Mechanical Properties and Experimental Study of a Composite Polishing Plate during Super-High Polishing

2010 ◽  
Vol 135 ◽  
pp. 337-342
Author(s):  
Li Zhou ◽  
Shu Tao Huang ◽  
Li Fu Xu
Keyword(s):  
Chemical Reaction ◽  
High Speed ◽  
Equivalent Stress ◽  
Stress Distributions ◽  
Centrifugal Forces ◽  
X Ray ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Von Mises Equivalent Stress ◽  
Von Mises

A new composite polishing plate for polishing of CVD diamond films has been designed. The displacement and stress distributions of the high speed rotation polishing plate have been investigated due to centrifugal forces, and the polishing mechanism of super-high polishing has been analyzed by using X-ray photo-electron spectroscopy. The results showed that the displacements both in axial and radial increase with the increasing of the rotational speed. When the rotation speed reached to 1200 rad/s, the von Mises equivalent stress is about 242 MPa, which is safe for the composite polishing plate. Additional, the polishing mechanism is mainly the chemical reaction between carbon and titanium during the super-high speed polishing. At elevated temperature, the chemical reaction between oxygen and titanium, oxygen and carbon can also occur.

High-speed rotating device for X-ray tomography with 10 ms temporal resolution

2021 ◽  
Vol 28 (1) ◽  
pp. 322-326
Author(s):  
Ryo Mashita ◽  
Wataru Yashiro ◽  
Daisuke Kaneko ◽  
Yasumasa Bito ◽  
Hiroyuki Kishimoto
Keyword(s):  
Synchrotron Radiation ◽  
Temporal Resolution ◽  
High Speed ◽  
X Ray ◽  
High Speed Rotation ◽  
Speed Rotation

The temporal resolution of X-ray tomography, using a synchrotron radiation X-ray source, has been improved to millisecond order in recent years. However, the sample must be rotated at a speed of more than a few thousand revolutions per minute, which makes it difficult to control the environment around the sample. In this study, a high-speed rotation device has been developed, comprising two synchronized coaxial motors movable along the direction of the axis, which can stretch or compress the rotating sample. Using this device, tomograms of breaking rubber were successfully obtained at a temporal resolution of 10 ms.

scholarly journals Evaluating the Effect of Wheel Polygons on Dynamic Track Performance in High-Speed Railway Systems Using Co-Simulation Analysis

2019 ◽  
Vol 9 (19) ◽  
pp. 4165 ◽  
Author(s):  
Song ◽  
Du ◽  
Zhang ◽  
Sun
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Concrete Slab ◽  
Equivalent Stress ◽  
Dynamic Responses ◽  
Traffic Density ◽  
Harmonic Order ◽  
High Speed Railway ◽  
Von Mises Equivalent Stress ◽  
Von Mises

With increases in train speed and traffic density, problems due to wheel polygons and those caused by wheel–rail impacts will increase accordingly, which will affect train operational safety and passenger ride comfort. This paper investigates the effects of polygonal wheels on the dynamic performance of the track in a high-speed railway system. The wheel–rail interaction forces caused by wheel polygons are determined using a dynamic vehicle–track model, and the results are entered into a slab track finite element model. The influence of the harmonic order and out-of-roundness (OOR) amplitude of wheel polygons on the transient dynamic characteristics of the track(von Mises equivalent stress, displacement, and acceleration) is examined under high-speed conditions. The results indicate that the vibration acceleration and von Mises equivalent stress of the rail increase in proportion to the harmonic order and the OOR amplitude and velocity of a polygonized wheel. The vibration displacement of the rail first increases and then decreases with a change in the harmonic order, and reaches a maximum at the ninth order. The dynamic responses of the concrete slab layer, cement-asphalt layer, and support layer increase linearly with the harmonic order and amplitude of wheel polygons and decrease from top to bottom. Through a combination of numerical simulations and real-time monitoring of rail vibrations, this study provides guidance on potential sensor locations to identify polygonized wheels before they fail.

A Three-Dimensional Finite Element Stress Analysis and Strength Prediction of CFRP Adhesive Laminated Plates Subjected to Static and Impact Out-of-Plane Loadings

2009 ◽  
Author(s):  
Yukiya Noshita ◽  
Toshiyuki Sawa ◽  
Yuya Omiya
Keyword(s):  
Equivalent Stress ◽  
Three Dimensional ◽  
Laminated Plates ◽  
Stress Distributions ◽  
Maximum Value ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
Three Dimensional Finite Element

Stress distributions in CFRP adhesive laminated plates subjected to static and impact out-of-plane loadings are analyzed using a three-dimensional finite-element method (FEM). For establishing an optimum design method of the laminated plates, the effects of some factors are examined. As the results, it is found that the maximum value of the von Mises equivalent stress σ eqv occurs at the edge of the CFRP’s interfaces. The maximum value of interface shear stress r i at CFRP interface decreases as the reinforced Young’s modulus and the thickness increases. However, the maximum value of σ eqv at the adhesive layer decreases as the reinforced Young’s modulus and the thickness decreases. In addition, the maximum value of r i at the CFRP’s interface of lower reinforced laminates under impact loadings shows opposite characteristics to those under static loadings. For verification of the FEM calculations, experiments were carried out to measure the strains at the interfaces and the laminates plates strengths. Concerning strain and strength prediction based on von Mises equivalent stress, fairly good agreements were found between the numerical and the experimental results. The FEM results of impacted strain are in fairly good consistent with the measured results. Discussion is made on the effects of some factors on interface stress distributions.

Finite element analysis of the wheel–rail impact behavior induced by a wheel flat for high-speed trains: The influence of strain rate

2017 ◽  
Vol 232 (4) ◽  
pp. 990-1004 ◽  
Author(s):  
Liangliang Han ◽  
Lin Jing ◽  
Longmao Zhao
Keyword(s):  
Shear Stress ◽  
Plastic Strain ◽  
Strain Rate ◽  
High Speed ◽  
Equivalent Stress ◽  
Equivalent Plastic Strain ◽  
Impact Behavior ◽  
Wheel Flat ◽  
Von Mises Equivalent Stress ◽  
Von Mises

The wheel–rail impact response induced by a wheel flat for high-speed trains is simulated numerically, based on the strain rate-dependent constitutive parameters of wheel–rail materials, using the finite element software LS-DYNA explicit algorithm. Influences of the speed of the train, the length of the wheel flat, and axle load on the wheel–rail impact behavior are discussed over a wide range, in terms of the vertical impact force, von Mises equivalent stress, shear stress, and equivalent plastic strain. The maximum wheel–rail impact forces are 2.6–4.4 times greater than the corresponding static axle loads due to the presence of a wheel flat. The maximum von Mises equivalent stress and equivalent plastic strain have occurred on the wheel–rail contact surface, while the maximum xy shear stress has often occurred on the subsurface of 4–6 mm below the contact surface. The wheel–rail impact responses induced by a wheel flat are sensitive to the speed of trains, flat length, and axle load. Besides, the strain rate effect of wheel–rail materials has a significant influence on the maximum von Mises equivalent stress, shear stress, and equivalent plastic strain, while it has no influence on the maximum vertical impact force. These findings are very helpful to guide the maintenance and repair of wheel–rail components in rail transport.

Exact Solution of Radial Displacement and Stress of Rotating Elastic Interference Fits

2013 ◽  
Author(s):  
Sheng Feng ◽  
Haipeng Geng ◽  
Baisong Yang ◽  
Lie Yu ◽  
Lihua Yang ◽  
...  
Keyword(s):  
Exact Solution ◽  
High Speed ◽  
Radial Displacement ◽  
Equivalent Stress ◽  
Elastic Plane ◽  
Stress Theory ◽  
Temperature Changes ◽  
Rotating Speed ◽  
Von Mises Equivalent Stress ◽  
Von Mises

Interference fits, which are widely used in flexible couplings, can transfer large torques while avoiding unbalance. Using the classic elastic plane stress theory, the equations of the rotating interference fits taking into account of the temperature changes are derived, and the exact solution of radial displacement and radial stress, hoop stress and tangential stress of the rotating interference fits are obtained, then taking the interference fits of the coupling for a high speed microturbomachinery as an example, the above solutions are plotted using the numerical method, and also Von Mises equivalent stress is calculated. It is found that there are significantly different for the radial displacements between the two cases of with/without taking into account the change of temperature under two kinds of parameters, one is rotating speed chosen as a parameter and other parameters keeps constant, the other is the inner radius of the shaft and rotating speed chosen as parameters.

scholarly journals Sound Noise Generated from Ball Bearing in High Speed Rotation

1978 ◽  
Vol 21 (158) ◽  
pp. 1306-1310 ◽  
Author(s):  
Akio NAGAMATSU ◽  
Masaho FUKUDA
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
High Speed Rotation ◽  
Speed Rotation

Analysis of the Lubrication Regimes at the Small End and Big End of a Connecting Rod of a High Performance Motorbike Engine

2012 ◽  
Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Daniele Dini
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
High Performance ◽  
Hydrodynamic Lubrication ◽  
Vertical Axis ◽  
Connecting Rod ◽  
Lubrication Regimes ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Squeeze Effect

In the present paper, the algorithm proposed by Giacopini et. al. [1], based on a mass-conserving formulation of the Reynolds equation using the concept of complementarity is suitably extended to include the effects of compressibility, piezoviscosity and shear-thinning on the lubricant properties. This improved algorithm is employed to analyse the performance of the lubricated small end and big end bearings of a connecting rod of a high performance motorbike engine. The application of the algorithm proposed to both the small end and the big end of a con-rod is challenging because of the different causes that sustain the hydrodynamic lubrication in the two cases. In the con-rod big end, the fluid film is mainly generated by the relative high speed rotation between the rod and the crankshaft. The relative speed between the two races forms a wedge of fluid that assures appropriate lubrication and avoids undesired direct contacts. On the contrary, at the con-rod small end the relative rotational speed is low and a complete rotation between the mating surfaces does not occurs since the con-rod only oscillates around its vertical axis. Thus, at every revolution of the crankshaft, there are two different moments in which the relative rotational speed between the con-rod and the piston pin is null. Therefore, the dominant effect in the lubrication is the squeeze caused by the high loads transmitted through the piston pin. In particular both combustion forces and inertial forces contribute to the squeeze effect. This work shows how the formulation developed by the authors is capable of predicting the performance of journal bearings in the unsteady regime, where cavitation and reformation occur several times. Moreover, the effects of the pressure and the shear rate on the density and on the viscosity of the lubricant are taken into account.

Research on Calibration Method of Tire Dynamic Balance Detection System

2012 ◽  
Vol 542-543 ◽  
pp. 828-832 ◽  
Author(s):  
Jing Fang Yang ◽  
Xian Ying Feng ◽  
Hong Jun Fu ◽  
Lian Fang Zhao
Keyword(s):  
High Speed ◽  
Detection System ◽  
Dynamic Balance ◽  
Calibration Method ◽  
Engineering Practice ◽  
Influence Coefficient ◽  
Quality Factors ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Upper Rim

Tire dynamic balance detection plays an important part in tire quality detection area. This paper uses the two-sided balance method to obtain the unbalance of the tire. According to the engineering practice, builds kinetic model and then introduces the calculating principle and operating procedures. In order to accurately determine the influence coefficient, a calibration method without tire is put forward. Further more, this new method is able to eliminate the unbalance caused by non-quality factors to some extent. But this method is presented based on the relative position invariance of the upper rim and lower rim, even both of them are under high-speed rotation situation. Finally, the experimental data acquired from both of the two methods are compared. The calibration method without tire is proved to be more feasible, efficient and accurate.

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