Research on the impact of surface properties of particle on damping effect in gear transmission under high speed and heavy load

2018 ◽  
Vol 98 ◽  
pp. 1116-1131 ◽  
Author(s):  
Wangqiang Xiao ◽  
Zhiwei Chen ◽  
Tianlong Pan ◽  
Jiani Li
Keyword(s):  
Surface Properties ◽  
High Speed ◽  
Gear Transmission ◽  
Heavy Load ◽  
Damping Effect ◽  
The Impact

scholarly journals Numerical Modeling and Experimental Verification for High-Speed and Heavy-Load Planar Mechanism with Multiple Clearances

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Fangang Meng ◽  
Shijing Wu ◽  
Fan Zhang ◽  
Liang Liang
Keyword(s):  
High Speed ◽  
Circuit Breaker ◽  
Fast Response ◽  
Transmission Mechanism ◽  
Heavy Load ◽  
Clearance Joints ◽  
Moving Contact ◽  
Center Path ◽  
The Impact ◽  
Impact Motion

Transmission mechanism is one of the most important parts of the Ultra-High Voltage (UHV) circuit breaker. It has specific characteristics such as fast response, high speed, and heavy load in the processes of open and close actions. This paper studies the effects of multiple clearances on the working characteristics of transmission mechanism system, especially the motion of its journal center path during operation. It builds a nonlinear kinetic model of transmission mechanism considering the system energy losses due to the impact and friction between the journal and bearing inside clearance joints. Also, an experimental platform is built to measure the displacement and velocity of the moving contact. The results show that the existence of 15 clearance joints in our mechanism system can cause hysteresis effects on the velocity and acceleration of the moving contact, as well as its acceleration fluctuation. Meanwhile, the increase of friction coefficient will stabilize the dynamic characteristic. In addition, both the experimental and simulation results indicate that the motion of the journal center, which is unevenly distributed along the circle, is characterized by three phases: free flight motion, contact motion, and impact motion.

scholarly journals Numerical Simulation of Gear Heat Distribution in Meshing Process Based on Thermal-structural Coupling

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Peixiang Xu
Keyword(s):  
Heat Conduction ◽  
High Speed ◽  
Element Model ◽  
Simulation Method ◽  
Spur Gear ◽  
Gear Transmission ◽  
Heat Distribution ◽  
Heavy Load ◽  
Structural Coupling ◽  
Meshing Process

The thermal balance state of high-speed and heavy-load gear transmission system has an important influence on the performance and failure of gear transmission and the design of gear lubrication system. Excessive surface temperature of gear teeth is the main cause of gluing failure of gear contact surface. To investigate the gear heat distribution in meshing process and discuss the effect of thermal conduction on heat distribution,a finite element model of spur gear is presented in the paper which can represent general involute spur gears. And a simulation approach is use to calculate gear heat distribution in meshing process. By comparing with theoretical calculation, the correctness of the simulation method is verified, and the heat distribution of spur gear under the condition of heat conduction is further analyzed. The difference between the calculation results with heat conduction and without heat conduction is compared. The research has certain reference significance for dry gear hobbing and the same type of thermal-structural coupling analysis.

scholarly journals Research on matching conditions of coaxial six-branch split-torsion herringbone gear transmission system

2021 ◽  
Vol 39 (2) ◽  
pp. 341-349
Author(s):  
Zhibin Li ◽  
Sanmin Wang ◽  
Fei Li ◽  
Qi'an Peng ◽  
Jianfeng Li
Keyword(s):  
Calculation Method ◽  
High Speed ◽  
High Reliability ◽  
Three Dimensional ◽  
Matching Condition ◽  
Transmission System ◽  
Gear Transmission ◽  
Heavy Load ◽  
Gear Transmission System ◽  
Herringbone Gear

Compared with traditional gear transmission, the multi-branch split-torsion gear transmission system has the advantages of large transmission power, small size and high reliability, so it is more and more used in high-speed heavy load occasions such as ships and aircraft. Since the transmission system of multi-branch split torsional gears belongs to over-constrained configuration, it is necessary to meet strict tooth matching condition in the design process in order to realize the correct synchronous meshing of each branch, which is of great significance to ensure its uniform installation and motion synchronization.Aiming at the coaxial six-branch twisted herringbone gear transmission system, this paper establishes a calculation method for the proper meshing conditions of each branch on the basis of considering the movement synchronization of each branch and preventing geometric interference.In addition, the calculation of gear allocation was carried out for a ship's power transmission system, and a parameter scheme that satisfies the requirements of transmission ratio, concentricity and synchronous meshing was obtained.The correctness of the calculation method of tooth matching in this paper is verified by three-dimensional modeling. This method has universal application value to the tooth matching design of other coaxial multi-branch gear transmissions.

The Study of Droplet Impact Behavior on Flat Surface with Different Surface Properties

2010 ◽  
Vol 297-301 ◽  
pp. 19-24
Author(s):  
Ku Zilati Ku Shaari ◽  
Richard Turton
Keyword(s):  
Surface Properties ◽  
High Speed ◽  
Liquid Droplet ◽  
Film Coating ◽  
Silicon Surfaces ◽  
Impact Behavior ◽  
Spreading Factor ◽  
Pharmaceutical Tablets ◽  
Coating Uniformity ◽  
The Impact

The impact behavior of a liquid droplet on solid surface is a complex phenomenon and yet is a basic component of various industrial processes particularly in the pharmaceutical industry. In this industry, film coating technique is used in tablet coating, in which coating uniformity is important especially if the coating is for functional purposes. Coating uniformity on a tablet could be affected by several factors, one of which is the impingements of droplets on its surface. In this work, the maximum spreading diameter and the initial impact behavior of a single droplet on pharmaceutical tablet surfaces and metal surfaces having different surface properties are investigated. A Charged-Coupled-Device (CCD) high-speed camera with framing rate of 2,000, attached to a 10X microscope, was used to capture the phenomena. The results show that the initial impact behavior of a droplet is not affected by the porosity of a surface. The results on the pharmaceutical tablets, stainless steel and etched silicon surfaces show that the rougher the surface the lower the spreading factor. The droplets on all surfaces demonstrate that a droplet that produces higher spreading factor gives a lower bouncing factor.

Analytical investigation on geared rotor system with multi-body fault based on finite element method

2018 ◽  
Vol 25 (2) ◽  
pp. 408-422 ◽  
Author(s):  
Wei Li ◽  
Daqian Pang
Keyword(s):  
Fault Diagnosis ◽  
High Speed ◽  
Structural Characteristics ◽  
Rapid Development ◽  
Transmission System ◽  
Gear Transmission ◽  
Heavy Load ◽  
Fault Type ◽  
Gear Transmission System ◽  
Multi Body

With the rapid development of modern industry, the situation of high speed and heavy load is becoming even more relevant in the gear transmission system. Under the condition of high speed and heavy load, the fault type and frequency of the gear transmission system are gradually increasing. Effective and accurate detection of fault location and fault type is one of the difficult problems in today’s fault diagnosis. In the case of high speed and heavy load, the probability of multi-body fault is greatly increased. However, most of the current fault diagnosis methods are limited to the study of single fault characteristics, and do not take into account the multi body fault. In this paper, the single crack, gear coupling crack, single shaft crack, and gear and shaft coupling crack signal are analyzed by means of the short-time Fourier transform, and the corresponding fault characteristics of different fault types are found out. The modal analysis of the fault state of the gear transmission system is carried out, the structural characteristics of the gear drive are verified, and the influence of the different fault forms on the vibration characteristics of the gear is compared.

The Effect of Nano-Structured Surfaces on Droplet Impingement Heat Transfer

2011 ◽  
Author(s):  
Gary Rosengarten ◽  
Anggito Tetuko ◽  
Ka Kit Li ◽  
Alex Wu ◽  
Robert Lamb
Keyword(s):  
Heat Transfer ◽  
Surface Properties ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
High Speed ◽  
Liquid Droplet ◽  
Droplet Impingement ◽  
Cooling Effectiveness ◽  
Structured Surfaces ◽  
The Impact

Droplet impingement is a fundamental process for many applications particularly those involving heat transfer. While there has been considerable work over many years on understanding the flow and heat transfer processes, we have only recently been able to fabricate controllable nanostructured surfaces. Surface structure can have a massive impact on the droplet impact process dynamics and the associated convective heat transfer from the liquid droplet to the surface. In this paper we examine the impact dynamics and heat transfer using simultaneous high speed thermal imaging of the liquid from below, and high speed video camera images from the side for different surfaces, ranging from hydrophilic to superhydrophobic. In this way we characterize the heat transfer process as a function of the droplet dynamics and the surface properties. We show that the heat transfer rate is primarily affected by the contact line dynamics and the wetted area. Due to the superhydrophobic roughness scale being relatively small, the interface resistance offered by the trapped air has only a small effect on the heat transfer rate, and only in the inertia dominated region before maximum spreading diameter. Finally we show that the overall cooling effectiveness of as single impinging droplet is very dependent on the surface properties with hydrophilic surfaces offering the highest cooling effectiveness.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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