Advanced Materials Research Vols. 538-541

Abstract: Three-dimensional model of the main shaft of JKM4×4 hoister was built based on Pro/E. After having applied boundary conditions and loads to the model, the finite element analysis for the main shaft was conducted under extreme operation conditions with ANSYS, the stress and displacement distribution was presented and the stress biggest hazard points were found. Based on the analysis results, improvement methods for the main shaft structure design was given out, which provides references for further optimal designing the main shaft of hoister.

Abstract: To make further researches into the elastohydrodynamic lubrication properties of a finite line contact roller, oscillating experiments were carried out on made overload experimental rig for oil film measurement using optical interference technique. Film thickness and shape were measured in two kinds of viscosity polyisobutylene. This study indicates that both lubricant viscosity and roller entrainment velocity play an important role on EHL of finite line contacts. On motion, the more increase in viscosity or speed, the thicker the oil film thickness, simultaneity edge effect is distinctly intensified and film thickness increases less on roller end, difference of the film thickness is increased between roller end and the central. Above two parameters are significant for logarithmic profile roller in crowning design.

Abstract: To reveal the principle of the close effect about the EHL finite roller, contraposing the log-convex roller, the finite line contact EHL film shape and thickness were observed through self-made heavy-load optical EHL experimental device. Experiments were carried out under several different pressure and viscosity, and three groups of interference pictures were obtained under three different entrainment velocities. As the load increased, both the length and width of the roller contact area added, and the width of the contact zone in the end was larger than that in the centre, the close effect was more obvious; when the entrainment velocity and lubricant viscosity increased, the film thickness in the central roller became thicker while the increase in the roller end was little, the high film thickness difference enhanced the close effect. The entrainment velocity, load and lubricant viscosity all have great effect on the EHL characteristics of the finite roller.

Abstract: In this paper, taking Chinese Nanjing Metro ALSTOM vehicle synthesis brake as an example, the subway with synthetic brake shoe for composition analysis, comparative study of multiple forming process, eventually developed to hybrid fiber as reinforcing material, modified phenolic resin as matrix material, and then filling friction modifier performance, using direct molding the mixture of dry moulding process made new domestic subway brake shoe. The product of the test performance indicators that can replace the similar foreign products.

Abstract: Abstract. In order to diagnose the fault of rolling bearing by the vibration signal, a new method of fault diagnosis based on weighted fusion and BP (Back Propagation) neural network was put forward. At first, the vibration signal from the sensors was wave filtered through the method of correlation function, then the fused signal was obtained by the classical adaptive weighted fusion method, the multi-type characteristics parameters was to be as a neural network input. Finally, the fault diagnosis of rolling bearing was realized by the BP neural network, and the results show that the multi-sensor information fusion fault diagnosis method can be proved effectively to achieve the fault diagnosis of rolling bearing.

Abstract: Based on the unified Reynolds equation model and fast Fourier transform (FFT) method, the lubrication performance of the piston pin bearing for high power density diesel engine was studied by numerical simulation. First of all, through the coupled solving of a unified Reynolds equation and elastic deformation equation, the influence of the viscous-pressure effect on the maximum film pressure and the minimum oil film thickness for piston pin bearing are investigated. The results show that, after considering the viscosity-pressure effect, the minimum oil film thickness and the maximum film pressure of semi-floating piston pin bearings for high power density increase, and the elastic deformation decreases in greatest load position. It confirms that the bearing capability is greatly enhanced while the viscosity- pressure effect is considered. Secondly, The eccentricity ratio of the piston pin bearing in vertical direction of the piston stroke is smaller, however it is much larger in the downward direction of the piston stroke, which indicate that the below area of the piston pin bearing bears greater load and occurs larger deformation. This is consistent with the reality that the below area of the piston pin bearing is prone to damage and wear

Abstract: Oil whip phenomenon is the common fault in rotor-bearing system. The reason why oil whip happens often has been researched in high-speed rotor-bearing system. But in practice engineering, due to the requirement of work condition, oil whip cannot be avoided all the time in rotor-bearing system. The paper is based on the relation criterion of oil whip happens in rotor-bearing system, the reliability mode and system reliability of oil whip are defined, and the reliability analysis method for avoiding oil whip in rotor-bearing system is carried out. The effect on reliability sensitivity of random parameters is studied. Numerical results are also presented and discussed.

Abstract: Water-lubricated thrust bearing is a key component of certain main pump motor. In this paper, the right structure of water-lubricated thrust graphite bearings is designed based on low viscosity hydrodynamic lubrication theory by combining the bearings running working condition, and the frictional accessory material is also determined by theoretical analysis and test. The factors influencing lubrication performances of water-lubricated thrust bearings are analyzed; the methods improving lubrication performances are put forward to guarantee that water-lubricated thrust graphite bearings have the good lubrication performances, good carrying capacity and longer work life.

Abstract: Structure parameters of muffler element with inserted tube are firstly determined, it is analyzed to the inserted length effecting on sound power of flow regeneration noise and frequency characteristic, and distribution feature of flow velocity and turbulence kinetic energy is explored by numerical computation of flow field. It is shown that flow regeneration noise of muffler element with inserted tube forms according to confined incomplete flow-inject, it presents wide frequency band, and its energy focus on middle and low frequency, especially it is about 600Hz, Strouhal Number is 0.5. When its structure parameters is constant, distribution feature of flow velocity and turbulence kinetic energy doesn’t change with flow velocity, and difference is numerical dimension, and turbulence kinetic energy distributes near inserted tube in wall, this is area occurring flow regeneration noise, so producing mechanism of flow regeneration noise from muffler element with inserted tube is achieved.

Abstract: With the development of manufacture technology, it is a critical problem for the reliability of avionic devices that components have to operate at high heat flux. And the package of components cannot meet the requirements of the heat dissipation. Therefore, it is essential to add heat sink on the top of power components. This paper presents the use of Taguchi method in optimizing the heat sink. The heat sink is designed to balance the weight and the temperate distribution of the component. At first, several parameters of the heat sink, including the base width, the base length, the fin height, the fin number, are chosen to be controllable factors. The machining errors are the uncontrollable factors. Then, four orthogonal arrays are used to lead the design of experiments (DOE). Finite-volume method (FVM) is used to calculate the case temperature of the component. Basing on the results generated by the Taguchi DOE method, the optimal design of heat sink can be chosen. Additionally, the heat sink can be optimized, while the reliability of component and device can be improved by using this method.