bluuebunny/crossref_metadata_2025 huggingface dataset:
A Method of Dynamic Modeling of a Large Floating Crane and its External Excitations
Authors: Zhang Qing , Zhang Jian Jie , He Ji , Li Yong Feng , Qin Xian Rong
Published: October 2010

According to the characteristics of floating cranes, an affordable numerical method to model the floating cranes and the external excitations such as wind, wave and shimmy loads was proposed. Local coordinates modifying wind, wave and shimmy loads which are determined separately were combined in the global coordinate system according to the geometric positions. The spectra of wind loads and wave loads were converted into time domain separately according to the linear method, while a shimmy load is determined according to the Lagrange’s Equation. As an example, the external excitation caused by random wind, wave and shimmy loads on a 7500-ton giant floating crane were simulated, and the transient dynamic response was predicted and discussed. Focusing on the characteristics of structure of floating cranes, the research indicates that the dominant frequency of the wave load is low, as compared to wind and shimmy loads, and that the shimmy load is closely related to the environmental excitations such as wind and wave loads. The results also suggest that the transient response of the crane is mainly related to the shimmy load.
Experimental and FEM Modal Analysis of Workbench for PCB Drilling Machine
Authors: Tang Hong Qun , Wang Cheng Yong , Wang Bing , Huang Li Xin , Hu Shan Shan , Chen Zhi Shun
Published: October 2010

X-axis and Y-axis workbenches are important parts of PCB drilling machine. Theirs dynamic properties directly affect the overall performance of drilling machine. Modal analysis method was adopted in this paper. Measurement and analysis on vibration of X-axis and Y-axis workbenches based on LMS Test. Lab was carried out. The modal parameters such as natural frequency, damping ratio and corresponding vibration modes were obtained. The results present that the X-axis and Y-axis workbenches have a high fundamental frequency, which is 564Hz and 1014Hz respectively. And the damping ratio is less than 4.91% and 2.99%, which shows that the stiffness of the X-axis and Y-axis workbenches are higher. The FEM modal analysis shows that it has the similar results with the experiments in modal parameters. The analysis of natural characteristics of workbench provides guidance for optimizing machining parameters of drilling and improving structure of workbench.
Vibration Analysis and Control in Amorphous Alloy Dry-Type Transformer Core
Authors: Yao Xiao Hu , Zhang Xiao Qing
Published: October 2010

The amorphous alloy dry-type transformer is one type of new energy-saving transformer. With the rapid development of amorphous alloy dry-type transformers, its vibration and noise also draws increasing attention. In this paper, the experiments of the amorphous alloy transformer core were carried out by vibration test systems. The influences of vibration in amorphous alloy transformer core under different support situation are analyzed. The influences of the winding under different sides and the Number of Windings are studied. It is shown that the boundary support has a greater impact on vibration of the core. The vibration of the core may be damped by exerting some restraint, especially in vertical direction. The different winding sides and the number of winding turns have little effect on the vibration of the core. The results presented in this paper can guide the application of the vibration and noise control of the amorphous alloy dry-type transformer.
Supports’ Dynamical Optimized Design for the External Pipeline of Aircraft Engine
Authors: Zhai Hong Bo , Li Bao Hui , Jiang Zhi Feng , Yue Zhu Feng
Published: October 2010

A three dimension model of some aircraft engine’s pipeline has been established to study dynamic characteristics of the pipeline under random excitation. The relationship between the supports’ parameters and the dynamic characters of the pipeline was also presented. In order to avoid the harmful resonance, depress the vibration level and reduce the dynamic stresses of the pipeline, a specific dynamical optimized method was proposed and the supports’ layout and parameters (location, quantity) were analyzed and optimized. The results show that 1) Under random excitation, the maximum stresses are located near the bushing with serious stress concentration and the ends of pipeline. Fracture failure easily occurs in these parts. 2) The supports’ optimized method of the pipeline proposed in this paper is reasonable and effective. And the optimized pipeline has less dynamic stress and better anti-vibration capability.
Research on Output Characteristics of Piezoelectric Accelerometers for Low-Frequency Vibration
Authors: Zhu Chao Fu , Qin Xu , Zheng Li Wen
Published: October 2010

Piezoelectric accelerometers are widely used for the measurement of middle- or high-frequency vibration. It is necessary to verify via experiments whether piezoelectric accelerometers can accurately measure low-frequency vibration. An experiment is designed to test the output characteristics of piezoelectric accelerometers for vibration of 1~5 Hz frequency, using a standard vibrator at low frequency (≤5Hz) and an accurately calibrated non-contact eddy current sensor as datum sensor. The experiment shows that the output characteristics of piezoelectric accelerometers are relatively stable when measuring vibration of 4~5Hz frequency. However, the output characteristics of accelerometers change with the frequencies and accelerations of vibration when the vibration frequencies are 1~3 Hz. It will affect the accuracy of vibration measurement.
Study on Vibration Signal Marginal Spectrum of Paper-Transferring System in Printing Press Based on EMD
Authors: Wang Yi Ming , Zhang Shao Hua , Zhang Zhi Hong , Li Jing
Published: October 2010

The precision of transferring paper is key factors to decide the print overprint accuracy, and vibration has an important impact on paper transferring accuracy. Empirical mode decomposition (EMD) can be used to extract the features of vibration test signal. According to the intrinsic mode function (IMF) by extracted, it is useful to analyze the dynamic characteristics of swing gripper arm on motion state. Due to the actual conditions of printing, the vibration signal of Paper-Transferring mechanism system is complex quasi periodic signals. Hilbert-Huang marginal spectrum that is based on empirical mode decomposition can solve the problem which is modals leakage by FFT calculated in frequency domain. Through the experimental research, the phase information of impact load at the moment of grippers opening or closing, which can be used for the optimization design of Paper-Transferring system and the improvement in the accuracy of swing gripper arm.
Study on Effect of Rotor Vibration on Tip Clearance Variation and Fast Active Control of Tip Clearance
Authors: Jia Bing Hui , Zhang Xiao Dong
Published: October 2010

The tip clearance flow of axial turbomachines is important for their aerodynamic and maneuver performance. And the tip clearance gap leakage flow is of continuing concern in reducing efficiency losses that occur within turbines. In order to gain significant reductions in emissions and specific fuel consumption as well as dramatic improvements in operating efficiency and increased service life of aero-engine, variation mechanism of blade tip clearance was analyzed and the equation of dynamic clearance was shown firstly, then the effect of rotor vibration in clearance variation which include flight loads and engine loads was studied in this paper; based on the dynamic measurements of blade tip clearance, a method that ensure tip clearance at optimal state in given mission profile through active rotor vibration control and active tip clearance control was presented. Besides, fuzzy control theory was used to solve the high nonlinear variation of tip clearance. The analysis result shows that this technique is useful.
Preparation of Railway Concrete Sleeper Blended with Perlite Admixture
Authors: Yu Le Hua , Ou Hui , Zhou Shuang Xi
Published: October 2010

The experimental data about concrete incorporating perlite admixture revealed that perlite admixture in content of 10%-20% replacing cement in equal mass enhanced effectively the workability, late-age mechanical strength and durability for concrete. The railway sleepers made of concrete with perlite admixture substituting for 20% cement were probingly produced in production line of manufactory without any modification to the conventional equipment or procedures. The summary was concluded that the concrete sleepers with 20% perlite admixture not only have met requirement of product quality, but also far better than demand of product quality on fatigue resistance, meanwhile prior to reference concrete sleepers without mineral admixture on major properties, such as fracture resistance. Consequently, the concrete sleeper considerably requires less maintenance and offers a longer service and reduced life-cycle costs.
Testing and Error Analysis of some Structure’s Impact Load
Authors: Wu Ji Ping , Cai You Xing
Published: October 2010

The shock response of single freedom system was studied based on impact theory. The shear blade of some merchant shearing machine was selected as the object. The static calibration and impact load testing was carried on the object. Based on the impact theory and finite element technology, the feasibility of the testing scheme and the influence of the shock wave shape on the testing accuracy were discussed. The results show that for the shear blade, when the impact load time history is 50ms and the natural frequency is 2848Hz, there only 0.42% difference between the maximum dynamic response and the static calibrated response. So it is practicable to use the static calibrated results to decide the relationship of the impact load and strain.
Study on the Application of Metal Rubber Isolator in Compressor Base
Authors: Fu Hai Long , Zou Long Qing , Dai Guang , Chi Xu
Published: October 2010

In this paper, the main problem is how to eliminate vibration came from the compressor base in petrochemical industry. The absolute transmissibility was calculated by building the compressor isolation system model. The spectrum information of compressor vibration was got through the vibration test, and the results can be acted as the condition for the isolator’s design. Isolators were designed with damping part connecting metal rubber with helical spring. Nonlinear simulation calculation was completed by finite element software. The results show that the maximum stress of isolator is about 494MPa and its maximum distortion is approximately 6mm. It verifies that the new-style isolator can satisfy vibration elimination of compressor. It is with wide-range rigidity and better capability of energy dissipation than that of general rubber isolator. It has a useful application and perspective on vibration elimination for the mechanical equipment in petrochemical industry.
Fast Steady Horizon Sensor Based on Filtering Vibration
Authors: Zhang Li Yong , Ran Yue Long
Published: October 2010

The liquid switch gyroscope is used as a reference of the original horizontal coordinate system in the inertial navigation system of ballistic rockets. The stability of gyro is significant for finding ground level when a missile enters the destination region. A damping is adapted to increase the tremor convergence rate which may be caused by vibrations of generators, crustal movement and others. This paper proposed several experiments of the liquid electrolyte in the gyro horizon. The damping rate is variational with the bubbles. As a result of that, small tremor can be eliminated and the gyrohorizon can achieve steady mode rapidly.
An Experimental Study on Selection Method of Vari-Speed Milling Parameters
Authors: Xue Xiao Qiang , He Ning , Li Liang , Zhao Wei , Wang Qi
Published: October 2010

This paper investigates the selection method of vari-speed milling parameters by experiments. The orthogonal experiments of vari-speed milling were studied on a given speed according to the stability lobes, and various parameters were selected. The experimental results show that varying speed milling approach possesses effects on vibration suppression on proper parameters selection though the acceleration damping ratio γa and the sound damping ratio γs. The variance analysis of dual factors test is adopted to data process and the acceleration damping ratio γa is taken as the evaluation index of vibration suppression. Finally, the preliminary conclusions on how to select proper parameters are obtained on the basis of the analysis of the experimental results, which is applied to online monitoring techniques using vibration to achieve automatic control of variable speed cutting.
Active Vibration Suppression Control Algorithm in Gyroscopic System
Authors: Zhang Zhi Huan , Siddiqui Sultan A.Q.
Published: October 2010

A new control method for suppressing vibration in a rotating beam system of a helicopter has been presented. The method used a non-linear dynamics equation to compute actual natural frequencies using FFT, not based on nominal natural frequencies of linear dynamics. A design based on linear coupling may not take account of the effect of non-linear coupling in the system, so a conceptual controller design has also been presented, and a detailed control algorithm has been developed. In fact, this is a non-linear dynamics optimization problem. In a gyroscopic system, tuning of the flywheel allows a commensurable relationship to be established between the natural frequencies of the system, resulting in a strong coupling between the vibrating modes. Having established a strong coupling within the system, damping was introduced in the flywheel via an actuator, resulting in rapid vibration suppression. Numerical simulation demonstrated the efficiency of the modification.
Performance Analysis of Large Radial Equal-Thickness Vibratory Feeder
Authors: Tang Zhi Chao , Yin Zhong Jun , Chen Bing , Zhang Lian Wan , Jin Ling
Published: October 2010

The radial equal-thickness feeder in the paper is designed for the rotary hearth furnace and achieves radial equal-thickness distributing for material. Vibratory feeder is a complex elastomer. Dynamic analysis is an important part for the large radial equal-thickness vibratory feeder. In order to attain the vibration characteristics of the basis and the screen body, such as amplitude, frequency, vibration locus, vibrating direction angle, and improve design quality, so the vibration feeder is tested and analyzed. Dynamic response parameters of large radial equal-thickness vibratory feeder are tested in field and the data in different time are collected by software DH5920. Material transportation speed and throughput are derived. The real average velocity is νmmax=0.054m/s, the real throughput is Q=3600hBνγ=25.19t/h. The results showed that the feeder can meet the production process requirements.
Analysis of Flexural and Torsional Vibration for Turbogenerator Shafts on Power Impact
Authors: Xiang Ling , Yang Shi Xi
Published: October 2010

Based on a Jeffcott rotor system with rigid support, the math models of flexural and torsional vibration were built, and their vibration characteristics were concluded. A simulation experiment in this paper was designed about the flexural and torsional vibration of shafts on a simulated turbine generator during network impacts. By analysis, flexural and torsional vibration characteristics were obtained, and the results showed the shafts flexural vibration and torsional vibration were interacted with each other. It was provided that torsional vibration could inhibit the complex shafts exercise. A new idea was suggested that the characteristics of torsion vibration should be considered as the symptom of faults diagnosis
Feature Analysis of Mechanical Fault Signals Based on the Wavelet Transform Technique
Authors: Wang Bing Cheng , Ren Zhao Hui
Published: October 2010

Simulated four different fault signals in the lab, the authors then used wavelet scalogram and amplitude spectrum to make analysis on the above four fault signals and abstract each spectrum characteristics. Wavelet scalogram was able to extract the characteristic’s frequency, show the impact components caused by rub-impact, show the beat phenomenon caused by oil whip and show the irreducible high frequency components as well as the complex low-frequency components. Amplitude spectrum was able to show the energy size distribution at various frequency bands and able to analyze and calculate the relationship between various frequency components. Thus they express the relationship between various frequency banks from a quantitative manner. Therefore, combining the wavelet scalogram and amplitude spectrum when making analysis, as they complement and verify each other, it will enhance the reliability when extract and analyze the characteristics of fault signal.
Fault Diagnosis of Rotating Machinery Based on FDR Feature Selection Algorithm and SVM
Authors: Li Sheng , Zhang Chun Liang , Yue Xia
Published: October 2010

To effectively avoid the loss of useful information, in this paper, feature information has been extracted from the fault signal of rotating machinery in different aspects such as amplitude-domain, time-domain and time-frequency domain. Then, for the multi-dimensional feature extraction was prone to the problem of “dimension disaster”, the principles of FDR was introduced in data mining to determine the classification ability of each individual feature, and the cross correlation coefficient was adopted to solve the problem that dealing with individual feature. Neglected the interrelationship between the features, a new feature selection algorithm was constructed. Finally, the eigenvectors were used for training and recognizing of SVM model. The experimental results showed the fault diagnosis system was valid and robust.
Pore Size Distribution and the Fatigue Properties of Several Cast Aluminum Alloys
Authors: Zhang Yuan Bin , Luo Hui , Zhai Tong Guang
Published: October 2010

The population and size of porosities in three kinds of cast aluminum alloys, i.e. A713, A356T6-1 and A356T6-2, were statistically measured using a commercial software Spirit, and several distribution functions were tried to fit the cumulative pore size distribution data. It was found that a general extreme value (GEV) distribution function was the most appropriate function to quantify the cumulative pore size distribution in these cast aluminum alloys. The stress-number of cycles to failure (S-N) curves of these alloys were characterized by four point bend fatigue testing on MTS810 materials testing system, with the parameter f=20Hz, R=0.1, and in ambient air. The fatigue strength of A713, A356T6-1 and A356T6-2 aluminum alloy was measured to be 94.5 MPa, 150.6MPa and 117.3MPa respectively. The fatigue properties of these alloys could not be evaluated just by population and size distribution of the pores, the microstructure state, shape and position of pores, and other weakest links that may initiate a fatigue crack should be taken into account synthetically.
Study of Concrete Pump Truck Structural Health Monitoring
Authors: Hua Guang Jun , Wu Yun Xin , Wang Shuai
Published: October 2010

Concrete pump truck is a kind of mobile construction machinery, with the characteristic of complex structure, poor working condition and difficult to maintenance. Therefore, adopting appropriate health monitoring methods, and accurate grasping the running status information of the pump truck is significant to the pump truck’s safety use and pre-judgment maintenance plan arrangement. In this paper, the traditional structural health monitoring methods was studied. And the structure, load and work environment characteristics of concrete pump truck were analyzed. Taking into account the economy and reliability of the structural health monitoring system, the technical route of the concrete pump truck structural health monitoring system and health evaluation criteria were proposed. The evaluation criteria takes into account both the cumulative health effect and timely health status of concrete pump truck structure.
Inner Leakage Fault Diagnosis of Hydraulic Cylinder Using Wavelet Energy
Authors: Tang Hong Bin , Wu Yun Xin , Ma Chang Xun
Published: October 2010

Inner leakage of hydraulic cylinder is a very serious failure in the hydraulic system and it can lead to many problems.A important fault diagnosis way is to detect the pressure signal.But the pressure signal is seriously influenced by pressure fluctuation and other noises.It is difficult to extract features from pressure singal. Aiming at the difficulty in extracting feature from pressure singal in fault diagnosis for leakage of hydraulic cylinder,a fault diagnosis approch based on monitoring preesure singal and wavelet energy is proposed in this article.According to the method, the enegry of different frequency bands after wavelet decomposition costitutes the eigenvectors at first, then these eigenvectors are input into BP network to identify faults. The experimental results show that three modes of no leakage, slighter leakage and severe leakage were correctly identified.This approach can be used in the leakage fault diagnosis of hydraulic cylinder.
Tool Condition Monitoring Based on Radial Basis Probabilistic Neural Networks and Improved Genetic Algorithm
Authors: Li Deng Wan , Gao Hong Li , Shou Yun , Du Peng , Xu Ming Heng
Published: October 2010

In order to accurately estimate tool life for milling operation, a novel tool condition monitoring system was proposed to improve classifying precision in different cutting condition. Lots of features were extracted from cutting forces signal, vibration signal and acoustic emission signal by different signal processing method, only a few features selected by principal component analysis (PCA) according to contribution rate, and constructed as input vector. The relation between tool condition and features was built by radial basis probability neural network which control parameter of kernel function and hidden central vector were optimized by improved genetic algorithm. The experimental results show that the method proposed in the paper achieves higher recognition rate, good generalization ability and better available practicality.
Study on Screw Pairs Life Prediction Based on Hidden Markov Model and Neural Networks
Authors: Gao Hong Li , Yu Si Tu , Li Deng Wan , Wu Xi Xi , Xu Ming Heng
Published: October 2010

In order to estimate and predict the screw performance in the process of machining, a screw life monitoring system was built. Current signal was processed and features sensitive to cutting force were selected, a virtual force sensor was constructed to model the relation between cutting force and current by BPNN. Cutting force was indirectly calculated by the model, so the rating life of screw in different condition could be known and residual life also be reckoned by historical database. A three-way vibration sensor was installed on screw pair base; screw condition could be induced by HMM which input was 15 vibration signal features. As machining condition changed, corresponding new HMM would be built by adaptive method. Finally, the residual life of screw could be gotten by multi-HMM and BPNN. The experimental results show the model proposed in the paper is effective and high precision.
Fault Diagnosis of Nuclear Power Equipment Based on HMM-SVM and Database Development
Authors: Zhu Hou Yao , Zhang Chun Liang , Yue Xia
Published: October 2010

This paper mainly introduced the basic theory of Hidden Markov Model (HMM) and Support Vector Machines (SVM). HMM has strong capability of handling dynamic process of time series and the timing pattern classification, particularly for the analysis of non-stationary, poor reproducibility signals. It has good ability to learn and re-learn and high adaptability. SVM has strong generalization ability of small samples, which is suitable for handling classification problems, to a greater extent, reflecting the differences between categories. Based on the advantages and disadvantages between the two models, this paper presented a hybrid model of HMM-SVM. Experiments showed that the HMM-SVM model was more effective and more accurate than the two single separate models. The paper also explored the application of its database system development, which could help the managers to get and handle the data quickly and effectively.
Dynamic Interpretation Method of XML Configuration Strategy for IP Mode Measurement and Control System
Authors: Hong Xiao Bin , Liu Gui Xiong , Xu Jian Long
Published: October 2010

The interoperability among diversified ubiquitous sensor network platforms can be solved well by employing XML technology. According to the requirement that implementing accurately remote XML configuration strategy for spot equipments, a new dynamic interpretation method of XML configuration strategy is proposed. First, an XML-based IP mode measurement & control system is introduced. On the basis of realizing graphical strategy editor, the innovative ways and technologies of some key problems for dynamic interpretation method were especially discussed in this paper, including configuration strategy conversion combining preorder binary tree traversal with stack, XML strategy decomposition based on DOM tree model and dynamical update of XML configuration strategy. Finally, an application example in IP mode ethanol concentration measurement & control system is introduced. Experimental results show that the new method can greatly simplify conversion from measurement & control strategy to microinstructions, which saves system resources and improves greatly the speed of interpretation.
Investigation on the Modeling of Rotor Axial Displacement Fault Diagnosis and Prognosis for Centrifugal Compressor
Authors: Wang Wei Min , Xin Zheng Qiu , An Wei Zheng
Published: October 2010

In this paper, a modeling about centrifugal compressor axial displacement fault diagnosis is proposed through investigating on the mechanical performance and failure mode of thrust bearing as well as the characteristics of axial displacement fault. In this paper, result of experimental studying of the force-displacement curve of rotor at different speed is presented. Numerical simulation method is used to predict the curve in diagnosis model. By comprising the experimental and numerical result, it can be seen that Finite Element Method(FEM) elastic-perfectly plastic material model can get more precise result than linear elastic model and Computational Fluid Dynamics(CFD) method provide a new insight to investigation the physics based diagnosis method. Result of the paper provides the foundation of axial displacement fault self-recovery.
Study of On-Line Condition Monitoring System for Roller Based on HMM
Authors: Tang Yong Hui , Lin Guo Xiang , Zhang Chun Liang
Published: October 2010

A kind of signal build mould and identification tool for roller of rolling mill was discussed. Basic algorithm of Hidden Markov model (HMM) theory was presented. For ψ500×2 shrewd roller of rolling mill, the paper led Short-time Fourier transform (STFT) into draw the feature of roller signal and chose Continues Gaussian Hidden Markov Model (CGHMM) to build and identify mould. The experiment installation major included: ψ500×2 shrewd rollers and roller performance test control work of rolling mill control machine as well as a set of online state inspection system. The experiment data was collected by two kinds: roller rotational speed from low to high and from high to low. The experiment shows that this system has better identification rate, and proves that this system is effective.
Study on the Fiber Distribution and Fiber Orientation in Low Pressure Sheet Molding Compounds
Authors: Li Jian , Huang Zhi Xiong
Published: October 2010

LPMC specimens were burned in an oven at 500oC for 3h to obtain the fiber images by a scanner. The fiber distribution and orientation was analyzed using MATLAB software. And the effect parameters and controlling methods on fiber orientation and mechanic properties of molded parts were studied, too. Results showed that when the viscosity of LPMC sheet was 5×106cp , the feeding area was 60% and the velocity of mould closing was 1.0 mm/s, the uniformity of fiber distribution was optimum. And proper velocity of mould closing (1.0 mm/s) could decrease the fiber orientation. In addition, the flexural strength (185MPa) and flexural modulus (14.2GPa) of LPMC specimens paralleled the fiber direction were much higher than vertical one (75.2MPa, 6.9GPa).
Research and Application on Chlorophyll Fluorescence On-Line Monitoring Technology
Authors: Ji Jian Wei , Xu Ming Hu , Li Zheng Ming
Published: October 2010

Chlorophyll fluorescence (CF) has become a powerful tool in plant photosynthesis research and stress detection, considered a rapid, highly sensitive and non-invasive probe of photosynthetic activity. With the rapid development of computer technology and sensor technology for weak signal, recently much attention has been paid to chlorophyll fluorescence on-line monitoring for estimation of plant photosynthesis. This paper analyzes the fundamental principle of chlorophyll fluorescence on-line monitoring technology, introduces a new measurement and control system for chlorophyll fluorescence, which bases on MINIPAM, using light-emitting diode (LED) excitation by means of measuring the fluorescence parameters, and introduces application of active fluorescence measurement and passive fluorescence measurement in the study of the biological information monitoring in plant photosynthesis. Finally, the future development trends, the prospect and the difficulties of chlorophyll fluorescence on-line monitoring technology are discussed.
De-Noising of Damage Signal in Wire Rope Based on Adaptive Lifting Wavelet
Authors: Zhan Wei Xia , Tan Ji Wen , Wen Yan
Published: October 2010

At the basis of the adaptive lifting wavelet transform, a method was proposed for solving the problem of noise suppression of the wire rope damage signals. A wavelet with damage property was constructed via lifting scheme, that is,the adaptive update-filter and the adaptive predict-filter were designed using the statistics information of the wire rope damage signals. And the compromise algorithm between software-threshold and hard-threshold was used in the threshold processing. The traditional wavelet and the above proposed transform are applied in de-noising of the practical acquisition of wire rope damage signal. The contrast experiments show that the noise elimination with the improved lifting scheme is better than that achieved by traditional wavelet transform. Moreover, this presented scheme retains the effective information in the break signals and greatly improves the design flexibility and the process speed.
Steam Turbine Blade MMM Testing and Failure Analysis
Authors: Xing Hai Yan , Wu Da Bo , Zhang Li Hong , Xu Min Qiang
Published: October 2010

Metal magnetic memory (MMM) method, based on the magneto-elasticity and mechanical effect theory, is a new nondestructive testing technology. This paper aims at the material property and failure analysis for steam turbine blade with MMM method. The failure blade and its fracture face are tested with MMM technology at workshop. It has been found that the MMM signal variation gradient of the crack transition zone in the fracture face is minimal, that of the crack initiation zone is in the middle, and that of the tear fracture zone is maximal. MMM testing results reflect material behavior degradation of the failure blade. In order to proof the MMM results, the dynamic stress of the steam turbine blade under the operation loading is calculated by WESTHOMES software and analyzed theoretically. It has proved the validity of the MMM method applied on material property evaluation and failure analysis for steam turbine blade.
The Remote Monitor for Smart Motion Device by Using VPN Technology
Authors: Wu Xiao Jun , Sun Shu Dong , Zhang Jin Wen
Published: October 2010

In order to realize remote monitor to the motion controller, a smart motion device with SIMOTION motion control system is researched. The application of virtual private network technology, combined with SCOUT tool, a remote control through Internet is used. This paper introduces the hardware and software of the motion control system, the structure and composition of remote control system and the core technology for specific steps. A detailed analysis of the application effect is shown. The result shows that the remote monitor system not only reduces response time of maintenance, but also saves a lot of human and material resources. Many enterprises design their smart motion device with motion controller as one parts of whole equipment. The application shows the feasibility of remote monitor to motion controller by using VPN technology for smart motion device.
Rolling Bearing Fault Diagnosis Based on AIS
Authors: Hu Yao Bin , Yue Xia , Zhang Chun Liang
Published: October 2010

In this paper, an approach of rolling bearing fault diagnosis based on artificial immune system (AIS) is presented. The features extracted from vibration signals are normalized as the original antigens, and an advanced clone selection algorithm (CSA) is applied to train the antibodies. Then use the antibody set to recognize the faults online. The experiments on rolling bearing show the approach is effective and feasible.
Curvature Mode Characteristics of the Simple Beam with a Local Damaged Crack
Authors: Tie Ying , Xu Ping , Chen Jiang Yi
Published: October 2010

General expressions of crack perturbations are given with perturbation method. With the delta function to express the crack position at the simple beam, the expressions of cross-section rotary inertia and mass per unit length of the whole beam are founded, and then the transverse free vibration equation of the simple beam with a damaged crack is established. The first and second order perturbations are considered as the linear combinations of corresponding mode shapes of intact state, according to the boundary conditions, and theoretical solutions about eigenvalues and mode shapes of the damage state are finally obtained. One simple beam is taken as a numerical example to calculate the modal parameters; the effects of first and second order perturbations on the results are compared. It is believed that the approach proposed in this paper could provide the necessary theoretical background for damage identification in simple beam.
One Method to Determine the Optimal Maintenance Time Based on Selective Attrition
Authors: Liu Jing , Ji Hai Peng , Zhu Qing Xiang
Published: October 2010

In the process of equipment fault evolution, equipment's attrition probability is different, namely selective attrition may be produced. This paper describes one method based on selective attrition, which achieves the aim of forecasting its optimal maintenance time by analyzing and handling the data of monitoring equipment. There are mainly two steps: first, get each part’s probability value of selective attrition under the current condition in use of association rule algorithm, then take the obtained probability value as the input, and get the optimal maintenance time through neural networks modeling. This method employs the real-time and dynamic decision-making method and adjusts the optimal maintenance time in real time according to the information in the equipment’s operating process, making it more conform to the actual condition. The feasibility of this method is showed by a simulation example.
A Method of Simulating Computation for the Fatigue Life Prediction
Authors: Zhao Wen Li , Liu De Gang
Published: October 2010

The fatigue life prediction and reliability analysis of dynamic systems under random excitement are important topics in modern engineering design. However, the stress power spectral density and the formulation of fatigue life prediction of a component in a dynamic system must be known when one predicts its fatigue life. A method of simulating computation for the fatigue life of a dynamic structure is presented. The method is based on the concept of unit load stress matrix. According to it, the relationship between the stress power spectral density of a structure in a system and the response spectra of the system can be established. Based on this, the formulation of the fatigue life prediction which is decided by the random stress process is obtained. With this method, the stress power spectral density simulation and the reliability fatigue life prediction for the CW-200 type vehicle truck are made. The method is suitable not only for the running dynamic structure but also for newly designed dynamic structures especially.
Engineering Machinery Engine System Reliability Analysis
Authors: Zhang Xiao Nan , Liu An Xin , Gao Qing Zhen , Qing Xing , Chang Xing
Published: October 2010

It exists in complexity and fuzziness in structure and failure character of engineering machinery complex system. To solve the problem, fuzzy theory was introduced into fault tree analysis, and then the steps, principles and methods of fuzzy fault tree are determined. Based on the analysis of engineering machinery typical engine systemic structure and fault criterion, a fuzzy fault tree is established. Used a fuzzy mathematics method of reliability analysis with fuzzy fault rate and the median method of fuzzy significance analysis, the fuzzy fault rate and fuzzy significance of parts and subsystems is calculated. The result indicates that this method can solve the fuzziness problem of failure criterion and data in fault tree analysis. The result provides valuable reference for the reliability analysis.
Study on the Method of Multi-Rope Hoist Rope Tension Imbalance Fault Monitoring and Diagnosis
Authors: Wang Shao Jin , Yang Zhao Jian , Du Fan
Published: October 2010

In order to solve the problem that the tension measurement data of mine hoist wire-rope is inaccurate and the method of fault diagnosis of multi-rope hoist rope tension imbalance is non-standard, the systematic study of monitoring, forecasting and fault diagnosis of rope tension imbalance was made by using the principles of vibration wave method in mechanical dynamics. A set of new methods about monitoring, forecasting and fault diagnosis were developed, which the test method of hoist wire-rope tension based on inhomogeneous chord vibration and the methods for fault diagnosis of steel rope unbalance tension were described deeply. The vibration wave method was also used in these methods. The field test indicated that these methods were simple to operate and had higher accuracy and reliability.
Monitoring of Drilling Tool Condition through Spindle Current
Authors: Ao Yin Hui
Published: October 2010

Drill wear or breakage often damages the work piece and/or machine tool. Spindle motor current reflects the cutting process and the signal can be easily and inexpensively obtained. This paper presents a strategy for on-line drilling tool wear and breakage monitoring. It employs Wavelet Transform (WT) of the spindle current signature to perform monitoring. A moving window technique is used to extract the cutting portion of data from the entire data sequence. A low pass de-nosing filter is employed to remove noise from the current signal. Features were extracted using WT node energy and selected based on their ability to detect tool wear and chipping. The Progression of tool wear based on feature of WT detail level 4 is analyzed and pointed out status of worn or chipped tool. Experimental results validate performance of the proposed algorithm.
Supervised Locally Linear Embedding for Fault Diagnosis
Authors: Li Zheng Wei , Nie Ru , Han Yao Fei
Published: October 2010

Fault diagnosis is a kind of pattern recognition problem and how to extract diagnosis features and improve recognition performance is a difficult problem. Local Linear Embedding (LLE) is an unsupervised non-linear technique that extracts useful features from the high-dimensional data sets with preserved local topology. But the original LLE method is not taking the known class label information of input data into account. A new characteristics similarity-based supervised locally linear embedding (CSSLLE) method for fault diagnosis is proposed in this paper. The CSSLLE method attempts to extract the intrinsic manifold features from high-dimensional fault data by computing Euclidean distance based on characteristics similarity and translate complex mode space into a low-dimensional feature space in which fault classification and diagnosis are carried out easily. The experiments on benchmark data and real fault dataset demonstrate that the proposed approach obtains better performance compared to SLLE, and it is an accurate technique for fault diagnosis.
Nanocomposite Materials Design and the Sintering Optimization Based on Interface Strengthening
Authors: Yang Fa Zhan , Zhou Jian Qiang , Meng Guang Yao , Li Chang He
Published: October 2010

Nanocomposite tool materials are developing very fast in engineering field for their highlighted advantage in mechanical properties and stability under high temperature. However, there are lots of puzzles to be discussed in the materials design theory and the fabrication processing due to the difference between the traditional materials and the nanocomposite. Therefore, in this paper, a new nanocomposite tool materials design method has been proposed based on the interface strengthening theory. The sintering temperature and the soaking time could be optimized based on the interface strengthening theory and the relative density of the tool materials. Meanwhile, a series of experiments were carried out to fabricate the nanocomposite tool materials under the guider of the interface strengthening theory. Results showed that experimental data agreed well with the calculation and the model was proved to be correct.
Transformation Behavior During Continuous Cooling of Mn-Mo-Nb-B Microalloyed Steel
Authors: Yuan Shao Qiang , Liang Guo Li
Published: October 2010

The microstructure of Mn-Mo-Nb-B microalloyed steel was investigated under different cooling rates after austenitic deformation by using thermo-simulation test, hardness measurement, metallographic and TEM analysis. The experimental results show that most constituents are mixed bainite ferrite and granular bainite at the cooling rate of 10 oC-50 oC /s. From the CCT curves, only polygonal ferrite and martensite could be obtained through the very slow and rapid cooling, respectively. The hardness of specimens keeps almost unchanged when cooling rate reaches above 10 oC /s (the utmost cooling rate is 50 oC /s in this simulation). Hence, the microstructure uniformity is attained, that is to say, the transformation products are insensitive to the cooling rates, which attributes to the appropriate component design and optimized hot simulation. Another experimental phenomenon is that the fine scale (<5 nm) carbonitride precipitates were observed in the relatively lower cooling specimens.
Research on Rotating Machinery Vibration Fault Based on Support Vector Machine
Authors: Zhang Chao , Liu De Qing
Published: October 2010

The research on support vector machine in fault diagnose has already obtained a lot of breakthroughs, such as the mode identify problems in small sample, nonlinearity, high dimension and so on. However, there are some limitations in the traditional support vector machine. In this paper, in allusion to the current rotating machinery fault diagnosis problem, the basic principles of support vector machine are studied. According to the complex characteristics of rotating machinery vibration fault, a fault extraction method is proposed based on the K-L transform. Multi-classification algorithm of support vector machine is improved, and the algorithm is used to analyze the rotating machinery vibration. By using its capabilities of model identification and system modeling, the initial symptom, occurrence, development of the typical faults are dynamically analyzed. These provide new ideas and methods for fault diagnosis of rotating machinery.
Visualization Design Technology of Hydraulic System in the Fault Diagnosis Research and Application
Authors: Fang Gui Hua , Li Xu Sheng , Liu Jin Feng
Published: October 2010

Hydraulic system is consists of mechanical, hydraulic and electrical devices. Therefore, hydraulic system malfunction are a lot of types. Based on the complexity and all-around of hydraulic system malfunction, it is very difficult to solve the hydraulic system malfunction. Hence how to quickly and accurately identify the mechanical is the forefront of current research projects. With the rapid development of computer communication technology, computer-aided diagnosis technology can solve the problem of fault diagnosis of hydraulic systems. In order to solve the hydraulic station mechanical, according to the existing hydraulic system failure analysis, it makes visual dynamic diagnosis. In this paper, the visual dynamic diagnostic technology is introduced, which works in the technical feasibility and tastes its convenience and practicality in the actual practice.
The Study on Piezoelectric Impedance Technique Used in Loading Damage Identification
Authors: Zhang Jun , Qin Zi Jian
Published: October 2010

The superiority and feasibility of piezoelectric impedance method used in damage detecting was expounded, and the research status of the technical was summarized. Then, the rationale of the basic theory of the technique used in damage identification and health monitoring was analyzed here. The experiment of the damage change of loaded beam was researched. The experiment of the beam which was loaded by a material property, the value of the beam was got by an impedance analyzer, while the beam with different pull force. The research indicates that while the testing frequency range should elect as 300k-800k, with the increasing of loading force, the value of real part impedance is descending, the damage index of beam is increasing. PZT can sensitively catch the influence brought by stress varying
Fault Diagnosis for Stiction of Pneumatic Control Valve
Authors: Zong Xue Jun , Yang Zhong Jun , Zheng Hong Yu
Published: October 2010

The stiction of control valve is one of main causes which make control loop instable in the process industry. Now a number of studies on the diagnosis of control valves are based on stiction. It needs developing a proper method which can detect, quantify, and compensate stiction. A non-invasive method has been used into the fault diagnosis for stiction of pneumatic control valve. Firstly, a two-parameter data-driven model about stiction has been established, and on the basis of separable least squares method, combined with the global search algorithm to deduce the model identification method. Secondly, ellipse fitting method has been adopt to confirm whether the stiction existed, thus the stiction could be quantified, and on this basis, the stiction was compensated. So it improved the performance of control system. Thirdly, the validity of the method was confirmed by simulation.
A New Method for Estimating Road Friction Coefficient
Authors: Lin Fen
Published: October 2010

Road friction coefficient is a critical component in traffic safety. The estimation of tire–road friction coefficient at tires allows the control algorithm in vehicle activity system to adapt to external driving conditions. This paper develops a new tire–road friction coefficient estimation algorithm based on tire longitudinal force estimation and tire slip estimation. Vehicle tire longitudinal forces are estimated by sliding mode observer combined with Kalman filter. Based on the tire forces estimation, road friction coefficient is estimated by recursive least squares algorithm (RLS). The test conditions which contain different friction level road are established in ADAMS/Car. The conclusions validate the reliability and efficiency of the proposed method for estimating the friction coefficient in different adhesion level roads. The research also indicates the theory of slip slope can also be reappeared in virtual experiment based on ADAMS.