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Shock and Vibration 15 (2008) 335–343 335 IOS Press Chaotic vibrations of closed cylindrical shells in a temperature field A.V. Krysko a , J. Awrejcewicz b,, E.S. Kuznetsova a and V.A. Krysko a a Saratov State Technical University, Department of Higher Mathematics, 77 Polytechnicheskaya St, 410054, Saratov, Russia b Technical University of Lodz, Department of Automatics and Biomechanics, Stefanowskiego 1/15, 90-924 Lodz, Poland Received 2007 Revised 2007 Abstract. Complex vibrations of cylindrical shells embedded in a temperature field are studied, and the Bubnov-Galerkin method in higher approximations and in the Fourier representation is applied. Both lack and influence of temperature field on the shell dynamics are analyzed. Keywords: Chaos, vibrations, shell, temperature field 1. Formulation of the problem Problems related to the investigation of chaotic vibrations of flexible plates and shells attract attention of many engineers and applied mathematicians [1–10]. This is mainly motivated by an observation that harmful vibrations of plates and shells occur in various industry branches including space and aircraft factories. In the frame of the nonlinear classical theory of shallow shells a closed cylindrical shell with circled cross section of finite length with both constant stiffness and density subjected to sign changeable loading and embedded into the temperature field is studied. Results of temperature field action are exhibited by shell buckling, which differs essentially from shell buckling yielded by mechanical load action. Thermal stresses occur owing to thermal extension of shell elements. Note that compression of the shell elements yields heat occurrence, whereas during shell elements extension a heat is absorbed. However, the frequently applied technical theory of shells does not introduce any differences between stresses produced directly by either temperature field or mechanical external loads. The obtained solutions to the investigated problem may have an important impact for both rocket design industry or harmful effects occurred during transported cylinder-types containers fulfilled with fluids. In the first case, depending on the atmosphere conditions as well as on a moving rocket height, the external load acting on the rocket changes in time and may also change depending on the rocket surface. In the second case a loading of a moving container modeled by the cylindrical shell depends strongly on the movement parameters because sloshing of fluids occurs. Therefore, we study the classical problem but with inclusion of the shell loading depending both on time and coordinates q = q(x, y, t). In addition, in a case of a moving rocket a key role plays a temperature field, what is taken into account of the investigated model. The system of coordinates with x axis coinciding with longitudinal coordinate, y axis coinciding with a circle coordinate, as well as z axis directed along a normal to the mean surface is introduced (Fig. 1). The cylindrical shell as a 3D object is defined in the following way in the given system of coordinates: Ω= {x, y, z |(x, y) [0; L] × [0; 2π], z h}. Corresponding author. E-mail: [email protected]. ISSN 1070-9622/08/$17.00 2008 – IOS Press and the authors. All rights reserved

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Shock and Vibration 15 (2008) 335–343 335IOS Press

Chaotic vibrations of closed cylindrical shellsin a temperature field

A.V. Kryskoa, J. Awrejcewiczb,∗, E.S. Kuznetsovaa and V.A. KryskoaaSaratov State Technical University, Department of Higher Mathematics, 77 Polytechnicheskaya St, 410054,Saratov, RussiabTechnical University of Lodz, Department of Automatics and Biomechanics, Stefanowskiego 1/15, 90-924 Lodz,Poland

Received 2007

Revised 2007

Abstract. Complex vibrations of cylindrical shells embedded in a temperature field are studied, and the Bubnov-Galerkin methodin higher approximations and in the Fourier representation is applied. Both lack and influence of temperature field on the shelldynamics are analyzed.

Keywords: Chaos, vibrations, shell, temperature field

1. Formulation of the problem

Problems related to the investigation of chaotic vibrations of flexible plates and shells attract attention of manyengineers and applied mathematicians [1–10]. This is mainly motivated by an observation that harmful vibrationsof plates and shells occur in various industry branches including space and aircraft factories.

In the frame of the nonlinear classical theory of shallow shells a closed cylindrical shell with circled cross sectionof finite length with both constant stiffness and density subjected to sign changeable loading and embedded intothe temperature field is studied. Results of temperature field action are exhibited by shell buckling, which differsessentially from shell buckling yielded by mechanical load action. Thermal stresses occur owing to thermal extensionof shell elements. Note that compression of the shell elements yields heat occurrence, whereas during shell elementsextension a heat is absorbed. However, the frequently applied technical theory of shells does not introduce anydifferences between stresses produced directly by either temperature field or mechanical external loads.

The obtained solutions to the investigated problem may have an important impact for both rocket design industryor harmful effects occurred during transported cylinder-types containers fulfilled with fluids. In the first case,depending on the atmosphere conditions as well as on a moving rocket height, the external load acting on the rocketchanges in time and may also change depending on the rocket surface. In the second case a loading of a movingcontainer modeled by the cylindrical shell depends strongly on the movement parameters because sloshing of fluidsoccurs. Therefore, we study the classical problem but with inclusion of the shell loading depending both on timeand coordinatesq = q(x, y, t). In addition, in a case of a moving rocket a key role plays a temperature field, what istaken into account of the investigated model.

The system of coordinates withx axis coinciding with longitudinal coordinate,y axis coinciding with a circlecoordinate, as well asz axis directed along a normal to the mean surface is introduced (Fig. 1). The cylindricalshell as a 3D objectΩ is defined in the following way in the given system of coordinates:Ω = x, y, z|(x, y) ∈[0;L]× [0; 2π],− z h.

∗Corresponding author. E-mail: [email protected].

ISSN 1070-9622/08/$17.00 2008 – IOS Press and the authors. All rights reserved

336 A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field

Fig. 1. Computation scheme.

The system of equations governing shell dynamics is presented in the following non-dimensional form [11]:1

12(1 − ν2)

[λ−2 ∂

4w

∂x4+ 2

∂4w

∂x2∂y2+ λ2 ∂

4w

∂y4

]− L(w,F ) − ky

∂2F

∂x2− ∂2w

∂t2− ε

∂w

∂t−

+1

12(1 − ν2)

(λ−1 ∂

2Mt

∂x2+ λ

∂2Mt

∂y2

)+ k2

yq(x, y, t) = 0, (1)

λ−2 ∂

4F

∂x4+ 2

∂4F

∂x2∂y2+ λ2 ∂

4F

∂y4+

12L(w,w) + ky

∂2w

∂x2+ λ−1 ∂

2Nt

∂x2+ λ

∂2Nt

∂y2

= 0.

The following non-dimensional parameters are introduced (with bars):

w = 2hw, F = E0(2h)3F, t =RL

2h√gE0

t, λ = L/R;x = Lx, y = Ry; ky = kyh

R2, q = q

E0(2h)4

L2R2,

whereL andR = Ry are the shell length and radius, respectively,t denotes time,ε is the damping coefficient of amedium where the shell is embedded,F is the stress (Airy’s) function,w denotes deflection,h is the shell thickness,ν is Poisson’s coefficient,E0 is the Young modulus,q(x, y, t) is the transversal load,ky is the shell curvatureregardingy. In addition,

L(w,F ) =∂2w

∂x2

∂2F

∂y2+∂2w

∂y2

∂2F

∂x2− 2

∂2w

∂x∂y

∂2F

∂x∂y, L(w,w) = 2

[∂2w

∂x2

∂2w

∂y2−

(∂2w

∂x∂y

)2]

are the known nonlinear operators,

Nt =1h

h2∫

−h2

Qdz

is the temperature-induced force,

Mt =12h3

h2∫

−h2

Qzdz

A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field 337

is the temperature-induced moment,Q(x, y, z) = T − T0 is the temperature increment, whereasT0 is the initialtemperature. For brevity of our considerations, bars over the non-dimensional quantities in Eq. (1) are omitted.

The system of Eq. (1) is supplemented by boundary and initial conditions, which are formulated below. Thetemperature fieldT is given in the following form:T (x, y) = C sin(πx) sin(πy).

Let us consider the dissipative system (ε = 0) subjected to transversal loading distributed in zone0 ϕ ϕ 0,0 x 1 and being changed harmonicallyq(t) = q0 sin(ωpt), whereq0 andωp are the amplitude and frequency ofthe exciting force, respectively.

2. The Bubnov-Galerkin method and Fourier representation

The boundary value problem regarding space coordinates is solved by the Bubnov-Galerkin method in higherapproximations. Functionsw andF being solutions to Eq. (1) are approximated by an expression consisting of theproduct of functions depending on time and coordinates of the following form

w =N1∑i=0

N2∑j=0

Aij(t)ϕij(x, y), F =N1∑i=0

N2∑j=0

Bij(t)ψij(x, y). (2)

In order to find approximated values of functionsw andF we take the coordinate systems of functions of the formϕij(x, y), ψij(x, y) (i, j = 0, 1, 2 . . .) in Eq. (2), which satisfy the following requirements:

1. ϕij(x, y) ∈ HA, ψij(x, y) ∈ HA, whereHA is the Hilbert space, which is further referred to as the energyspace.

2. ∀i, j functionsϕij(x, y) andψij(x, y) are linearly independent, continuous together with their up to the fourthorder derivatives in spaceΩ.

3. ϕij(x, y) andψij(x, y) satisfy rigorously main boundary conditions (and initial conditions if any).4. ϕij(x, y) andψij(x, y) satisfy completeness property inHA.5. ϕij(x, y) andψij(x, y) should representN first elements of a complete system of functions.

CoefficientsAij(t) andBij(t) are the functions of time being sought. For convenience, the left hand sides ofequations (1) given in brackets are denoted byΦ 1 andΦ2, respectively, and therefore Eq. (1) takes the followingform:

Φ1

(w,F,

∂2w

∂x2,∂2F

∂x2, . . . ;Mt,

∂2Mt

∂x2,∂2Mt

∂y2

)+ k2

yq(x, y, t) = 0,(3)

Φ2

(w,F,

∂2w

∂x2,∂2F

∂x2, . . . ;Nt,

∂2Nt

∂2x,∂2Nt

∂2y

)= 0.

Applying the Bubnov-Galerkin procedure to Eq. (3) one gets1∫

0

ξ∫0

1ϕkl(x, y)dxdy+

x2∫x1

y2∫y1

k2yq(x, y, t)ϕkl(x, y)dxdy = 0,

(4)1∫

0

ξ∫0

2ψkl(x, y)dxdy = 0,k = 0, 1, . . . , N1; l = 0, 1, . . .N2.

Now and further on we takeξ = 2π for the closed cylindrical shell. Owing to Eq. (4), Eq. (3) take the followingform∑

kl

[∑ij

AijSijrskl +∑ij

BijC1,ijkl + k2yQkl +H1kl −

∑ij

Aij

∑rs

BrsD1,ijrskl

−∑ij

[d2Aij

dt2+ ε

dAij

dt

]Gijkl = 0, (5)

∑kl

[∑ij

AijC2,ijkl+∑ij

Bij

∑rs

Pijrskl +∑ij

Aij

∑rs

ArsD2,ijrskl +H2kl] = 0.

338 A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field

Symbol∑

kl [∗] before every equation of system Eq. (5) means that each of these equations is understood as thesystem ofkl equations of these types, and the associated Bubnov-Galerkin integrals have the following form

Sijrskl =

1∫0

ξ∫0

112(1 − ν2)

[1λ2

∂2ϕij

∂x2

∂2ϕrs

∂x2+ λ2 ∂

2ϕij

∂y2

∂2ϕrs

∂y2+ 2

∂2ϕij

∂x∂y

∂2ϕrs

∂x∂x

]ϕkldxdy,

C1,ijkl =

1∫0

ξ∫0

[−ky

∂2ψij

∂x2

]ϕkldxdy, C2,ijkl =

1∫0

ξ∫0

[ky∂2ϕij

∂x2

]ψkldxdy,

D1,ijrskl =

1∫0

ξ∫0

L(ϕij , ψrs)ϕkldxdy, D2,ijrskl =

1∫0

ξ∫0

12L(ϕij , ϕrs)ψkldxdy, (6)

Pijrskl =

1∫0

ξ∫0

[1λ2

∂2ψij

∂x2

∂2ψrs

∂x2+ λ2 ∂

2ψij

∂y2

∂2ψrs

∂y2+ 2

∂2ψij

∂x∂y

∂2ψrs

∂x∂x

]ψkldxdy,

Gijkl =

1∫0

ξ∫0

ϕijψkldxdy, Qkl =

1∫0

ξ∫0

ϕklq(x, y, t)dxdy,

H1kl =

1∫0

ξ∫0

112(1 − ν2)

[λ−1 ∂

2Mt

∂x2+ λ

∂2Mt

∂y2

]ϕkldxdy,

H2kl =

1∫0

ξ∫0

[λ−1 ∂

2Nt

∂x2+ λ

∂2Nt

∂y2

]ψkldxdy.

Integrals Eq. (6), except ofQkl corresponding only to the part of the shell area, are computed regarding the wholeshell surface. After application of the Bubnov-Galerkin procedure the obtained system of ordinary differentialequations with respect to functionsAij(t) andBij(t) has the following matrix form

G(A+ εA) + SA+ C1B + D1AB = Qq(t) + H1,(7)

C2A+ PB + D2AA = H2,

where:G = [Gijkl ], S = [Sijrskl ], C1 = [C1ijkl ], C2 = [C2ijkl ], D1 = [D1ijrskl ],D2 = [D2ijrskl],P = [Pijkl ] –square matrices of dimension2 ·N1 ·N2 × 2 ·N1 ·N2, andA = [Aij ], B = [Bij ], Q = [Qij ] are the matrices ofdimension2 ·N1 ·N2 × 1.

Further, the second equation of system Eq. (7) is solved regarding matrixB, and then it is solved by the methodof inversed matrix on each time step:

B = [−P−1D2A − P−1C2]A + P−1H2C2A+ PB + D2AA = H2. (8)

Multiplying the first equation of Eq. (8) byG−1 and introducing notation.

A = R the following Cauchy problemregarding nonlinear first order ODEs is formulated

R = −εR + G−1D1AB − G−1SA+ q(t)G−1Q + G−1H1,

A = R ., (9)

The introduced transformation is allowed since the inverse matricesG−1 andP−1 exist if the coordinate functionsare linearly independent.

Equations (9) are supplemented by boundary and initial conditions and the obtained Cauchy problem is solvedby the fourth-order Runge-Kutta method. A step in time is chosen via the Runge rule. Results given by various

A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field 339

computational methods are compared in reference [12], where it is shown that integration by the fourth Runge-Kuttamethod is sufficient and the application of higher order Runge-Kutta approaches are time consuming and they donot yield improvement of the results.

3. A numerical example

In this section we study vibrations of a ball-type supported cylindrical shell along its edges and having thehomogeneous boundary conditions [13]

w = 0;∂2w

∂x2= 0; F = 0;

∂2F

∂x2= 0 for x = 0; 1, , (10)

and the following initial conditions

w(x, y)|t=0 = 0,∂w

∂t|t=0 = 0. (11)

In this caseϕij , ψij in Eq. (2) are approximated by the product of two functions, where each depends only on oneargument which satisfies boundary conditions Eq. (10):

w =N1∑i=1

N2∑j=0

Aij(t) sin(iπx) cos(jy),F =N1∑i=1

N2∑j=0

Bij(t) sin(iπx) cos(jy). (12)

The Bubnov-Galerkin algorithm described briefly so far allows a wide class of problems, both static and dynamic,to be solved. A solution to static problems is obtained via the set-up method first applied by Feodos’ev (the so called“set up method”) [14], and widely applied for instance in monograph [5]. In order to solve static problems of platesand shells, various approximate methods have been applied allowing the partial differential equations to be reducedto the system of nonlinear algebraic equations, which is usually further linearized. In the set-up method a solutionto PDEs is reduced to that of the Cauchy problem of ODEs. Results of static solutions to PDEs are reported andillustrated in reference [15].

Using the example of a closed cylinder type shell with parametersky = 112.5 andλ = 2, embedded in thetemperature field and subjected to the following transversal loadq(t) = q 0 sin(ωpt) distributed on the wholeshell surface0 ϕ 2π, 0 x 1, for fixed loading amplitudeq0 = 0.1 we are going to study how thecharacter of vibrations changes owing to the change of temperature intensity coefficientC in relationT (x, y) =C sin(πx) sin(πy).

The fundamental characteristics such as signalw(t), phase portraitw(w ′), power spectrumS(ωp) depending onthe boundary conditions are shown in Table 1. The values ofC are called threshold ones, since between the reportedvalues ofC a picture is almost unchanged. Observe the following particularities of the shell behavior.

1. If C = 0, then it means that there is no temperature field. The first row of the table exhibits harmonic shellvibrations. A phase portrait has the form of a circle and vibrations appear on the fundamental frequency:ωp = ω0 = 26.1256, whereωp is the excitation frequency, which is clearly manifested in the frequencyspectrum.

2. For0 < C 24.2 the temperature intensity increases, but the signal shape is not changed qualitatively, andvibrations are harmonic. The phase portrait exhibits a set of one rotated cycle.

3. Increasing the temperature field intensity by 0.04, i.e. forC= 24.4, the vibration character is changed, and thesystem transfers into chaos associated with an increase of deflection. The phase portrait is irregular, and powerspectrum exhibits chaotic vibrations associated with both fundamental and its half frequencies.

4. In interval24.4 < C 29 changes appear in the vibration character, and from the broad band power spectrum“chaotic frequency part” is going to vanish.

5. ForC = 30 the signal is stabilized, and the phase plot exhibits a strange attractor. Power frequency spectrumconsists of a linear combination of independent frequencies and bifurcations. A detailed analysis of the systembehavior associated with the value ofC is given below.

340 A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field

Table 1Temperature amplitudes signals, phase portraits and power spectra of the cylindrical shell

0

24.2

24.4

29

30

31

A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field 341

Table 2Influence of variations in parameterq0 for fixed C = 30

0.052

0.0522

0.09

0.1

0.15

342 A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field

6. An increase of parameterC intensity yields also the beam chaotic dynamics, however with different structurethan that forC = 24.4 since chaotic zones are mainly produced by period doubling bifurcations in this case.

Below, we will study the system behavior for fixed value ofC = 30 and for different values of external excitationamplitudeq0. The same characteristics as previously are applied as reported in Table 2.

The results presented in Table 2 are briefly summarized below.

1. Forq0 = 0.052 the beam exhibits periodic dynamics with the fundamental frequencyω 0, and the Poincaresection clearly exhibits one point.

2. A slight variation ofq0 by the amount of 0.002 (q0 = 0.0522) changes qualitatively the system behavior.Namely, subharmonic vibrations appear with the fundamental frequencyω p1 = ωp/2 = 13.0628, and a firstindependent frequency appearsω1 = 2.8471 producing the following linear combinationω 2 = ωp1 − ω1 =10.2157, i.e. quasi-periodic vibrations appear with two frequenciesω p1 andω1. Dobled-torus is also manifestedin the phase projection.

3. Forq0 = 0.09 a period doubling bifurcation occursω p2 = ωp1/2 = 6.5314. In the Poincare map four pointsappear, whereas the broadband structure of the phase portrait indicates occurrence of quasi-periodic vibrations.

4. A further increase ofq0 is associated with many period doubling bifurcations, and forq 0 > 0.1 the beamexhibits chaotic dynamics.

In other words, the described system behavior mainly concerns a transition from periodic and quasi-periodicdynamics to chaotic one.

4. Concluding remarks

Complex vibrations of the mechanical system represented by a closed cylindrical shell with a circled cross sectionand of finite length are studied in this work. The investigations are carried out using the Bubnov-Galerkin methodwith Fourier representation and with higher approximation regarding spatial coordinates.

The novel scenario of the studied shell transition from periodic to chaotic vibrations via the collapse of quasi-periodic vibrations with one independent frequency and period doubling bifurcation is illustrated and discussed.Analysis of the system behavior with the change of parameterC (temperature intensity) in the formulaT (x, y) =C sin(πx) sin(πy) and for the fixed value ofq0 = 0.1 (Table 1) as well as for fixed value ofC = 30 (Table 2) hasbeen carried out. Additionally, it is shown (Table 2) how for various intensities of the temperature field, includingits lack, an increase of the loading induces qualitative changes in the investigated shell dynamics, and how chaoticzones are transmitted into harmonic ones and vice versa.

References

[1] V.S. Avduyevskiy, B.M. Galitseyskiy and G.A. Glebov,Introduction to Heat Transfer in Airplanes and Rocket-Cosmic Techniques,Avduyevskiy, Koshkin, Mashinostroyeniye, Moscow, 1992, in Russian.

[2] J. Awrejcewicz and V.A. Krysko, Feigenbaum scenario exhibited by thin plate dynamics,Nonlinear Dynamics 24 (2001), 373–398.[3] J. Awrejcewicz, V.A. Krysko and A.V. Krysko, Spatio-temporal chaos and solitons exhibited by von Karman mode,International Journal

of Bifurcation and Chaos 12(7) (2002), 1465–1513.[4] J. Awrejcewicz and A.V. Krysko, Analysis of complex parametric vibrations of plates and shells using Bubnov-Galerkin approach,Archive

of Applied Mechanics 73 (2003), 495–504.[5] J. Awrejcewicz and V.A. Krysko,Nonclassic Thermoelastic Problem in Nonlinear Dynamics of Shells, Springer-Verlag, Berlin, 2003.[6] J. Awrejcewicz, V.A. Krysko and A.F. Vakakis,Nonlinear Dynamics of Continuous Elastic Systems, Springer-Verlag, Berlin, 2004.[7] V.M. Bakulin, I.F. Obraztsov and V.A. Potopakhin,Dynamical Problems of Theory of Composite Shells, Influence of Thermo-Dynamic

Loads and Concentrated Energy Flows, Moscow, FizMatLit, 1998, in Russian.[8] V.A. Krysko, J. Awrejcewicz and T.V. Shchekaturova, Chaotic vibrations of spherical and conical axially-symmetric shells,Archive of

Applied Mechanics 74(5–6) (2005), 338–358.[9] V.A. Krysko and I.V. Kravtsova,Control of Chaotic Vibrations of Flexible Spherical Shells, Izvestia RAS, Mekhanika Tverdogo Tela, 1,

2005, pp. 140–150, in Russian.[10] J. Awrejcewicz, V.A. Krysko and A.V. Krysko,Thermo-Dynamics of Plates and Shells, Springer-Verlag, Berlin, 2007.[11] A.S. Volmir, Stability of Elastic Systems, Moscow, Fizmatgiz, 1963, in Russian.

A.V. Krysko et al. / Chaotic vibrations of closed cylindrical shells in a temperature field 343

[12] V.A. Krysko and G.G. Narkaytis,Comparison of Various Computational Methods using Example of Vibration Modelling of Flexible InfinitePlates Subjected to Sign Changeable Loads, Proceedings of XXI International Conference on Plate and Shell Theories, Saratov, 2005,pp. 281–288.

[13] M.S. Kornishin,Nonlinear Problems of Plates and Shallow Shells and Methods of Their Solution, Moscow, Science, 1964, in Russian.[14] V.I. Feodos’ev, On the method of solution of stability of deformable systems,Prikladnaya Matematika i Mekhanika 27(2) (1963), 265–275,

in Russian.[15] V.A. Krysko, N.E. Saveleva and K.F. Shagivaleev, Statics and dynamics of closed cylindrical shells subjected to non-uniform transversal

loading,Izvestia VUZ, Mashinostroyeniye 1 (2005), 3–14, in Russian.

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