Advanced Materials Research Vol. 902

Abstract: Scaling and corrosion are the two problems of the cooling system. In this paper, the influence of emulsion on the corrosion and scaling on pipelines of cooling system deep coal mine is studied by the experiment. Firstly, the characteristics of water consist in the pipe of cooling system are received; secondly, 12 kinds of emulsion were prepared in the experiment and characteristics of the water mixed with emulsion are tested; Finally, we calculated the I_S, I_R at the cases of different temperatures and put forward the mass fraction of emulsion which can prevent the scaling and corrosion. The results are as follows.1) When the water temperature is higher than 37°C, there will be no corrosion and scaling when no joins of emulsion.2) When the water temperature is 27~37°C, the pipeline surface will be little corroded by the mining water, and the joining of emulsion with the mass fraction of 1~2% can prevent scaling and corrosion.3) When the water temperature is higher than 27°C, the pipeline surface will be corroded by the mining water, and the joining of emulsion with the mass fraction of 3~4% can prevent scaling and corrosion. The research is of great importance to the cooling under deep coal mine, at the same time to the scale inhibition and anticorrosion on the geothermal engineering.

Abstract: Based on the probabilistic fracture mechanics approach, durability test on the fine details of wagon side frame is simulated, the structural damage degree is evaluated from the four aspects of the survival probability, the stress amplitude, the crack formation time and economic repair limit size according to general EIFS distribution, and its economic life is predicted by combining with the stress spectrum measured in practice. The result shows that the EIFS follows the Weibull distribution and passes the K-S test, the structural damage degree can be quantitatively measured on the basis of the probabilistic model of crack exceedance, the economic life predicted tends to increase with the increase of crack exceedance probability, the rationality and validity of the analysis method is proved.

Abstract: In this work the design and manufacturing of a new test machine to simulate the Rolling Contact Fatigue (RCF) wear on pavement surfaces is carried out. The method of Quality Function Deployment (QFD) was used to determine the conceptual design of the machine; from this a detailed design of the machine was developed, through additional computer aided design software. The machine basically consists of a frame and two mechanisms; one is for transmitting the force and the other one the motion. The static conditions were calculated and a finite element analysis was performed by computer aided engineer software to determine the failure due to mechanical stresses. Finally it is showed the machine assembly and some preliminary tests in order to verify the performance of the tribological prototype.

Abstract: This paper is proposed to reveal the stable equilibrium on the boring bar during heavy-duty deep-hole boring trepanning processing environment, including three conditions considering vortex instability caused by outside cutting fluid, perturbation instability caused by inside cutting fluid and synthesized instability accompanied both inner and outer cutting fluid, respectively. Every position of stable equilibrium and formula of rotation speed in instability are obtained. It is shown that the system instability induced by no matter how different situations, is resulted from half frequency vortex and perturbation, through case calculation and simulation on system stability.

Abstract: An important source of transformer core vibration is magnetostriction of the thin silicon-steel lamination. In the power grid, direct current (DC) may form by solar magnetic storms and DC transmission. Transformer core supersaturation and harmonic increase in current caused by DC bias will intensify magnetostriction and produce additional transformer core vibration. In order to obtain transformer core vibration under DC bias, the magnetization curve and magnetostriction characteristics of thin silicon-steel lamination are measured. Then, this paper establishes a numerical magneto-mechanical strong coupling model including magnetostrictive effect under DC bias for three-phase three-column dry transformers. On the basis of the proposed model, and the measured magnetic characteristics of the thin silicon-steel lamination, transformer core vibration under DC bias and no-load condition has been calculated. In order to verify the proposed model, transformer core vibration under DC bias and no-load condition is studied experimentally. Numerical calculation results together with experimental results confirm the validity of the proposed method.

Abstract: Motor vibration is one of the main causes of the motor noise, and the vibration of the motor also brings great harm for the safe and reliable operation of the motor load system. The vibration and noise level is one of the essential elements in evaluating the electrical machines quality. Accurate calculation of the stator natural frequencies and harmonic response of an electrical machine is essential to the prediction of the vibration. This paper takes the common Y series induction motors as the sample. The motor is a complex electromechanical coupling system, which includes stator and rotor. The finite element analysis is used to study on the stator modal shapes and natural frequencies of the induction motor. Then this paper calculates the electromagnetic force by using the finite element method, and gets the spectrum distribution of the radial electromagnetic force. Thus it provides a good method for the motor design by predicting natural frequency and optimizing the motor parameters to avoid resonance. All of them provide theory fundamental basis and technical support for reducing vibration and noise of the motor.

Abstract: Residual stresses inside molded glass lenses contribute to image quality degradation. In this research, a circular polariscope was employed to investigate the residual stresses inside molded glass lenses. Residual stresses were calculated from optical measurements obtained by using of the circular polariscope. From the measurements both the magnitude and distribution of residual stresses in a molded glass lens were obtained.

Abstract: In this paper, the structure, the characteristics and the working principle of vibrating cone crusher with dual exciters were introduced. The hysteretic features of material layers were analyzed. The hysteretic force model with bidirectional symmetrical clearances for the material layer was presented. The mechanical model of two-degree of freedom with bilinear hysteresis and the nonlinear vibration equations of the system were proposed. The equivalent damping and stiffness coefficients of the vibrating system were calculated by asymptotic method. The displacement responses of the system were computed by numerical method and asymptotic method. The results showed that the system responses obtained by an approximate analytical solution were basically identical with the numerical simulation results of the original system.

Abstract: This paper first studied the parameters and power loss of the transformer, then conducted a thorough analysis of differences in technical parameters of transformer, the rate of active power loss and reactive power consumption rate of transformer change as the load. For the characteristics of large load fluctuations, large loss for a long time in the light-load and no-load operation of the distribution transformer, the paper analyzed and introduced in detail the selection of the economic operation mode of distribution transformer, the interval of economic operation, the load regulation and economic load distribution of the transformer.

Abstract: As a disastrous weather, hazards of freezing rain can not be ignored. The important thing to be solved at present is using advanced technology and material to correctly detect and improve the forecasting ability of freezing rain. Based on the damage of freezing rain and excellent properties of the giant magnetostrictive materials, this paper gives a giant magnetostrictive freezing rain sensor. When there is different thickness of freezing rain, natural frequency of the sensor will change. Resonance is regained by adjusting the frequency of the power. From natural frequency change, the thickness of the freezing rain can be known. Using COMSOL software, modal analysis of different thickness freezing rain for the giant magnetostrictive freezing rain sensor is studied. The results show that there is big difference in natural frequency with difference thickness of freezing rain, which is easy to achieve automatic frequency tracking and monitor.