Accepted ManuscriptNonlinear dynamic response and vibration of shear deformable imperfect eccentrically stiffened S-FGM circular cylindrical shells surrounded on elastic foundations Nguy
Trang 1Accepted Manuscript
Nonlinear dynamic response and vibration of shear deformable
imperfect eccentrically stiffened S-FGM circular cylindrical shells
surrounded on elastic foundations
Nguyen Dinh Duc, Pham Toan Thang
PII: S1270-9638(14)00230-2
Reference: AESCTE 3163
To appear in: Aerospace Science and Technology
Received date: 4 September 2014
Revised date: 1 November 2014
Accepted date: 9 November 2014
Please cite this article in press as: D.D Nguyen, T.T Pham, Nonlinear dynamic response and vibration of shear deformable imperfect eccentrically stiffened S-FGM circular cylindrical shells surrounded on elastic
foundations, Aerosp Sci Technol (2014), http://dx.doi.org/10.1016/j.ast.2014.11.005
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Trang 2Nonlinear dynamic response and vibration of shear deformable imperfect
eccentrically stiffened S-FGM circular cylindrical shells
surrounded on elastic foundations
Nguyen Dinh Duc*, Pham Toan Thang Vietnam National University, Ha Noi, 144 XuanThuy – Cau Giay – Ha Noi – Viet Nam Email: ducnd@vnu.edu.vn; thangpt_55@vnu.edu.vn, Tel: +84-4-37547978; Fax: +84-4-37547424
Abstract: This paper presents an analytical approach to investigate the nonlinear dynamic response
and vibration of imperfect eccentrically stiffened functionally graded thick circular cylindrical shells surrounded on elastic foundations using both of the first order shear deformation theory and stress function with full motion equations (not using Volmir's assumptions) Material properties are graded in the thickness direction according to a Sigmoid power law distribution (S-FGM) in terms of the volume fractions of constituents with metal - ceramic - metal layers The S-FGM shells are subjected to mechanical and damping loads Numerical results for dynamic response of the shells are obtained by Runge-Kutta method The results show the influences of geometrical parameters, the volume fractions
of metal – ceramic – metal layers, imperfections, theelastic foundations, eccentrically stiffeners, pre–loaded axial compression and damping loads on the nonlinear dynamic response and nonlinear vibration of functionally graded cylindrical shells The proposed results are validated by comparing with other results reported in literature
Keywords: Nonlinear dynamic response, vibration, Sigmoid FGM thick circular cylindrical shells, the first order shear deformation theory, elastic foundations
1 Introduction
The idea of FGMs was first introduced in 1984 by a group of Japanese material scientists [1] Functionally graded materials (FGMs) are composite materials obtained by combining and mixing two or more different constituent materials, which are distributed along the thickness in
Corresponding author: Duc.N.D E-mail address: ducnd@vnu.edu.vn
Trang 3accordance with a volume fraction law The FGM have received considerable attention in recent years due to their high performance heat resistance capacity and excellent characteristics
in comparison with conventional composites
Regarding to the dynamic and vibration of FGM plates and shells, Loy et al [2] analyzed the vibrations of the FGM cylindrical shells They found that the natural frequencies are affected by the constituent volume fractions and configurations of the constituent materials Pradhan et al [3] studied the vibration characteristics of FGM cylindrical shells made of stainless steel and zirconia under different boundary conditions Free vibration analysis of functionally graded cylindrical shells with holes was researched in [4] Ebrahimi and Najafizadeh [5] investigated the free vibration of a two-dimensional functionally graded circular cylindrical shell The equations of motion are based on the Love’s first approximation classical shell theory Shen [6] researched the large amplitude vibration behavior of a shear deformable FGM cylindrical shell of finite length embedded in a large outer elastic medium and in thermal environments Najafizadeh and Isvandzibaei [7,8] studied free vibration of FGM cylindrical shells with ring support by using Ritz method based on the first order and higher order shear deformation shell theories Haddadpour et al [9]considered free vibration of simply supported FGM cylindrical shells with four sets of in-plane boundary conditions by using Galerkin method based on the classical shell theory Alibeigloo et al [10] presented the numerical free vibration analysis for FGM cylindrical shell embedded thin piezoelectric layers Sofiyev and Kuruoglu [11] focused the torsional vibration and buckling of un-stiffened cylindrical shell with functionally graded coatings surrounded by an elastic medium Bich and Nguyen [12] used the displacement functions to investigate the nonlinear vibration of FGM un-stiffened cylindrical shells subjected to axial and transverse mechanical loads Their results shown that the Volmir’s assumption can be used for nonlinear dynamic analysis with an acceptable accuracy Shariyat [13] studied the dynamic buckling of imperfect FGM cylindrical shells with integrated surface-bonded sensor and actuator layers subjected to some complex combinations of thermo-electro-mechanical loads Shen [14-16] presented a postbuckling analysis of FGM cylindrical thin shells and FGM panels subjected to axial compression or external pressure in thermal environments Shen and Noda [17] obtained the postbuckling analysis for FGM cylindrical shells with piezoelectric actuators subjected to lateral pressure in
Trang 4thermal environments Loy et al [18] investigated the vibration of FGM cylindrical shells composed of stainless steel and nickel, considering the influence of the constituent volume fractions and the effects of the constituent materials on the frequencies Meiche et al [19] proposed a new hyperbolic shear deformation theory taking into account transverse shear deformation effects for the buckling and free vibration analysis of thick functionally graded sandwich plates Benachour et al [20] used the four variable refined plate theory for free vibration analysis of plates made of functionally graded materials with an arbitrary gradient Hebali et al [21] developed a new quasi-three-dimensional (3D) hyperbolic shear deformation theory for the bending and free vibration analysis of functionally graded plates Bessaim et al [22] studied a new higher-order shear and normal deformation theory for the bending and free vibration analysis of sandwich plates with functionally graded isotropic face sheets Larbi et al [23] investigated an efficient shear deformation beam theory based on neutral surface position
is developed for bending and frees vibration analysis of functionally graded beams Bouremanaet al [24] studied a new first-order shear deformation beam theory based on neutral surface position is developed for bending and free vibration analysis of functionally graded beams Meziane et al [25] proposed an efficient and simple refined shear deformation theory is presented for the vibration and buckling of exponentially graded material sandwich plate resting on elastic foundations under various boundaries Draiche et al [26] investigated the use
of trigonometric four variable plate theory for free vibration analysis of laminated rectangular plate supporting a localized patch mass
Today, functionally graded shells involving circular cylindrical shells are widely used in many important details of space vehicles, aircrafts, nuclear power plants and many other engineering applications For example, the strategic missiles using solid materials, they capable fly far beyond the continent with great velocity, so their hull could stand very high strength and high temperatures To satisfy it, the shell of the strategic missiles usually is made
of composite carbon-carbon or functionally graded materials (FGM) FGM circular cylindrical shell also could be used as the shell of a nuclear reactor or special engineering pipes, Regarding to the static and dynamic analysis of the FGM circular cylindrical shells, Duc and Thang [27] studied an analytical approach to investigate the nonlinear static buckling and postbuckling for imperfect eccentrically stiffened functionally graded thin circular
Trang 5cylindrical shells surrounded on elastic foundation with ceramic–metal–ceramic layers and subjected to axial compression Duc and Thang [28] also investigated the nonlinear static buckling for imperfect functionally graded thin circular cylindrical shells reinforced by stiffeners in thermal environment
Some researchers have used the first-order and high-order shear deformation theories for buckling analysis of the perfect and imperfect thick composite cylindrical shells [29-31] Sheng and Wang [32] studied dynamic behavior for the functionally graded cylindrical shell with surface-bonded PZT piezoelectric layer under moving loads Shahsiah and Eslami [33] investigated the thermal buckling of FGM cylindrical shells under two types of thermal loads based on the first order shear deformation shell theory Shen [34] researched the large amplitude vibration behavior of a shear deformable FGM cylindrical shell of finite length embedded in a large outer elastic medium and in thermal environments Shahsiah and Eslami [35] presented the buckling temperature of simply supported FGM cylindrical shells under two cases of thermal loading using the first order shear deformation shell theory Bouderba et al [36] studied the thermomechanical bending response of functionally graded plates resting on Winkler-Pasternak elastic foundations.Tounsi et al [37] proposed a refined trigonometric shear deformation theory (RTSDT) taking into account transverse shear deformation effects is presented for the thermoelastic bending analysis of functionally graded sandwich plates Bourada et al [38] performed the use of a new four-variable refined plate theory for thermal buckling analysis of functionally graded material (FGM) sandwich plates Belabed et al [39] presented an efficient and simple higher order shear and normal deformation theory for functionally graded material (FGM) plates Bouiadjra [40] studied the nonlinear behavior of functionally graded material (FGM) plates under thermal loads using an efficient sinusoidal shear deformation theory Fekrar et al [41] developed a new sinusoidal higher-order plate theory for bending of exponential graded plates Bousahla et al [42] proposed a new trigonometric higher-order theory including the stretching effect for the static analysis of advanced composite plates such as functionally graded plates.Saidi et al [43] included an analytical solution to the thermo-mechanical bending analysis of functionally graded sandwich plates by using a new hyperbolic shear deformation theory Houari et al [44]developeda new higher order shear and normal deformation theory to simulate the thermoelastic bending of
Trang 6e research
d functional
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Trang 7For an S-FGM cylindrical shell made of two different constituent materials with ceramic-metal layers, the volume fractions V z c and V z m can be written in the Sigmoid power law distribution as [27-28,47]
metal-2
22
21,
V z
z h
with volume fraction index N dictates the material variation profile through the S-FGM shell
thickness, the subscriptsm andc are metal and ceramic constituents respectively
The shell-foundation interaction is represented by Pasternak model as
Trang 8( , )( , )( , ),
, ,, ,
e displacem
y
G denote t
SDT and verately large
te system of
fo
rder shear dligible and displaceme
ment compothe mid-pla
von-Karma
er deflection
f a circular undations
deformationnormal doent field fo
onent alongane rotation
, z coordinaransverse no
displacemenobtain
ounded on e
ch assumes dicular to thwithin the
(4)
ate directioormal abou
nt relation
elastic
that the
he shell is
mid-ons, and
ut the y
n which
Trang 9y x
G G
Trang 10E I I
h
h
j j
0 0
( )( )
where the coupling parameters C C x, y are negative for outside stiffeners and positive for inside one; I I x, y are the second moments of cross-section areas; s s x, y are the spacing of the
Trang 11longitudinal and circumferential stiffeners; ,z z x yare the eccentricities of stiffeners with respect
to the middle surface of shell; and the width and thickness of longitudinal and circumferential stiffeners are denoted by ,d h x x andd h respectively y, y A A are the cross-section areas of x, y
stiffeners And K is correction factors, 4
y x
y x
y x
F
G G
F
G G
H
ss
ss
ss
Trang 122 2
h
¨ (14) ,
f x y is stress function defined by
, , , , ,
N f N f N f (15) Substituting Eq (15) into Eqs (13a) and (13b) yields
2 2
Trang 130 2 2 1
0
,,
,
x x
y y
G G
s
Trang 14y y
Assume thatw x y , is a known function representing initial small imperfection, Eqs (21) for
an imperfect S-FGM circular cylindrical shell can be modified as the following form [19-20]:
Trang 15' * 2
2 2
0 2 2
y x
x
y x
y
y x
F
G G
F
G G
H
ss
ss
ss
Trang 16elastic foundations using the first order shear deformation theory
3 Nonlinear dynamic analysis
An imperfect S-FGM circularcylindrical shell considered is assumed to be simply supported and subjected to uniformly distributed pressure of intensity q and axial compression P x.Thus the boundary conditions are
The initial imperfection w*is assumed to have the same form of the shell deflectionw, i.e
Trang 17in which W0 is known initial amplitude
Substituting Eqs (29) and (30) into the compatibility equation (27), we define the stress function as
(33)
in which specific expressions of coefficients H i1i( 1,5),H jk(j2,3,k 1,3),n m m( 1,10),S1
are given in Appendix A
3.1 Natural frequencies
Taking linear parts of Eqs (33) and putting q 0, the natural frequencies of the perfect shell
can be determined directly by solving determinant
Trang 183.2 Nonlinear dynamic responses
Consider a functionally graded circular cylindrical shell acted on by an uniformly distributed transverse load q t Qsin8 ( Q is the amplitude of uniformly excited load, t 8 is the frequency of the load) The system Eqs (33) have the form
dt
For further research, we next consider the hypothetical case of rotations ,' ' exist, but the x yinertial forces caused by the rotation angles ,' ' are small so they can be ignored The x ysystem Eqs (35) can be written as follows
Trang 19in which specific expressions of coefficients b i i 1,6 is give in Appendix B
In other hand, from Eq (37) the fundamental frequencies of a perfect shell can be determined approximately by an explicit expression
Trang 20Seeking solution as W Asin8 and applying Galerkin procedure to Eq (40), the t
amplitude-frequency relation of nonlinear forced vibration is obtained
4 Numerical results and discussions
In order to illustrate the present approach, we consider an FGM shell that consists of aluminum (metal) and alumina (ceramic) with the following properties [46]
Trang 21To validate the analysis, result for the natural frequencies of the isotropic circular cylindrical shell obtained from expression Eq (34) with N 0 (in this case, the S-FGM shell and the P-FGM shell are same and they are made of full metal) is compared with Loy et al [18] In Table
1, the comparison shows that the present result is agreed well with those in the literature
Fig 2 and Table 2 show the comparison of dynamic response of the S-FGM shells in this paper based on the first order shear theory and the results in Bich et al [12] for the P-FGM shell based on the classic theory with the same geometrical parameters without elastic foundations Clearly, in Table 2 we can see that there is very a little difference between natural frequencies, but in Fig 3, it is easy to recognize that the obtained amplitudes of frequency in this paper of the S-FGM shell are smaller than the one of the P-FGM shell in [12]