Papers by Keyword: Self-Excited Vibration

Abstract: The reaming process with rigid single blade reamers boring is one kind of deep processing methods which develop rapidly in recent years,which has a series of advantages such as high-speed cutting, auto-oriented, low surface roughness and so on.Appear as one kind of precision hole processing technology in the deep hole processing currently,and shows the superiority of processing.The self-excited vibration is a common phenomenon in deep processing,and seriously affect the stability of hole machining and processing quality.It performance very obvious in rigid single blade reamers boring processing,and has a certain degree of particularity. Established as a mathematical model of the rigid boring reamerThe analysis of mechanism of Self-excited vibration in reaming processing of single blade rigid boring reamer, and the study the impact of the friction characteristics of the guide block and the hole in self-excited vibrations,provide the basis for the inhibition of self-excited vibration.

Abstract: The self-excited vibration of machinery is a common vibration in mechanical vibrations. Mechanical self-excited vibration destroys the normal working of the mechanical device and leads to mechanical fatigue damage. If the self-excited vibration reaches to the vibration frequency of machinery, it can produce the resonance and result in the scrapping of mechanical devices. The study of mechanical self-excited vibration has great significance. According to mathematical finite element methods, this paper establishes the mathematical model of the mechanical natural frequency through the finite volume method and gives the mathematical derivation formula of mechanical devices self-vibrated frequency. The second part of the paper simulates self-vibrated process of machinery using the professional software ANSYS software. First, it establishes a three-dimensional model of the mechanical device through the pre-processing module and analyzes mechanical self-excited vibration through calculation module and gets the frequency modal map of self-excited vibration process. It studies the mechanism of the mechanical self-excited vibration combining with modern signal analysis techniques--wavelet analysis. It gets the vibration source location which provides a reliable theoretical basis for the study of mechanical self-excited vibration.

Abstract: In order to investigate self-excited vibration mechanism of wheel-rail lateral contact system, a two DOF elasticity position wheelset lateral vibration model is established which considers the dry friction; the mechanism of the wheelset lateral self-excited vibration is investigated from the energy point of view. It shows that: the bifurcation diagram of this wheel-rail lateral contact system has a supercritical Hopf bifurcation. The energy of self-excited vibration derives from a part of traction energy; the creep rate in the wheel-rail system act as a feedback mechanism in the wheelset lateral self-excited vibration system. The stability of the wheelset self-excited vibration system depends mainly on the total energy removed from and imported into the system.

Abstract: This paper is concerned with analytical treatment of nonlinear oscillation of a self-excited system. An analytic approximate technique, namely OHAM is employed for this purpose. Our procedure provides us with a convenient way to optimally control the convergence of solutions, such that the accuracy is always guaranteed. An excellent agreement of the approximate solutions with the numerical ones has been demonstrated. Three examples are given and the results reveal that the procedure is very effective and accurate, demonstrating the general validity and the great potential of the OHAM for solving strongly nonlinear problems.

Abstract: Modal analysis of chisel subsoiling shovel, arrow subsoiling shovel and double-wings subsoiling shovel were made, which was based on the analysis of the vibration characteristics of subsoiler-soil self-excited vibration system and finite element analysis software ANSYS13.0 was used. Natural frequency and the mode of vibration were determined. Then self-excited vibration conditions of the subsoiling system were studied. All these analysis results could provide theoretical references for the self-excited vibration subsoiling system optimization and design.

Abstract: This paper studies complex nonlinear dynamic behaviors of a woodpecker robot system which can only operate in the presence of friction as it relies on combined impacts and jamming. The woodpecker robot can periodically move without any drives and controls based on self-excited vibration principle. The whole time histories of the dynamic parameter simulations in successive periods indicate that the robot is able to achieve cyclical, stable passive movement.

Abstract: This paper studies complex nonlinear dynamic behaviors of a woodpecker robot system which can only operate in the presence of friction as it relies on combined impacts and jamming. The woodpecker robot can periodically move without any drives and controls based on self-excited vibration phenomena. The whole time histories of the dynamic simulations in successive periods indicate its cyclical, stable passive movement. Keywords: Passive movement; Self-excited vibration; Dynamic simulation; impact and friction

Abstract: On account of the self-excited vibration in No. 5 stand of 1420 cold rolling mill, the relationship between rolling lubrications and self-excited vibration of rolling mill was theoretically studied. The self-excited vibration in No.5 stand of the mill was restrained by optimizing the lubrication technical parameters, and the critical stabilized rolling speed was increased from650 m/min to above 900m/min. The important problem disturbing the mill was accordingly resolved.

Abstract: Aerostatic guideway is an essential sub-system for high-accuracy measurement. As compressible air is used for suspension, several problems arise aside of its other advantages. The most important aspect that should be taken into consideration is self-excited vibration activated by inner or/and outer environments. This paper discusses how the orifice layouts and the orifice diameter affect the self-excited vibration of the aerostatic guideway, or two-dimension x-y stage as a whole. Theoretical formulas for flow coefficient of orifices are obtained and experiment of differential pressure test is conducted. Both theoretical and experimental approaches of aerostatic guideway design and characteristics of vibration attenuation are proposed in this research. The results show that by optimizing orifice diameter and orifice layouts, good effect on reduction of self-excited vibration can be achieved, with the time of vibration attenuation reduced from 1.8s to 0.9s.

Abstract: Many existing subsoilers in these days often suffer from problems such as insufficient tillage depth, large traction resistance, and high energy consumption. To address these problems, we conduct an analysis on, with the self-excited vibratory subsoiling technology, how to reduce resistance effectively. Based on the analysis, a detailed structural design of subsoiling equipments and experimental study is conducted, in order to increase tillage depth without a substantial addition of power, as required in modern agriculture.