Advanced Materials Research Vols. 317-319

Abstract: Amino silicone (PDMS) with lower viscosity were synthesized at a certain temperature by ring opening copolymerization of octamethylcyclotetrasiloxane (D4), N-β-aminoethyl-γ- aminopropyl methyl dimethoxysiloxane (YDH-602), hexamethyldisiloxane (MM) with KOH as catalyst and DMSO as accelerating agent. The chemical structure was characterized via IR and 1HNMR. And the important factors were investigated carefully and the best technology of synthesis was obtained: reaction temperature 100-110°C, time 3h, KOH 0.05%, DMSO 0.5% and MM 5-7%, distilling at 110°C/0.095Mpa for 40 min.

Abstract: The blade and blisk manufacturing includes polishing process when the surface roughness and size requirement of profile are disqualified after milling process. This polishing process is mainly carried out manually by skilled workers or NC machines. However, the existing polishing technology always leads to surface quality instability and inconsistency because of the complex free-form surface of blade and blisk. Therefore, in this paper, based on the research of polishing requirements and methods of blade and blisk, an automatic 6-axis polishing machine was proposed in order to enhance surface quality. And then, a polishing mechanism was designed using flexible technique to make the polishing tool accommodate surface waviness which was produced in milling process. In addition, the working principle and control method of flexible polishing mechanism were studied. Finally, the polishing test results of blade and blisk showed that the profile error was about 0.06mm and the surface roughness was less than Ra0.4 after automatic polishing. Compared with the manual polishing process, the automatic polishing technology not only increased the polishing efficiency and quality stability, but also reduced labor intensity largely.

Abstract: A new interior permanent magnet synchronous motor (IPMSM) control method is presented for electrical vehicle drive system. Based on the differential geometry theory, the nonlinear system is changed into a linear system with input-output decoupling technique. Then, by the maximum torque per ampere (MTPA) control strategy, the output torque of the drive system is added. And then, a load torque observer is designed to resist the variable load. In the end, Based on the linearization model, an controller is given. Simulation results show that the electrical vehicle drive system based on decoupling robust control has fast transient responses, good load disturbance resistance responses and good tracking responses.

Abstract: Topology optimization is one of the most important methods of reducing the weight of structure. Optimality Criteria method (OC) as a heuristic way can be used to deal with this problem efficiently. Popular SIMP method implements micro-structural density as the design variable. During the process of optimization, numerical instabilities are always observed; Moreover, higher penalty factor is not better for decreasing intermediate density elements. In this paper a penalty factor is imposed in OC method, and a relation between the filtering area and elements is also obtained. Meanwhile, the nodal density is used as design variable for more smoothing boundary. The results show that numerical stability can be obtained, checkerboard patterns haven’t been observed, and the clear boundary of structure has been developed.

Abstract: On the basis of analyzing technology processes and control demands of concrete mixing station, a design of control system for this construction machinery based on SIEMENS S7-300 PLC and eView touch screen was introduced in this paper, including hardware selection, PLC LAD diagram programming and HMI design, etc. All expected demands for weighing, batching, deposit, mixing, unloading, conveying of the whole technology processes of concrete mixing are reached, and a totally automatic production can be realized also. The practical operation verifies that the control system is highly reliable and stable, and it greatly enhances the control accuracy and meets the equipments requirements of energy-saving.

Abstract: In terms of the problem of paving of asphalt coiled waterproof material on express railway bridge, developed an effective paving machine, and describe the total structure of the machine and the function of important parts. Introducing the characteristic and function of the walking system, automatic speed regulation system for uncoiling coiled waterproof material, agitating and leaking system of binding agent, coiled waterproof material paving self-adapted mechanism of the asphalt road surface, and describing the fundamental principle and function of the machine’s hydraulic control system. The machine can adapt the condition of road surface, realizing wide area paving of waterproof material. It ensures the quality of the paving, and at the same time, enhances the paving efficiency, increases automatic level, and eases labor of technicians.

Abstract: Open solicitation for qualified suppliers, expert assessment, establishment of qualified suppliers database, reassessment and other procurement modes are applied in bids of large-scaled public construction engineering so that contractors could select the materials according to the qualified suppliers database and an effective way could be ensured to the procurement of large public construction engineering with high technical contents, high construction costs and key roles in the operation of the system. Such modes have been applied in the renovation of Guangzhou Asian Games Stadiums during which the whole process control measures have been taken from the qualification verification, sample test, orders, manufacturing to on-site quality inspection, installation, commissioning, etc. so as to ensure the conformity of materials and electromechanical equipment to the design requirements and guarantee the construction quality.

Abstract: In this paper, a shape recognition method based on Freeman chain code has been proposed. According to the detected corners, feature vector of a contour shape can be obtained. And the descriptor of each corner in the feature vector has three components, which are the normalized distance between the corner and the centroid of all the corners, the local main trend of both sides of the corners. By using the feature vector, the matching judgment has been given, and the results of the experiment are shown.

Abstract: In natural medium, engineering materials and structures, it can be found that there are cavities everywhere. When structure is impacted by dynamic load, the scattering field will be produced because of the cavities, and it could cause dynamic stress concentration at the edge of the cavities. In this paper, the solution of displacement field for elastic semi-space with multiple cylindrical cavities by anti-plane SH-wave is constructed. In complex plane, considering the symmetry of SH-wave scattering, the displacement field aroused by the anti-plane SH-wave and the scattering displacement field impacted by the cylindrical cavities comprised of Fourier-Bessel series with undetermined coefficients which satisfies the stress-free condition on the ground surface are constructed. Through applying the method of multi-polar coordinate system, the equations with unknown coefficients can be obtained by using the stress free condition of the cylindrical cavities in the radial direction. According to orthogonality condition for trigonometric function, these equations can be reduced to a series of algebraic equations. Then the value of the unknown coefficients can be obtained by solving these algebraic equations. The total wave displacement field is the superposition of the displacement field aroused by the anti-plane SH-wave and the scattering displacement field. By using the expressions, an example is provided to show the effect of the change of relative location of the cylindrical cavities. Based on this solution, the problem of interaction of multiple cylindrical cavities and a linear crack in semi-space can be investigated further.

Abstract: Escalators are important conveyance in the vertical direction at subway stations for the capacity influences the transportation efficiency of stations. Therefore we should pay much attention to the design. England has formed mature theory in the design of escalators. The paper mainly introduces the design methods and the relevant specifications about the design factors of escalators, the technical parameters and number of escalators, the capacity and the size of queuing area of escalators in England. At last the paper summarizes several design experience abroad we can draw lessons from by comparing the England specification and China manual.