Papers by Keyword: Geometric Model

Abstract: This paper aims to demonstrate how to model, mesh and simulate a hydraulic propeller turbine runner based on the geometrical specification of the runner blade. Modeling process is divided into preparation and implementation phase. Preparation phase illustrates how to develop stream surfaces and passages, how to create and transform meanline and how to create an rtzt file. The profile in rtzt file has a certain fix thickness which has to be altered later. Implementation phase describes operations necessary in creating a propeller runner model in ANSYS BladeGen which consist of importing rtzt file, modifying the trailing edge properties and altering profile thickness distribution to that of 4 digits NACA airfoil standard. Grid is generated in ANSYS TurboGrid utilizing ATM Optimized topology. CFD simulation is done using the ANSYS Fluent with pressure inlet and pressure outlet boundary conditions and k-ε turbulence model. Hydraulic efficiency of the runner is calculated utilizing Turbo Topology module in ANSYS Fluent. The authors will share the advantages that may be obtained by using ANSYS BladeGen compared with the use of general CAD Systems.

Abstract: The paper presents the process of building and testing a geometric and kinematic model of a five-axis machining center, which can be used for accurate cutting processes simulation of complex parts. After building the model, it was be tested by simulating the machining process of a hip joint prosthetic device. The prosthetic device was chosen because of its complex shape and because it was obtained by a 3D scanning process, which means that the part was reconstructed using meshes, instead of surfaces, which makes the toolpath control more difficult.

Abstract: Existed in the work of wireless positioning error, the need to suppress NLOS (Non line of sight) transmission problem of positioning the bad influence of the NLOS system model is put forward and the novel geometric positioning model, the introduction of appropriate NLOS channels model to suppress NLOS error, and make full use of the propagation characteristics of derived meet MS (Mobile Station) coordinates equation, with two NLOS paths can only calculate the position of MS, and using only a single base Station can complete the MS positioning, overcome the base Station number too little to pinpoint the flaws of the MS. This paper also gives a method of least squares and maximum likelihood algorithm, using the NLOS paths to improve the positioning accuracy. So as to realize the movement of the MS in NLOS environment position tracking. Through the theoretical analysis and computer simulation analysis, the results show that the positioning method in NLOS environment on the effectiveness and accuracy of the MS positioning.

Abstract: For complex structure of the product parts, we can have the aid of ICT measurement equipment to obtain the product slice images, use the analytical calculation, digital image-processing and CAD software to establish the product geometric model. This paper focused on the digital product model which was obtained by the digital image processing of ICT slices. Used the FDK reconstruction algorithm to deal with the tapered beam of counter projection problem, improved the efficiency and shorten the reconstruction time.

Abstract: This paper outlined the basic working principle of flip-flow Screen and and then established the screen surface kinetic equation of simplified geometric model. The midpoint motion law of the flip-flow Screen surface, the screen surface-particle trajectory and the inclination of the particle trajectory were studied. The characteristic curve made by Matlab showed unique dynamic characteristics of the screen surface, which provided a theoretical basis for its design and application.

Abstract: At present, CAD/CAM technology is applied in many areas, and machinery manufacturing was one of these areas in which CAD/CAM technology is the first and most widely used. With the development of CAD/CAM technology, CAD/CAM technology has become a key technology to improve the design and manufacturing standards, and enhance the competitiveness of the industry. In this paper, the concept of point-based geometric models used in CAD/CAM is proposed, the definition of the point-based geometric model and its CAD/CAM application process are suggested, and the geometric characteristics of the point-based geometric model and the CAD/CAM system development methodology are analysed.

Abstract: Displacement is one of the most important parameters of vane pump, but the physical meaning of the pumps’ displacement is relatively difficult to understand. A new approach is presented to simplify the calculation process. On the basis of analyzing the working principle of vane pumps, corresponding visual geometric models were separately built, and then the displacement of vane pump can be directly calculated by those models. This method is applicable not only to single-acting pump but to double-acting pump, it shows a novel vision and is easy to master.

Abstract: In order to obtain high-quality analytical results of the finite element model, it is essential to construct a three dimensional geometric model. The paper reconstructed an accurate three dimensional geometric model of cervical spine segments (C4-C7). The process of reconstruction included three-dimensional reconstruction, smooth processing, contour generation, grid generation and fitting surface. Moreover, the result of reconstruction was evaluated ultimately. The model was validated to be smooth and reasonable, and could meet the requirements of finite element analysis. The method is not merely applied to reconstruct the geometric model of the cervical spine. It is a way to construct the model of the skeletal system of the human body.

Abstract: Modeling for complex spiral wire rope structures, on which the mechanical performances largely depend, are paramount to finite element analysis application. Three mathematical modeling thoughts were brought out to create the geometric models of wire rope strands. The first one was presented based on the centerline times of the helical structures, as the centerline times can be decreased through transitional coordinate system. For the second, the centerlines of the wire rope were formed by the helical movement of predefined point. In the third one, a local coordinate system which can be transformed into the world coordinate system by their relationship was employed. The above three ideas were implemented by different kinds of derivation. The geometric parameter equations were presented to express the accurate wire rope models. These approaches are beneficial for parametric modeling and analysis of wire rope strands.

Abstract: Aiming at the problem that thermal boundary resistance (TBR) has an effect on heat transportation of superconducting magnet when Superconducting Magnetic Energy Storage (SMES) is cooled directly, from perspective of numerical calculation, truncated cone, circular arc and triangular models are used to simulate the solid to solid contact surface, and finite element method is adopted to carry on numerical simulation calculation for thermal boundary resistance. With comparison and analysis of the calculation results of the three models, knowing that the value calculated with the triangular model when its control angle is 30° is close to the measured value and its relative error is 17%. Meanwhile, the error source is analyzed. This dissertation can be a good reference to the research on superconducting magnet heat transportation.