Applied Mechanics and Materials Vols. 52-54

Abstract: An airport runway frictional coefficient measuring vehicle is the important ground support equipment which is essential to the aircraft safety of taking off and landing. The modeling method of the measuring vehicle affects the measure result directly. The bond-graph modeling method is used to model the hanging system and measuring system of the measuring vehicle, the surface roughness of the runway produced by power spectral density and the discrete Fourier inverse transformation is utilized as the input excitation. The validity of the system models is verified based on the simulation.

Abstract: The airport snow removal operation optimization and dispatch system based on the GPS/GIS/GPRS technology and breadth-first search algorithm is designed in this paper. The airport snow removal vehicle is positioned by GPS system. The information between the vehicle mobile termination and the control center is transmitted by GPRS communication system. The graphic display and safety warning of the airport snow removal vehicle is realized by the GIS technology. The Breadth-first search algorithm is adopted to optimize the scheduling of operation and dispatch the snow removal vehicle. As a result, the efficiency of snow removing work can be improved and the delayed time of the airport opening in snowy day can be decreased.

Abstract: This article reports an approach of light-weighted mirror design and analysis to increase the weight reduction ratio and improve optical performance based on the finite element method and opto-mechanical analysis. The approach is to represent mirror surface deformation derived from finite element analysis (FEA) by Zernike polynomials, such that the impact of deformation on optical system performance can be evaluated by the optical design and analysis program. The experimental modal analysis was also performed to validate the FEA results. The numerical result shows that the light-weighted primary mirror of Cassegrain telescope is obtained by this approach and predicted deformation fulfills the requirements of optical design.

Abstract: With the research object of cutterhead rotation electric drive system, influencing factors of the system synchronous coordination and the multi-motor torque synchronization control strategy is studied. The paper analyzes the dynamics of the cutterhead rotary motors-driving system, discusses the interaction mechanism between motors and gear nonlinear transmission unit, and then the mathematical model of the cutterhead rotary driving system with consideration of gear frequency cycle error and backlash is presented. Based on that, the multi-drive synchronization control based on the ring coupling strategy is given. Simulation results using Matlab platform show the effectiveness of the proposed strategy.

Abstract: A new approach to conceptual design based on path decomposition of digraph is presented in the paper. The set of basic mechanisms is firstly defined and every single mechanism is taken as a basic element in the set. The relationships among basic elements are described with paths or loops in the graph theory. Therefore, the conceptual design can be visualized as searching a suitable loop in the set of basic mechanisms. The digraph and the path decomposition in the graph theory are applied to represent solutions of conceptual design, such as the sequence, existence and the concatenation formation and repetition. And then, an illation formula is derived and a construction tree of conceptual design process is provided. The generated schemes are further filtered using character restriction operation which followed corresponding rules, so as to identify feasible solutions. Finally, a design example is given to demonstrate the effectiveness of the proposed approach.

Abstract: For principle of the particle system, using Visual C++ combining with the object-oriented technology and open graphic library method, the shapes of oil atomization under different voltages were simulated. By comparing the simulating images with the experimental pictures, charged oil atomization process was basically reflected by the simulated results, and it was correspondent with the experimental observation.

Abstract: The key to guarantee bending mold interchangeability is the precise detection of the cutting edge angle, symmetry and the distance from its center to the fitting surface of CNC bending mold. According to the features of the Key Dimension of the Bending Mold (KDBM), it is detected using a 3-DOF mechanical arm connected in series. The mechanical arm has a horizontal DOF, a vertical DOF, and a rotational freedom of the gauge head which is placed at the end of the mechanical arm. The Precision Detection Device (PDD) for KDBM that we have designed has high accuracy, good stability and rapid response.

Abstract: Micro powder injection molding (µPIM) is the combination of micro injection molding and powder injection molding (PIM) technology. The increasing demands on market of microparts further intensify the development of this technology. µPIM process enables the use of a wide range of materials and broadens the applications of micro components. This process is well suitable for large volume production of micro-components at low costs. Requirement of powder and binder is more stringent since product fabricate in micron scale, therefore criterion of the powder and binder has been reviewed in this paper. In addition, the process parameter and development in the computer aid plays an important due to the narrow process window requires even tighter as the quality of the micro-component is sensitive to the parameter. This paper outlines recent development in µPIM. Challenges and further explore for µPIM is concluded in the last part of this paper.

Abstract: Micro powder injection molding (µPIM) is a preferred technology for the production of micro parts or micro structured parts which derived from the well known thermoplastic injection molding technique. It is suitable for a large-scale production of ceramic and metallic parts without final machining. In the hardmetal industry, submicron and ultrafine hardmetals are the most demanding and also the fastest growing grades in production and application. Four stages involve in µPIM are mixing, injection, debinding and sintering. The volumetric ratio of solid powder to the total volume of powder and binder, which is usually called powder loading, largely determines the success or failure of subsequent processes. Critical solid loading of the powder can be estimated by torque variation, density, melt flow, density and viscosity versus composition. In this paper, critical solid loading of WC-10%Co is determined using torque variation method and its rheological behavior is studied. During the process, the wet surface of the powder particle WC-10%Co will cohesive together and resulted to the torque. Progressive powder is added-in after torque decrease and critical solid loading is identified when torque becomes unstable. Hence, critical solid loading WC-10%Co with WC (APS < 1 µm) is 46% and 42, 43 and 44 vol% of powder loading are selected to mix with wax-based binder system. The viscosity of feedstock show the pseudoplastic behavior and flow index (n) are 0.444, 0.491 and 0.492 for powder loading 42%, 43% and 44% respectively.

Abstract: Neural Networks are powerful data modeling tools that are capable of capturing and representing complex input/output relationships. The motivation for the development of neural network technology stemmed from the desire to develop an artificial system that could perform "intelligent" tasks similar to those performed by the human brain. Using artificial neural network in approximating of complex data is one of easy way to save time and cost. Ultrasonic vibrations can be applied on the die during the extrusion process. Numerical and experimental analyses have been already performed in the literature on the application of ultrasonic vibrations on the wire drawing, deep drawing, upsetting and rolling processes. No attempts have been made to investigate on the effects of ultrasonic vibrations on the forward extrusion process, yet. A detailed analysis and understanding of the mechanism of improvement is not possible on the basis of conventional experimental observations because ultrasonic vibration processing phenomenon occur at high speeds. Hence, in order to progress the perceptive of the mechanism of ultrasonic vibration extrusion, the finite element analysis was performed by using the explicit analysis procedure. The proposed approach builds on a comprehensive Neuro-Finite Element simulation of the effects of ultrasonic vibration on the forward extrusion. Then use the resulting data to train a Multi-Layer Perceptron (MLP) Neural Network which would predict –accurately enough- those quantities throughout the speeds, vibration amplitudes and frequencies, friction factors and reductions body for any given input vector. The resulting neural simulator is intended to replace the computationally expensive cost-function evaluators that are traditionally used in numerical optimization algorithms. To demonstrate the applicability of the proposed approach, we examine data from FEM as from training with together ultrasonic vibration using the constructed neural simulator and present the results.