Advanced Materials Research Vols. 148-149

Abstract: In order to calculate the parameters of roller leveling process, the 3D mathematical models of plate leveling based on the curvature integral by elastic-plastic differences were set up. The calculation results by the models showed a good correlation with the measured data from a plate mill which adopts the advanced control system by SMS. The analytic models can be developed which analyzed the leveling process so efficiently that it can be used for process controlling. Additionally, the plastic deformation ratio was analyzed which can account for the leveling phenomenon, and the model was regressed which can be used easily for engineering calculation.

Abstract: Design of an experimental apparatus to simulate the geophysics is vital to understand the structural and evolutionary phenomena of a complex geological system. In China that lacking of a suitable comprehensive experimental apparatus for such purposes is a major factor that greatly restricts the developments of geological modeling towards the quantitative and repeatable requirements. In line with the analysis according to geological theories, and change rules of stress-strain of a geological body, the paper provides a design of a powering unit, by means of a PLC based controller, capable of performing functions specified by the experimental apparatus. Some results, obtained from using standard procedures for tectophysics simulation study, of using such an experimental apparatus are given, which showcase that the design is in properly functioning and therefore can be used for similar geological experimental study.

Abstract: Airport gate assignment is to appoint a gate for arrival or leave flight and to ensure that the flight is on schedule. Assigning the airport gate with high efficiency is a key task among the airport ground operation. As the core of airport operation, aircraft stands assignment is known as a kind of complicated combinatorial optimization problem. In this paper, occupied gates in order to optimize the efficiency of the target index, the purpose of parking gates in order to save the resource utilization and to improve the speed of flight at the same time working to meet the requirements of the quality of passenger services, An integer program (IP) model is developed, and a tabu search algorithm was put forward to resolve the model. The algorithm results in the calculation of time and extent to optimize the effectiveness of certain.

Abstract: Effects of hydrogen on machinability involving cutting force, surface roughness and chips morphology of BT25y alloy with semi finish machining were carried out. The microstructures and phase composition of different concentrations were studyed by metallurgical microscopy, transmission electron microscope (TEM), and X-ray diffractions (XRD). The results show that existing a optimum hydrogen concentration (0.20wt.%) for machinability of BT25y alloy in which cutting force decreases 179N and surface roughness reduces about 24%, in addition, chips morphology are transferred from continuous to segmental. The grain refinement, hydride precipitations and thermal conductivity resulting from hydrogen can improve the machinability of BT25y alloy.

Abstract: Computer Aided Assembly Process Planning and Simulation in 3D environment depends mainly on the manner of human-computer interaction currently in the airplane manufacturing industry, and in fact it’s just a recorder for recording the designers’ assembly intention. It’s short of supports for a designer to execute the 3D assembly process planning and simulation, for lacking a strict process flow definition and a pilot method. In this respect, we propose a decomposition modeling method of 3D assembly process planning and simulation for airplane subassembly named Assembly Process Micro-Planning and Simulation (APMPS), which defines a standardization flow and a data-information modeling method. By using this method, the assembly process can be designed and validated form assembly-design-intention to assembly-process-planning to assembly-process-simulation with the five process levels’ definition (AJATAOAAAM). This method is validated by a central-wing’s assembly process design in an airplane manufactory. The result shows that the APMPSS is in accordance with the Concurrent Engineering’s requirements, and it can be carried out fast in 3D environment.

Abstract: Under the situations of distribution center and customer demand, a mathematical model of Vehicle Routing Problem with Time Windows(VRPTW) is set up, where the main factors of less total distance of vehicles driving and less delayed time of vehicles are considered. For the "premature" convergence in Genetic Algorithms, Simulated Annealing Algorithm is introduced, and GSA is designed to optimize and analyse the VRPTW examples. It is shown that the performance of GSA is better than Genetic Annealing(GA).

Abstract: This paper brings a new method of adaptive control with constant pressure on large-scale surface grinding machine. The existing problem of uneven in the process of abrasive belt grinding on titanium alloy composite plates is solved effectively. And the grinding head and the belt follow the plate surface ups and downs effectively through contacting the workpiece with the constant pressure. Not only did ensure the grinding depth and the size of the titanium alloy plates, but also improved the surface processing quality. After experiment, the satisfactory control effect was obtained. The research results have some practical value on adaptive control theory and industrial practice.

Abstract: The properties of the final product greatly depend on the cooling rate from the material surface in many manufacturing processes, such as stretching sheets or filaments that are extruded continuously from a die. Therefore, the thermal transport behavior may play an important role in such manufacturing processes. In this paper we present an analysis of momentum and thermal transport for the magnetohydrodynamic (MHD) flow of an electrically conducting fluid over a stretching sheet with prescribed surface temperature. The effects of free convection, Joule heating and viscous dissipation are taken into consideration. The transformed governing equations are solved numerically for this non-similar coupled flow problem. To reveal the tendency of the solutions, typical results for velocity profiles, temperature distributions and the local Nusselt number are presented for different values of governing parameters.

Abstract: A new procedure of surface activation without using palladium salt is proposed for electroless nickel plating (Ni-P) on carbon fiber. The optimal formula and technical conditions for palladium-free activated electroless Ni-P were obtained by orthogonal experiments. The effects of nitric acid processing time on the quality of nickel coating was investigated .The effects of varying concentrations of Ni2 + on the rate of weight gain during the Ni2 + complex adsorption process were also analyzed and the kinetic equation of the process was established. The theoretical values calculated by the equation were proven to be consistent with the experimental verification. The material characteristics of the deposited layers were analyzed by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and X-ray diffraction (XRD). The tensile strength of the carbon fibers was analyzed by the Weibull method, and this showed that when the thickness of the Ni-P coating reached 0.150μm, the tensile strength reached a maximum value. The experimental results showed that the nickel deposition on the carbon fiber surface obtained by this method, had the same uniformity, compactness and adhesive properties as the one by conventional electroless Ni-P.

Abstract: Cu-Al2O3 composites were prepared by a new simplified internal oxidation process integrating with powder metallurgical process, and then the hot extrusion and the cold rolling processes were carried out. The microstructure, electrical conductivity, hardness, tensile strength and thermal stability of the composites were investigated. The results show that Cu-Al2O3 composites were fabricated successfully by the simplified process in which internal oxidation completed during the sintering. There are a mass of fine Al2O3 particles in size varying from 5 nm to 20nm dispersed in copper matrix after sintering 950 for 4h. After sintered at 950 for 4h and extruded at 950 followed with the cold deforming of 80%, the electrical conductivity, hardness, tensile strength and softening temperature of composite reach 81％IACS, 137HV, 561MPa and 850 respectively. It is considered that the dispersion strengthening and strain hardening have greatly contribution to the Cu-Al2O3 composites fabricated with the simplified process.