Applied Mechanics and Materials Vols. 278-280

Abstract: In this study, one type of magnetorheological fluid dampers (MRD) used in tracked vehicle is chosen as a research object. Firstly, the dynamic response process is analyzed and the dynamic response time of MRDs is defined. In this study, we consider that the dynamic response time of MRDs includes four components, i.e. the electrical power response time, the electromagnetic response time, the response time of magnetorheological fluid (MRF) and the structure response time. The electrical power response time is tested and the electromagnetic response process and the electromagnetic response time of the MRD are analyzed through the method 3D magnetic finite element analysis. Lastly, the response time of the MRD used in tracked vehicle in various working conditions is tested by MRD response time testing system. With the comparison between testing data and analysis of the electromagnetic response process, we can conclude that the structure response time and the electromagnetic response time occupy the largest proportions of the dynamic response time of the MRD and the feasible methods to shorten the response time is to increase rigidity of the MRD system and reduce the eddy effect.

Abstract: Abstract. A diffraction limited circularly symmetric optical imaging system with “0,π” phase pupil mask was studied, which extended depth of field. The optimal radiuses of the mask in the different amount of defocus are calculated, which in a certain contrast value 0.05 and 0.1, can provide the largest spatial frequency band. On the other hand, the effect of mask manufacturing error is analyzed, and the performance of the simulation imaging system has been verified experimentally that the image system still can obtain the high quality output images even without any post-processing.

Abstract: In this paper, a novel three-dimensional autonomous chaotic system with six terms and two quadratic nonlinearities is presented. Some basic dynamical properties of the new chaotic system are analyzed by means of equilibrium points, eigenvalue structures, Lyapunov exponent and Lyapunov dimension. In order to overcome the external conditions affected by the analog circuit’s chaotic system, digital implementation of the new chaotic system based on LabVIEW is also proposed. The results show that the experimental results by LabVIEW are consistent with the theoretical simulation results by Matlab, and the method is an effective digital implementation method.

Abstract: The MacPherson suspension mode is established by Adams/Car (vehicle multi body kinematics and dynamics software). The influence of the vehicle tire stiffness on vehicle handling performance is investigated by different tire stiffness. This study has certain guiding sense in the new vehicle development and auto fancier’s vehicle modification.

Abstract: This paper applies the homotopy analysis method to solve Klein-Gordon equation, Firstly, structure a zero-order deformation equation. Then get the formal approximation of the model from high-order deformation equation and prove the effectiveness of the solution in the end.

Abstract: Over the past three decades, coupled structures vibration research has steadily gained momentum from proposed research concepts to actual implementation. Numerous passive and active control strategies have been considered for low- to high-rise buildings. This paper contains a literature review of coupled structures control, and reviewed from the aspects including neural control method, laboratory test, and engineering application. The existing problem and the future developing in application are also summarized respectively.

Abstract: In this paper, the dynamic characteristics of Duffing strong nonlinear vibration absorber system with additional hard spring is analysed qualitatively. Based on synovial variable structure algorithm, the active control system model of the nonlinear dynamic vibration absorber is designed, and the effectiveness of the control model is verified by elevant examples. It’s found that with the additional hard spring Duffing strong nonlinear vibration absorber, the control effect of active absorption is superior to the passive absorber, so which has has important guiding significance to the design of actual engineering nonlinear vibration absorber.

Abstract: In order to reduce the vast total harmonic distortion (THD) caused by hysteresis loop space vector control strategy in three-phase Voltage Source Rectifier (VSR), an optimized strategy based on fuzzy rules is proposed in the paper. In the new strategy, a current error vector threshold value was pre-set. When the actual current error value is less than the threshold, the hysteresis loop space vector control strategy will be adopted to reduce the switching frequency and loss. However, when the current error value is larger than the threshold, the optimized hysteresis loop control strategy based on fuzzy rules will be adopted to achieve the fast current tracking. Based on the new strategy, the simulation model has been established and simulated by matlab/simulink. And the results show that the optimized control strategy not only ensures the fast dynamic response with low switching frequency, but also reduces the current THD significantly. Finally, the feasibility and the superiority of the optimized strategy based on fuzzy rules have been further verified under a 1kW experiment system.

Abstract: The left-hand rule and the right-hand rule are widely used in electromagnetics but are often confusing. Based on an analysis of the differences and commonalities of the two rules, a uniform rule using coordinate rotation is proposed to determine the direction of the magnetic force and the induced electromotive force (emf) or the induced current in a static magnetic field. Furthermore, we discuss how to use the uniform rule to determine the direction of the induced emf or current in a moving magnetic field, which is traditionally determined by Lenz's law. The uniform rule is easy to understand and remember.

Abstract: A compact plasma system is set up at Ravenshaw University, India. The plasma system consists of a curved vacuum chamber which is nothing but a part of a toroid (θ=700) having minor radius, r= 0.3 m and major radius, R= 0.5 m, vacuum system, electromagnet, gas injected washer stacked plasma gun to produce plasma blobs/filaments, pulse forming network to energise plasma gun, diagnostic tools like electric probes, magnetic probes, spectrometer, high speed CCD camera, digital pulse/delay generator to synchronise the diagnostic tools. A pair of copper coil is wound over the chamber and capacitive pulse is fed to the coil to produce non-uniform magnetic field inside the chamber. The gas injected washer stacked plasma gun is a mono-anode - multi cathode system having five cathodes made up of brass and an anode made up of copper. The gun impedance is ~ 15 Ω. The pulse forming network (PFN) is Guillemin E type which consists of capacitors having equal capacitance 5.5 μF and inductors having equal inductances 1.5 μH. The pulse width of the PFN is ~ 7.6 μs for a seven stage network, as tested with known resistive circuit. Magnetic probes are designed and calibrated using a Helmholtz coil to map the radial magnetic field profile of the plasma chamber. Electric probes like Langmuir triple probe, velocity probes are designed to measure plasma parameters like blob velocity, density, temperature etc. Emission spectroscopy method is used to identify charged species inside the plasma. High speed CCD camera is used to interpret the structure of the plasma. A digital pulse/trigger generator is used to synchronise the CCD, spectrometer and switching thyristor etc. Preliminary results are also reported.