Advanced Materials Research Vols. 482-484

Abstract: Unanticipated disturbances in outdoor environments are the main impediments to the development of motion control for transmission vehicles. Classical synchronous approaches which neglect the mechanical coupling effect are unsuitable for such types of mechanisms. To address this concern, much effort has been made to overcome such difficulties. A synchronous decoupled control framework was proposed based on the multivariable model, in which a decoupling transformation matrix was adopted for improving the corresponding performance. The concept of the proposed control framework is intuitive and quite straightforward. To demonstrate the capacity of the mathematical model as well as the effectiveness of the control scheme, a power-wheelchair was utilized as an illustrated example, where the synchronous performance can be enhanced by almost 50% as compared to the classic approach.

Abstract: A well-defined graft copolymer poly(ethylene oxide-co-glycidol)-graft-Poly(lactide) [poly(EO-co-Gly)-g-PLA] of poly(ethylene oxide-co-glycidol) [(poly(EO-co-Gly)] as main chain and poly(lactide) (PLA) as the side chain was successfully prepared via combination of anionic polymerization and ring-opening polymerization. The glycidol was protected by ethyl vinyl ether first to form 2, 3-epoxypropyl-1-ethoxyethyl ether (EPEE), and then copolymerized with EO by initiation with the mixture of diphenylmethylpotassium and triethylene glycol to obtain the well-defined poly(EO-co-EPEE). The latter was hydrolyzed in the acidic conditions and then coordination-insertion ring-opening polymerization of lactide(LA) with poly(EO-co-Gly) was completed. The object products and intermediates were characterized by 1HNMR, MALDI-TOF-MS and GPC in detail. The experimental results confirmed that poly(EO-co-Gly)-g-PLA showed strong conjugation ability with the dyes.

Abstract: Gearbox was a key component of wind turbine but with the highest failure rate, so it was necessary to analyze its safety and reliability. In this paper, gears in MW wind turbine gearbox were analyzed by nonlinear finite element contact analysis method. The changing regularity of the stress was found as tooth mesh, and it was proved to be reliable by comparing with the result of theoretical calculations. The maximum contact stress existed on the second engaged tooth as well as the vicinity of the pitch circle of gears. The stress concentration phenomena occurred at the tooth root fillet which caused the main failure form of gears.

Abstract: Octadecylated poly (vinyl alcohol) (PVA-C18) comb-like polymer was prepared through the reaction between PVA and 1-bromooctadecane via O-alkylation method. The structure, thermal properties and packing mode of PVA-C18 comb-like polymer were detailed investigated with Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), and X-ray diffraction (XRD). The results show that octadecyl side chains had been successfully grafted onto PVA backbones, and PVA-C18 comb-like polymer exhibit the better thermal storage properties with enthalpy of 29.3kJ/mol , indicated that it is one kind of solid-solid phase change materials.

Abstract: The working space of manipulator is an important dynamic index. Based on Monte-Carlo method, working space of the 6-DOF (degrees of freedom) underwater manipulator is analyzed in this paper. The virtual prototype of the manipulator is established. Simulation graph is obtained with the aid of arithmetic procedure and computer graphical. Simulation result shows that the manipulator’s working space is bigger and has obtained better effect, which can meet the 6-DOF underwater manipulator operational requirements. The results provide an important reference for the 6-DOF underwater manipulator body design and trajectory planning.

Abstract: This essay describes the design methodology of Hall component based on ANSYS soft emulation, and analyses the key parameters of Hall component affecting its performance in the design process. The ANSYS software emulation results shows that Hall voltage will be affected by the Hall components with different length to width ratio and the plus electrode in different length and width. The length to width ratio of 1.5 to 2 will get better results, and it proves that the width of the electrode should be less than one-tenth the size of length. The Hall voltage within a certain range will increase with increasing length of Hall components plus electrode. So it is important to choose the best size ratio when designing the Hall components.

Abstract: This paper presents a crowding niche cellular genetic algorithm (referred to NCGA) aiming at solving the problems of local convergence and non-uniform population distribution in traditional genetic algorithm. The selecting operation in traditional genetic algorithm is improved by bringing in the concept of neighbors of cellular genetic algorithm, and the population distribution is greatly enhanced by introducing crowding niche mechanism, which betters the ability of global searching and helps to avoid the population local convergence. Meanwhile, the paper describes the crowding niche cellular genetic algorithm in details and compares it with simple genetic algorithm （SGA） and simple niche genetic algorithm （NGA）; the comparison results reveal that, NCGA outperforms the other two algorithms in terms of convergence rate and population diversity.

Abstract: A two-beam pumped Ti:sapphire laser with femtosecond and picosecond cavities was manufactured. Three operating modes, independent self mode-locking, cross mode-locking and multi-pulse operating, were achieved. In the independent self mode-locking mode, femtosecond and picosecond laser pulses were generated in the two cavities, respectively. In the cross mode-locking mode, synchronized femtosecond and picosecond laser pulses were obtained in the two cavities. In the multi-pulse mode, multi-pulses were produced in the picosecond cavity. The results show that, the independent self mode-locking mode is dominated mainly by group velocity dispersion and self-phase modulation, the cross mode-locking mode is governed primarily by cross-phase modulation and the multi-pulse operating is ruled largely by self-amplitude modulation.

Abstract: Through the discussion of main shortages of the high-speed electromagnetic valve used in electronic fuel injection system, the author introduced a new design thought of fuel injector based on 2D technology. Axial displacement of controlling valve was used to control the volume of gushing oil, while radial revolution of spool valve was used to change the time of injection. Additionally, mathematic modeling and MATLAB simulating indicated that, the injector designed based on 2D technology acquired the advantages of quick response and also realized the ideal shape of fuel injection rate.

Abstract: Seven commonly used ductile fracture criteria are briefly reviewed and the validity of predicting the failure of AZ31 Mg alloy sheet by using these ductile fracture criteria is evaluated. Through fitting the experimental FLCs, the damage parameters for these ductile fracture criteria are determined firstly. Integrating these seven ductile fracture criteria into Abaqus/Explicit via VUMAT subroutine, the warm deep drawing process of AZ31 Mg alloy sheet is simulated. The limit drawing ratios (LDR) of AZ31 Mg alloy sheet at different temperature are predicted. The comparison of predictions with the experimental results has shown that the combination of the finite element simulation and the ductile fracture criterion is useful for predicting the fracture occurred in warm deepdrawing of AZ31 Mg alloy sheet.