Applied Mechanics and Materials Vol. 312

Abstract: Ball screw feeding system is a very important part of the machine tool. The ball screw of High-speed at the same time bring the vibration, noise, temperature rise due to friction and many problems. Noise and temperature rise are the key factors constrain the ball screw in the High-speed. The article summarized the ball screw causes of the vibration, noise, comprehensive both at home and abroad research results to the ball screw vibration and noise generating mechanism .Then pointed out that the ball screw noise generation is the main reason of the screw groove waveness arouses nut forced vibration.Introduced the latest progress of the ball screw drive system modeling and the vibration model analysis,specific introduces several methods of reducing vibration and noise reduction. And talk about the development trend of ball screw vibration and noise to the future.

Abstract: The equilibrium of the die-cutting pressure plays a decisive role in the die-cutting quality and the service life of a die cutter. The number and the distribution of the cutting balance knife influence the cutting pressure distribution. Using the transducer to collect vibration signal and converted into die cutting pressure qualitatively, which can comprise the balance of the cutting pressure, compared with the traditional pressure paper it has the advantages of quick, direct, etc., capable of measurement range is much larger than the pressure transducer, providing a new method for the determination of the super pressure by using acceleration transducer measuring pressure.

Abstract: The dynamic road adhesion coefficients at 30km/h and 50km/h for dry condition were measured through the real vehicle equipped with a test system driving on the asphalt dry road. The test system included the fifth wheel instrument, the wheel speed sensors, the programmed strain amplifier and ACME portable industrial personal computer. The results show that longitudinal peak adhesion coefficients at 30km/h and 50km/h for the dry condition are about 0.7. Longitudinal adhesion coefficient increases rapidly with the slip rate increasing and soon reaches the maximum. The longitudinal peak adhesion coefficient occures when the slip rate is about 12%.

Abstract: This paper presents the dynamics-simulation and research of vibration characteristic on deep-groove ball bearing. It introduces an analysis of the vibration frequency in different damage of bearing and spectrum analysis of the fault signal on bearing to draw response on vibration characteristics in bearing, so as to provide a simple method on research of dynamic fault characteristic of bearing. This work shows some kind, characteristics signal and frequency of fault on bearing. The normal model and other two models which have raceway crack in inside track and out ring are set up by using ADAMS software to analyse the dynamic of them, the test program that vibration signal of three models are obtained by acceleration sensors to instead of that of real condition is simulated. In addition, the test signal of vibration is given in time domain respectively, and the vibration characteristic is identification by using spectrum analysis method, so that it can provides technical support for diagnosis of fault bearing. In the study of fault diagnosis, several experimental results provide that the uncertainty of fault diagnosis and interference of other complicated factors are avoided effectively in real environment. The result of simulated analysis is consistent with the theory calculation. This method is more effective, convenient and expansibility than a research of practical fault-diagnosis.

Abstract: By establishing and analyzing mathematical model for vibration bench of vehicle suspension, this paper optimized and simulated vibration bench of vehicle suspension based on finite element. As a result, the paper got stress field and its distribution during transformation process and set a foundation for structural design of vibration bench of suspension.

Abstract: To improve the working frequency band and the damping effect of vibration absorber, an active-adaptive vibration absorber (AAVA) was presented. The AAVA can be considered as the integration of adaptive tuned vibration absorber (ATVA) and active vibration absorbers (AVA). The principle and the dynamic character of the proposed AAVA were theoretically analyzed. Based on the analysis, a prototype was designed and manufactured. Its dynamic properties and vibration attenuation performances were experimentally investigated. The experimental results demonstrated that the damping ratio of the prototype was significantly reduced by the active force. Consequently, its vibration attenuation capability was significantly improved compared with the ATVA.

Abstract: The hysteresis curves that show the relationship between the tangential friction force and relative displacement of the contact surface were measured. The equivalent stiffness and damping of the friction contact surface under different normal loads were computed by harmonic balance method (HBM). The finite element model of steam turbine blades with new friction damping structures was established. The effects of friction between the contact surfaces were considered by using spring damping elements to connect the friction damper and the blade. The equivalent stiffness and damping which were calculated by the experiment results were applied to the spring damping elements under different rotational speeds. Based on the natural frequencies which were computed by finite element analysis, the Campbell diagram of the whole blades was obtained. The results showed that there were no 3-coincide points in the working speed range.

Abstract: Press vibration characteristic is the basic of press fault diagnosis and static optimization. We get press vibration characteristics with Operational Modal Analysis .Comparing theoretical analysis of the finite element method for press with operation modal analysis of test method for press in the actual condition. We get vibration modal orders and vibration modes of press wallboard under natural excitation. The experimental results show that the test modal frequency identification value of Operational Modal Analysis for the press components is highly accurate.

Abstract: The paper make optimal design of NW planetary gear reducer. While all the design factor has been considered, the optimal mathematical model and constraint conditions of each independent variable is determined. On the basis of simplifying model, the MATLAB is used to develop the algorithm program. Then the program is carried out. Finally, the operational results are revised and checked. The operational results show that this method can ensure the design quality. At the same time, the method also can enhance the efficiency of programming.

Abstract: Stability and safety performance of aircraft is determined by reliability of aviation airborne equipment, airborne equipment mounting rack work under severe mechanical vibration. To improve the system reliability, we established accurate parametric finite element model, obtained modal of frequency and vibration by analysis, confirmed correctness of this method by experiment, laid the foundation of its comprehensive dynamic analysis and structure optimization design for structure and working conditions of a electronic equipment mounting rack in this paper.