Comparison of MATLAB and GA optimization for three-dimensional pattern synthesis of circular arc arrays

2004 ◽  
Author(s):  
A. Erentok ◽  
K.L. Melde
Keyword(s):  
Three Dimensional ◽  
Pattern Synthesis ◽  
Circular Arc

A fast, two-point, three-dimensional raytracing algorithm using a simple step search method

1988 ◽  
Vol 78 (3) ◽  
pp. 1190-1198 ◽  
Author(s):  
W. A. Prothero ◽  
W. J. Taylor ◽  
J. A. Eickemeyer
Keyword(s):  
Simplex Method ◽  
Velocity Structure ◽  
Three Dimensional ◽  
Computer Time ◽  
Sine Wave ◽  
Search Method ◽  
Minimum Time ◽  
Circular Arc ◽  
Path Distance ◽  
Simple Step

Abstract The simplex method of function minimization is used to find the ray that follows the path of minimum time through an arbitrary three-dimensionally varying medium. The advantage of this method is that it is extremely fast, always converges, and lends itself to a variety of velocity parameterizations. The first step in the algorithm is to find the minimum time circular arc path between the source and receiver using an exhaustive search method. Then perturbations, consisting of a sum of N sine wave harmonics with their zero crossings at the endpoints, are made to the circular arc path. The simplex method searches for the amplitude coefficients that produce the path of least time. On a VAX-750 running the VMS operating system, the first arriving ray for a station receiver distance of 96 km is computed to an accuracy of 0.02 sec, computed in a southern California velocity structure using less than 26 sec of computer time. The required computer time decreases as the ray path distance decreases.

Study on Virtual Simulation Machining of Double Circular Arc Profile Spiral Bevel Gear

2009 ◽  
Vol 16-19 ◽  
pp. 1253-1257 ◽  
Author(s):  
Rui Liang Zhang ◽  
Ming Lv ◽  
Tie Wang ◽  
Hong Yuan Li
Keyword(s):  
Three Dimensional ◽  
Bevel Gear ◽  
Virtual Simulation ◽  
Spiral Bevel Gear ◽  
Circular Arc ◽  
Meshing Equation ◽  
Gear Geometry ◽  
Spiral Bevel ◽  
Movement Parameters ◽  
Cutter Head

Following spatial mesh principle, the gear cutting meshing equation was established in the paper through analyzing the relation between the machining principle of the double circular arc profile spiral bevel gear and the movement of the machine tool. The parameters of cutter head and the machine tool’s movement were then obtained through the equation. VERICUT was applied to build the three-dimensional virtual simulation machining model by which the gear geometry parameters, cutter parameters and machining tool movement parameters were calculated for a given gear to be processed and virtual simulation machining proceeded to prove the validity of the model.

scholarly journals Radiation of a Circular Arc Source in a Limited Angle for Non-uniform Conformal Arrays

2020 ◽  
Author(s):  
Giovanni Leone ◽  
Fortuna Munno ◽  
Rocco Pierri
Keyword(s):  
Inverse Problem ◽  
Degrees Of Freedom ◽  
Angular Width ◽  
Pattern Synthesis ◽  
Circular Arc ◽  
Conformal Antennas ◽  
Radiation Properties ◽  
Near Zone ◽  
Conformal Arrays

Conformal antennas lack of general analysis methods of their radiation properties. For a circumference source, we examine the role of the angular width of the observation domain both in far and near zone in determining the set of radiated fields. By an inverse problem approach, the evaluation of the number of independent pieces of information, i.e. the number of degrees of freedom (NDF), and the analysis of the reconstructions of point-like sources allow to introduce optimal array configurations. The results are relevant to the radiation pattern synthesis problem and to array diagnostics applications.

Research of Advancing Mechanism with Three Circular Arc Equidistant Profile Connection of Drill

2011 ◽  
Vol 179-180 ◽  
pp. 895-898
Author(s):  
You Xin Luo ◽  
Heng Shu Li ◽  
Hui Jun Wen ◽  
Yu Zhou
Keyword(s):  
Stress Concentration ◽  
Three Dimensional ◽  
Circular Arc ◽  
Three Dimensional Modeling ◽  
Rock Drill ◽  
Dimensional Modeling ◽  
Intermediate Shaft ◽  
New Type ◽  
Loaded Rock ◽  
The Common

Study the existing advancing mechanism of drill, analyze the disadvantage of the flat key and the spline, and the feature of the three circular arc equidistant profile connection. Taking the common chain advancing mechanism as basis, using three circular arc equidistant curve to make sprocket bore and intermediate shaft external cylindrical fit constitute the three circular arc equidistant profile keyless connection. Then introduce the advancing mechanism with three circular arc equidistant profile connection of drill. Applying Solidworks2010, we created the three-dimensional modeling of the mechanism, which lay the foundation for the further research and application. The new type advancing mechanism has many advantages, such as automatic-centering accurately, convenient in assembling and disassembling, eliminating the stress concentration, simplicity of the fit section，transferring bigger torque, suitable for heavy-loaded rock drill machine.

scholarly journals An Improved Pattern Synthesis Iterative Method in Planar Arrays for Obtaining Efficient Footprints with Arbitrary Boundaries

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2358
Author(s):  
Aarón Ángel Salas-Sánchez ◽  
Cibrán López-Álvarez ◽  
Juan Antonio Rodríguez-González ◽  
María Elena López-Martín ◽  
Francisco José Ares-Pena
Keyword(s):  
Dynamic Range ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Test Cases ◽  
Pattern Synthesis ◽  
Maximum Order ◽  
Space Applications ◽  
Planar Arrays ◽  
Aperture Distribution

In the present paper, an iterative technique devoted to reproducing efficient footprints with arbitrary boundaries for planar arrays is addressed. The methodology here depicted is based on exploiting the nature of the continuous aperture distribution by expressing it as a Fourier series of moderately high orders. In this manner, the resulting illumination boundary is defined by a target three-dimensional flat-topped pattern composed of stretching and shrinking modified circular Taylor patterns and the maximum order of the series to obtain a good reconstruction is determined by means of the iterative process. Examples and comparisons with the previous literature were conducted by analyzing square and rectangular contoured beams as test cases. Additionally, interesting potentials regarding space applications from a geostationary satellite are outlined by means of the EuTELSAT (European Telecommunications Satellite Organization) European coverage case study. In such a way, its numerical approach was analyzed by including subarray architectures and discussing improvements about dynamic range ratio of the excitations without critical power losses within the illumination region.

scholarly journals Radiation of a Circular Arc Source in a Limited Angle for Non-uniform Conformal Arrays

2020 ◽  
Author(s):  
Giovanni Leone ◽  
Fortuna Munno ◽  
Rocco Pierri
Keyword(s):  
Inverse Problem ◽  
Degrees Of Freedom ◽  
Angular Width ◽  
Pattern Synthesis ◽  
Circular Arc ◽  
Conformal Antennas ◽  
Radiation Properties ◽  
Near Zone ◽  
Conformal Arrays

Conformal antennas lack of general analysis methods of their radiation properties. For a circumference source, we examine the role of the angular width of the observation domain both in far and near zone in determining the set of radiated fields. By an inverse problem approach, the evaluation of the number of independent pieces of information, i.e. the number of degrees of freedom (NDF), and the analysis of the reconstructions of point-like sources allow to introduce optimal array configurations. The results are relevant to the radiation pattern synthesis problem and to array diagnostics applications.

Mathematical Model to Describe Double Circular Arc and Multiple Circular Arc Compressor Blading Profiles

2021 ◽  
Author(s):  
John Kidikian ◽  
Chelesty Badrieh ◽  
Marcelo Reggio
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Circular Arc ◽  
Engineering Software ◽  
Through Flow ◽  
Compressor Design ◽  
Design Software ◽  
Cartesian Coordinate ◽  
The One

Abstract For the past seven decades, a compressor aerodynamicist has developed various methodologies to design, analyze, and simulate compressor stages. In compressor design, three major subsequent steps can be identified: the one-dimensional mean-line methodology, the two-dimensional through-flow analysis, and the three dimensional computational fluid dynamics. One of the interconnecting threads, between these various x-dimensional analysis, is the compressor blade profile shape. This shape, of known and controllable geometric parameters, is usually accompanied by, or related to, loss models and known flow physics, either defined by theory or through experimental test. In this paper, a novel mathematical approach is described to define axial compressor airfoil profile shapes. These shapes, developed in a Cartesian coordinate system, can be used to create Double Circular Arc, Multiple Circular Arc, and a hybrid combination of the two types. The proposed methodology, based on the mathematics of circles, can be easily applied using generalized software such as Python or MATLAB, or be embedded in specialized engineering design software. In doing so, researchers and engineers can create compressor airfoil shapes which are consistent and flexible with respect to geometric parameter manipulation. Full details of the formulas, with respect to the camber line definition and the calculation of the profile intrados and extrados, are presented. A URL link to an equivalent MATLAB code, and a specialized engineering software, has been provided for those researchers that wish to apply the formulations and review its use.

The Three-Dimensional Aerodynamic Design and Test of a Three-Stage Transonic Compressor

1999 ◽  
Author(s):  
Y. S. Li ◽  
R. G. Wells
Keyword(s):  
Gas Turbines ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Design System ◽  
Test Results ◽  
Aerodynamic Design ◽  
Circular Arc ◽  
Transonic Compressor ◽  
Performance Improvements ◽  
Conventional Design

This paper presents the aerodynamic design and initial test results from a three-stage transonic compressor developed by ALSTOM Gas Turbines Ltd. The Advanced Transonic Compressor (ATC) was designed using a design system based on three-dimensional (3D) Navier-Stokes CFD codes in contrast to the more conventional design approach centred around the use of throughflow and blade to blade solvers. The customised 3D multiple-circular-arc (MCA) and controlled-diffusion (CD) airfoils have replaced the double-circular-arc (DCA) profiles used previously. The use of both single row and multistage 3D CFD codes has enabled the potential performance improvements from the application of new blade designs to be predicted and comparisons between conventional and new blades to be made. Rig test results have confirmed that the target design mass flow rate and pressure ratio have been successfully achieved in the first build with a design point efficiency higher than that possible from the conventional design. Tests have demonstrated that the compressor has the required surge margin at design and off design speeds to ensure satisfactory operation when transferred to the multistage compressor environment.

Modeling Micro-Scaffold-Based Implants for Bone Tissue Engineering

2008 ◽  
Author(s):  
Y. Holdstein ◽  
A. Fischer
Keyword(s):  
Bone Tissue ◽  
Bone Structure ◽  
Three Dimensional ◽  
Bone Diseases ◽  
Structural Level ◽  
Micro Structure ◽  
Current Standard ◽  
Pattern Synthesis ◽  
Metabolic Bone Diseases ◽  
Micro Implants

Metabolic bone diseases are at the forefront of scientific and biomedical research worldwide. Diseases such as osteoporosis are characterized by increased bone fragility, which leads to micro-architectural deterioration of bone tissue and eventually to micro fractures. At the micro-structural level, bone is constructed from thin rods known as trabeculae and plates. These rods and plates are arranged in semi-regular, three-dimensional patterns and constitute highly anisotropic and heterogenic material. The bone micro-structure is stochastic in nature and varies according to patient, bone type and location within a specific bone. Diagnostic abilities rely on high technology and advanced methods for 3D micro scanning, modeling and analyzing the bone micro-structure. We propose a novel method for modeling scaffold-based implants that have the stochastic structure of bone and can be customized according to given bone structures. The method for designing these implants is based on a 3D pattern synthesis technique that can be applied to the diseased cavities of a given bone. The implants will replace these cavities in the cancellous bone. Recognizing these cavities is a difficult process, since such bone is characterized by a complex micro-structure composed of thin cylindrical rods and plates. Cavities with this 3D micro-structure will be identified by measuring the volumes of those cavities and comparing them to a specified threshold. The in-filling will be based on a 3D pattern growing scheme that takes the exerted forces into account so that the global directionality of the micro-structure is preserved. Furthermore, the goal is to optimize the topology according to mechanical rules. Due to the complexity of the problem, the approach is initially examined only for 2D medical images. The main contribution of this method is that the structure of the micro-implants will not be the current standard structure (cubes with holes), which lack the characteristics of a given bone structure. Moreover, this method can be used to design and manufacture customized micro-implants according to the specific stochastic micro-structure of a given bone. These customized designed implants can be manufactured using micro-RP technology.

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