Advanced Materials Research Vols. 538-541

Abstract: Traditional shift schedule of automatic transmission cannot meet driving requirements when vehicle is running under conditions of complex road and special driving intentions. On the basis of the analysis of vehicle dynamics, recognition methods of road environment and driving intentions were proposed according to the changes of vehicle dynamic parameters. Traditional shift schedule was rectified and simulation was carried out in vehicle equiped with dual clutch transmission. The results shown that the rectified shift schedule can meet driving requirements. This study can provide an effective shift schedule for automatic transmission.

Abstract: Frame of solar sweeper is complexly welded structure with thin steel plate. The finite element method is applied of the frame strength analysis in two working conditions, full-load static and braking state. HyperMesh software is used for analysis of integral and welded frame model. CWELD is created to simulate the welding connection. The numerical results show that maximum stress of integral frame is 60.24MPa, and maximum stress of welded frame is 70.7MPa under full-load static state. The maximum stress different is 14.8% of two working conditions. The frame of solar sweeper satisfy strength requirement under the two working conditions, when the welding connection is considered. And the frame can be optimized by using these results.

Abstract: To reduce the excessive vibration of a high-speed rotor system as it passes its critical speed, a viscoelastic-friction damper(VEFD) are introduced into the support. Its stiffness factor is analyzed. Results show, the stiffness factor decreases with the cone angle increasing among 55-80 degrees monotonically. And it is the same trend when the stiffness of the damping material ring decreases. In the case of friction coefficient among 0.1-0.5, the stiffness factor increases monotonically. So adopted a proper structure, suitably chosen the above parameters and the axial stiffness of the outer-ring, the damper can present appropriate stiffness.

Abstract: The flexible robotic arm drived by hydraulic are widely applied in most kinds of large engineering equipments, such as concrete pump truck, bridge monitor truck,etc. Nevertheless, the flexible distortion always break the precision of end-position and cause liberation of the whole arm system. In this paper, the movement of flexible hydraulic robotic arm and hydraulic cylinders are separately analyzed with flexible multi-body dynamics. And the dynamic differential equation is built with the driving force of the hydraulic cylinder as the main force. The equation is based on the theory of flexible multi-body dynamics, building the coupled model of robotic arm system and hydraulic-driving system to study the relation between the end-position, angle and the hydraulic system. What’s more, the simulation model of the mechanical arms is built by the dynamic simulation software. The project will theorectically support the intelligent control or auxiliary control of large engineering equipments.

Abstract: Data exchange (load transfer) between boundaries is a key technique in multi-physics coupling numerical simulation. Based on the relationships of point and triangle, an improved data exchange algorithm, namely Inside Projective Constant-Volume Tetrahedron (IPCVT), is proposed to improve the precision, in which the tetrahedron has higher quality to ensure that the subpoint of the target point locates inide the source triangle. Furthermore，the achieved data of the target point is calculated by tri-linear interpolation function in the projective palne, which greatly simplifies the computation and enhances the data-processing ability of the algorithm. The application of the algorithm to an example shows that IPCVT can well control the oscillation of Constant-Volume Tetrahedron (CVT) when there are large gaps or overlaps between the boundary meshes, and get a good precision in data exchange.

Abstract: It sets up the system structure model of materiel system reliability simulation based on Adaptive Agent in the paper, emphasizes the mission-oriented reliability impact model and the devising thinking on MA, which helps to mission environment-oriented reliability analysis.

Abstract: The roll forming process is a technique for forming ring with complex cross section, which widely used in the fields of aviation, aerospace and other high technology industries. To predict and control the roll forming quality, a 3D elastic-plastic finite element (FE) model of ring with complex cross section for roll forming was developed using the explicit code ABAQUS/Explicit. During the modeling process, several key techniques are solved, such as materials modeling, geometry modeling and grid optimal design. Then the reliability of the model was verified. Furthermore, numerical simulation and analysis of the roll forming process of ring with complex cross section have been carried out by using the model. The distribution regularities of equivalent strain in the process have been analyzed. The results show that with the progressing of roll forming, the equivalent strain increase sharply in the initial stage, then slightly varies, and the W shape of ring cross section is produced gradually.

Abstract: As the global properties of traditional optimization algorithm was weak, the local solution of it appeared easily.The simulated annealing algorithm’s cooling rate was slower and he local searching ability was insufficient. Use the simulated annealing compound method that is combined of the simulated annealing algorithm and compound method. Research the optimization design of elastic suspension with the genetic compound method and compare with the traditional optimization methods. The results show that the algorithm is correct and effective in solving multi variable and constraint optimization problem of elastic suspension.

Abstract: Tool steel - SKD 11 is frequently used in industries for making dies and molds. This grade is chosen for its toughness, strength, and hardness maintained up to high temperature. However, the same properties make the steel extremely difficult and expensive to machine using conventional approaches. Heat assisted machining has been found wide spread application in recent years to improve machinability of difficult-to-cut materials. This research paper presents the outcome of an investigation on heat assisted end milling of SKD 11 conducted on a vertical machining center using ball nose coated carbide inserts. The Design of Experiments (DoE) was done using the Response Surface Methodology, in order to develop empirical mathematical models of surface roughness and vibration in terms of cutting speed, feed, axial depth of cut, and heating temperature. The models were checked for significance using Analysis of Variance (ANOVA). 3-D response surface graphs of the interactions of primary cutting parameters with the responses were plotted. Optimization was then performed by using the desirability function approach. From the graphs and optimized results it was concluded that the primary input parameters could be controlled in order to reduce vibration amplitude and produce semi-finished machined surfaces applying induction heat assisted technique.

Abstract: The characteristic of air pressure field in melt blowing with dual slots was studied. The main research method was the numerical simulation of three dimensional. The results show that the air pressure field is symmetric. There exist two sections: the pressure difference section and the zero-pressure difference section along the whole centerline. In the pressure difference section, there also exist three sub-sections.