torsional stiffness and pre-load related axial stiffness of worm shaft. Then sensitivity with respect to individual stiffness element is derived based on partially differentiating method. Simulation results show that the closer to the end gear pair or shaft is, the more sensitive meshing stiffness or torsional stiffness is.

The vBow: a virtual violin bow controller for mapping gesture to synthesis with haptic feedback

2002 ◽  
Vol 7 (2) ◽  
pp. 215-220 ◽  
Author(s):  
Charles Nichols
Keyword(s):  
Physical Model ◽  
Rotational Motion ◽  
Degrees Of Freedom ◽  
Haptic Feedback ◽  
Vertical Motion ◽  
Longitudinal Motion ◽  
Lateral Motion

The vBow, a virtual violin bow musical controller, has been designed to provide the computer musician with most of the gestural freedom of a bow on a violin string. Four cable and servomotor systems allow for four degrees of freedom, including the lateral motion of a bow stroke across a string, the rotational motion of a bow crossing strings, the vertical motion of a bow approaching and pushing into a string, and the longitudinal motion of a bow travelling along the length of a string. Encoders, attached to the shaft of the servomotors, sense the gesture of the performer, through the rotation of the servomotor shafts, turned by the motion of the cables. The data from each encoder is mapped to a parameter in synthesis software of a bowed-string physical model. The software also sends control voltages to the servomotors, engaging them and the cables attached to them with a haptic feedback simulation of friction, vibration, detents and elasticity.

Finite Element Contact Analysis for Sprocket of an Armoured Face Conveyor

2011 ◽  
Vol 697-698 ◽  
pp. 740-744
Author(s):  
B.Y. He ◽  
Y.H. Sun ◽  
G.P. Li ◽  
S. Z. Chen
Keyword(s):  
Finite Element ◽  
True Strain ◽  
Element Model ◽  
Transmission System ◽  
Torsional Stiffness ◽  
Stiffness Coefficient ◽  
Test Results ◽  
Finite Element Software ◽  
Static Tensile ◽  
Simulation Results

Sprocket has an important role in improving the transport performance and life of the armoured face conveyor, which is the key component in the transmission system of armoured face conveyor (AFC). In this paper, true stress-true strain curves of materials of the sprocket and the ring chain are obtained by computing the data of static tensile test. A simplified symmetric finite element contact model is established based on the nonlinear finite element software ABAQUS. Stress field and torsional stiffness coefficient of the sprocket are calculated according to loads and boundary conditions. Simulation results are in good accordance with the test results. The finite element model and the simulation results provide useful guidance for design and test of the sprocket. Meanwhile, accurate torsional stiffness coefficient of the sprocket is obtained for simulation of the transmission system of AFC.

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