• 제목/요약/키워드: donnell shell theory

검색결과 26건 처리시간 0.135초

보강 개구부가 있는 복합재료 원통셸의 축방향 하중에 따른 응력해석 (Stress Analysis on Composite Cylindrical Shells with a Reinforced Cutout Subjected to Axial Load)

  • 이영신;류충현;김영완
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 1999년도 추계학술발표대회 논문집
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    • pp.211-214
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    • 1999
  • The stress distribution around the cutout of composite cylindrical shells with a circular or elliptical reinforced cutout subjected to axial compression or tension is studied by asymptotic method. Analytical solutions used a Donnell type orthotropic shell theory are presented by the defined stress concentration factor and are compared to experimental results. The experiment used the universal testing machine (UTM), strain gage and fixtures designed/manufactured for axial tension test of a cylindrical shell is carried and the composite material used in the experiment is plain weave glass fiber reinforced plastic (GFRP).

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Thermal buckling analysis of functionally graded sandwich cylindrical shells

  • Daikh, Ahmed Amine
    • Advances in aircraft and spacecraft science
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    • 제7권4호
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    • pp.335-351
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    • 2020
  • Thermal buckling of functionally graded sandwich cylindrical shells is presented in this study. Material properties and thermal expansion coefficient of FGM layers are assumed to vary continuously through the thickness according to a sigmoid function and simple power-law distribution in terms of the volume fractions of the constituents. Equilibrium and stability equations of FGM sandwich cylindrical shells with simply supported boundary conditions are derived according to the Donnell theory. The influences of cylindrical shell geometry and the gradient index on the critical buckling temperature of several kinds of FGM sandwich cylindrical shells are investigated. The thermal loads are assumed to be uniform, linear and nonlinear distribution across the thickness direction. An exact simple form of nonlinear temperature rise through its thickness taking into account the thermal conductivity and the inhomogeneity parameter is presented.

複合材 圓筒쉘의 動的 擧動 硏究 (Dynamic Behavior of Laminated Orthotropic Cylindrical Shells)

  • 김천욱;김치균
    • 대한기계학회논문집
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    • 제16권10호
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    • pp.1807-1815
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    • 1992
  • 본 연구에서는 적층 복합재 원통쉘의 동적특성을 검토한다. 복합재료 원통 쉘의 설계에서 주요 관심 대상인 직교이방성 변수가 진동특성과 어떤 관계를 갖는지 알아보기 위하여 직교이방성이론으로 한정시켜 해석하였다. 지배방정식은 면내관성 항을 고려한 Donnell 운동방정식을 사용하며, 진동수방정식은 Rayleigh-Ritz법을 이용 하여 유도하였다. 임의의 경계조건에 적용될 수 있도록 보특성함수를 사용하여 고유 진동수를 간단히 구하였다. 기존의 연구자들이 채용한 복합재료의 물성치들과 복합 재 원통쉘의 고유진동수사이에 어떤관계가 있는지 규명하도록 하였다.

비원형 단면을 가진 적층복합재료원통셸의 좌굴 및 진동해석 (Buckling and Vibration of Laminated Composite Non-Circular Cylindrical Shells)

  • 이영신;안상균;이우식
    • 대한기계학회논문집
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    • 제13권5호
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    • pp.807-819
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    • 1989
  • 본 연구에서는 Donnell과 Flugge 셸 이론을 이용하여 단순지지된 비원형 단면을 가진 angle-ply 적층원통셸의 좌굴과 진동해석을 Soldatos의 해석과정을 따라 수행하고, 적층방법(stacking sequence)과 섬유각(fiber angle)의 변화에 따른 고유진 동수와 좌굴하중의 변화를 고찰하였으며, 초기 축하중을 받는 경우에 대한 고유진동수 의 변화에 대해서고 고찰하였다.

Free vibration analysis of functionally graded cylindrical shells with different shell theories using semi-analytical method

  • Khayat, Majid;Dehghan, Seyed Mehdi;Najafgholipour, Mohammad Amir;Baghlani, Abdolhossein
    • Steel and Composite Structures
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    • 제28권6호
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    • pp.735-748
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    • 2018
  • In this study, the semi-analytical finite strip method is adopted to examine the free vibration of cylindrical shells made up of functionally graded material. The properties of functionally graded shells are assumed to be temperature-dependent and vary continuously in the thickness direction according to a simple power law distribution in terms of the volume fraction of ceramic and metal. The material properties of the shells and stiffeners are assumed to be continuously graded in the thickness direction. Theoretical formulations based on the smeared stiffeners technique and the classical shell theory with first-order shear deformation theory which accounts for through thickness shear flexibility are employed. The finite strip method is applied to five different shell theories, namely, Donnell, Reissner, Sanders, Novozhilov, and Teng. The approximate procedure is compared favorably with three-dimensional finite elements. Finally, a detailed numerical study is carried out to bring out the effects of power-law index of the functional graded material, stiffeners, and geometry of the shells on the difference between various shell theories. Finally, the importance of choosing the shell theory in simulating the functionally graded cylindrical shells is addressed.

연성된 쉘 구조물의 진동 파워흐름해석 (Vibration Power Flow Analysis of Coupled Shell Structures)

  • 김일환;홍석윤;박도현;길현권
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문집
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    • pp.492-497
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    • 2002
  • In this paper, Power Flow Analysis(PFA) method has been applied to the prediction of vibration energy density and intensity of coupled shell structures in the medium-to-high frequency ranges. To consider the wave transformation at joint between shell elements, power transmission and reflection coefficients are investigated for various joint angles, and here Donnell-Mushtari thin shell theory has been used. For validations computations are performed to analyze the response of coupled shells by changing the excitation frequency and damping loss factor.

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The dynamic instability of FG orthotropic conical shells within the SDT

  • Sofiyev, Abdullah H.;Zerin, Zihni;Allahverdiev, Bilender P.;Hui, David;Turan, Ferruh;Erdem, Hakan
    • Steel and Composite Structures
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    • 제25권5호
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    • pp.581-591
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    • 2017
  • The dynamic instability of truncated conical shells subjected to dynamic axial load within first order shear deformation theory (FSDT) is examined. The conical shell is made from functionally graded (FG) orthotropic material. In the formulation of problem a dynamic version of Donnell's shell theory is used. The equations are converted to a Mathieu-Hill type differential equation employing Galerkin's method. The boundaries of main instability zones are found applying the method proposed by Bolotin. To verify these results, the results of other studies in the literature were compared. The influences of material gradient, orthotropy, as well as changing the geometric dimensions on the borders of the main areas of the instability are investigated.

Vibrational behavior of exponentially graded joined conical-conical shells

  • Rezaiee-Pajand, Mohammad;Sobhani, Emad;Masoodi, Amir R.
    • Steel and Composite Structures
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    • 제43권5호
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    • pp.603-623
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    • 2022
  • This article is dedicated to predict the natural frequencies of joined conical shell structures made of Functionally Graded Material (FGM). The structure includes two conical segments. The equivalent material properties are found by using the rule of mixture based on Voigt model. In addition, three well-known patterns are employed for distribution of material properties throughout the thickness of the structure. The main objective of the present research is to propose a novel exponential pattern and obtain the related equivalent material properties. Furthermore, the Donnell type shell theory is used to obtain the governing equations of motion. Note that these equations are obtained by employing First-order Shear Deformation Theory (FSDT). In order to discretize the governing system of differential equations, well-known and efficient semi-analytical scheme, namely Generalized Differential Quadrature Method (GDQM), is utilized. Different boundary conditions are considered for various types of single and joined conical shell structures. Moreover, an applicable modification is considered for the continuity conditions at intersection position. In the first step, the proposed formulation is verified by solving some well-known benchmark problems. Besides, some new numerical examples are analyzed to show the accuracy and high capability of the suggested technique. Additionally, several geometric and material parameters are studied numerically.

Nonlinear forced vibration of axially moving functionally graded cylindrical shells under hygro-thermal loads

  • Jin-Peng Song;Gui-Lin She;Yu-Jie He
    • Geomechanics and Engineering
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    • 제36권2호
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    • pp.99-109
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    • 2024
  • Studying the dynamic behavior of axially moving cylindrical shells in hygro-thermal environments has important theoretical and engineering value for aircraft design. Therefore, in this paper, considering hygro-thermal effect, the nonlinear forced vibration of an axially moving cylindrical shell made of functionally graded materials (FGM) is studied. It is assumed that the material properties vary continuously along the thickness and contain pores. The Donnell thin shell theory is used to derive the motion equations of FGM cylindrical shells with hygro-thermal loads. Under the four sides clamped (CCCC) boundary conditions, the Gallekin method and multi-scale method are used for nonlinear analysis. The effects of power law index, porosity coefficient, temperature rise, moisture concentration, axial velocity, prestress, damping and external excitation amplitude on nonlinear forced vibration are explored through parametric research. It can be found that, the changes in temperature and humidity have a significant effect. Increasing in temperature and humidity will cause the resonance position to shift to the left and increase the resonance amplitude.

Thermal post-buckling behavior of GPLRMF cylindrical shells with initial geometrical imperfection

  • Yi-Wen Zhang;Gui-Lin She;Lei-Lei Gan;Yin-Ping Li
    • Geomechanics and Engineering
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    • 제32권6호
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    • pp.615-625
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    • 2023
  • Initial geometrical imperfection is an important factor affecting the structural characteristics of plate and shell structures. Studying the effect of geometrical imperfection on the structural characteristics of cylindrical shell is beneficial to explore the thermal post-buckling response characteristics of cylindrical shell. Therefore, we devote to investigating the thermal post-buckling behavior of graphene platelets reinforced mental foam (GPLRMF) cylindrical shells with geometrical imperfection. The properties of GPLRMF material with considering three types of graphene platelets (GPLs) distribution patterns are introduced firstly. Subsequently, based on Donnell nonlinear shell theory, the governing equations of cylindrical shell are derived according to Eulerian-Lagrange equations. Taking into account two different boundary conditions namely simply supported (S-S) and clamped supported (C-S), the Galerkin principle is used to solve the governing equations. Finally, the impact of initial geometrical imperfections, the GPLs distribution types, the porosity distribution types, the porosity coefficient as well as the GPLs mass fraction on the thermal post-buckling response of the cylindrical shells are analyzed.