Advanced Materials Research Vols. 139-141

Abstract: The vibration tests of the double crank ring-plate-type cycloid reducer driven by three gears are tested and analyzed with the HEAD acoustics multi-channel vibration test and analysis system. The tests of the reducer are completed under the condition of different rotational speeds and different loads. The vibration distribution rules of the reducer are obtained. The three dimensional model of the ring-plates of the double crank four ring-plate-type cycloid reducer with Pro/E are established, the modality analysis are carried out on the model by the use of ANSYS. The natural frequencies and the corresponding vibration models of the ring-plates are gained. The results are well consistent with that of the vibration tests which provide the basis for further study of vibration and noise reduction.

Abstract: Derrick is the basic equipment during drilling, fatigue and failure are the problems that effect drilling efficiency, the strong vibration of derrick is the main reason that caused derrick failure. The various kinds of vibration of drilling derrick are analyzed in this paper. The model of derrick JJ60/38-W is set up, the phenomena of vibration of derrick are studied, and the vibration state behaves many dynamic situations under the bad condition, including axial, lateral, torsional vibration. These vibrations are studied; the rule of various kinds of vibration is obtained. The modal vibration and harmonic vibration are analyzed, the situation of harmonic vibration of different nodes of derrick are obtained. The software ANSYS is applied in this paper, the result can be used for the actual drill case.

Abstract: Insulating glass is an important architecture energy saving material, large vertical glass edging machine is one of the indispensable facilities on insulating glass product line, the vibration situation of grinding wheel mechanism on large vertical glass edging machine has an important effect on grinding quality. The paper has established the dynamic equation of grinding wheel mechanism and it was simulated by using MATLAB. The simulating result indicates that the distance (l) of grinding wheel mechanism to the top bearing has an important influence on the vibration of grinding wheel mechanism, the larger l value the higher amplitude, it should be considered when designing large vertical glass edging machine. In addition, the paper puts forward some effective solutions to reduce the vibration amplitude of grinding wheel mechanism such as improving the dynamic balance precision of grinding wheel, reducing the mass of grinding wheel mechanism and enhancing the rigidity of ball leadscrew.

Abstract: Because the two components have relative motion, pair clearance is inevitable. With the machine’s speed increasing, nonlinear vibration phenomenon caused by clearance is much obviously. The state of damping in pair clearance will often make mechanism’s nonlinear vibration appear different status. For the study of damping in joint clearances impact to nonlinear vibration, four-bar mechanism with clearance is taken as research object. A nonlinear dynamic model has been established based on continuous contact model. Through analysis the nonlinear vibration in different damping and clearance, it can be found that in weak damping condition, nonlinear vibration in small pair clearance is more sensitive to the small changes of damping than that in large pair clearance. So, it’s very important to keep the pair clearance in proper lubrication conditions.

Abstract: The 2-DOF linkage mechanism system is investigated in this paper. Based on the air-gap field of non-uniform airspace of motor caused by the vibration eccentricity of rotor, the electro- mechanical coupling relation in the real running state of motor is analyzed. And the electro- mechanical coupling nonlinear dynamic model of the system is established by the finite element method. The dynamic equation is the bases on which the subharmonic resonance properties of the system caused by self-excited inertial force effected by the actual operating frequency of the rotor of the controllable motor are analyzed by the multiple scales method. The first-order stationary solution is obtained under that condition. The work presented in the paper is benefit for further studies on the inner connections between dynamic characteristics and motors electromagnetism parameters of such mechanism system, a numerical example is presented.

Abstract: Based on electromagnetic-thermal coupling field mechanism, a large-scale finite element analysis model for electromagnetic-thermal coupling global damper is established by ANSYS software. Electromagnetic field and temperature field sequential coupling analysis method is used in this study. Relative permeability and resistivity of magnetic material with temperature is also considered in the FE model. The simulation results show that the temperature of self- decoupling magnetic damper rises rapidly under external excitation, the temperature changes the magnetic fluid yoke and the materials’ core parameters, magnetic flux density in damper channel gradually decreases with the time, and the damping force decreases, finally the high temperature decline phenomenon is revealed.

Abstract: Because of special structure and dynamic behavior, the dynamic equations of metamorphic mechanism are variable during the process of configuration change. In order to combine dynamics analysis and structure design of metamorphic mechanisms intimately, a new method of forming dynamic model of metamorphic mechanisms is proposed based on fully Cartesian coordinate’s method and the relation between origin mechanism and sub-configuration. A new concept named origin constraint equation is introduced which can be converted into constraint equations of each sub-configuration easily by adding corresponding constraint equations of configuration change. Constraint equations commonly used in configuration change and dynamic equations of each configuration are given in the form of natural coordinates. Finally, a four-bar spherical metamorphic mechanism is used as an example to validate this dynamic modeling method.

Abstract: During exploitation of horizontal well drilling engineering, the problem of drill string failure is very serious, there are many reasons, and drill string vibrations are main reasons. In this paper drill string of horizontal well is object being studied. The models about various vibrations are set up. The vibration rule of drill string is obtained under different situation; the axial and lateral frequency of drill string vibration in free state is studied. The analysis of modal vibration of drill string is the basis of the analysis of harmonic vibration of drill string. The harmonic vibrations rules of drill string of horizontal well are studied. All sorts of resonance frequencies are obtained practicability. This study can prove basic method for optimizing drill tool of horizontal well and reducing drill string failure.

Abstract: In this paper, a two-stage optimization approach for structural dynamic design was proposed on the basis of Component Mode Synthesis (CMS in short) technique. To improve the convergence of the optimization, the optimization was decomposed to two stages, i.e. the global and the local stages. The dynamic performance of the global assembled structures was optimized at the global stage by minimizing the total mass, taking the position of nodes as design variables. At the local stage, the performance of the local components was optimized by keeping the component mass less than the initial value, and getting the performance of the global structure improved. The CMS technique was integrated in the optimization to reduce the modeling cost and to determine the objective function of the local stage optimization. The dynamic optimization of the metal structure of an escalator was taken as an example to illustrate the feasibility and effectiveness of the proposed approach.

Abstract: In China, a new railway middle-span emergency steel truss girder, which can adapt to the technical requirements about quickly repairing the damaged railway bridges, is developed under the new situation. The old emergency steel truss girder for the railway bridges can not adapt to the current technical requirements. So, the new railway middle-span emergency steel truss girder (hereinafter referred to as the new girder) is developed after hard work. The great changes on the structure, the connections, the structural details and the multi-purpose have taken place on it compared to the existing old similar girder. In this paper, the structure and technical characteristics of the new girder are introduced. In order to improve the new girder’s design, the dynamic responses of the new girder are calculated using the train-bridge coupling vibration theory. In the paper, the 32m-span girder are the main object of study. The vibration-related laws are revealed versus the different train speeds, and the proposals about the largest traffic safety speed are given.