Theoretical and Experimental Investigation of an Externally Pressurized Porous Annular Thrust Gas Bearing and Its Optimal Design

1997 ◽  
Vol 119 (3) ◽  
pp. 486-492 ◽  
Author(s):  
Changzhi Cui ◽  
Kyosuke Ono
Keyword(s):  
Experimental Investigation ◽  
Surface Layer ◽  
Optimal Design ◽  
Design Method ◽  
Dynamic Stiffness ◽  
Damping Ratio ◽  
The Body ◽  
Design Parameters ◽  
Darcy Model ◽  
Gas Bearing

Static and dynamic characteristics of an externally pressurized porous annular thrust gas bearing (PATGB), which has a thin restricted surface layer, are investigated by numerical analysis and experiment. In the analysis, it is assumed that the fluid flow obeys Darcy’s law in the porous material, restricted with Darcy’s restrictor (Darcy-Darcy model) or orifice restrictor (Darcy-Orifice model) in the surface layer. From experimental investigation, it is found that the theoretical results calculated by the Darcy-Darcy model agree with the experimental data better than those of the Darcy-Orifice model. Based on the Darcy-Darcy model, the unique relationships among the design parameters, which can provide the maximum damping ratio, were derived as functions of feeding parameter under the conditions of allowable static stiffness and the local minimum dynamic stiffness. Considering the dimensionless mass of the body supported by the bearing, an optimal design method is proposed to maximize the damping ratio at the natural frequency, while maintaining the required stiffness in the low frequency region.

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.

Development of High-Speed Response Electromagnetic Linear Actuator Using for Pneumatic Control Valve

2014 ◽  
Vol 532 ◽  
pp. 41-45 ◽  
Author(s):  
Myung Jin Chung
Keyword(s):  
Optimal Design ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Control Valve ◽  
Design Parameters ◽  
Linear Actuator ◽  
Analytic Model ◽  
Electromagnetic Linear Actuator ◽  
Quadratic Programming Method

Analytic model of electromagnetic linear actuator in the function of electric and geometric parameters is proposed and the effects of the design parameters on the dynamic characteristics are analyzed. To improve the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design method aims to minimize the response time and maximize force efficiency. By this procedure, electromagnetic linear actuator having high-speed characteristics is developed.

An Optimal Design Method for Artificial Neural Networks by Using the Design of Experiments

2007 ◽  
Vol 11 (6) ◽  
pp. 593-599 ◽  
Author(s):  
Eiichi Inohira ◽  
◽  
Hirokazu Yokoi
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Optimal Design ◽  
Design Method ◽  
Feedforward Neural Networks ◽  
Learning Rate ◽  
Design Parameters ◽  
Approximation Accuracy ◽  
Artificial Neural ◽  
Trained Neural Network

This paper presents a method to optimally design artificial neural networks with many design parameters using the Design of Experiment (DOE), whose features are efficient experiments using an orthogonal array and quantitative analysis by analysis of variance. Neural networks can approximate arbitrary nonlinear functions. The accuracy of a trained neural network at a certain number of learning cycles depends on both weights and biases and its structure and learning rate. Design methods such as trial-and-error, brute-force approaches, network construction, and pruning, cannot deal with many design parameters such as the number of elements in a layer and a learning rate. Our design method realizes efficient optimization using DOE, and obtains confidence of optimal design through statistical analysis even though trained neural networks very due to randomness in initial weights. We apply our design method three-layer and five-layer feedforward neural networks in a preliminary study and show that approximation accuracy of multilayer neural networks is increased by picking up many more parameters.

scholarly journals Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object

2016 ◽  
Vol 41 (1) ◽  
pp. 119-131 ◽  
Author(s):  
Min-Chie Chiu ◽  
Ying-Chun Chang ◽  
Long-Jyi Yeh ◽  
Chiu-Hung Chung
Keyword(s):  
Optimal Design ◽  
Energy Harvester ◽  
Damping Ratio ◽  
Electrical Power ◽  
Electromagnetic Energy ◽  
Design Parameters ◽  
Helical Springs ◽  
Spring Wire ◽  
Excitation Period ◽  
Mass Spring

Abstract The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.

Optimal Design for Broadband Dynamic Damper

2012 ◽  
Vol 490-495 ◽  
pp. 2723-2727
Author(s):  
Yan Ting Ai ◽  
Jing Tian ◽  
Qi Fu ◽  
Feng Ling Zhang
Keyword(s):  
Genetic Algorithm ◽  
Optimal Design ◽  
Frequency Ratio ◽  
Design Method ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Linear Dynamic ◽  
Dynamic Absorber ◽  
Optimal Design Method ◽  
Definition Of

This paper presents a new optimal design method based on genetic algorithm（GA）for broadband linear dynamic absorber. A New definition of the suppression bandwidth is described firstly. Then the method and procedure to optimize multi-parameters of broadband dynamic absorber is proposed. Effects of the natural frequency ratio, excitation frequency ratio, mass ratio, main system damping ratio and absorber ratio on the suppression bandwidth are discussed systematically. Finally the merits of genetic algorithm used for broadband linear dynamic absorber design are illustrated by contrasting it to a numerical method.

Optimal Design of Vibration Absorber Systems Supported by Elastic Base

1992 ◽  
Vol 114 (2) ◽  
pp. 280-283
Author(s):  
H. Ashrafiuon
Keyword(s):  
Optimal Design ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Elastic Base ◽  
Design Parameters ◽  
Primary System ◽  
Vibration Absorbers ◽  
Equivalent Damping ◽  
System Equations ◽  
Flexible Models

This paper presents the effect of foundation flexibility on the optimum design of vibration absorbers. Flexibility of the base is incorporated into the absorber system equations of motion through an equivalent damping ratio and stiffness value in the direction of motion at the connection point. The optimum values of the uncoupled natural frequency and damping ratio of the absorber are determined over a range of excitation frequencies and the primary system damping ratio. Optimal design parameters are computed and compared for the rigid, and flexible models of the base as well as different levels of base flexibility.

scholarly journals Research of the Process of Surface Tillage Using Innovative Rollers

2021 ◽  
pp. 9-13
Author(s):  
I.A. Sharonov ◽  
◽  
V.I. Kurdyumov ◽  
V.V. Kurushin ◽  
V.E. Proshkin ◽  
...  
Keyword(s):  
Surface Layer ◽  
Optimal Design ◽  
Spring Wheat ◽  
Economic Effect ◽  
Design Parameters ◽  
Operating Modes ◽  
Required Quality

Tillage rollers have been developed that provide the required quality of tillage of the surface layer of the soil during sowing. Their optimal design parameters and operating modes have been substantiated. The increase in yield was determined when using the developed tools in comparison with the serial ones. The annual economic effect was revealed, which amounted to 4,648 to 5,045 rubles per one hectare of spring wheat crops.

scholarly journals A Simulation-Based Multi-Objective Optimization Design Method for Pump-Driven Electro-Hydrostatic Actuators

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 274 ◽  
Author(s):  
Longxian Xue ◽  
Shuai Wu ◽  
Yuanzhi Xu ◽  
Dongli Ma
Keyword(s):  
Energy Consumption ◽  
Design Method ◽  
Dynamic Stiffness ◽  
Control Surface ◽  
Design Parameters ◽  
Design Phase ◽  
Multi Objective Optimization ◽  
Python Script ◽  
Multi Objective ◽  
Simulation Based

A pump-driven actuator, which usually called an electro-hydrostatic actuator (EHA), is widely used in aerospace and industrial applications. It is interesting to optimize both its static and dynamic performances, such as weight, energy consumption, rise time, and dynamic stiffness, in the design phase. It is difficult to decide the parameters, due to the high number of objectives to be taken into consideration simultaneously. This paper proposes a simulation-based multi-objective optimization (MOO) design method for EHA with AMESim and a python script The model of an EHA driving a flight control surface is carried out by AMESim. The python script generates design parameters by using an intelligent search method and transfers them to the AMESim model. Then, the script can run a simulation of the AMESim model with a pre-set motion and load scenario of the control surface. The python script can also obtain the results when the simulation is finished, which can then be used to evaluate performance as the objective of optimization. There are four objectives considered in the present study, which are weight, energy consumption, rise time, and dynamic stiffness. The weight is predicted by the scaling law, based on the design parameters. The performances of dynamic response energy efficiency and dynamic stiffness are obtained by the simulation model. A multi-objective particle swarm optimization (MOPSO) algorithm is applied to search for the parameter solutions at the Pareto-front of the desired objectives. The optimization results of an EHA, based on the proposed methodology, are demonstrated. The results are very useful for engineers, to help determine the design parameters of the actuator in the design phase. The proposed method and platform are valuable in system design and optimization.

Experimental Investigation on the Vortex-Induced Vibration of the Cylinders with Helical Strakes

2011 ◽  
Vol 117-119 ◽  
pp. 747-750
Author(s):  
Yang Zhou ◽  
Wei Ping Huang
Keyword(s):  
Experimental Investigation ◽  
Optimal Design ◽  
Cross Flow ◽  
Comprehensive Analysis ◽  
Design Parameters ◽  
Vortex Induced Vibration ◽  
Flow Response ◽  
Helical Strakes ◽  
Uniform Current ◽  
Made In

The tests on the vortex-induced vibration (VIV) of the cylinders with different helical strakes were carried out in a uniform current. Both in-line and cross-flow responses were measured and a comprehensive analysis was made in order to understand the phenomenon of VIV mitigation by helical strake and find optimal design parameters, which are more effective for VIV mitigation, of helical strakes. The results show that the cross flow response of the cylinders with helical strakes could be reduced significantly and its in-line response may be enhanced severely. Therefore, much attention should be paid to the design of helical strake.

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