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Hindawi Publishing Corporation Mathematical Problems in Engineering Volume 2012, Article ID 717543, 12 pages doi:10.1155/2012/717543 Research Article Nonlinear Response of Vibrational Conveyers with Nonideal Vibration Exciter: Superharmonic and Subharmonic Resonance H. Bayıro ˘ glu, 1 G. F. Alıs ¸ veris ¸c ¸i, 1 and G. ¨ Unal 2 1 Yıldız Technical University, 34349 Istanbul, Turkey 2 Yeditepe University, 34755 Istanbul, Turkey Correspondence should be addressed to H. Bayıro ˘ glu, [email protected] Received 17 October 2011; Accepted 24 November 2011 Academic Editor: Swee Cheng Lim Copyright q 2012 H. Bayıro ˘ glu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumping method. Common unbalanced-mass driver oscillates the trough. The motion is strictly related to the vibrational parameters. The transition over resonance of a vibratory system, excited by rotating unbalances, is important in terms of the maximum vibrational amplitude produced and the power demand on the drive for the crossover. The mechanical system is driven by the DC motor. In this study, the working ranges of oscillating shaking conveyers with nonideal vibration exciter have been analyzed analytically for superharmonic and subharmonic resonances by the method of multiple scales and numerically. The analytical results obtained in this study agree well with the numerical results. 1. Introduction The load-carrying element of a horizontal shaking conveyer performs, as a rule, linear or sometimes circular or elliptical symmetrical harmonic oscillations—with a sinusoidal variation of exciting force. In vertical shaking conveyers, the load-carrying element performs double harmonic oscillations: linear along the vertical axis and rotational around that axis i.e., longitudinal and torsional oscillations. Conveyer drives with centrifugal vibration exciters may have 1 a single unbalanced-mass, 2 two equal unbalancing masses, 3 a pendulum-type unbalanced-mass, 4 four unbalanced-masses in two shafts, 5 four rotating unbalanced-masses for three principal modes of oscillation, that is, linear, elliptical, and circular. To induce strictly oriented linear oscillations of the load-carrying element, the conveyer drive should be arranged so that the line of excitation force passes through the

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Page 1: Nonlinear Response of Vibrational Conveyers with Nonideal ...downloads.hindawi.com/journals/mpe/2012/717543.pdfMathematical Problems in Engineering 3 where the constants k 1 and k

Hindawi Publishing CorporationMathematical Problems in EngineeringVolume 2012, Article ID 717543, 12 pagesdoi:10.1155/2012/717543

Research ArticleNonlinear Response of Vibrational Conveyers withNonideal Vibration Exciter:Superharmonic and Subharmonic Resonance

H. Bayıroglu,1 G. F. Alısverisci,1 and G. Unal2

1 Yıldız Technical University, 34349 Istanbul, Turkey2 Yeditepe University, 34755 Istanbul, Turkey

Correspondence should be addressed to H. Bayıroglu, [email protected]

Received 17 October 2011; Accepted 24 November 2011

Academic Editor: Swee Cheng Lim

Copyright q 2012 H. Bayıroglu et al. This is an open access article distributed under the CreativeCommons Attribution License, which permits unrestricted use, distribution, and reproduction inany medium, provided the original work is properly cited.

Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumpingmethod. Common unbalanced-mass driver oscillates the trough. The motion is strictly related tothe vibrational parameters. The transition over resonance of a vibratory system, excited by rotatingunbalances, is important in terms of the maximum vibrational amplitude produced and the powerdemand on the drive for the crossover. The mechanical system is driven by the DC motor. Inthis study, the working ranges of oscillating shaking conveyers with nonideal vibration exciterhave been analyzed analytically for superharmonic and subharmonic resonances by the method ofmultiple scales and numerically. The analytical results obtained in this study agree well with thenumerical results.

1. Introduction

The load-carrying element of a horizontal shaking conveyer performs, as a rule, linear(or sometimes circular or elliptical) symmetrical harmonic oscillations—with a sinusoidalvariation of exciting force. In vertical shaking conveyers, the load-carrying element performsdouble harmonic oscillations: linear along the vertical axis and rotational around that axis(i.e., longitudinal and torsional oscillations). Conveyer drives with centrifugal vibrationexciters may have (1) a single unbalanced-mass, (2) two equal unbalancing masses, (3)a pendulum-type unbalanced-mass, (4) four unbalanced-masses in two shafts, (5) fourrotating unbalanced-masses for three principal modes of oscillation, that is, linear, elliptical,and circular. To induce strictly oriented linear oscillations of the load-carrying element, theconveyer drive should be arranged so that the line of excitation force passes through the

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2 Mathematical Problems in Engineering

inertial centre of the entire oscillating system. Nonideal drives find application in suspendedand supported vibrational conveyers and feeders [1].

By the characteristics and adjustment of the elastic support elements (oscillatingsystem), we can distinguish between shaking conveyers with a resonant, subresonant, andsuperresonant system.

A practical difficulty with unbalanced-mass exciters, observed as early as 1904 by ASommerfeld, is that local instabilities may occur in operating speed of such devices.

Rocard [2], Mazert [3], Panovko, and I. I. Gubanova [4] have studied the problem ofthe stability of the unbalanced-mass exciter.

The first detailed study on the nonideal vibrating systems is presented by Kononenko.He obtained satisfactory results by the comparison of the experimental analysis and theapproximated method [5].

After this publication, the nonideal problem was presented by Evan-Ivanowski [6] orNayfeh and Mook [7]. These authors showed that sometimes dynamical coupling betweenenergy sources and structural response that had not to be ignored in reel engineeringproblems.

Theorical studies and computations of Ganapathy and Parameswaran have indicatedthe beneficial effect of the “material load” during the starting and transition phase of anunbalanced-mass-driven vibrating conveyor [8].

Bolla et al. analyzed through the multiple scales method a response of a simplifiednonideal and nonlinear vibrating system [9].

Gotzendorfer in [10] presented amacromechanical model for the transport of granularmatter on linear and horizontal conveyors subject to linear, circular or elliptic oscillations andcompared it to experimental results [10].

2. The Governing Equations of the Motion

The equations of motion for themodified rocard systemmay be obtained by using Lagrange’sequation

d

dt

(∂T

∂qi

)+∂D

∂qi− ∂T

∂qi+∂V

∂qi= 0, (2.1)

where T , the kinetic energy, is

T =12My2 +

12m[(y + θe cos θ

)2 + (θe sin θ

)2] + 12Imotθ

2, (2.2)

where e is the eccentricity of the mass m, m is the unbalanced-mass, M is the mass of thetrough and the conveyed material on the trough of the conveyor, θ is the angle of rotation ofthe shafts carrying unbalanced-masses, Imot is the moment of inertia of the rotating parts inthe motor, V , the potential energy, is

V =12k1y

2 +14k2y

4 +mge(1 + sin θ), (2.3)

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Mathematical Problems in Engineering 3

where the constants k1 and k2 are the linear and nonlinear elastic coefficients, respectively,D,the Rayleigh dissipation function, is

D =12cy2 +

12K(ωs − θ

), (2.4)

and qi is the generalized coordinate. Applying Lagrange’s equation for the two coordinatesqi = y and qi = θ gives the differential equations of motion

My +my + cy + k1y + k2y3 = me

(θ2 sin θ − θ cos θ

),

⎛⎜⎝Imot +me2︸ ︷︷ ︸

Isys

⎞⎟⎠θ +me

(y cos θ + g cos θ

)=

12

[∂K

∂θ

(θ −ωs

)+K

].

(2.5)

Equation (2.5) can be rewritten as follows:

y +ω20y = ε

[−2μy − αy3 − eθ cos θ

]+ κ

(θ2 sin θ

), (2.6)

θ = ε[−I cos θ(y + g

)+ E

(θ)], (2.7)

where

I =(m +M)e

Isys, κ =

me

m +M, 2μ =

c

m, α =

k2m

,

k1m +M

= ω20,

m

m +M= ε, E

(θ)=

(m +M)L(θ)

mIsys,

L(θ)=

12

[∂K

∂θ

(θ −ωs

)+K

],

(2.8)

where c is the damping coefficient of the vibrating conveyor, g is acceleration due to gravity,Isys = (Im + IM + Imot) is the total moment of inertia of all the rotating parts in the system, andωs is the synchronous angular speed of the induction motor [9].K is the instantaneous drivetorque available at the shafts. Note that E contains L(θ) that is the active torque generated bythe electric circuit of the DC motor, shown in Figure 1.

3. Analytical Solution

Ideal system: if there is no coupling between motion of the rotor and vibrating system andθ = constant (θ = ωt, θ = 0), (2.6) becomes

y +ω20y = ε

[−2μy − αy3

]+ κω2 sinωt. (3.1)

On the right side of the equation, a function of time is present.

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4 Mathematical Problems in Engineering

Figure 1: Vibrating model of the system.

Nonideal system:

θ = ε[−I cos θ(y + g

)+ E

(θ)],

y +ω2ny = ε

[−2μy − αy3 − eθ cos θ

]+ κ

(θ2 sin θ

),

(3.2)

where E(θ) = Mm(θ) − H(θ) is the difference between the torque generated by the motorand the resistance torque. Function E(θ) = u1 − u2θ is approximated by a straight line, whereu1 is a control parameter that can be changed according to the voltage, and u2 is a constantparameter, characteristic for the model of the motor.

We will obtain an approximate analytical solution to (3.2) by using the multiple scalesmethod:

θ(t, ε) ≈ θ0(T0, T1) + εθ1(T0, T1) + ε2θ2(T0, T1),

y(t, ε) ≈ y0(T0, T1) + εy1(T0, T1) + ε2y2(T0, T1),

Tn = εnt, n = 0, 1, . . . , T0 = t, T1 = εt

(3.3)

where the fast scale T0 = t and slow scale T1 = εt. The time derivatives transform according to

d

dt=

dT0dt

∂T0+dT1dt

∂T1+ · · · = D0 + εD1 + · · ·

d2

dt2= D2

0 + 2εD0D1 + · · · ,(3.4)

where Dn = ∂/∂Tn, (n = 0, 1, . . .); then,

θ =dθ

dt≈ D0θ0 + ε(D1θ0 +D0θ1) + · · · ,

θ =d2θ

dt2≈ D2

0θ0 + ε(2D0D1θ0 +D2

0θ1)+ · · · ,

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Mathematical Problems in Engineering 5

y =dy

dt≈ D0y0 + ε

(D1y0 +D0y1

)+ · · · ,

y =d2y

dt2≈ D2

0y0 + ε(2D0D1y0 +D2

0y1

)+ · · · .

(3.5)

Substituting (3.5) into (3.2), we will obtain

D20θ0 = ε

[−2D0D1θ0 −D2

0θ1 − I cos θ(D2

0y0 + g)+ E

(θ)],

D20y0 + ε

(2D0D1y0 +D2

0y1

)+ω2

n

(y0 + εy1

)

= ε[−2μD0y0 − α

(y0)3 − eD2

0θ0 cos θ]+ κ[D0θ0 + ε(D1θ0 +D0θ1)]

2 sin θ],

(3.6)

and equating coefficients of a like powers ε, we obtain(i) for ε0

D20θ0 = 0,

D20y0 +ω2

0y0 = κ(D0θ0)2 sin θ,

(3.7)

(ii) for ε1

D20θ1 = −2D0D1θ0 − I cos θ

(D2

0y0 + g)+ E

(θ), (3.8)

D20y1 +ω2

0y1 = −2D0D1y0 − 2μD0y0 − α(y0)3 − eD2

0θ0 cos θ

+ κ 2D0θ0(D1θ0 +D0θ1) sin θ.(3.9)

The solution of (3.7) can be written as

θ0 = BT0 + σT1, (3.10)

y0 = Λ sin(T0Ω) +A(T1)eiω0T0 +A(T1)e−iω0T0 , (3.11)

where

cos(θ0 + εθ1) = cos(θ0) +O(ε), sin(θ0 + εθ1) = sin(θ0) +O(ε),

Λ =−κΩ2(

Ω2 −ω20

) . (3.12)

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6 Mathematical Problems in Engineering

Table 1: Vibrational conveyer parameters in SI units.

ε α μ c I e(m) E1 E0 g ω0 k1 k2 m M

0.05 0.01 0.01 1 0.9 0.2 1.5 1.6 9.81 1 2 000 100 5 200

3.1. Subharmonic Resonances Ω ≈ 3ω0 (Table 1)

Near resonance:

D0θ0 = Ω, (3.13)

Ω = 3ω0 + εσ. (3.14)

The solution of (3.13) can be written as

θ0 = ΩT0 = 3ω0T0 + σT1. (3.15)

Taking

A[T1, T2] =a[T1]2

eiβ[T1], (3.16)

where a and β are real, and substituting it into (3.11), we will obtain

y0 =12e−iT0ω0−iβ(T1)a(T1) +

12eiT0ω0+iβ(T1)a(T1) + Λ sin(T0Ω),

θ1 =1

8(Ω3 −Ωω2

0

)2 e−i(T0ω0+β(T1))

× I(− 4Ω2ω2

0a(T1)

×((

1 + e2i(T0ω0+β(T1)))(

Ω2 +ω20

)cos(T0Ω) − 2i

(−1 + e2i(T0ω0+β(T1))

)Ωω0 sin(T0Ω)

)

−2ei(T0ω0+β(T1))(Ω2 −ω2

0

)cos(T0Ω)

(−4g +

(−κΩ2 + Λω2

0

)sin(T0Ω)

)),

y1 =(e−i(3T0Ω+4T0ω0+3β(T1))

×(−8e3iβ(T1)Ω

(Ω3 + 3Ω2ω0 −Ωω2

0 − 3ω30

)

×(ieiT0(4Ω+3ω0)ω2

0

(3αΛ3 + 8iΛμΩ + Iκ2Ω2 − IκΛω2

0

)(36Ω4 − 13Ω2ω2

0 +ω40

)

+ ieiT0(2Ω+3ω0)ω20

(−3αΛ3 + 8iΛμΩ − Iκ2Ω2 + IκΛω2

0

)(36Ω4 − 13Ω2ω2

0 +ω40

)

+ 4eiT0(Ω+3ω0)gIκω20

(9Ω4 − 10Ω2ω2

0 +ω40

)+ 4eiT0(5Ω+3ω0)gIκω2

0

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Mathematical Problems in Engineering 7

×(9Ω4 − 10Ω2ω2

0 +ω40

)+ 8e3iT0(Ω+ω0)gIκ

(36Ω6 − 49Ω4ω2

0 + 14Ω2ω40 −ω6

0

)

− ie3iT0(2Ω+ω0)ω20

(4Ω4 − 5Ω2ω2

0 +ω40

)(αΛ3 + Iκ

(κΩ2 −Λω2

0

))

−ie3iT0ω0ω20

(4Ω4 − 5Ω2ω2

0 +ω40

)(−αΛ3 + Iκ

(−κΩ2 + Λω2

0

)))

+ 2e2iβ(T1)ω20

(36Ω5 + 108Ω4ω2

0 − 39Ω2ω30 + Ωω4

0 + 3ω50

)

×(eiT0(5Ω+2ω0)(Ω +ω0)2

(2IκΩω2

0 + 3αΛ2(−Ω +ω0))

+ ei(T0(Ω+4ω0)+2β(T1))(Ω +ω0)2(2IκΩω2

0 + 3αΛ2(−Ω +ω0))

+ ei(T0(Ω+2ω0)(Ω −ω0)2(2IκΩω2

0 − 3αΛ2(Ω +ω0))+ ei(5T0Ω+4T0ω0+2β(T1))

×(Ω −ω0)2(2IκΩω2

0 − 3αΛ2(Ω +ω0)))

a(T1) + 24iei(T0(2Ω+ω0)+β(T1))α

×ΛΩω20

(−(−1 − 2e2i(T0ω0+β(T1)) + 2e2i(T0(Ω+ω0)+β(T1)) + e2i(T0(Ω+2ω0)+2β(T1))

+(−1 + 6e2i(T0ω0+β(T1)) − 6e2i(T0(Ω+ω0)+β(T1)) + e2i(T0(Ω+2ω0)+2β(T1))

)ω0

)

×(36Ω6 − 49Ω4ω2

0 + 14Ω2ω40 −ω6

0

)a(T1)2 + e3iT0Ω

(1 + e6i(T0ω0+β(T1))

)αΩ

×(Ω2 −ω2

0

)2(36Ω5 + 108Ω4ω0 − 13Ω3ω2

0 − 39Ω2ω20 + Ωω4

0 + 3ω50

)a(T1)3

)

× (cos(T0ω0) + i sin(T0ω0)))/(64Ω

(6Ω2 − 5Ωω0 +ω2

0

)

×(−Ω2ω0 +ω3

0

)2

×(6Ω3 + 23Ω2ω0 + 16Ωω2

0 + 3ω30

)).

(3.17)

Secular terms will be eliminated from the particular solution of (3.8) if we choose A to be asolution of

−2εσ ′ + E(θ). (3.18)

In addition to the terms proportional to e(±iω0T0) or proportional to e[±i(Ω−2ω0)T0] there isanother term that produces a secular term in (3.9). We express (Ω − 2ω0)T0 in terms of ω0T0according to

(Ω − 2ω0)T0 = ω0T0 + εσT0 = ω0T0 + σT1. (3.19)

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8 Mathematical Problems in Engineering

Table 2: Vibrational conveyer parameters in SI units.

ε α μ c I e(m) E1 E0 g ω0 k1 k2 m M

0.05 0.01 0.01 1 0.9 0.2 1.5 1.6 9.81 10 200 000 100 5 200

3.2. Superharmonic Resonances Ω ≈ (1/3)ω0 (Table 2)

We consider

3Ω = ω0 + εσ. (3.20)

In addition to the terms proportional to e(±iω0T0) in (3.9), there is another term thatproduces a secular term in (3.9). This is −αΛ3e(±3iΩT0). T0 eliminate the secular terms, weexpress 3ΩT0 in terms of ω0T0 according to

3ΩT0 = (ω0 + εσ)T0 = ω0T0 + σεT0 = ω0T0 + σT1. (3.21)

Eliminating secular terms in equations, taking (3.16), and separating real and imaginaryparts, the system of equations solved it is as follows [11]:

y0 =12e−iT0ω0−iβ(T1)a(T1) +

12eiT0ω0+iβ(T1)a(T1) + Λ sin(T0Ω),

θ1 =1

8(Ω3 −Ωω20)

2e−i(T0ω0+β(T1))

× I(−4Ω2ω2

0a(T1)

×((

1 + e2i(T0ω0+β(T1)))(

Ω2 +ω20

)cos(T0Ω) − 2i

(−1 + e2i(T0ω0+β(T1))

)Ωω0 sin(T0Ω)

)

−2ei(T0ω0+β(T1))(Ω2 −ω2

0

)cos(T0Ω)

(−4g +

(−κΩ2 + Λω2

0

)sin(T0Ω)

)),

y1 =(e−i(2T0Ω+5T0ω0+3β(T1))

×(−8e3iβ(T1)Ω

(Ω4 − 10Ω2ω2

0 + 9ω40

)

×(4eiT0(4Ω+5ω0)gIκω2

0

(Ω2 −ω2

0

)− 4e5iT0ω0gIκω2

0

(−Ω2 +ω2

0

)

+ ieiT0(3Ω+5ω0)ω20

(4Ω2 −ω2

0

)(3αΛ3 + 8iΛμΩ + Iκ2Ω2 − IκΛω2

0

)

+ eiT0(Ω+5ω0)ω20

(−4Ω2 +ω2

0

)(3iαΛ3 + 8ΛμΩ + iIκ2Ω2 − iIκΛω2

0

)

+ 8eiT0(2Ω+5ω0)gIκ(4Ω4 − 5Ω4ω2

0 +ω40

))+ 2e2iβ(T1)ω2

0

(4Ω4 − 37Ω2ω2

0 + 9ω0

)

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Mathematical Problems in Engineering 9

×(e4iT0(Ω+ω0)(Ω +ω0)2

(2IκΩω2

0 + 3αΛ2(−Ω +ω0))+ e2i(3T0ω0+β(T1))(Ω +ω0)2

×(2IκΩω2

0 + 3αΛ2(−Ω +ω0) + e4iT0ω0(Ω −ω0)2(2IκΩω2

0 − 3αΛ2(Ω +ω0))

+ e2i(2T0Ω+3T0ω0+β(T1))(Ω −ω0)2(2IκΩω2

0 − 3αΛ2(Ω +ω0)))

a(T1)

− 24ieiβ(T1)αΛΩω20

(4Ω4 − 5Ω2ω2

0 +ω40

)

×(2ei(3T0Ω+5T0ω0+2β(T1))

(Ω2 − 9ω2

0

)− 2ei(T0(Ω+5ω0)+2β(T1))

(Ω2 − 9ω2

0

)

− eiT0(Ω+3ω0)(Ω2 − 4Ωω0 + 3ω2

0

)+ ei(3T0Ω+7T0ω0+4β(T1))

(Ω2 − 4Ωω0 + 3ω2

0

)

+ e3iT0(Ω+ω0)(Ω2 + 4Ωω0 + 3ω2

0

)− ei(T0(Ω+7ω0)+4β(T1))

×(Ω2 + 4Ωω0 + 3ω2

0

))a(T1)2

+(e2iT0(Ω+ω0) + e2i(T0(Ω+4ω0)+3β(T1))

)αΩ

(Ω2 −ω2

0

)2

×(4Ω4 − 37Ω2ω2

0 + 9ω40

)a(T1)3

))/

(64(−Ω2ω0+ω3

0

)2(4Ω5−37Ω3ω2

0+9Ωω40

)).

(3.22)

4. Stability Analysis

We analyzed in this system the stability (a, γ) in the equilibrium point, using (4.1), where F isthe Jacobianmatrix of (4.2), and γsub = 3β[T1]−T1σ[T1], γsup = [β[T1]−T1σ[T1]]. Stability of theapproximate solutions depends on the value of the eigenvalues of the Jacobian matrix F [12].The solutions are unstable if the real part of the eigenvalues is positives Figures 2(a1) and2(a2). Figure 2 shows the frequency-response curves for the subharmonic and superharmonicresonance of the unbalanced vibratory conveyor:

a′sub = −μa − 3

8ω0αΛa2 cos

[γ],

γ ′sub = −3(2IκΩ2ω2

0 + 3αΛ2(−Ω2 +ω20

))4(Ω2 −ω2

0

)ω0

+9

8ω0αa2 − 9

8ω0αΛa sin

[γ] − σ,

a′sub = −μa − 3

8ω0

(αΛ3 + Iκ

(κΩ2 −Λω2

0

))cos

[γ],

γ ′sub = −(2IκΩ2ω2

0 + 3αΛ2(−Ω2 +ω20

))4(Ω2 −ω2

0

)ω0

+3αa2

8ω0+

(αΛ3 + Iκ

(κΩ2 −Λω2

0

))sin

[γ]

8ω0a− σ,

(4.1)

F ={∂af1, ∂γf1

},{∂af2, ∂γf2

}, f1 = a′, f2 = γ ′. (4.2)

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10 Mathematical Problems in Engineering

Subharmonic resonance 10

9

8

7

6

5

4

3

0.5 1 1.5 2 2.5

a

σ, (α = 0.8, μ = 0.05)

(a1)

Superharmonic resonance

(a2)

−0.5 0.5 1.500

1

2

3

4

5

6

7

1

a

σ, (α = 0.8, μ = 0.05)

(b1) (b2)

10

9

8

7

6

5

4

a a

−0.5−1.5 −1 0.50 00

0.5

1

1.5

2

2.5

3

2 4 6 8 10

κ(σ = 0.5, σ = 3 , σ = 8) κ(σ = 0.5, σ = 1 , σ = 3)

(c1) (c2)

10 20 30 40 50

10

8

6

4

2

0

a

σ, (μ = 0.1, μ = 1) σ, (μ = 0.2 , μ = 0.5)

a

00 2 3

0.5

1

1.5

2

− 1− 2

σ = 0.5σ = 3σ = 8

σ = 0.5σ = 1σ = 3

μ = 0.1μ = 1

μ = 0.2μ = 0.5

Figure 2: Subharmonic resonance and superharmonic resonance. (a) Frequency-response curves withstability, — stable, · · · unstable {(a1) : a = 2.78–10, σ = 0.43258–2.62092 and (a2): a = 2.73–7.21,σ = 0.6782–0.986448}, (b) effect of detuning parameter, and (c) effect of damping parameter.

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Mathematical Problems in Engineering 11

0 1 2 3 4 5 60

0.2

0.4

0.6

0.8

1

Pow

er s

pect

rum

(a)

0 1 2 3 4 5 60

0.2

0.4

0.6

0.8

1

Pow

er s

pect

rum

(b)

0 0.005

0

0.002

0.004

v

Velocity-displacement

−0.005

−0.002

−0.004

y

(c)

0 0.005

0

0.002

0.004

y

v

Poincare map velocity-displacement

−0.002

−0.004

−0.005

(d)

Figure 3: Subharmonic resonance: (a) power spectrum and superharmonic resonance, (b) power spectrum,(c) phase portrait, and (d) Poincare sections.

5. Numerical Results

The numerical calculations of the vibrating system are performed with the help of thesoftware Mathematica [13, 14]. We analyze the subharmonic resonance Ω ≈ 3ω0 andsuperharmonic resonance 3Ω ≈ ω0. Figure 3 shows the power spectrum, phase portrait andthe Poincare map for superharmonic resonance and Figure 3 shows the power spectrum forsuperharmonic resonance.

6. Conclusions

The vibrating system is analyzed, analytically, and numerically for superharmonic andsubharmonic resonance by the method of multiple scales. Very often in the motion of thesystem near resonance the jump phenomenon occurs. The frequency-response curves of thesubharmonic resonance consist of two branches; the left one is stable and the right one isunstable (saddle node bifurcation). The frequency-response curves of the superharmonicresonance consist of three branches; the left one is stable, the middle one is unstable, andthe right one is stable (pitchfork bifurcation). The stable motions of the oscillator are shown

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12 Mathematical Problems in Engineering

with one peaks in the power spectrum for superharmonic resonance and with two peaks inthe power spectrum for subharmonic resonance. Both analytical and numerical results thatwe have obtained are in good agreement. The system studied here exhibits chaotic behaviourin case of strong nonlinearity. This will be reported in the forthcoming paper. Furthermore,control methods in the passage through resonance await for future publication.

Acknowledgment

The authors greatly appreciate the comments of an anonymous referee.

References

[1] J. M. Balthazar, D. T. Mook, H. I. Weber et al., “An overview on non-ideal vibrations,”Mechanica, vol.38, no. 6, pp. 613–621, 2003.

[2] Y. Rocard, General Dynamics of Vibrations, Ungar, New York, NY, USA, 3rd edition, 1960.[3] R. Mazert, Mecanique Vibratoire, C. Beranger, editor, Paris, France, 1955.[4] Y. G. Panovko and I. I. Gubanova, Stability and Oscillations of Elastic Systems, Consultans Bureau, New

York, NY, USA, 1965.[5] V. O. Kononenko, Vibrating Problems with a Limited Power Supply, Iliffe, London, UK, 1969.[6] R.M. Evan-Ivanowski, Resonance Oscillations in Mechanical Systems, Elsevier, Amsterdam, The Nether-

lands, 1976.[7] A. H. Nayfeh and D. T. Mook, Nonlinear Oscillations, John Wiley & Sons, New York, NY, USA, 1979.[8] S. Ganapathy and M. A. Parameswaran, “Transition over resonance and power requirements of an

unbalanced mass-driven vibratory system,” Mechanism and Machine Theory, vol. 21, no. 1, pp. 73–85,1986.

[9] M. R. Bolla, J. M. Balthazar, J. L. P. Felix, and D. T. Mook, “On an approximate analytical solution toa nonlinear vibrating problem, excited by a nonideal motor,” Nonlinear Dynamics, vol. 50, no. 4, pp.841–847, 2007.

[10] A. Gotzendorfer, Vibrated granular matter: transport, fluidization, and patterns, Ph.D. thesis, UniversityBayreuth, 2007.

[11] V. Piccirillo, J. M. Balthazar, and B. R. Pontes Jr., “Analytical study of the nonlinear behavior of a shapememory oscillator: part II-resonance secondary,”Nonlinear Dynamics, vol. 60, no. 4, pp. 513–524, 2010.

[12] J. Awrejcewicz and C. H. Lamarque, Bifurcation and Chaos in Nonsmooth Mechanical Systems, WorldScientific, River Edge, NJ, USA, 2003.

[13] A. H. Nayfeh and C. M. Chin, Perturbation Methods with Mathematica, Dynamics Press, Virgina, va,USA, 1999.

[14] S. Lynch, Dynamical Systems with Applications Using Mathematica, Birkhaauser, Boston, Mass, USA,2007.

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