Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle

Based on the principle of energy variation, a calculation model for the free vibration characteristics of a cylindrical shell with a finite submerged depth considering the influence of the free liquid surface is established in this paper. First, the Euler beam function is used instead of the shell a...

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Autores principales: Rui Nie, Tianyun Li, Xiang Zhu, Cheng Zhang
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Lenguaje:EN
Publicado: MDPI AG 2021
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Acceso en línea:https://doaj.org/article/ef6ac322ce5f4c4e8d72390fe0d45b90
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spelling oai:doaj.org-article:ef6ac322ce5f4c4e8d72390fe0d45b902021-11-25T19:07:15ZAnalysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle10.3390/sym131121622073-8994https://doaj.org/article/ef6ac322ce5f4c4e8d72390fe0d45b902021-11-01T00:00:00Zhttps://www.mdpi.com/2073-8994/13/11/2162https://doaj.org/toc/2073-8994Based on the principle of energy variation, a calculation model for the free vibration characteristics of a cylindrical shell with a finite submerged depth considering the influence of the free liquid surface is established in this paper. First, the Euler beam function is used instead of the shell axial displacement function to obtain the shell kinetic energy and potential energy. Then, by using the mirror image method, the analytical expression of the fluid velocity potential considering the free surface is obtained, and the flow field is added to the system energy functional in the form of fluid work. Then the energy functional is changed to obtain the shell–liquid coupled vibration equation. Solving the equation can obtain the natural frequencies and modes of the structure. The comparison with the finite element calculation results verifies the accuracy of the calculation model in this paper. The research on the influence of the free liquid surface shows that compared to the infinite domain, the free liquid surface destroys the symmetry of the entire system, resulting in a difference in the natural frequency of the positive and negative modes of the shell, and the circumferential mode shapes are no longer mutually uncoupled trigonometric functions. The existence of free liquid surface will also increase the natural frequency of the same order mode, and the closer to the free surface, the natural frequency is greater. As the immersion depth increases, the free vibration characteristics will quickly tend to the result of infinite domain. Additionally, when the immersion depth is equal to or greater than four times the radius of the shell structure, it can be considered that the free liquid surface has no effect. These law and phenomena have also been explained from the mechanism. The method in this paper provides a new analytical solution pattern for solving this type of problem.Rui NieTianyun LiXiang ZhuCheng ZhangMDPI AGarticlefree surfacecylindrical shellimage methodMathematicsQA1-939ENSymmetry, Vol 13, Iss 2162, p 2162 (2021)
institution DOAJ
collection DOAJ
language EN
topic free surface
cylindrical shell
image method
Mathematics
QA1-939
spellingShingle free surface
cylindrical shell
image method
Mathematics
QA1-939
Rui Nie
Tianyun Li
Xiang Zhu
Cheng Zhang
Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
description Based on the principle of energy variation, a calculation model for the free vibration characteristics of a cylindrical shell with a finite submerged depth considering the influence of the free liquid surface is established in this paper. First, the Euler beam function is used instead of the shell axial displacement function to obtain the shell kinetic energy and potential energy. Then, by using the mirror image method, the analytical expression of the fluid velocity potential considering the free surface is obtained, and the flow field is added to the system energy functional in the form of fluid work. Then the energy functional is changed to obtain the shell–liquid coupled vibration equation. Solving the equation can obtain the natural frequencies and modes of the structure. The comparison with the finite element calculation results verifies the accuracy of the calculation model in this paper. The research on the influence of the free liquid surface shows that compared to the infinite domain, the free liquid surface destroys the symmetry of the entire system, resulting in a difference in the natural frequency of the positive and negative modes of the shell, and the circumferential mode shapes are no longer mutually uncoupled trigonometric functions. The existence of free liquid surface will also increase the natural frequency of the same order mode, and the closer to the free surface, the natural frequency is greater. As the immersion depth increases, the free vibration characteristics will quickly tend to the result of infinite domain. Additionally, when the immersion depth is equal to or greater than four times the radius of the shell structure, it can be considered that the free liquid surface has no effect. These law and phenomena have also been explained from the mechanism. The method in this paper provides a new analytical solution pattern for solving this type of problem.
format article
author Rui Nie
Tianyun Li
Xiang Zhu
Cheng Zhang
author_facet Rui Nie
Tianyun Li
Xiang Zhu
Cheng Zhang
author_sort Rui Nie
title Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
title_short Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
title_full Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
title_fullStr Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
title_full_unstemmed Analysis of Free Vibration Characteristics of Cylindrical Shells with Finite Submerged Depth Based on Energy Variational Principle
title_sort analysis of free vibration characteristics of cylindrical shells with finite submerged depth based on energy variational principle
publisher MDPI AG
publishDate 2021
url https://doaj.org/article/ef6ac322ce5f4c4e8d72390fe0d45b90
work_keys_str_mv AT ruinie analysisoffreevibrationcharacteristicsofcylindricalshellswithfinitesubmergeddepthbasedonenergyvariationalprinciple
AT tianyunli analysisoffreevibrationcharacteristicsofcylindricalshellswithfinitesubmergeddepthbasedonenergyvariationalprinciple
AT xiangzhu analysisoffreevibrationcharacteristicsofcylindricalshellswithfinitesubmergeddepthbasedonenergyvariationalprinciple
AT chengzhang analysisoffreevibrationcharacteristicsofcylindricalshellswithfinitesubmergeddepthbasedonenergyvariationalprinciple
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