Advanced Materials Research Vol. 711

Abstract: The detection mechanism of Magnetic Flux Leakage (MFL) Method of elevator cable is proposed. Using Gauss-Mercury method to analyze the influence of different factors that lift-off value, fracture width, broken wires number and diameter and depth all that based on the collecting experimental system of MFL signals. The method can be used to optimize the detection probe design and detection signal processing.

Abstract: To analyze the rock slope stability of open pit, limit equilibrium theory is used and the safety factor of slope stability is calculated by Geo-slope software. Then, the region where local instability or overall instability may occur is determined. Finally, some optimization plans and appropriate protective measures are suggested, providing a theoretical basis for engineering practice.

Abstract: Hydrocyclone has been increasingly used in mineral, food and chemical industrial processes as common solid-liquid separation equipment. Small-sized hydrocyclone is generally applied to separate fine particle which is hard to separate by conventional sized hydrocyclone. However, the separation efficiency could be reduced due to the limitations of inlet width and capacity in this case. A novel impeller hydrocyclone is designed to solve this problem, and the influences of impeller on inner fluid flow rate have been discussed by simulating fluid flow patterns using a common CFD software, FLUENT. The results show that increasing the speed of rotating blade section is an effective way to improve the particle separation efficiency due to the increase in centrifugal force.

Abstract: Using the FLUENT software, this paper taking the wind load shape coefficient in the current code for the design of building structures as the comparison standard, have numerical wind tunnel simulation of the wind the surface wind pressure on low layer double slope roof. It focused on the effect of four convective term difference schemes on the numerical simulation, such as First-Order Upwind, Second-Order Upwind, Power Law and Quadratic Upwind Interpolation for ConvectiveKinematics. It provided reasonable reference for selection of convective term difference format.

Abstract: Using the FLUENT software, this paper taking the wind load shape coefficient in the current code for the design of building structures as the comparison standard, have numerical wind tunnel simulation of the wind the surface wind pressure on arch roof. It focused on the effect of the different turbulence models on the numerical simulation, such as Spalart-Allmaras, Standard k ε, RNGk ε, Realizablek ε, Standard k ω, SST k ωand RSM. It provided reasonable reference for selection of turbulence model.

Abstract: EMD is now a commonly used nonlinear and instable signal processing method, but it has boundary runaway and modal aliasing. The single disunited IMF cannot well reflect the characteristics of the respective vibration source. Therefore, in order to suppress the boundary runaway that will appear in the process of EMD, the image method is used to extend the length of signal data. To solve the modal aliasing, it is necessary to decompose the extended data by the EMD method, to distinguish the IMF that produces modal aliasing after decomposition, to integrate it according to the integrity of the EMD and then to re-decompose it after adding broadband white noise with the average value of zero. On the basis of that, it is better to improve NS-EMD method and realize the AM-FM demodulation by standardized method. By the spectrum analysis, we extract the fault characteristics of rolling bearings and propose a method to diagnose faults of rolling bearing. The results of analyzing the simulation and the vibration signal of fault rolling bearing shows that the method can effectively extract fault characteristics of rolling bearing.

Abstract: This paper analyzes the power quality measuring principles according to the national power quality indicator. And a power quality monitoring system based on LabVIEW has been designed. Five indexes are introduced simply in the paper. They are voltage deviation, frequency deviation, three-phase unbalance degree, power harmonic and voltage fluctuation and flicker. Virtual instrument technology is used in the system. Through the combination of software and hardware and with the help of software simulation, the system gets signal data and analyses the power quality. The main program interface has been shown. Simulation showed that the system is feasible. Compared with the traditional instruments, the system has a friendly man-machine interface and strong processing capacity. It can be operated simply and extended conveniently.

Abstract: With the vibration exciter, the experimental modal analysis and vibration analysis of high-speed industrial sewing machine was carried out in this paper. The results show that the sewing machine will be of resonance at the operating speed of 4000r/min, which means the structure of the chassis of the sewing machine should be optimized.

Abstract: ntroduction was made to the working principle of topology for the half-bridge LLC resonant converter. Steady-state models of the high power LLC resonant network were researched. The high power half-bridge LLC converter was modeled and analyzed with First Harmonic Approach so as to obtain the optimal parameters. The turn ration of the converter was selected. The resonant inductance, resonant capacitance and excitation inductance were designed. The feasibility of the high power LLC converter design has been verified through simulation.

Abstract: Harmonic gear reducer is the key component of the electric servo system, its transmission error analysis and testing play a crucial role in the development, production, testing, assembly of gear reducer. According to the thin shell elastics deformation theory, the harmonic transmission principle is analyzed, and the harmonic transmission error sources. The calculation of transmission error is further discussed; the transmission error formula of harmonic gear reducer considering the case of gear backlash and stiffness is given. A harmonic gear reducer transmission error testing system is designed. This system can achieve the detection for the static and dynamic transmission error of harmonic gear reducer, the accuracy of measuring angular is batter than .