Advanced Materials Research Vols. 694-697

Abstract: Original noise of tandem vibratory roller is measured in according to national standard. Using surface noise intensity measurement, noise intensity has been analyzed in including before , after, left and right sides on the roller, left and right sides on the engine and the cab floor. Under the conditions between vibration and no vibration, noise distribution principle is similar and noise source of whole roller concentrated in the position installed engine. Noise source and engine components frequency characteristics have been obtained based on spectrum analysis. The major noise source on the left 7.5m is engine combustion noise, following by exhaust fan noise; the major noise source on the right 7.5m is exhaust fan noise, following by engine combustion noise; leak noise of cab floor is fan and engine combustion noise, meanwhile middle-high frequency noise impact greatly on interior of cab; exhaust noise belonging to broadband noise concentrates in lower frequency and middle-high frequency.

Abstract: Based on UG and ADAMS software, the virtual prototype of a large wind turbine is established in this paper. Through the dynamic simulation of wind turbine tower, the time domain and frequency domain of vibration acceleration of X and Y direction on tower is obtained and compared to the actual measured data. The analysis results provide a theoretical basis for optimal structure design and further improvement of wind turbine.

Abstract: In recent years, coal mining machines intellectualization, automation, digitization and informatization have become the development trend in coal mining industry and have gotten more and more researchers attention. This paper presents the research on the vibration state monitoring method of a coal shearer. It shows the vibration intensity of the traction system is quite low when the machine is running, so the fault probability for this part caused by vibration is very low. The research will be beneficial to understand the vibration characteristics of the coal shearer, and provides methods of structure optimization design and fault diagnosis for a coal shearer.

Abstract: This paper presents a dynamic response analysis of the blade of horizontal axis wind turbines using finite element method. The blade is treated as a thin-walled beam based on the classical lamination theory, and accounts for arbitrary material layup and non-linear anisotropic fibre-reinforced composites. Applying the proposed method,A 29 m rotor blade, previously reported in specialized literature, was chosen as a case study the dynamic behaviour built in a FEM software tool. It is developed to predict natural frequencies and corresponding vibration modes in rotating blade in-plane and out-of-plane. Numerical results are serve as a design tool for the large composite wind turbine blade structure required during design and optimization.

Abstract: Ultrasonic EDM which is a novel machining approach for hard materials is developed quickly. In ultrasonic EDM processing the piezoelectric vibrator has a very important influence on the quality of the machining. The purpose of the paper is to study the performance parameters such as the first longitudinal modal frequency, node plane and vibration amplitude of the vibrator . Through FEM (finite element method ) simulation method the relation between structure parameters and the performance parameters are obtained. The results of the paper are very effective to design a vibrator for ultrasonic EDM.

Abstract: The requirements of higher speed, safety and more smooth and comfortable travelling are increasing strongly, this leads to the need of predictive maintenance of railway line, tamping machines have been used for this purpose. This paper presents the results of vibration characteristic of tamping device. Firstly, the basic working principle of tamping device was simply described; Then a simulation model of tamping device was established using SIMULINK in terms of mechanism principle; Finally, some vibration parameters were researched, such as velocity, acceleration, displacement of tamping device, which reflect the vibration characteristic of tamping device. In addition, the modeling process of simulation model was described, the function of SIMULINK was also simply recommended. The main aim of this paper is to propose an analysis method on facility vibration characteristic, which visualized reflects the kinematics characteristic of mechanism. The results show that the application of the technology can make the simulation process more visualization. The modeling process more simply, thus greatly improve modeling and simulation efficiency, and directly achieve our aims.

Abstract: A simplified model of bearingless rotor was investigated using Hamilton principle. The equations of rotor/body coupling system instability were obtained. Perturbed equations were obtained after linearized perturbation. Stability results of rotor blades were presented using eigenvalue analysis. The shape function matrix was obtained using spline interpolation. The results indicated that the new method is efficiency and can obtain satisfactory results, and is complete in analysis.

Abstract: This paper deals with the formulation and analysis of dynamic mechanism for joint flexibilities whose relevant magnitudes of stiffnesses are investigated by using linear and torsional springs. The equation of motion is derived by using a generic joint in the middle of clamped-clamped beam. A behavior of natural frequency sensitivities is studied as a function of nondimensional linear and torsional spring stiffnesses.

Abstract: The type of suspension bridge is used all over the world because of its long span. But the cable system which forced the main load is vulnerable to damage and corrosion. In order to discuss the dynamic characteristics of typical long-span suspension bridges, a finite-element model of a typical long-span bridge was set up with ANSYS, and its top ten frequencies and vibration types were calculated. What’s more the dynamic characteristics under the variations such as modulus of elasticity, sectional size of the cable system, initial strain of the cable, as well as the deficiency of suspender cable were discussed. According to the analysis, the researchers got the conclusion that how the cable system impacts the whole bridge and which suspender cable plays the most significant role. Moreover, the results could serve as some valuable references for the optimization design and preservation of long-span suspension bridges.

Abstract: The contemporary four-high mills are unstable and four-high rolling mill vibrations take place in six DOF leading to spatial behaviors involving vertical, horizontal, axial, reverse, cross and swinging vibration modes resulting in complex relative motions between the rolls. In this paper, a spatial vibration characteristic analysis of two four-high rolling mills with different stability will be presented based on the transfer matrix method (TMM) and Finite Element Method (FEM). The natural frequency and mode shape of four-high rolling mill are obtained. Vibration experimental results will be presented to prove the validity of the spatial vibration of rolling mill.