Applied Mechanics and Materials Vols. 80-81

Abstract: Stress concentration coefficient of welded joints has a crucial influence on mechanical properties of welded structures. Geometrical parameters of welded joints seriously affect the stress concentration coefficient. In order to increase the mechanical properties and using safety of welded structures, it has great significance for reducing stress concentration coefficient and improving the mechanical properties of welded structures by researching and improving the geometry of welded joints . In this paper, the effect of weld toe inclination angle θ and weld edge transition arc radius r on the stress concentration coefficient of welded butt joints were analyzed by using ABAQUS finite element program, and the change rule of stress concentration coefficient with the variation of the two parameters was also researched. The calculation results indicate that reducing weld toe inclination angle or increasing transition arc radius can effectively decrease the stress concentration coefficient of welded butt joints, so as to improve the mechanical properties of welded structures. For the safe use of welded structures, the true weld edge transition arc radius r should be greater than 3mm, and weld toe inclination angle θ should be smaller than 30°.

Abstract: Regenerative braking of electric vehicles can not only conserve energy, but also increase driving range. Regenerative braking control strategy formulate proportional relation of regenerative braking and mechanical braking, how to distribution regenerative braking and mechanical braking has become the key problem of raising regenerative braking energy[1]．This paper research on the distribution of braking force in the braking process, formulate mathematical models and put forward a new control strategy. The new control strategy is simulated and analyzed in the ADVISOR. Used new control strategy, the results indicate that fuel economy, emission and dynamic of simulation vehicle are improved.

Abstract: Gripper with two claws of automatic placing and removing manipulator is designed in this paper, and structure characteristics, working theory and positional error analysis are introduced. This gripper has the function of automatic center aligning and size control. The chucking size of gripper can be modified automatically in order to be adaptable when clamping different work pieces and this gripper, which could shorten the time and improve the efficiency, is designed to place and remove workpiece at one time beat. The gripper has a virtue of better ability to locate and move, improving the precision of automatic feeding manipulator and lathe cutting. The grippers have the advantages of simple structure, small volume and weight, which can solve the problems of complicated structure and massive volume for typical translational gripper. They also could simplify the control system of manipulator; meet the demand of placing and removing workpiece instead of complicated and heavy manual work.

Abstract: For the purpose of improving the design automaticity for mechanical design, this paper explores the parameter designing for thread fasteners with SolidWorks as the operation platform and Visual Basic 6.0 as the development tool. The method and steps of parameter designing have been introduced here with the hexagonal head bolt as an example for users to conveniently transfer a series of hexagonal head bolt parts by inputting different parameter values on the man-machine dialogue window in the VB interface.

Abstract: Vehicle safety is one of the most important design elements for all types of vehicles designed for use on public streets or roadways. Compared with traditional vehicles, besides other safety issues to be considered, a new issue that is the high voltage management problem should be taken in consideration very carefully in the electric vehicle development. This paper analyses the high voltage system in the electric vehicle and proposed a high voltage management system which implements several functions like power-up and power-down control of the high voltage system, high-voltage-circuit interlock protection, protection of electric leakage of the HV system etc. Because of the high voltage management, the electrical safety goals could be achieved and the protection of human being from high voltage hazardous becomes possible.

Abstract: By carrying on the stress and transform analysis of the box of a kind of transfer case which was self-designed and manufactured for vehicles,by ROMAX modeling get accurate bearing load and conducting ANSYS finite element analysis. it is shown that structure design of the transfer case box is very important for the intension capability of the box,and for the transmission functions of the transfer case.The hidden trouble of the transfer case transmission due to the designers was solved,which couldn’t estimate the transform of transfer case box by traditional design method,and provided the necessary basis for further optimizing and ameliorating the whole transfer case system.We constructed a complicated model of the box by using the UG software,and carried on a series of accurate intension and fatigued analyses for the model by using AN SYS software.

Abstract: Battery electric vehicle is to be researched and developed as the best alternative for fuel vehicle. Dynamic performance is the basic performance of a vehicle. In the prior period of research and development, studying on the sensitivity of relevant parameters to dynamic performance can determine the degree of influences that the relevant parameters have on it. This paper establishes mathematical model for the dynamic performance of battery electric vehicle, and deduces computational methods of the dynamic parameters sensitivity. Improving these parameters will provide the basis for improving the dynamic performance of battery electric vehicle.

Abstract: In this paper the nonlinear model of zero open symmetrical cylinder controlled by four-way slide valve system was established base on power bond graph. The flexible simulation model was building up by the use of simulink toolbox in MATLAB. The model’s dynamic characteristics were stimulated. The simulation results showed the nonlinear model could reflect the dynamic characteristics of the valve controlled cylinder accurately. So it provided scientific basis for estimating the characteristics and correct using of the controlled cylinder system.

Abstract: Non-Obstructive Particle Damping (NOPD) is a new damping technique which is based on traditional particle damping and impact damping technique. NOPD Structure has a good effect on decreasing sound and vibration. A new improved algorithm based on the endochronic theory is researched in the paper. Response calculation by the algorithm and tests for NOPD beam have been done in conditions of one, two and three holes filled with tungsten particles. Results show it feasible to calculate the response of NOPD structure by the improved algorithm, which affords an effective analysis method for engineering application of NOPD technique.

Abstract: Stiction is one of the most important and almost unavoidable problems in MEMS, which usually occurs when the restoring forces of the microstructures are unable to overcome the interfacial forces. Stiction could compromise the performance and reliability of the MEMS devices or may even make them malfunction. One of the pivotal process of advancing the performance and reliability of MEMS is to comprehend the failure modes and failure mechanisms of these microdevices. This article provides a critical investigation on the stiction failure mechanisms of the micromachined electrostatic comb-drive structures, which is significant to improve the reliability of microdevices, especially for microfilters, microgrippers, microaccelerometers, microgyroscopes, microrelays, and so on.