scholarly journals To the problem of optimal control of a cylindrical shell motion.

2017 ◽  
Vol 70 (4) ◽  
pp. 50-56
Author(s):  
L.A. Movsisyan
Keyword(s):  
Optimal Control ◽  
Cylindrical Shell ◽  
Shell Motion

Investigation on Vibro-Acoustic Characteristics from Submerged Cylindrical Shell with Double Damping Layers

2013 ◽  
Vol 345 ◽  
pp. 94-98
Author(s):  
Chao Zhang ◽  
De Jiang Shang ◽  
Qi Li
Keyword(s):  
Cylindrical Shell ◽  
Low Frequency ◽  
Acoustic Characteristics ◽  
Radiated Power ◽  
Shell Models ◽  
Antiresonance Frequency ◽  
Shell Motion ◽  
Vibration And Sound Radiation ◽  
Thin Shell Theory ◽  
Large Frequency

The vibration and sound radiation from submerged cylindrical shell with double damping layers are presented. The cylindrical shell motion was described with classical thin shell theory. The double damping layers motion was described with the Navier viscoelasticity theory. For different Youngs modulus parameters of double damping layers, the sound radiated power and the radial quadratic velocity of cylindrical shell models were calculated and analyzed. The results show that the sound radiated power and radial quadratic velocity are reduced to varying degrees due to double damping layers in a large frequency domain except low frequency. The double damping layer with soft inner layer and hard outer layer can make the sound radiated peaks move to high frequency, can help to reduce the radial quadratic velocity on outer surface of damping layer, and can help to reduce the vibration of model at antiresonance frequency.

Accurate compact solution of fluid-filled FG cylindrical shell inducting fluid term: Frequency analysis

2021 ◽  
pp. 109963622199389
Author(s):  
Muzamal Hussain ◽  
Muhammad N Naeem
Keyword(s):  
Cylindrical Shell ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Integral Form ◽  
Energy Functional ◽  
Acoustic Wave Equation ◽  
Partial Differential ◽  
Motion Equations ◽  
Constituent Material ◽  
Shell Motion

Shell motion equations are framed with first order shell theory of Love. Vibration investigation of fluid-filled three layered cylindrical shells is studied here. It is also exhibited that the effect of frequencies is investigated by varying the different layers with constituent material. The coupled and uncoupled frequencies changes with these layers according to the material formation of fluid-filled FG-CSs. A cylindrical shell is immersed in a fluid which is a non-viscous one. These equations are partial differential equations which are usually solved by approximate technique. Robust and efficient techniques are favored to get precise results. Use of acoustic wave equation is done to incorporate the sound pressure produced in a fluid. Hankel’s functions of second kind designate the fluid influence. Mathematically the integral form of the Lagrange energy functional is converted into a set of three partial differential equations.

scholarly journals On Certain Problems of Identification of Thermal Density of the Temperature State of the Hollow Cylinder Shell

2020 ◽  
pp. 32-40
Author(s):  
Albina Aralova
Keyword(s):  
Finite Element Method ◽  
Optimal Control ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Gradient Methods ◽  
Quadratic Functions ◽  
Temperature State ◽  
Piecewise Quadratic Functions ◽  
Theory Of Optimal Control ◽  
Element Method

Introduction. In conditions of the active use of composite materials, as when accomplishing the tasks of extending the service life of existing structures, problems on recovering unknown parameters of their components under the known data on their surface arise. In [1-4], to solve the problems of identification ofparameters of a wide range, it is proposed to construct explicit expressions of the gradients of residual functionals by means of the corresponding conjugate problems obtained from the theory of optimal control of the states of multicomponent distributed systems, which is the development of the corresponding researches of Zh. Lyons. In [5-7], this technology is extended to the problem of thermoelastic deformation of multicomponent bodies. In this article some problems of optimal control of the temperature state of a cylindrical body with a cavity are considered. The purpose of the paper is to show the algorithm for identifying the parameters of a cylindrical hollow shell, based on the theory of optimal control and using the gradient methods of Alifanov. Results. Based on the theory of optimal control, the temperature control of a cylindrical shell is studied. To solve the problem of identifying the parameters of a hollow cylindrical shell, namely, finding the heat flux powers on its surfaces, based on [1,2,5-7], a direct and conjugate problem and gradients of non-viscous functionals are constructed. Discretization by the finite element method using piecewise quadratic functions is carried out and accuracy estimates for it are presented. The initial problem in the model examples presented is solved using gradient methods, where at each step of determining the (n + 1) the approximation of the solution, the direct and adjoint problems are solved using finite element method with the help piecewise quadratic functions by minimizing the corresponding energy functional. A number of model examples solved.

Sound Radiation From a Finite Cylindrical Shell Covered With a Compliant Layer

1991 ◽  
Vol 113 (2) ◽  
pp. 267-272 ◽  
Author(s):  
B. Laulagnet ◽  
J. L. Guyader
Keyword(s):  
Cylindrical Shell ◽  
Frequency Domain ◽  
Mathematical Analysis ◽  
Strong Influence ◽  
Sound Radiation ◽  
Radiated Power ◽  
Shell Motion ◽  
Compliant Layer ◽  
Finite Cylindrical Shell ◽  
Large Frequency

The aim of this work is to present the mathematical analysis and numerical results about sound radiation from a finite cylindrical shell covered with a compliant layer, immersed in water. The shell motion is obtained using Flu¨gge’s operator whereas the layer is described by a locally reacting material. The results are presented both in shell radial quadratic velocity and radiated power. Two major conclusions can be drawn when looking at results: (1) a reasonable stiffness layer allows one to reduce the radiated power in a large frequency domain; (2) the layer has a strong influence on the shell velocity which exhibits an antiresonance phenomenon when covered.

Dynamic Model of Elastically Mounted Machinery with Cylindrical Shell

2013 ◽  
Vol 419 ◽  
pp. 423-431
Author(s):  
Wei Xu ◽  
Chang Geng Shuai ◽  
Zhi Qiang Lv
Keyword(s):  
Cylindrical Shell ◽  
System Design ◽  
Dynamic Model ◽  
Reaction Force ◽  
Thin Wall ◽  
Electric Motors ◽  
Isolation System ◽  
Vibration Excitation ◽  
Shell Motion ◽  
Shell Equation

Mounting machinery by isolators can reduce vibration transmitted to the base and attenuated environmental noise. In this paper the machine having cylindrical shell such as electric motors is modeled by thin-wall cylindrical shell motion equation. The reaction force exerted by isolator is considered as point force and integrated in the shell equation. The typical vibration excitation of machinery is represented by point and line excitations. The forces transmitted to the base through isolators are then calculated under different excitations. Conclusions with respect to machinery and isolation system design are presented based on numerical results.

Optimal Control of Piezoelectric Laminated Parabolic Cylindrical Panels

2013 ◽  
Author(s):  
S. D. Hu ◽  
H. Li ◽  
H. S. Tzou
Keyword(s):  
Optimal Control ◽  
Cylindrical Shell ◽  
Feedback Control ◽  
Vibration Control ◽  
Control Algorithm ◽  
Damping Ratio ◽  
Design Parameters ◽  
Distributed Sensors ◽  
Control Gain ◽  
And Control

Vibration control of parabolic cylindrical shell panels by piezoelectric patches using optimal control algorithm is presented in this study. Laminated piezoelectric patches serve as distributed sensors and actuators. Dynamic behaviors and mode shape functions in three directions are obtained by the Rayleith-Ritz method. The sensing sensitivity of the piezoelectric sensor and the actuation force of the piezoelectric actuator are obtained. Feedback control gain between sensing and control signals is solved using the LQ optimal control algorithm. LQ controllers for independent modes are designed, and relative optimal control gains and control voltages are presented. Control results with respect to independent mode and optimal design parameters are evaluated in case studies. Numerical results show that the LQ optimal controller with optimal feedback control gain is effective for the vibration control of parabolic cylindrical shell panels. The damping ratio can be greatly enhanced; the maximal damping ratio reach 7.79% for mode (1,3). Studies on parametric designs suggest that relatively larger Q22 and/or smaller R results in rapider reduction of mechanical motion with more control energy cost, and vice versa. These results would provide a design reference in practical engineering.

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