Applied Mechanics and Materials Vols. 16-19

Abstract: In order to improve the drifting accuracy of aerostatic bearings, the manufacturing errors effects on disturbing torque of aerostatic bearings is studied by using the finite element method. The finite element mathematic model of the major influence factors of disturbing torque is established. Then, the finite element equation in the gas film domain is solved and the disturbing torque in the presence of disturbing factors is calculated. The research focuses on elliptical error and prismatic error of journal and incline error of throttle slit. The setting angle of journal, incline position angle of throttle slit and radial eccentricity ratio which affect the disturbing torque is also studied. The results show that roundness error of journal and incline error of throttle slit affect the disturbing torque significantly, that is the greater roundness error of journal and incline error of throttle slit the greater disturbing torque. Disturbing torque is periodic function of setting angle of journal and incline position angle of throttle slit. Radial eccentricity ratio affects the disturbing torque, and there is specific radial eccentricity ratio makes disturbing torque to be extreme point or zero point. In the research, the theoretical disturbing torque value is compared with the experimental value of a certain aerostatic bearing, find that they are on the whole accordant with each other and then prove that the finite element model and the method use to solve the problem is correct. The research is of great significance for designing, manufacturing and assembling aerostatic bearings and for performance prediction of aerostatic bearings.

Abstract: The linear rolling guideway is one of the most essential parts of the machine tool. So it is very important to analyze the dynamic-static characteristic of the machine tool consider rolling guideway and to study the effect on machinery function. The paper’s research is based on a NC machine tool produced by a certain plant of machine tools. Methods of simulating the rolling guideway support are studied, and the configuration of the spring damper elements of the bearing supports are also studied, and the finite element analysis on the CKS6125 machine tool has been made to confirm its dynamic characteristics. Then the finite element analysis models are validated by some experiments.

Abstract: Extrusion force plays a significant role on sheet metal extrusion process. It is characterized by various process parameters including material properties, extrusion ratio, friction, tool shape etc. In this paper, a reasonable FEM model of sheet metal extrusion process was established and validated by comparing the results of simulation and experiment firstly. Based on the reliable model, the effect on extrusion force of various process parameters was investigated with orthogonal experimental design combined FEM simulation. The work presented in this paper has laid certain foundation for further work of modeling and optimizing extrusion force.

Abstract: The purpose of MH/Ni power battery positive mill is to make it have the certain density, thickness and good tenacities. The thickness of positive battery is different, its capacity, the efficiency of charge and discharge, the utilization efficiency of the electrode material is also different. Positive battery has variable delay and variable gain in the mill process, so it is suitable for using neural networks to control.

Abstract: A new free-form surfaces shape-adaptive polishing tool is introduced in this paper, which can change its pose with the surface of workpiece. The simulation of this tool system’s polishing process is taken using ADAMS, and the kinematics of the shape-adaptive tool on the curvature varying surfaces of the workpiece is investigated. The simulating results indicate that the tool system can fit the varying curvature and slope of the workpiece’s surface very well.

Abstract: The stress field simulation is carried on to the solenoid valve product during the impulsive load using the ANSYS software in this article, and the stress calculation and fatigue strength assessment to the key dangerous section of valve are done. The result indicates that the dangerous section is proved to satisfy the strength requirement during the impulsive load, and the theory basis has been provided for the further structure optimization design and the performance improvement of solenoid valve.

Abstract: 3-D velocity and temperature fields of mold filling and solidification processes of large turbine blade casting were simulated. It indicated that the velocity field of upright casting is faster and steadier than lying casting. The deformation was predicted and the rule of deformation was reflected by analyzing stress field during solidification of upright casting. The casting processes were optimized, and then applied to produce castings.

Abstract: Wear course was experimental analyzed and mechanism of electrode wear was discussed based on finite element analysis and electromagnetic theory. Cu–TiN nano composite electrode was prepared on Cu electrode by electro deposition and effects of the electrode on discharging were studied. It is shown that electric field distortion and skin effect are two of the basic reasons on electrode wear. Cu–TiN nano composite electrode is one of the the effective ways for uniform wear of electrode in EDM.

Abstract: Rollover and jack-knifing of tractor semitrailer on high speed obstacle avoidance under emergency are serious threats for motorists. A tractor semitrailer model was built with multi-rigid-body method in this paper. The steering performance of tractor semitrailer has been analyzed, as well as the stability control theory, including yaw rate following, anti-rollover. The dynamics simulation for yaw rate following and anti-rollover has been performed on the dynamic tractor semitrailer. The results show that the vehicle dynamics control proposed in this paper can stabilize the tractor semitrailer, rollover and jack-knifing are prevented and the tractor semitrailer more accurately follows the driver's desired path.

Abstract: Accurate predictive modeling is an essential prerequisite for optimization and control of production in modern manufacturing environments. For slender bar turning operations, dimensional deviation is one of the most important product quality characteristics due to the low stiffness of part. In this study, radial basis function neural network is employed to investigate dimensional errors in slender bar turning. The relationship between cutting parameters and dimensional errors is firstly described by the proposed model. Simulation is provided to investigate the effects of cutting parameters on dimensional errors. Further, real-time predictive model based on radial basis function neural network is developed to perform the dimensional error monitoring during slender bar turning process. Experiments verify that the proposed in-process predictive system has the ability to monitor efficiently dimensional errors within the range that they have been trained.