Key Engineering Materials Vol. 693

Abstract: Finite element simulation is an effective method to study the thermal characteristics of high-speed motorized spindle, how to improve the simulation accuracy has become the key point of this research field. This paper presents a FEA method using ANSYS to precisely predict the thermal characteristics of high-speed spindle. Firstly, the heating and cooling characteristics of high-speed spindle are analyzed, main heating source, convective heat transfer coefficient, and thermal contact resistance are calculated. Secondly, FEA model of the machine center is built, the temperature field and thermal deformation of the spindle system are simulated. Thirdly, an experimental system to test thermal characteristics is designed, simulation results are compared with the experimental results. The result shows that the simulation errors are controlled in a relative low range, the FE modelling method can precisely predict the thermal characteristics of the motorized spindle.

Abstract: An improved train model, which contributes to obtain the aerodynamic characteristic of the high-speed train equipment bay, is established. By building a VEB (vehicle equipment bay) model in it, this improved model can demonstrate air flow around the VEB. The result shows that pressure fluctuation appears around the VEB, which gives visible difference from the classical train model. Applying the spectral analysis, the influence factors (include position and train speed) of the pressure fluctuation is studied.

Abstract: To improve the efficiency of contactless power transmission (CPT) and the operation stability of ultrasonic vibration system, an improved design method for key parts of the contactless power transmission system was proposed and studied. By integrating both inductor model and mutual inductance model, as well as considering the fringing flux effect introduced by the air gap, this design method would be more accurate and reasonable. Considering constraint conditions, such as the operating flux density of the core, mutual inductance between primary and secondary coils, electrical signals loaded on ultrasonic vibrator, the coils and cores were designed. Simulation and experimental studies which were developed on flux density, mutual inductance and amplitude output ability of the system, verified that the key parts of CPT system could stay stable during operation and the CPT system was able to transfer ultrasonic energy efficiently.

Abstract: Multi-component force sensors are often calibrated by single component. A multi-component force standard machine based on Stewart structure can generate and measure force and torque in any direction, so the mechanical measurement and performance of multiple components can be calibrated at the same time. In this article, we analyze the loading system base on Stewart structure and present our structural design and the type selection method. We model and analyze the moving platform, the linear actuator and the whole loading system of the Stewart platform respectively. The work provides a theoretical basis for improving the accuracy and the repeatability of the loading system base on Stewart structure.

Abstract: Wave propagation is introduced to analyze out-of-plane vibration problem of a rotating ring. Harmonic wave solutions are found for the coupled equations of the axial and torsional motion. Wavenumber spectra and phase velocity map are obtained, and the ratio of axial displacement to torsional displacement and the cut-off frequencies are determined. Examples for the free vibration of the uniform rotating thin ring are given to illustrate the validity of the wave propagation. This research will be valuable in the application of a solid cage in high speed roller bearing.

Abstract: When power equipments are suspended under the under-frame of a rail train vehicles, dynamic and vibration characteristics of the car body will be changed. In order to study suspended parameters of the car body dynamic system, the vertical dynamic coupling model of rigid car body and power equipment under different exciting force was established. Results showed: when the exciting force of suspended power equipment is zero, the elastic suspension stiffness and damping can be designed according to the principle of Dynamic Vibration Absorber (DVA); when the exciting force acting on the rigid car body is zero, the vibration isolation problem of equipment is consistent to the base isolation problem, a good vibration isolation effect can be obtained as; when the body and power equipment simultaneously be excited, vibration absorbing and isolation must be simultaneously designed: the DVA is meet on at first, when ,the suspension isolation system appeared two different frequency peaks, but only , a good vibration isolation can be obtained for suspension system.

Abstract: Fossil energy is increasing depletion, renewable energy sources plays an important role in our life and Vehicle-to-Grid (V2G) is proved to be feasible. Electric Vehicles (EVs) can not only store energy, but also can be used as a medium between the battery energy stored in EVs and the power grid through Vehicle-to-Grid (V2G). And then, the energy in the batteries of electric vehicles can move with EVs. This paper introduces an energy distribution network, which is consisting of EVs, charge stations and renewable energy sources. After analyzing the characteristics of energy distribution network, we introduce a new commercial operation mode called mobile electrical grid, which is compared with the integrated grids. To calculate the life cycle energy loss for this novel operation mode, a mathematical model is developed, and then what we have deduced is demonstrated to be a lasso optimization problem with linear constraints, which is convex.

Abstract: According to the special technology requirement of conjugate cam beating-up mechanism, this study introduce the motion law which acceleration curve is a combination of trigonometric functions and linear to mathematical model of cam pressure angle. With the help of computer software MATLAB programming, more detailed analysis and study on this motion law property were given and the variables great impact on the performance of beat-up motion were demonstrated clearly.

Abstract: The continuous growth of labor Cost, Study on the flexible robotic polishing systems has important realistic meanings. In this paper, After fully understanding the requirements of designing polishing tool based on polishing technology, a robot end-effector polishing tool held by the arm of robot is designed, and the establishment of a dynamic model and the equations of motion dynamics, which to provide technical support and theoretical basis for further development and optimization of flexible robotic polishing systems.