scholarly journals Cavitator Design for Straight-Running Supercavitating Torpedoes

2021 ◽  
Vol 11 (14) ◽  
pp. 6247
Author(s):  
Min-Jae Kim ◽  
Seon-Hong Kim ◽  
Kurn-Chul Lee ◽  
Bu-Geun Paik ◽  
Moon-Chan Kim
Keyword(s):  
Mathematical Models ◽  
Design Method ◽  
Design Procedure ◽  
Hydrodynamic Forces ◽  
Small Scale ◽  
Total Drag ◽  
Level Flight ◽  
Supercavitating Vehicle ◽  
Maximum Range ◽  
Design Requirements

A practical cavitator design method for straight-running-type supercavitating torpedoes was developed in this paper. Design requirements were first drawn in terms of torpedo performance characteristics, such as maximum range and motion stability. This method determines the optimum cavitator satisfying the design requirements that not only minimize the total drag of the torpedo, extending the maximum range, but also provide hydrodynamic forces required for straight level flight. The design procedure includes determining a design cavitation number and cavitator type (disk or cone) for obtaining the optimal cavitator that minimizes the total drag of a torpedo in straight level flight. To determine such an optimal cavitator, the equations of force and moment equilibrium for straight level flight were iteratively solved by the existing mathematical models that determine the cavity shapes generated by disk- and cone-shaped cavitators and hydrodynamic forces acting on the vehicle. For validation, model experiments on a small-scale supercavitating vehicle were conducted in a towing tank, and the results agree well with those of the mathematical models used in this study. A preliminary design based on the newly proposed method was also implemented for a realistic supercavitating vehicle. More precise computations using CFD should be conducted to investigate the physics in more detail in the near future.

AN INDEPENDENT ACTIVE BALANCER FOR PLANAR MECHANISMS

2007 ◽  
Vol 31 (2) ◽  
pp. 167-190 ◽  
Author(s):  
Zhang Ying ◽  
Yao Yan-An ◽  
Cha Jian-Zhong
Keyword(s):  
Working Conditions ◽  
Design Method ◽  
Design Procedure ◽  
Vibration Absorber ◽  
Planar Mechanisms ◽  
Dynamic Balancing ◽  
Joint Coupling ◽  
Design Requirements ◽  
Novel Concept ◽  
Two Degree Of Freedom

This paper proposed a novel concept of active balancer for dynamic balancing of planar mechanisms. Somewhat similar to a vibration absorber, the active balancer is designed as an independent device, which is placed outside of the mechanism to be balanced and can be installed easily. It consists of a two degree-of-freedom (DOF) linkage with two input shafts, one of which is connected to the output shaft of the mechanism to be balanced by a joint coupling, and the other one is driven by a controllable motor. Flexible dynamic balancing adapted to different working conditions can be achieved by varying speed trajectories of the control motor actively. A design method is developed for selecting suitable speed trajectories and link parameters of the two DOF linkage of the balancer to meet various design requirements and constraints. Numerical examples are given to demonstrate the design procedure and to verify the feasibility of the proposed concept.

Design of an Experimental Setup for Testing Multiphysical Effects on High Speed Mini Rotors

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Emre Dikmen ◽  
Peter J. M. van der Hoogt ◽  
André de Boer ◽  
Ronald G. K. M. Aarts ◽  
Ben Jonker
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Rotation Speed ◽  
Design Procedure ◽  
Background Information ◽  
Small Scale ◽  
Experimental Setup ◽  
Research Projects ◽  
Design Decisions ◽  
Design Requirements

Recently, there have been numerous research projects on the development of minirotating machines. These machines mostly operate at speeds above the first critical speed and have special levitation systems. Besides, the multiphysical effects become significant in small scale. Therefore, advanced modeling approaches should be developed and innovative experimental rigs with the foregoing requirements should be constructed in order to test the developed techniques. In the current study, the design of an experimental setup for testing the multiphysical effects has been outlined. First, the previously developed multiphysical models (Dikmen, E., van der Hoogt, P., de Boer, A., and Aarts, R., 2010, “Influence of Multiphysical Effects on the Dynamics of High Speed Minirotors—Part I: Theory,” J. Vibr. Acoust., 132, p. 031010; Dikmen, E., van der Hoogt, P., de Boer, A., and Aarts, R., 2010, “Influence of Multiphysical Effects on the Dynamics of High Speed Minirotors—Part II: Results,” J. Vibr. Acoust., 132, p. 031011) for the analysis of small scale rotors are described briefly for background information. Second, an analysis of the effect of the rotor parameters (diameter, length, rotation speed, etc.) on the dynamics of the rotor under multiphysical effects is presented. Afterward the design process which includes the design decisions based on these results, the availability, simplicity, and applicability of each component is presented in detail. Finally, the experimental results have been presented and the efficiency of the design has been evaluated. In summary, the design requirements for an experimental setup for testing multiphysical effects on minirotors have been analyzed. The design procedure and evaluation of the design have been presented.

An optimum synthesis for gripping mechanisms by using natural coordinates

2002 ◽  
Vol 216 (6) ◽  
pp. 643-653 ◽  
Author(s):  
M Ceccarelli ◽  
J Cuadrado ◽  
D Dopico
Keyword(s):  
Design Problem ◽  
Optimization Design ◽  
Design Method ◽  
Design Procedure ◽  
Natural Coordinates ◽  
Dimensional Synthesis ◽  
Efficient Procedure ◽  
Optimum Synthesis ◽  
Practical Design ◽  
Design Requirements

In this paper a simple and efficient procedure for optimum dimensional synthesis of gripping mechanisms is presented. The proposed design method is based on a suitable formulation of grasping performance of gripping mechanisms and makes use of a description of mechanisms by means of natural (fully Cartesian) coordinates. The optimization design problem is formulated by an objective function describing the main grasping performance and constraints prescribing practical design requirements and mechanism peculiarities. A numerical example is reported and discussed to illustrate the engineering feasibility of the proposed design procedure.

Integrated Design Methodology for High-Precision/Speed Servomechanisms

2005 ◽  
Vol 219 (8) ◽  
pp. 843-852 ◽  
Author(s):  
M-S Kim ◽  
S-C Chung
Keyword(s):  
High Precision ◽  
Design Method ◽  
Integrated Design ◽  
Design Procedure ◽  
Optimization Method ◽  
Design Variables ◽  
Mechanical Subsystem ◽  
Speed Performance ◽  
Parametric Studies ◽  
Design Requirements

An integrated design method for a high-precision/speed servomechanism including interactions of mechanical and electrical subsystems is proposed in this article. On the basis of the multiobjective optimization method, a non-linear optimal design procedure of the mechanical subsystem is performed simultaneously through the design process of the electrical subsystem satisfying the desired performance. Mechanical and electrical constraints have been formulated according to design requirements. Both mechanical and electrical parameters are considered as design variables. Validity of the integrated design problem is verified on the different application areas. Parametric studies of the design variables have also been conducted in this article. Case studies show that the integrated design method for an x-y positioning system satisfies the desired high-precision/speed performance.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

scholarly journals Novel Robust Design Method of Multilayer Optical Coatings

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suyong Wu ◽  
Xingwu Long ◽  
Kaiyong Yang
Keyword(s):  
Robust Design ◽  
Optimization Design ◽  
Design Method ◽  
Analytical Calculation ◽  
Design Procedure ◽  
Deposition Process ◽  
Practical Significance ◽  
Optical Coatings ◽  
Optical Films ◽  
Robust Design Method

We present a novel fast robust design method of multilayer optical coatings. The sensitivity of optical films to production errors is controlled in the whole optimization design procedure. We derive an analytical calculation model for fast robust design of multilayer optical coatings. We demonstrate its effectiveness by successful application of the robust design method to a neutral beam splitter. It is showed that the novel robust design method owns an inherent fast computation characteristic and the designed film is insensitive to the monitoring thickness errors in deposition process. This method is especially of practical significance to improve the mass production yields and repetitive production of high-quality optical coatings.

Research on the Conformal Phased-Array Antenna

2014 ◽  
Vol 685 ◽  
pp. 324-327
Author(s):  
Shuang Zhao ◽  
Yu Bo Yue
Keyword(s):  
Mathematical Model ◽  
Antenna Array ◽  
Phased Array ◽  
Design Method ◽  
Array Antenna ◽  
Phased Array Antenna ◽  
Conformal Antenna ◽  
Conformal Array ◽  
Design Requirements ◽  
The Mathematical Model

The mathematical model of conformal antenna array is the premise and basis of the conformal array antenna signal processing. Based on the analysis of the antenna array, a design method for adjusting the direction of the conformal array antenna is proposed. Through simulation, the pattern of antenna meets the actual needs of the project and it reaches pre design requirements.

Durability design of composite bridges with given life in seasonal freezing region

2021 ◽  
Author(s):  
Xuefei Shi ◽  
Qi Xu
Keyword(s):  
Service Life ◽  
Life Cycle Cost ◽  
Mechanical Performance ◽  
Design Method ◽  
Protective Layer ◽  
Highway Bridges ◽  
Seasonal Freezing ◽  
Durability Design ◽  
Composite Bridges ◽  
Design Requirements

<p>Steel-concrete composite bridges are currently widely used in highway bridges in China. To reduce durability problems in seasonal freezing region, a design method with given service life is used. The service life is given on the basis of the environment condition and design requirements; then the structural design and safety analysis are carried out, and the durability design and analysis of the structural components are conducted. With the consideration of the mechanical performance, construction convenience and life-cycle cost, the structural scheme for bridges using twin-I girders, cross beams and precast full-width deck is recommended. Weather resistant steel is recommended to be used in nonmarine seasonal freezing regions with stabilization treatment, waterproof and drainage design, local anti-corrosion coating. Finally, a design process considering material, protective layer thickness and construction control is proposed to improve concrete deck durability.</p>

Multi Mode Vibration Control and Broder Band Motion Control of Three Dimensional Shaking Table

2005 ◽  
Author(s):  
Tsunehiro Wakasugi ◽  
Toru Watanabe ◽  
Kazuto Seto
Keyword(s):  
Vibration Control ◽  
Controller Design ◽  
Design Method ◽  
Three Dimensional ◽  
Design Procedure ◽  
Equation System ◽  
State Equation ◽  
Shaking Table ◽  
Mode Vibration ◽  
And Control

This paper deals with a new system design method for motion and vibration control of a three-dimensional flexible shaking table. An integrated modeling and controller design procedure for flexible shaking table system is presented. An experimental three-dimensional shaking table is built. “Reduced-Order Physical Model” procedure is adopted. A state equation system model is composed and a feedback controller is designed by applying LQI control law to achieve simultaneous motion and vibration control. Adding a feedforward, two-degree-of-freedom control system is designed. Computer simulations and control experiments are carried out and the effectiveness of the presented procedure is investigated. The robustness of the system is also investigated.

scholarly journals Semi-Inverse Design of Compressor Cascades, Including Supersonic Inflow

1990 ◽  
Author(s):  
A. Kirschner ◽  
H. Stoff
Keyword(s):  
Flow Field ◽  
Design Method ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Design Procedure ◽  
Meridional Plane ◽  
Simple Method ◽  
Blade Loading ◽  
Through Flow ◽  
Blade Element

A cascade design-method is presented which complements the meridional through-flow design procedure of turbomachines. Starting from an axisymmetric flow field and the streamline geometry in the meridional plane this simple method produces a solution for the quasi three-dimensional flow field and the blade-element geometry on corresponding stream surfaces. In addition, it provides intra-blade data on loss and turning required for a consistent design and a convenient means of optimizing blade loading. The purpose of this paper is to describe the theoretical basis of the method and to illustrate its application in the design of transonic compressors.

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