1 A New Concept of Sampling A New Concept of Sampling Surfaces in Shell Theory Surfaces in Shell Theory S.V. Plotnikova S.V. Plotnikova and and G.M. Kulikov G.M. Kulikov Speaker: Professor Gennady M. Kulikov Speaker: Professor Gennady M. Kulikov Department of Applied Mathematics & Mechanics Department of Applied Mathematics & Mechanics
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1 A New Concept of Sampling Surfaces in Shell Theory S.V. Plotnikova and G.M. Kulikov Speaker: Professor Gennady M. Kulikov Department of Applied Mathematics.
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A New Concept of Sampling A New Concept of Sampling Surfaces in Shell TheorySurfaces in Shell Theory
Speaker: Professor Gennady M. KulikovSpeaker: Professor Gennady M. Kulikov
Department of Applied Mathematics & MechanicsDepartment of Applied Mathematics & Mechanics
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Kinematic Description of Undeformed ShellKinematic Description of Undeformed ShellKinematic Description of Undeformed ShellKinematic Description of Undeformed Shell
Figure 1. Geometry of the shellFigure 1. Geometry of the shellFigure 1. Geometry of the shellFigure 1. Geometry of the shell
33 eer aa ,, A
33 egeRg IIII cA ,,
Base Vectors of Midsurface and S-SurfacesBase Vectors of Midsurface and S-Surfaces Base Vectors of Midsurface and S-SurfacesBase Vectors of Midsurface and S-Surfaces
eeii - orthonormal vectors; - orthonormal vectors; AA, , kk - - Lamé coefficients and principal curvatures of midsurfaceLamé coefficients and principal curvatures of midsurface
cc = 1+k = 1+k33 - shifter tensor at S-surfaces; - shifter tensor at S-surfaces; 33 - transverse coordinates of S-surfaces (- transverse coordinates of S-surfaces (I I = 1, 2, …, = 1, 2, …, N)N)II II II
rr((11, , 22) - position vector of midsurface ) - position vector of midsurface
RR = = rr++33ee33 - position vectors of S-surfaces - position vectors of S-surfaces
I I = 1, 2, …, = 1, 2, …, NN
II II II
3
Kinematic Description of Deformed ShellKinematic Description of Deformed ShellKinematic Description of Deformed ShellKinematic Description of Deformed Shell
Figure 2. Initial and current configurations of the shellFigure 2. Initial and current configurations of the shellFigure 2. Initial and current configurations of the shellFigure 2. Initial and current configurations of the shell
Base Vectors of DeformedBase Vectors of Deformed S-SurfacesS-SurfacesBase Vectors of DeformedBase Vectors of Deformed S-SurfacesS-Surfaces
)(,, ,,,IIIIIIII3333 uegugRg
((11, , 22) - derivatives of 3D displacement vector at S-surfaces () - derivatives of 3D displacement vector at S-surfaces ( I I = 1, 2, …, = 1, 2, …, N)N)I
III uRR
Position Vectors of Deformed S-SurfacesPosition Vectors of Deformed S-SurfacesPosition Vectors of Deformed S-SurfacesPosition Vectors of Deformed S-Surfaces
(3)(3)
(4)(4)
u u ((11, , 22) - displacement vectors of S-surfaces) - displacement vectors of S-surfaces
II = 1, 2, …, = 1, 2, …, NN
I
4
Green-Lagrange Strain Tensor at S-SurfacesGreen-Lagrange Strain Tensor at S-Surfaces
Representation for Displacement Vectors in Surface Representation for Displacement Vectors in Surface FrameFrame
)( Ij
Ii
Ij
IiI
jIiji
Iij
ccAAgggg
12
333331
2
112
eeue
eueu
IIII
II
II
II
I
cA
cAcA
,,
,,
i
iIi
I
ii
Ii
I u ee ,u
(5)(5)
(6)(6)
(7)(7)
5
Representation for Derivatives of Displacement VectorsRepresentation for Derivatives of Displacement Vectors
Strain ParametersStrain Parameters
StrainStrainss of S- of S-SSurfacesurfaces
Representation for Derivatives of Displacement VectorsRepresentation for Derivatives of Displacement Vectors
Strain ParametersStrain Parameters
StrainStrainss of S- of S-SSurfacesurfaces
i
iIi
I
Aeu,
1
III
IIIIIII
ukuA
uBuA
ukuBuA
,
,, )(,
33
3
1
11
IIII
II
II
II
I
c
cc
333331
2
112
,
Remark 1.Remark 1. Strains (10) exactly represent all rigid-body shell motions in any convected curvilinear Strains (10) exactly represent all rigid-body shell motions in any convected curvilinear coordinate systemcoordinate system
(8)(8)
(9)(9)
(10)(10)
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Displacement Distribution in Thickness DirectionDisplacement Distribution in Thickness Direction
Presentation for Derivatives of 3D Displacement Vector Presentation for Derivatives of 3D Displacement Vector
Strain Distribution in Thickness DirectionStrain Distribution in Thickness Direction
Displacement Distribution in Thickness DirectionDisplacement Distribution in Thickness Direction
Presentation for Derivatives of 3D Displacement Vector Presentation for Derivatives of 3D Displacement Vector
Strain Distribution in Thickness DirectionStrain Distribution in Thickness Direction
Higher-Order Shell TheoryHigher-Order Shell TheoryHigher-Order Shell TheoryHigher-Order Shell Theory
II
J
Ji
IJIi LMuM 33 ,,)(
I
Iij
Iij L
IJJI
JI
I
Ii
Ii
L
uLu
33
33
LL ( (33) -) - Lagrange polynomials of degree Lagrange polynomials of degree N N - 1- 1 ((I I = 1, 2, …, = 1, 2, …, N)N) I
(11)(11)
(12)(12)
(13)(13)
(14)(14)
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Stress ResultantsStress Resultants
Variational EquationVariational Equation
Constitutive EquationsConstitutive Equations
Presentation for Stress ResultantsPresentation for Stress Resultants
Stress ResultantsStress Resultants
Variational EquationVariational Equation
Constitutive EquationsConstitutive Equations
Presentation for Stress ResultantsPresentation for Stress Resultants
2
2321
/
/
h
h
Iij
Iij dccLH
WddAAupccupccH
I ji iii
Nii
NNIij
Iij 2121
112
1121
,
mk
kmijkmij C,
J mk
Jkm
IJijkm
Iij DH
,
2
2321
/
/
h
h
JIijkm
IJijkm dccLLCD
Remark 2.Remark 2. It is possible to carry out exact integration in (19) using the n-point Gaussian quadrature It is possible to carry out exact integration in (19) using the n-point Gaussian quadraturerule with rule with nn = = NN+1+1
ppi i , p, pi i - surface loads acting on bottom and top surfaces- surface loads acting on bottom and top surfaces
(15)(15)
(16)(16)
(17)(17)
(18)(18)
(19)(19)
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Finite Element FormulationFinite Element FormulationFinite Element FormulationFinite Element Formulation
Numerical ExamplesNumerical ExamplesNumerical ExamplesNumerical Examples1. Square Plate under Sinusoidal Loading1. Square Plate under Sinusoidal Loading1. Square Plate under Sinusoidal Loading1. Square Plate under Sinusoidal Loading
Figure 4. Simply supported square plate Figure 4. Simply supported square plate with a = b =1 , E = 10with a = b =1 , E = 1077 and and = 0.3 = 0.3 Figure 4. Simply supported square plate Figure 4. Simply supported square plate with a = b =1 , E = 10with a = b =1 , E = 1077 and and = 0.3 = 0.3
Table 1. Results for a thick square plate withTable 1. Results for a thick square plate with a / h = a / h = 22 Table 1. Results for a thick square plate withTable 1. Results for a thick square plate with a / h = a / h = 22
hzapzaauEhU
pzaaSapzahS
apzhSapzaahS
/,/),/,/(
/),/,/(,/),/,(
/),,(,/),/,/(
34
033
3
0333301313
2012
212
2011
211
22100
222010
00102210
10
aa / / hh NN = 5 = 5 Exact Vlasov’s solutionExact Vlasov’s solution
Table 2. Results for thick and thin square plates with five equally located S-surfaces Table 2. Results for thick and thin square plates with five equally located S-surfaces Table 2. Results for thick and thin square plates with five equally located S-surfaces Table 2. Results for thick and thin square plates with five equally located S-surfaces
Figure Figure 55. Distribution of stresses S. Distribution of stresses S1313 and S and S3333 through the plate thickness: through the plate thickness:
Vlasov’s solution ( ) and present higher-order shell theory for N = 7 ( )Vlasov’s solution ( ) and present higher-order shell theory for N = 7 ( )
Figure Figure 55. Distribution of stresses S. Distribution of stresses S1313 and S and S3333 through the plate thickness: through the plate thickness:
Vlasov’s solution ( ) and present higher-order shell theory for N = 7 ( )Vlasov’s solution ( ) and present higher-order shell theory for N = 7 ( )
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2. Cylindrical Composite Shell under Sinusoidal Loading2. Cylindrical Composite Shell under Sinusoidal Loading2. Cylindrical Composite Shell under Sinusoidal Loading2. Cylindrical Composite Shell under Sinusoidal Loading
Table 3. Results for a thick cylindrical shell with R / h = 2Table 3. Results for a thick cylindrical shell with R / h = 2Table 3. Results for a thick cylindrical shell with R / h = 2Table 3. Results for a thick cylindrical shell with R / h = 2
Table 4. Results for thick and thin cylindrical shells with seven S-surfacesTable 4. Results for thick and thin cylindrical shells with seven S-surfacesTable 4. Results for thick and thin cylindrical shells with seven S-surfacesTable 4. Results for thick and thin cylindrical shells with seven S-surfaces
Figure 7. Distribution of stresses SFigure 7. Distribution of stresses S3333 through the shell thickness: through the shell thickness:
exact solution ( ) and present higher-order shell theory for N = 7 ( )exact solution ( ) and present higher-order shell theory for N = 7 ( )
Figure 7. Distribution of stresses SFigure 7. Distribution of stresses S3333 through the shell thickness: through the shell thickness:
exact solution ( ) and present higher-order shell theory for N = 7 ( )exact solution ( ) and present higher-order shell theory for N = 7 ( )
Table 5. Results for a thick spherical shell with R / h = 2Table 5. Results for a thick spherical shell with R / h = 2Table 5. Results for a thick spherical shell with R / h = 2Table 5. Results for a thick spherical shell with R / h = 2
33. Spherical Shell under Inner Pressure. Spherical Shell under Inner Pressure33. Spherical Shell under Inner Pressure. Spherical Shell under Inner Pressure
hzRpzEhuU
pzSRpzhS
/,/),,(
/),,(,/),,(
32
033
0333301111
0010
000010
Figure 8. Spherical shell under inner pressure with R = 10, Figure 8. Spherical shell under inner pressure with R = 10, = 89.98= 89.98, E = 10, E = 1077 and and = 0.3 = 0.3
(modeled by 64(modeled by 641 mesh)1 mesh)
Figure 8. Spherical shell under inner pressure with R = 10, Figure 8. Spherical shell under inner pressure with R = 10, = 89.98= 89.98, E = 10, E = 1077 and and = 0.3 = 0.3
Table 6. Results for thick and thin spherical shells with seven S-surfacesTable 6. Results for thick and thin spherical shells with seven S-surfacesTable 6. Results for thick and thin spherical shells with seven S-surfacesTable 6. Results for thick and thin spherical shells with seven S-surfaces
Figure 9. Distribution of stresses SFigure 9. Distribution of stresses S1111 and S and S3333 through the shell thickness: through the shell thickness:
LamLaméé’s solution ( ) and present higher-order shell theory for N = 7 ( )’s solution ( ) and present higher-order shell theory for N = 7 ( )
Figure 9. Distribution of stresses SFigure 9. Distribution of stresses S1111 and S and S3333 through the shell thickness: through the shell thickness:
LamLaméé’s solution ( ) and present higher-order shell theory for N = 7 ( )’s solution ( ) and present higher-order shell theory for N = 7 ( )
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ConclusionsConclusionsConclusionsConclusions
A simple and efficient concept of S-surfaces inside the shell body has A simple and efficient concept of S-surfaces inside the shell body has been proposed. This concept permits the use of 3D constitutive been proposed. This concept permits the use of 3D constitutive equations and leads for the sufficient number of S-surfaces to the equations and leads for the sufficient number of S-surfaces to the numerically exact solutions of 3D elasticity problems for thick and thin numerically exact solutions of 3D elasticity problems for thick and thin shellsshells
A new higher-order theory of shells has been developed which permits A new higher-order theory of shells has been developed which permits the use, in contrast with a classic shell theory, only displacement the use, in contrast with a classic shell theory, only displacement degrees of freedomdegrees of freedom
A robust exact geometry four-node solid-shell element has been built A robust exact geometry four-node solid-shell element has been built which allows the solution of 3D elasticity problems for thick and thin which allows the solution of 3D elasticity problems for thick and thin shells of arbitrary geometryshells of arbitrary geometry
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Thanks for your attention!Thanks for your attention!Thanks for your attention!Thanks for your attention!