Advanced Materials Research Vols. 308-310

Abstract: Wavelet analysis, as a new kind of time-frequency representation technique, has made great progress recently and been applied widely in different engineering practice. To solve the problem of full-wave Fourier algorithm which is disable to filter decaying DC component and has worse frequency characteristic, it is presented an improved algorithm depending on the combination of subtraction filter and full-wave Morlet complex wavelet, to get out the fundamental wave amplitude of the current in the distribution line, by studying each parameter’s influence on the performances of Morlet complex wavelet algorithm. It can filter decaying DC component efficiently and has better frequency characteristic.

Abstract: Knowledge management plays an important role in the management and control of product quality. In order to improve the efficiency of knowledge utilization in the product processing and study the knowledge flow with consideration of knowledge providers, a new method based on social network analysis is proposed in this work. Considering the social background of the different knowledge providers, the center degree of each provider could be obtained. With this value of center degree, the position of different kinds of knowledge could be calculated as well. Meanwhile, the use of correlation analysis software could help to optimize the tactic of task. Thus, on the one hand, the using and the flow efficiency of the knowledge in the product processing can be optimized more comprehensively, and on the other hand the management and control process of the product quality could be greatly improved.

Abstract: The design characteristic and effect of DMU (Digital Mock-Up) are simply introduced. According as the design characteristic of complex product, the request for DMU platform in product life cycle is analyzed, and function analysis of DMU platform is finished. The whole frame and logic configuration are illuminated based function analysis, the realization method of design validation and optimization, design cooperation, maintenance support are emphatically analyzed, and some applied examples of DMU are displayed. The future imperative studies for DMU are discussed based the developed work and existent problem.

Abstract: This paper includes some conceptions of symmetrical cryptology such as ” Liner Feed Back Shift Register”(LFSR) and RC5 arithmetic. The paper also introduces the application of symmetrical cryptology in encryption system designing.

Abstract: By numerical simulation computation, after passing the pulsating flow, enhanced heat transfer mechanism in spirally fluted tubes was researched. Numerical result shows that pulsating flow can cause the outlet pressure to fluctuate cyclical and the extent of fluctuation increases with the pulsating flow frequency. The pulse flowing can make the fluid generate the whirlpool nearby the spirally fluted tubes and the phenomenon of periodic production, drift, and fall-off appears. Because of the vortex, the fluid motion and relative motion are enhanced. The pulse flowing can improve the coordination level between velocity and temperature, thus has strengthened the heat transfer effect.

Abstract: Compared with sewing machine driven by traditional match motor, industry sewing machine driven by AH20 motor have economy energy, intelligent degree, install convenience, operation simple and ability completely etc. It has vast applied foreground and huge market potential. But the lifting up structure has problems of vibration and noises in use, and seriously obstructed the progress of its market expansion. The causes were found through theoretical calculation, modal analysis and experiment analysis, and the structure was improved. The experiment results confirmed the validity of the changes.

Abstract: Starting from second-order effect, the governing differential equation of a tapered beam considering effects of axial force and shear deformation is established, the exact element stiffness matrix of a tapered beam with effects of shear deformation is proposed, and whose inertia moment is quadratic along the longitudinal axis. When the effect of shear deformation is ignored, the proposed stiffness matrix will degenerate into the Bernoulli-Euler ones. By using of the presented stiffness matrix, the stability and nonlinear of structures which contain tapered elements can be analyzed. Finally, the stability of some typical structures are analyzed in the numerical examples, the results prove that when the slenderness ratio is small, the effect of shear deformation can’t be neglected; As increasing, the results of beam considering shear-deflection are close to Bernoulli-Euler ones’.

Abstract: In this paper, the dynamic stability of stepped columns under the axial resonant force is investigated, and the dynamic stability, which is also known as parametric resonance, of stepped columns with two ends simply supported and clamped ones are studied, respectively. The dynamic stability of multi-stepped columns is obtained by using Mathieu Equation deduced by Hamiliton Principle. The formula of the dynamic stability region is given and the effect of stiffness of stepped columns on the dynamic stability is analyzed. Results show that the area of dynamic instability decreases with the increase of the ratio of each section’s stiffness, and that the dynamic stability would be better when each section is of similar size.

Abstract: This paper discusses the subject that including the dynamic compensation of finger force sensor researching, the dynamic compensation based on the FLANN method and the dynamic compensator realization. This design mainly uses the operational amplifier to carry on dynamic compensation, its mathematical model is equivalent two step model to design dynamic compensator, which enhance the dynamic response characteristic of the fingertip sensor.

Abstract: CNC(Computer Numerical Control) machine tool is the foundation and core of modern manufacturing systems, advanced CNC technology is the key to sustainable development of machine tool manufacturing industry. This thesis presents ARM as the main chip, motion control chip MCX314, the operating system using μC / OS-II, to build a CNC system development hardware platform and software platform, to explore the new ways for numerical control system development and design. This thesis can be divided into: CNC system hardware platform structures, including ARM and external hardware selection, hardware interface design and testing; MCX314 hardware platform design and testing; Software Platform, including the use of real-time operating system μC / OS-II to achieve the mission of the NC system, scheduling, management, μC / OS-II transplantation on ARM; MCX314 hardware platform building and testing; application framework built , program design and testing. Test results showed that: ARM as the main chip, MCX314 as a motion controller of the CNC system is feasible, its motion performance can meet the design requirements.