Influence of the Initial Temperature on the Clutch Hot Judder

2018 ◽  
Author(s):  
Liang Yu ◽  
Il Yong Kim
Keyword(s):  
Initial Temperature ◽  
Friction Torque ◽  
Reactive Force ◽  
Element Analysis ◽  
Clutch Engagement ◽  
Vibration Model ◽  
The Finite Element Analysis ◽  
Engagement Process ◽  
Friction Surfaces ◽  
Maximum Surface Temperature

In order to explore the effects of the initial temperature on the clutch hot judder, the thermodynamic analysis was conducted during the clutch engagement process. The finite element analysis was adopted to explore the contact pressure based on the consideration of the concentrated reactive force on the circlip. A 4-degree-of-freedom torsional vibration model was established to evaluate the hot judder behavior. The results demonstrated that the closer the surface was to the circlip, the greater the friction torque generated on friction surfaces was. Moreover, the higher the initial temperature was, the shriller the clutch hot judder was. The increased initial temperature not only resulted in the increase in the maximum surface temperature, but also could make the clutch engagement much shorter.

Modeling and experimental research on engaging characteristics of wet clutch

2019 ◽  
Vol 71 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Yanzhong Wang ◽  
Yuan Li ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Contact Surface ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Lubricating Oil ◽  
Centrifugal Effect ◽  
Element Analysis ◽  
Content Type ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Engagement Process

PurposeTo gain in-depth understandings of engaging characteristics, the purpose of this paper is to improve the model of wet clutches to predict the transmitted torque during the engagement process.Design/methodology/approachThe model of wet clutch during the engagement process took main factors into account, such as the centrifugal effect of lubricant, permeability of friction material, slippage factor of lubricant on contact surface and roughness of contact surface. Reynolds’ equation was derived to describe the hydrodynamic lubrication characteristics of lubricant film between the friction plate and the separated plate, and an elastic-plastic model of the rough surfaces contact based on the finite element analysis was used to indicate the loading force and friction torque of the contact surface.FindingsThe dynamic characteristics of wet clutch engagement time, relative speed, hydrodynamic lubrication of lubricating oil, rough surface contact load capacity and transfer torque can be obtained by the wet clutch engagement model. And the influence of the groove shape and depth on the engaging characteristics is also analyzed.Originality/valueThe mathematical model of the wet clutch during the engagement process can be used to predict the engaging characteristics of the wet clutch which could be useful to the design of the wet clutch.

scholarly journals The Optimization of FDM 3D Printer’s Structure Based on Finite Element Analysis

2019 ◽  
Vol 257 ◽  
pp. 02004
Author(s):  
Zhenhai Huang ◽  
Tingchun Shi ◽  
Xiuyan Yue
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Common Type ◽  
3D Printer ◽  
Deformation Characteristics ◽  
Structure Model ◽  
Element Analysis ◽  
Vibration Model ◽  
The Finite Element Analysis

In view of the forming accuracy of the 3D printer, the paper, from the structure of the printer itself, discussed the influence on the precision of the printer via improving the structure of 3D printer. A typical 3D printer, such as a common type of FDM, was selected, and SOLIDWORKS software was used for solid modeling, after establishing the model, the finite element analysis was carried out on the whole structure model to obtain the deformation characteristics and the main vibration model of the printer. On the basis of finite element analysis, the influence of the level shaft bearing diameter, material properties and symmetry of the parts on the overall mechanical properties of the printer was discussed respectively. On this basis, the overall structure of the machine has been optimized and achieved remarkable results.

Based on ANSYS Analysis of Suspension Bridge Transient Dynamics

2013 ◽  
Vol 438-439 ◽  
pp. 869-873
Author(s):  
Bang Sheng Xing ◽  
Xue Feng Wang ◽  
Wei Li
Keyword(s):  
Natural Vibration ◽  
Excitation Frequency ◽  
Suspension Bridge ◽  
Angular Frequency ◽  
Resonance Phenomenon ◽  
Bridge Structure ◽  
Element Analysis ◽  
Ansys Analysis ◽  
Vibration Model ◽  
The Finite Element Analysis

By using the finite element analysis software ANSYS to do the first 10 order modal analysis of suspension bridge, obtaining the natural frequency and natural vibration model, to avoid the structure has resonance phenomenon. The results show that inherent frequencies of the first 10 order of the suspension bridge are far less than the excitation frequency of vehicle, the speed of mobile has obvious influence on the mid-span nodes deflection, when the vehicle goes through the suspension bridge, it usually travels at low speed; vehicles traveling at the same direction have a greater impact on the suspension bridge structure, the maximum mid-span node deflection of the suspension bridge decreases with the increasing of angular frequency.

scholarly journals Optimal control for jitter suppression of clutch engagement in upshift process of electric vehicles

2016 ◽  
Vol 8 (12) ◽  
pp. 168781401667484
Author(s):  
Junqiu Li ◽  
Yihe Wang ◽  
Yizheng Wang
Keyword(s):  
Optimal Control ◽  
Dynamic Model ◽  
Automatic Transmission ◽  
Friction Torque ◽  
Dynamic Responses ◽  
Lumped Mass ◽  
Virtual Displacement ◽  
Motor Torque ◽  
Clutch Engagement ◽  
Engagement Process

In the shift process of large-order automatic transmission, jitter phenomenon is common in clutch engagement process, which greatly affects the ride comfort of the vehicle. In this article, the jitter dynamic model of clutch engagement process was established with lumped mass method and virtual displacement principle. Specific to clutch engagement stage, the optimal control of the coordination between driving motor and wet clutch was studied. In accordance with the jitter dynamic model, the state–space equation with controlling variables of motor torque and clutch friction torque was established. In this optimization problem, the torsion angle, torsion angular velocity, and shift jerk are selected as optimization targets. Utilizing the linear quadratic optimal control theory, the optimal trajectory of motor torque and clutch friction torque was obtained. Aiming at the dynamic responses in clutch engagement process, the optimal control in different conditions of weight coefficients, initial torsion angles, and resistance torques was studied. Results showed that the optimal control strategy could obviously reduce the jitter; in addition, the weight coefficient should be determined according to actual situation reasonably.

scholarly journals Effects of Attraction of Vacuum Extractors of Different Materials and Pressures on the Fetal Head During Delivery

2021 ◽  
Author(s):  
Yu-Hsuan Chen ◽  
Kuo-Min Su ◽  
Ming-Tzu Tsai ◽  
Chi-Kung Lin ◽  
Cheng-Chang Chang ◽  
...  
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Von Mises Stress ◽  
Reactive Force ◽  
Fetal Head ◽  
Element Analysis ◽  
Vacuum Extractor ◽  
The Finite Element Analysis ◽  
Von Mises ◽  
Analysis Models

Abstract PurposeIn some cases where operative deliveries are required with vacuum extractor, and obstetricians could choose the vacuum extractor to facilitate the process smoother and safer. However, there is no related biomechanical literature about the influences of vacuum extractors fabricated from different materials and pressures of vacuum on the fetal head. Hence, we utilized the finite element method to investigate the influences of vacuum extractors manufactured from different materials on the fetal head under various extractive pressures.MethodsFirst, the finite element analysis models of vacuum extractor and fetal head were established. The vacuum extractor model was designed as a hemispherical shape and we compared silicone rubber and stainless steel for the materials of vacuum extractor. Subsequently, four different vacuum pressures were applied as the factors for investigation—500-cm H2O, 600-cm H2O, 700-cm H2O, and 800-cm H2O. Finally, we observed and analyzed the reactive force on the fetal head, von Mises stress of vacuum extractor, and von Mises stress on the skull of fetal head to evaluate the influences of vacuum extractors of different materials under different pressures. ResultsThe results demonstrated that different vacuum pressures had only a slight difference of influences on the fetal head. The use of stainless-steel vacuum extractors caused a relatively larger reactive force (358.04–361.37 N) and stress (13.547–13.675 MPa) on the fetal head. ConclusionsNon-metallic or relatively softer materials could be selected when using a vacuum extractor for operative delivery to avoid complications such as scalp scratch, and even cephalohematoma and intracerebral hemorrhage.

The Finite Element Analysis of Derrick of Coal-Bed Methane Rigs

2012 ◽  
Vol 215-216 ◽  
pp. 758-761
Author(s):  
Liu Zhi ◽  
Di Wu ◽  
Bao Shan Sun
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Coal Bed ◽  
Analysis Software ◽  
Element Analysis ◽  
Drilling Rig ◽  
Vibration Model ◽  
The Finite Element Analysis ◽  
Calculation Results

Using the finite element analysis software ANSYS established derrick model of CBM drilling rig car and calculated its static strength and model analysis. The maximum Mises stress and the weakest position of derrick was determined and given its four bands of natural frequencies and corresponding vibration model. The conclusion can be gotten from calculation results that the structure of derrick meet the requirements of design.

Analysis of the influence of engine torque excitation on clutch judder

2016 ◽  
Vol 23 (4) ◽  
pp. 645-655 ◽  
Author(s):  
Li-kun Yang ◽  
He-yan Li ◽  
Mehdi Ahmadian ◽  
Biao Ma
Keyword(s):  
Angular Velocity ◽  
Friction Torque ◽  
Torsional Stiffness ◽  
Engine Torque ◽  
Clutch Engagement ◽  
Fluctuation Amplitude ◽  
The Mean ◽  
Three Degree Of Freedom ◽  
Friction Surfaces ◽  
Engine Excitation

A simplified three-degree-of-freedom dynamic model with nonlinear friction torque and engine torque excitation, capable of identifying the effect of the engine excitation on clutch judder, is presented. The analysis of harmonic order is performed and a sinusoidal contact pressure between friction surfaces is considered, along with an analytical solution for the relative angular velocity of the clutch plates. The average fluctuation amplitude of the clutch relative angular velocity is used to evaluate the judder. Numerical calculations indicate that the clutch judder increases significantly when the angular velocity of the crankshaft, corresponding to the harmonic orders of the engine, is equal or close to the natural frequency of the driveline. An identical frequency of the engine excitation and the oil pressure fluctuation contributes little to the clutch judder, unless the excitation is at or near the resonance frequency. The amplitudes of oscillations due to the engine excitation grow when the pulsating torque of the engine increases. The mean torque of the engine has little influence on the judder, although it governs the clutch engagement time. The results further show that clutch judder attenuates as the torsional stiffness of the system increases.

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.

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