Applied Mechanics and Materials Vols. 236-237

Abstract: In order to lessen the worsened formability, failures and fractures occurring in the cold stamping process, the hot stamping technology was adopted in the forming of DP steel engine dumping plank. The simulation technology of finite element method was also used to forecast the forming defects in the stamping process of the DP steel engine dumping plank. In the paper, the forming limit, the influences of stamping gaps and the influences of different blank holder force on the stamping part were analyzed by using eta/DYNAFORM software. Meanwhile, the thickness changes and the materials flow conditions of the DP plank during the hot stamping process were also analyzed. Through the experimental analysis, the result of the finite element numerical simulation complied very well with that of actual production results. The research results show that duplex steel plate can meet the performance requirements of car engine dumping plank forming, which offers theory basis for the production of similar parts.

Abstract: In this paper a new MR damper presents, every stage coil connection is independent. The fluid channel congestion and single axial magnetic field problems, existing on the old MR damper worked under the high impact load were solved. With this connection type, MR damper can generate an axial time–varying magnetic field with different input current every stage. The MR damper’s electromagnetic model was built, and the simulation analysis of new and old MR damper under impact load based on the PID control algorithm was finished. According to the simulation results, compared the anti-impact-load performance between new and old damper. The results show that working on the same impact load, the newly designed MR damper can reduce the displacement and the energy consumption simultaneously compared to the prior damper.

Abstract: This paper presents a new design approach of parallel robot for quick grasp based on parallelogram mechanism，and derives the dynamics model. Using SimMechanics toolbox and simlink toolbox in Matlab Software, and guiding the three dimensional solid model into it, the dynamics simulation and control on two DOF parallel robot is designed and studied. The experimental results show that the design mechanism obtains the anticipated requirement.

Abstract: This paper presents a methodology for pencil-cutting regions detection in five axis NC machining of free-form surfaces. The local interference of surface occurs when the radius of the local surface curvature is smaller than that of the cutter. It is a time-consuming work to calculate the free-form surface curvature by differential geometry, so the arc radius is used to approximately compute the curvature radius of the surface to judge the local interference. Computer implementation and practical examples are also presented in this paper.

Abstract: Gray balance is the basic and critical control parameters of color reproduction, which plays important rule as lever in color reproduction which balance the correlation of material characters and process control parameters. This paper focused on investigation about gray balance data variation caused by slight chromaticity deviation of printing material. In the experiment the creation procedure of gray balance curve was simulated by EPSON Stylus Pro7880c ink-jet printer, and delivered curves were compared with each other. Accordingly the tone value variation of primary color was analyzed in terms of chromaticity deviation of paper. Meanwhile the variation tendency of gray balance impacted by ink and paper property was qualitatively discussed according to data comparison with G7 method. Results show that tone value of Y is so sensitive to paper chromaticity deviation that even the dominant relation between Y and M tone will be altered. At the same time, the more the ink and paper property coincide with ISO standard, the more curve of gray balance curve coincide with theoretically ideal value.

Abstract: In this paper,the mechanical properties of a certain type of CNC lathe spindle box are analyzed by the finite element software HyperWorks. On this basis, the topology optimization of the CNC lathe spindle box is done by the variable density method. where the spindle box relative density is taken as the design variable and the minimum volume of the spindle box as the objective function, its static deformation and the low modes as constraints．That is to find the optimal layout of the structure,and then the size optimization of the spindle box is done to make further amendments of the topology optimization results. This design method achieves the lightweight design of the spindle box, reduces manufacturing costs,and provides a theoretical basis for enterprises to improve the structure of CNC lathe spindle box.

Abstract: 3D shape of the weld pool surface can be used to infer the penetration state of the weld pool, which has an importance influence on weld quality. In this paper, a novel stereo camera system that used only one camera and a biprism placed in front of the lens was applied to capture virtual image pair of the weld pool surface. The most advantage of the system setup is that corresponding points lie on the same scan line automatically, i.e. the stereo image pair is self rectified. The calibration of the system was done using plane pattern by Zhang’s algorithm and the standard SSD stereo matching algorithm was applied to find the corresponding points in the left and right image. The reconstructed 3D shape of the weld pool surface during base current period of P-GMAW by the system has shown that the technique has potential application for control of weld process

Abstract: In view of the disadvantage of current FAT-based fault diagnosis method in large-scale complicated system, fault diagnosis method of heavy NC machine based on FTA and Bayesian is discussed. Firstly, building fault trees with the help of reachability matrix, and to set the determinate conditions at every node of fault tree combining FTA with rule reasoning, the minimum cut set of fault reasons are determined as a result of step by step screening fault tree from top-down; Secondly, Bayesian method is integrated into the fault tree diagnostic method to calculate the posterior probability triggered by each fault tree in order to locate the fault tree where the fault had occurred and ensure high efficiency of fault diagnosis; Finally, B/S based intelligent fault diagnosis system for large-scale CNC equipments is developed, and the feasibility and efficiency of this method are proved in an example of fault diagnosis of Φ 160 NC boring and milling machine.

Abstract: In this paper, we present an analysis of the data capacity for different types of laser disc technologies. Two design factors, laser wavelength (infrared, red or blue) and disc drive mechanics (CLV or CAV) are studied, and brief introductions to these two design factors are given. Moreover, diffraction, technical data and background information about disc drive mechanics are discussed, the conclusion is drawn that CAV-type is more than CLV type of capacity, consistent with its production principles.

Abstract: The main circuit of tungsten inert gas (TIG) arc welding power (AWP), which is mode of the inverter for intermediate frequency and full-bridge IGBT, is designed based on DSP (Digital Signal Processor). The control designing, also based on DSP, include the sampling signal circuit, the control circuit for external characteristics, the PWM (Pulse-Width -Modulation) control circuit of TIG-AWP, the IGBT drive circuit and etc. This designing can strengthen the reliability of feedback regulation property on TIG-AWP; can enhance the stability of the parameters from the power system. The experimental result shows that the designed TIG-AWP has good feedback regulation and stability properties during the TIG welding process.