Optimum Design of Elastically Supported Gyroscopes for Ship Stabilization

1984 ◽  
Vol 106 (4) ◽  
pp. 387-392
Author(s):  
K.-N. Lee ◽  
A. Seireg
Keyword(s):  
Optimal Design ◽  
Dynamic Model ◽  
Optimum Design ◽  
Design Procedures ◽  
System Parameters ◽  
Ship Roll ◽  
Elastically Supported ◽  
Elastic Spring

The study reported in this paper deals with the development of a dynamic model for the analysis of elastically supported gyroscopic absorber systems for ship stabilization. The gryoscopes are mounted on elastically supported platforms at the fore and aft ends of the ship to minimize both the roll and pitch movements. Springs and dampers are also utilized between the gyroscope gimbal and the platform. Several design configurations of the absorber are considered. Optimal design procedures are utilized to find the system parameters for best performance in each case. The performance of the resulting optimum absorber shows that introducing the elastic spring and damper between the gimbal and platform has a significant effect on reducing the ship-roll action.

Spring-Arrangement Effect on Flow-Induced Vibration of a Circular Cylinder

2021 ◽  
Author(s):  
Koki Yamada ◽  
Yuga Shigeyoshi ◽  
Shuangjing Chen ◽  
Yoshiki Nishi
Keyword(s):  
Circular Cylinder ◽  
Dynamic Model ◽  
Geometric Nonlinearity ◽  
Water Channel ◽  
Fluid Flows ◽  
Flow Induced Vibration ◽  
Theoretical Evaluation ◽  
Circulating Water ◽  
Linear Dynamic ◽  
Elastically Supported

Abstract Purpose This study elucidated the effect of an inclined spring arrangement on the flow-induced vibration of a circular cylinder to understand if the effect enhances the harnessing of the energy of fluid flows. Method An experiment was conducted on a circulating water channel. A circular cylinder was partially submerged. It was elastically supported by two springs whose longitudinal directions were varied. With the speed of the water flow varied, the vibrations of the circular cylinder were measured. The measured vibrations were interpreted by la linear dynamic model. Results and discussion In a few cases, a jump in response amplitudes from zero to the maximum was observed with the spring inclination at reduced velocities of 6 to 7, whereas gradually increasing response amplitudes were observed in other cases. The inclined spring arrangement achieved greater velocity amplitudes than in cases without spring inclination. A theoretical evaluation of the measured responses indicates that the effect of the inclined springs was caused by geometric nonlinearity; the effect would be more prominent by employing a longer moment lever.

Framework for investigating the effect of different design lives on the design of bridges

2021 ◽  
Author(s):  
Egor Svechnikov ◽  
Johan Maljaars ◽  
Bert Snijder ◽  
Johan de Boon ◽  
Eize Drenth
Keyword(s):  
Optimal Design ◽  
The Netherlands ◽  
Optimum Design ◽  
Functional Capacity ◽  
Road Network ◽  
Developed Countries ◽  
Research Activities ◽  
Design Life ◽  
National Road ◽  
Structural Solutions

<p>Many developed countries have a national road network including a significant number of bridges in need of renovation or replacement in the coming years. The reason for this is their technical and functional capacity becoming insufficient due to aging and changes in societal demands. Therefore, these bridges need to be adjusted or replaced. National authorities in The Netherlands currently require a design life of 100 years for new bridges, however nowadays it seems reasonable to have a certain flexibility for this parameter. Since the selected design life has its implications on structural solutions and choice of materials, the identification of the optimal design life for bridges seems necessary. This paper gives a summary on the issue regarding the optimum design life of bridges and it highlights the framework of the upcoming research activities.</p>

Optimal Control of Turbine Engines

1979 ◽  
Vol 101 (2) ◽  
pp. 117-126 ◽  
Author(s):  
R. L. DeHoff ◽  
W. Earl Hall
Keyword(s):  
Optimal Control ◽  
Optimal Design ◽  
Control Design ◽  
Multivariable Control ◽  
Turbine Engines ◽  
Linear Modeling ◽  
Turbofan Engine ◽  
Turbine Engine ◽  
Design Procedures ◽  
Modeling Techniques

Multivariable control design for turbine engines has been studied for over 20 years. In the last 10 years, the application of linear, optimal design techniques has produced a number of turbine engine controllers. A group of these design procedures is described and a discussion of the procedures’ performance, complexity and implementation is presented. The design of a full-envelope controller for the F100 turbofan engine based on linear, optimal synthesis and locally linear modeling techniques is discussed. A perspective of optimal control design for turbine engines is presented and the future is examined.

Dynamic model orbits and Earth system parameters from combined GPS and LEO data

2005 ◽  
Vol 36 (3) ◽  
pp. 431-437 ◽  
Author(s):  
R. König ◽  
Ch. Reigber ◽  
S.Y. Zhu
Keyword(s):  
Dynamic Model ◽  
Earth System ◽  
System Parameters

scholarly journals Nonlinear modeling and stability analysis of a pilot-operated valve-control hydraulic system

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401881066 ◽  
Author(s):  
Wei Wei ◽  
Hongchao Jian ◽  
Qingdong Yan ◽  
Xiaomei Luo ◽  
Xuhong Wu
Keyword(s):  
Dynamic Model ◽  
Hydraulic System ◽  
Nonlinear Modeling ◽  
Orifice Diameter ◽  
Operating Pressure ◽  
Nonlinear Dynamic Model ◽  
System Parameters ◽  
Excited Vibration ◽  
The Stability ◽  
Valve Control

A nonlinear dynamic model is developed to analyze the stability of a pilot-operated valve-control hydraulic system. The dynamic model includes motion of the valve spool and fluid dynamics in the system. Characteristics such as pressure flow across the valve port and orifices, pressure, and flow rate in valve chambers are taken into consideration. Bifurcation analysis is proposed and examined by numerical simulation results when the feedback orifice diameter changes. The effects of different system parameters such as pilot-operating pressure, spring stiffness, and overlap of inlet port on the stability border of the system are studied by two-dimensional bifurcation analyses. The study identifies that bifurcation can occur in the system and lead to sustained self-excited vibration with parameters in certain region of the parameter space. It suggests that the vibration can be effectively predicted and prevented by selecting system parameters from the asymptotic stable parameter region.

scholarly journals Experimental Active Vibration Control in Truss Structures Considering Uncertainties in System Parameters

2008 ◽  
Vol 2008 ◽  
pp. 1-14 ◽  
Author(s):  
Douglas Domingues Bueno ◽  
Clayton Rodrigo Marqui ◽  
Rodrigo Borges Santos ◽  
Camilo Mesquita Neto ◽  
Vicente Lopes
Keyword(s):  
Vibration Control ◽  
Dynamic Model ◽  
Electromechanical Coupling ◽  
Active Vibration Control ◽  
Experimental Methodology ◽  
Truss Structures ◽  
Linear Matrix ◽  
System Parameters ◽  
Identification Method ◽  
Active Vibration

This paper deals with the study of algorithms for robust active vibration control in flexible structures considering uncertainties in system parameters. It became an area of enormous interest, mainly due to the countless demands of optimal performance in mechanical systems as aircraft, aerospace, and automotive structures. An important and difficult problem for designing active vibration control is to get a representative dynamic model. Generally, this model can be obtained using finite element method (FEM) or an identification method using experimental data. Actuators and sensors may affect the dynamics properties of the structure, for instance, electromechanical coupling of piezoelectric material must be considered in FEM formulation for flexible and lightly damping structure. The nonlinearities and uncertainties involved in these structures make it a difficult task, mainly for complex structures as spatial truss structures. On the other hand, by using an identification method, it is possible to obtain the dynamic model represented through a state space realization considering this coupling. This paper proposes an experimental methodology for vibration control in a 3D truss structure using PZT wafer stacks and a robust control algorithm solved by linear matrix inequalities.

Perfect Dynamic Model and Optimal Design of Vibration-Impact Rammer

2011 ◽  
Vol 422 ◽  
pp. 525-528
Author(s):  
Ke Chen ◽  
Zhi Shan Duan ◽  
Jia Qi Fei
Keyword(s):  
Optimal Design ◽  
Real Time ◽  
Dynamic Model ◽  
Computer Programming ◽  
New Method ◽  
Body System ◽  
The Real ◽  
Vibration Impact ◽  
Plastic Theory

In order to find a better method of optimal design of vibration-impact rammer, perfect the dynamic model of vibration-impact rammer. Based on the viscoelastic-plastic theory of soil body, the dynamic model and equation set of vibration-impact rammer and soil body system are built. After computer programming, the real-time working data of vibration-impact rammer is obtained and a new method for optimal design of vibration-impact rammer is provided.

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