scholarly journals Research on the Influence of Wheel Polygonization on Axle Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Fubing Zhang ◽  
Qunsheng Wang ◽  
Zhengqiao Zhang ◽  
Bin Zhu ◽  
Zhenhuan Yang
Keyword(s):  
Dynamic Stress ◽  
Vibration Mode ◽  
Great Influence ◽  
Elastic Vibration ◽  
Test Results ◽  
Flexible Bodies ◽  
First Order ◽  
Track System ◽  
Coupling Dynamic ◽  
Bending Modes

To study the influence of wheel polygonization on the dynamic stress of the wheel axle, a vehicle-track rigid-flexible coupling dynamic model was established. In the model, the wheelset, axle box, and track system were modelled as flexible bodies to consider the influence of elastic vibration. At the same time, the dynamic stress on key positions of the axle under the wheel polygonization excitation was measured on the high-frequency vibration test rig. The accuracy of the model was verified by comparison with the test results. The wheel axle stress under the excitation of the wheel polygonization with different orders, wave depths, and running speed was calculated. The results show that the wheel polygonization can increase the amplitude of the axle dynamic stress, and the larger the wave depth of the wheel polygonization, the larger the stress amplitude. When the wheel polygonization frequency is close to the frequency of the wheelset elastic vibration mode, the wheelset first-order bending and second-order bending modes have a great influence on the axle stress. The resonance vibration of the wheelset elastic modal can cause the dynamic stress on key positions of the axle increase sharply.

The Floating Suspension System in the Transonic Wind Tunnel for Full-Model Flutter Test

2013 ◽  
Vol 816-817 ◽  
pp. 328-334
Author(s):  
Bin Bin Lv ◽  
Bo Lu ◽  
Xing Hua Yang ◽  
Li Yu ◽  
Hong Tao Guo ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Vibration Mode ◽  
Steel Wire ◽  
Axial Direction ◽  
Elastic Vibration ◽  
Suspension System ◽  
Free Movement ◽  
Test Results ◽  
Control Effect ◽  
The Impact

Aiming at the 2.4m×2.4m wind tunnel, this paper introduces the floating suspension system (“FSS”) in the full-mode flutter test, analyzes the impact of the model’s “free” movement to the elastic vibration mode and verifies the control effect of the system to the pitching and rolling movements of the model. Test results show that the FSS system may realize the free movement of the flutter model in five directions other than the axial direction without impacting the elastic vibration mode; FSS system controls through two independent channels, namely, the pitch and the roll; load reduction on the model and the steel wire may be realized by cutting down the pitch and roll angles of the model and the control of FSS to the pitching and rolling movement of the model get guaranteed by selecting appropriate control parameters.

Photocatalytic Discolouration of Solutions of Reactive Dyes in the Presence of H2O2

1995 ◽  
Vol 30 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Deng Nansheng ◽  
Tian Shizhong ◽  
Xia Mei
Keyword(s):  
Photochemical Reaction ◽  
Uv Light ◽  
Reactive Dyes ◽  
Solar Light ◽  
Rate Equations ◽  
Oh Radical ◽  
Test Results ◽  
Dye Molecules ◽  
First Order ◽  
Dye Solutions

Abstract Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed. The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.

scholarly journals Fatigue Life Prediction of Rolling Bearings Based on Modified SWT Mean Stress Correction

2020 ◽  
Author(s):  
Aodi Yu ◽  
Hong-Zhong Huang ◽  
Yan-Feng Li ◽  
He Li ◽  
Ying Zeng
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Stress Ratio ◽  
Prediction Models ◽  
Great Influence ◽  
Sensitivity Coefficient ◽  
Model Verification ◽  
Mean Stress ◽  
Test Results ◽  
Rolling Bearings

Abstract Mean stress has a great influence on fatigue life, commonly used stress-based life prediction models can only fit the test results of fatigue life under specific stress ratio or mean stress but cannot describe the effect of stress ratio or mean stress on fatigue life. Smith, Watson and Topper (SWT) proposed a simple mean stress correction criterion. However, the SWT model regards the sensitivity coefficient of all materials to mean stress as 0.5, which will lead to inaccurate predictions for materials with a sensitivity coefficient not equal to 0.5. In this paper, considering the sensitivity of different materials to mean stresses, compensation factor is introduced to modify the SWT model, and several sets of experimental data are used for model verification. Then, the proposed model is applied to fatigue life predictions of rolling bearings, and the results of proposed method are compared with test results to verify its accuracy.

Vibrational Characteristics of Composite Shafts

1999 ◽  
Author(s):  
A. S. Sekhar ◽  
N. Ravi Kumar
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Deformation Theory ◽  
Great Influence ◽  
Shear Deformation Theory ◽  
Stacking Sequence ◽  
Shell Elements ◽  
First Order ◽  
Composite Shaft ◽  
Vibrational Characteristics

Abstract The present study aims in performing eigenvalue analysis and unbalance response for a rotor system having a composite shaft, modelled based on first order shear deformation theory using finite element method with shell elements. Different materials such as boron epoxy, carbon epoxy and graphite epoxy have been tried for various stacking sequences. From the study it is clear that the stacking sequence and material have great influence on the vibrational characteristics of composite shafts.

scholarly journals A new vertical dynamic model for railway vehicle with passenger-train-track coupling vibration

2019 ◽  
Vol 234 (1) ◽  
pp. 134-146
Author(s):  
Yuewei Yu ◽  
Leilei Zhao ◽  
Changcheng Zhou
Keyword(s):  
Dynamic Model ◽  
Railway Vehicle ◽  
Train Track ◽  
Passenger Train ◽  
Railway Vehicles ◽  
Vertical Coupling ◽  
Track System ◽  
Coupling Dynamic ◽  
Train System ◽  
Coupling Dynamic Model

In order to further reveal the vertical random vibration characteristics of railway vehicles, using the system engineering method, taking the passenger, the train system, and the track system (ballast track) as a unified whole, a passenger-train-track vertical coupling dynamic model is established, and the vibration differential equations of the model are derived. In the model, passengers are regarded as a single-degree-of-freedom system attached to the bottom of the carriage, the train system is represented as a 10-degree-of-freedom multi-rigid body model, the track system is regarded as the infinite long Euler beam model with three layers of continuous elastic point support, and the Hertz nonlinear elastic contact theory is applied to the wheel and rail coupling relationship. Based on this, the time-domain numerical solution of the passenger-train-track vertical coupling dynamic model is given by using Newmark- β implicit integration algorithm, and the correctness of the model is verified by the real vehicle test. This study can provide some theoretical basis for the design of railway vehicles and provide fundamentals for the coordinated control and system optimization of railway vehicle ride comfort.

scholarly journals Comparative analysis of cycloid pump based on CFD and fluid structure interactions

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097353
Author(s):  
Wang Yanhua ◽  
Huang Longlong ◽  
Liu Yong ◽  
Xu Jingsong
Keyword(s):  
Model Building ◽  
Contact Point ◽  
Great Influence ◽  
Test Results ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Mean Values ◽  
Calculation Results ◽  
Different Temperatures ◽  
Set Up

At present, in the aspect of numerical simulation of cycloid pump, most studies focused on CFD (Computational Fluid Dynamics) in analyzing the pump performance under different service conditions (such as speed, temperature, etc.). The characteristics of the pump under FSI (Fluid Solid Interaction) have not been considered yet. By means of the dynamic mesh technique in the rotating domain, the fluid structure coupling interface is set up on a cycloidal pump model building in COMSOL. The simulation results obtained by applying CFD and FSI are improved by experimental verification. The results show that: (1) the average flow rate of FSI simulation is closer to the test results, and the mean values of CFD and FSI pressure are closer to the actual outlet boundary settings; (2) by comparing the velocity and pressure of rotation region of CFD and FSI at different temperatures, it is concluded that the pressure CFD calculated in the region is more than FSI, and the velocity CFD calculated is less than FSI; (3) by comparing the pressure distribution at some contact point of the fluid structure coupling interface, it is concluded that the fluctuation value of the pressure of CFD with time is greater than that of FSI. Through the comparison, it is found that the coupling has a great influence on the calculation results. The FSI analysis of the pump makes the analysis results more real and more conducive to the analysis of the flow field and rotor dynamics characteristics of the pump.

scholarly journals A Dynamic Analysis of the Rotary Cutting System of King Grass Shredder

2020 ◽  
Vol 145 ◽  
pp. 02080
Author(s):  
Zunxiang Li ◽  
Ou Zhongqing ◽  
Jiao jing ◽  
Huang xiaohong ◽  
Du jihua
Keyword(s):  
Finite Element ◽  
Critical Speed ◽  
Great Influence ◽  
Second Order ◽  
Belt Drive ◽  
Finite Element Models ◽  
Rotating Shaft ◽  
First Order ◽  
Rotary Cutting ◽  
Cutting System

With the rotary cutting system of king grass shredder as the research object, this paper established finite element models for rotating shaft, rotating shaft-belt pulley, rotating shaft-rotary cutting part and rotary cutting system and analyzed the influences of belt pulley and rotary cutting part on the dynamic characteristics of rotary cutting system. The results showed that the belt pulley and rotary cutting part had a great influence on the second order critical speed of rotary cutting system, and the rotary cutting part had a greater influence on the critical speed of first order forward precession than the belt pulley. Meanwhile, the critical speed of rotary cutting system that conformed to facts was calculated. There was a big difference between its first order and second order critical speeds, but the critical speed of first order backward precession was lower. Finally, it was found after analysis that the natural frequency of rotary cutting system was lower than the vibration frequency induced by belt drive, so the shredder can run safely.

Structure Characteristics and Improvement of Oil Seal of Turbo-Supercharger

2013 ◽  
Vol 779-780 ◽  
pp. 1130-1133
Author(s):  
Hui Gan ◽  
Kun Yu Yang
Keyword(s):  
High Speed ◽  
High Reliability ◽  
Great Influence ◽  
Pressure Change ◽  
Exhaust Gas ◽  
Test Results ◽  
Chamber Volume ◽  
Sealing Performance ◽  
Complementary Action ◽  
Ring Seal

Through the analysis of the sealing mechanism of the oil seals in exhaust gas turbo supercharger and the comparative test of different oil seals with the pressure change in the oil-return chamber, a seal that uses a caulking ring with reverse threads is designed, and an optimum combination of oil seal is selected. The combination of caulking ring and the oil-return thread structure has better complementary action on oil sealing, because for the seal with oil-return reverse thread there is better dynamic and static seal effect on ring seal and has good sealing performance and high reliability at high speed. The test results of screening selection of combination seals show that different combinations of caulking ring and the oil-return threads have great influence on the pressure of the oil-return chamber. The combination of caulking ring outside and oil-return threads inside is recommended to be used. In addition, the smooth return of the oil can be ensured as far as possible by increasing the supercharger oil-return chamber volume. The improved structure of the oil seal has effectively enhanced the reliability of the whole unit of the exhaust gas turbo supercharger.

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