scholarly journals Study on contact angle of double-decker bearing with consider of centrifugal expansion

2021 ◽  
Vol 231 ◽  
pp. 03005
Author(s):  
Jing Hu ◽  
XiaoLi Qiao ◽  
QiongYing Lv ◽  
XinMing Zhang ◽  
JiuTong Zhai ◽  
...  
Keyword(s):  
Contact Angle ◽  
Numerical Calculation ◽  
Numerical Analysis ◽  
Potential Application ◽  
High Speed ◽  
Dynamic Properties ◽  
Object A ◽  
Analysis And Design ◽  
Double Decker ◽  
Middle Ring

Improving the precision of numerical calculation of double-decker bearing is the basis of exploring its potential application value. This paper takes double-decker bearing as the research object, a modified quasi-statics model of double-decker bearing was established by considering the influence of the centrifugal expansion of the inner and middle ring of double-decker bearing at high speed and solve it with soft of Matlab. The influence of centrifugal expansion on the contact angle of the double-decker bearing was analyzed. The results show that the centrifugal expansion caused by the inner ring and middle ring under high speed can not be ignored, and the centrifugal expansion has a greater influence on the contact angle of inner bearing than that of outer bearing. The influence of centrifugal expansion on the dynamic properties of different materials is different, and the change of contact angle caused by ceramic as the inner ring and middle ring is greater than that of steel. It provides the basis for more accurate numerical analysis and design of the double-decker bearing.

scholarly journals Research on the Mechanical Properties of “Z” Type Double-Decker Ball Bearings

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Chengtao Yu ◽  
Longxiang Xu ◽  
Xudong Yu
Keyword(s):  
Contact Angle ◽  
Carrying Capacity ◽  
High Speed ◽  
Static Load ◽  
Radial Deformation ◽  
Load Carrying Capacity ◽  
Heavy Load ◽  
Double Decker ◽  
Load Carrying ◽  
Simulation Results

The mechanical model of a “Z” type double-decker ball bearing under the action of radial load is established in this paper on the basis of the Hertz contact theory. According to the security contact angle theory, the influences of inner and outer bearings' internal clearances on the bearing's static load carrying capacity, radial deformation, radial stiffness, and load distribution of balls are analyzed. This model is verified in both stationary and rotational loading experiments. Moreover, the simulation results show that the static load carrying capacity of Z type bearing is smaller than that of either inner bearing or outer bearing that is contributed to compose the Z type bearing. The static load carrying capacity of a Z type bearing reduces with the increase of the inner and outer bearings' internal clearance. These simulation results also indicate that the contact angle of the maximum loaded ball in the outer bearing easily exceeds its security contact angle compared with the inner bearing, which, as the main factor, may cause the Z type bearing to overload and to fail. In this sense, the investigated Z type bearings are unfit to apply to situations with heavy load, high speed, or high precision.

Numerical Analysis to Impact of Different Heights for Subgrade Connecting in High-Speed Railway

2010 ◽  
Vol 168-170 ◽  
pp. 1256-1259
Author(s):  
Jian Yi Yuan ◽  
Ya Yu Lv
Keyword(s):  
Numerical Calculation ◽  
Numerical Analysis ◽  
High Speed ◽  
Vertical Direction ◽  
Important Research ◽  
High Speed Railway ◽  
Construction Engineering ◽  
Railway Construction ◽  
Safety Operation ◽  
Surface Increase

Subgrade connecting has become an important research project in high-speed railway construction engineering. Combining the hub project of Hefei railway, numerical calculation was executed with different subgrade heights to existing line’s safety operation and subgrade stability by FLAC software. It shows that deformations in the vertical direction of the connection between the new subgrade and the old and the old subgrade surface increase following the increment of subgrade height, and the velocity of deformation increment also aggrandize. Reduction of subgrade height is beneficial to trains safety on existing line and subgrade integration property. It will be instructive to control differentia deformation for the connecting subgrade projects in high-speed railway.

Analysis and Design of Manipulators With Decoupled and Configuration-Invariant Inertia Tensors Using Remote Actuation

1992 ◽  
Vol 114 (2) ◽  
pp. 204-212 ◽  
Author(s):  
K. Youcef-Toumi
Keyword(s):  
High Speed ◽  
Dynamic Properties ◽  
Sufficient Conditions ◽  
Kinematic Chain ◽  
Degree Of Freedom ◽  
Direct Drive ◽  
Analysis And Design ◽  
Remote Actuation ◽  
Three Degree Of Freedom ◽  
Necessary And Sufficient

The dynamics of manipulators with diagonal and/or constant inertia tensors are described by simple differential equations. This feature greatly simplifies the control of high speed manipulators. This paper presents design methods, which incorporate selection of arm structure and link inertial properties, to achieve simplified manipulator dynamics. First the concept of remote actuation is described. A model is then developed in order to analyze the effects of remote actuation on the manipulator kinematics and dynamics. The modeling is based on Kane’s partial rates along with a set notation to concisely express the system’s dynamics. Second, necessary and sufficient conditions for achieving such dynamic properties for open and closed kinematic chain linkages are derived. These techniques are then applied in the design of three degree-of-freedom planar manipulator and the three degree-of-freedom spatial M. I. T direct-drive manipulator. The mass distribution conditions for which the arm inertia tensors are diagonal and configuration-invariant are derived. The resultant dynamic equations of these manipulators are shown to be very simple.

Tribological and dynamical analysis of a brake pad with multiple blocks for a high-speed train

2019 ◽  
Vol 234 (11) ◽  
pp. 1771-1788
Author(s):  
YK Wu ◽  
JL Mo ◽  
B Tang ◽  
JW Xu ◽  
B Huang ◽  
...  
Keyword(s):  
High Speed ◽  
Wear Behavior ◽  
Dynamical Analysis ◽  
Brake Disc ◽  
Brake Pad ◽  
High Speed Train ◽  
Brake Squeal ◽  
Element Analysis ◽  
Single Block ◽  
Middle Ring

In this research, the tribological and dynamical characteristics of a brake pad with multiple blocks are investigated using experimental and numerical methods. A dynamometer with a multiblock brake pad configuration on a brake disc is developed and a series of drag-type tests are conducted to study the brake squeal and wear behavior of a high-speed train brake system. Finite element analysis is performed to derive physical explanations for the observed experimental phenomena. The experimental and numerical results show that the rotational speed and braking force have important influences on the brake squeal; the trends of the multiblock and single-block systems are different. In the multiblock brake pad, the different blocks exhibit significantly different magnitudes of contact stresses and vibration accelerations. The blocks located in the inner and outer rings have higher vibration acceleration amplitudes and stronger vibration energies than the blocks located in the middle ring.

scholarly journals NanoLEDs for energy-efficient and gigahertz-speed spike-based sub-λ neuromorphic nanophotonic computing

Nanophotonics ◽  
2020 ◽  
Vol 9 (13) ◽  
pp. 4149-4162 ◽  
Author(s):  
Bruno Romeira ◽  
José M. L. Figueiredo ◽  
Julien Javaloyes
Keyword(s):  
Neural Networks ◽  
Energy Efficient ◽  
High Speed ◽  
Dynamic Properties ◽  
Optical Computing ◽  
Differential Conductance ◽  
Rate Equations ◽  
Dynamical Equations ◽  
Electrical Modulation ◽  
High Bandwidth

AbstractEvent-activated biological-inspired subwavelength (sub-λ) photonic neural networks are of key importance for future energy-efficient and high-bandwidth artificial intelligence systems. However, a miniaturized light-emitting nanosource for spike-based operation of interest for neuromorphic optical computing is still lacking. In this work, we propose and theoretically analyze a novel nanoscale nanophotonic neuron circuit. It is formed by a quantum resonant tunneling (QRT) nanostructure monolithic integrated into a sub-λ metal-cavity nanolight-emitting diode (nanoLED). The resulting optical nanosource displays a negative differential conductance which controls the all-or-nothing optical spiking response of the nanoLED. Here we demonstrate efficient activation of the spiking response via high-speed nonlinear electrical modulation of the nanoLED. A model that combines the dynamical equations of the circuit which considers the nonlinear voltage-controlled current characteristic, and rate equations that takes into account the Purcell enhancement of the spontaneous emission, is used to provide a theoretical framework to investigate the optical spiking dynamic properties of the neuromorphic nanoLED. We show inhibitory- and excitatory-like optical spikes at multi-gigahertz speeds can be achieved upon receiving exceptionally low (sub-10 mV) synaptic-like electrical activation signals, lower than biological voltages of 100 mV, and with remarkably low energy consumption, in the range of 10–100 fJ per emitted spike. Importantly, the energy per spike is roughly constant and almost independent of the incoming modulating frequency signal, which is markedly different from conventional current modulation schemes. This method of spike generation in neuromorphic nanoLED devices paves the way for sub-λ incoherent neural elements for fast and efficient asynchronous neural computation in photonic spiking neural networks.

Penetration Dynamics of Solid Particles into Liquids High-Speed Experimental Results and Modelling

2005 ◽  
Vol 473-474 ◽  
pp. 429-434 ◽  
Author(s):  
Olga Verezub ◽  
György Kaptay ◽  
Tomiharu Matsushita ◽  
Kusuhiro Mukai
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Aqueous Solutions ◽  
Particle Velocity ◽  
Weber Number ◽  
High Speed ◽  
Solid Particles ◽  
Bulk Liquid ◽  
Distilled Water ◽  
Critical Weber Number

Penetration of model solid particles (polymer, teflon, nylon, alumina) into transparent model liquids (distilled water and aqueous solutions of KI) were recorded by a high speed (500 frames per second) camera, while the particles were dropped from different heights vertically on the still surface of the liquids. In all cases a cavity has been found to form behind the solid particle, penetrating into the liquid. For each particle/liquid combination the critical dropping height has been measured, above which the particle was able to penetrate into the bulk liquid. Based on this, the critical impact particle velocity, and also the critical Weber number of penetration have been established. The critical Weber number of penetration was modelled as a function of the contact angle, particle size and the ratio of the density of solid particles to the density of the liquid.

Numerical Analysis of Influence of Roughness of Material Surface on High-Speed Liquid Droplet Impingement

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Hirotoshi Sasaki ◽  
Yuka Iga
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Erosion Rate ◽  
Liquid Droplet ◽  
Material Surface ◽  
Liquid Droplets ◽  
Fluid Machinery ◽  
Droplet Impingement ◽  
Surface Liquid ◽  
Droplet Impingement Erosion

This study explains why the deep erosion pits are formed in liquid droplet impingement erosion even though the droplets uniformly impinge on the entire material surface. Liquid droplet impingement erosion occurs in fluid machinery on which droplets impinge at high speed. In the process of erosion, the material surface becomes completely roughened by erosion pits. In addition, most material surface is not completely smooth and has some degree of initial roughness from manufacturing and processing and so on. In this study, to consider the influence of the roughness on the material surface under droplet impingement, a numerical analysis of droplets impinging on the material surface with a single wedge and a single bump was conducted with changing offsets between the droplet impingement centers and the roughness centers on each a wedge bottom and a bump top. As results, two mechanisms are predicted from the present numerical results: the erosion rate accelerates and transitions from the incubation stage to the acceleration stage once roughness occurs on the material surface; the other is that deep erosion pits are formed even in the case of liquid droplets impinging uniformly on the entire material surface.

Numerical Calculation of Aerodynamic Noise for the Nose Cone Surface in High Speed Airflow Field

2014 ◽  
Vol 488-489 ◽  
pp. 886-891
Author(s):  
Ai Jian Zheng ◽  
Feng Niu ◽  
Hai Jiang Zhu
Keyword(s):  
Numerical Calculation ◽  
High Speed ◽  
Aerodynamic Noise ◽  
Element Analysis ◽  
Analysis Theory ◽  
Nose Cone ◽  
Flow Induced Noise ◽  
Airflow Field ◽  
Boundary Element Analysis ◽  
Acoustic Boundary Element

This paper presents two nose cones models and their numerical calculation of aerodynamic noise in high speed airflow field combining the analysis theory of fluid dynamics with the acoustic boundary element analysis method. The noise sound pressure levels (SPL) of these two models are calculated under the different speed airflow. And we compare the SPL of the better model with that of commercial nose cone models. These simulated results show that the aerodynamic noise of the nose cone with a ellipsoid head has lower flow-induced noise than that of commercial nose cone models at relative high air flow velocities at most frequencies.

The Analysis and Design of the Dynamic Information Service System Network Architecture of the SOA Based on WAVE Technology

2014 ◽  
Vol 1044-1045 ◽  
pp. 1380-1383
Author(s):  
Guang Li Yin
Keyword(s):  
Network Architecture ◽  
High Speed ◽  
Service System ◽  
Road Traffic ◽  
Rapid Development ◽  
Information Service ◽  
Advanced Technology ◽  
Living Standard ◽  
Vehicle Speed ◽  
Analysis And Design

Safety problem is one of the most attention and concern of driving. This paper in the high-speed on the road cars and car, car and road communications, vehicle real-time status, through the network information service system integration on a platform, on the use of related technologies are analyzed, the design of the software system based on SOA architecture.Keywords: network, GPS module, SOA cross platformI. IntorductionWith the development of science and technology and the improvement of people's living standard, Car popularity rate is high, it's hard to believe, families has two or three car. Whether it is the bus or private car is such rapid development, this will bring a lot of problems in road traffic, such as traffic congestion, traffic accident. These problems affect the normal life and travel, it is necessary to carry out management and provide information service for road use advanced technology. Using mobile phone GPS positioning module can obtain the vehicle speed and the basic information, through processing and optimization of information service system, the analysis of data useful, so as to divert traffic, both for the convenience of the user, but also improve the expressway management ability.

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