Nonlinear Vibration of Porous Funcationally Graded Cylindrical Panel Using Reddy’s High Order Shear Deformation

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1

Original Article

^

Nonlinear Vibration of Porous Funcationally Graded Cylindrical Panel Using Reddy’s High Order

Shear Deformation

Vu Minh Anh

¹

, Nguyen Dinh Duc

^1,2,*

1Department of Construction and Transportation Engineering,

VNU University of Engineering and Technology, 144 Xuan Thuy, Cau Giay, Hanoi, Vietnam

2Infrastructure Engineering Program, VNU Vietnam-Japan University (VJU), My Dinh 1, Tu Liem, Hanoi, Vietnam

Received 02 December 2019 Accepted 06 December 2019

Abstract: The nonlinear dynamic response and vibration of porous functionally graded cylindrical panel (PFGCP) subjected to the thermal load, mechanical load and resting on elastic foundations are determined by an analytical approach as the Reddy’s third order shear deformation theory, Ahry’s function… The study results for dynamic response of PFGCP present the effect of geometrical ratio, elastic foundations: Winkler foundation and Paskternak foundation; loads: mechanical load and thermal load; and the material properties and distribution type of porosity. The results are shown numerically and are determined by using Galerkin methods and Fourth-order Runge-Kutta method.

Keywords: Nonlinear dynamic response, porous functionally graded cylindrical panel, the high order shear deformation theory, mechanical load, thermal load, nonlinear vibration.

1. Introduction

With the requirements of working ability such as bearing, high temperature in the harsh environment of some key industries such as defense industries, aircraft, space vehicles, reactor vessels and other engineering structures, in the world, many advanced materials have appeared, including Functionally Graded Materials (FGMs). FGMs is a composites material and is made by a combination of two main materials: metal and ceramic. Therefore, the material properties of FGMs will have all the ________

Corresponding author.

Email address: ducnd@vnu.edu.vn

https//doi.org/ 10.25073/2588-1124/vnumap.4444

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outstanding properties of the two-component materials and vary with the thickness of the structure. With these outstanding properties, FGMs have attracted the attention of scientists in the world. In recent years, a lot of research carried out on FGMs, dynamic FGMs.

Contact mechanics of two elastic spheres reinforced by functionally graded materials

(FGM) thin coatings are studied by Chen and Yue [1] . Li et al. [2] determined nonlinear structural stability performance of pressurized thin-walled FGM arches under temperature variation field.

Dastjerdi and Akgöz [3] presented new static and dynamic analyses of macro and nano FGM plates using exact three-dimensional elasticity in thermal environment. Wang and Zu [4] researched about nonlinear dynamic thermoelastic response of rectangular FGM plates with longitudinal velocity.

Dynamic response of an FGM cylindrical shell under moving loads is investigated by Sofiyev [5]. Wang and Shen [6] published nonlinear dynamic response of sandwich plates with FGM face sheets resting on elastic foundations in thermal environments. Shariyat [7] gave vibration and dynamic buckling control of imperfect hybrid FGM plates with temperature-dependent material properties subjected to thermo-electro-mechanical loading conditions. Nonlinear dynamic analysis of sandwich S- FGM plate resting on pasternak foundation under thermal environment are reseached by Singh and Harsha [8].

Nonlinear dynamic buckling of the imperfect orthotropic E- FGM circular cylindrical shells subjected to the longitudinal constant velocity are studied by Gao [9]. Reddy and Chin [10] studied thermo- mechanical analysis of functionally graded cylinders and plates. Babaei et al. [11] investigated thermal buckling and post-buckling analysis of geometrically imperfect FGM clamped tubes on nonlinear elastic foundation. 3D graphical dynamic responses of FGM plates on Pasternak elastic foundation based on quasi-3D shear and normal deformation theory is presented by Han et al [12]. Ghiasian et al. [13]

researched about dynamic buckling of suddenly heated or compressed FGM beams resting on nonlinear elastic foundation. Geometrically nonlinear rapid surface heating of temperature-dependent FGM arches are gave by Javani et al. [14]. Shariyat [15] presented dynamic thermal buckling of suddenly heated temperature-dependent FGM cylindrical shells, under combined axial compression and external pressure. Babaei et al. [16] published large amplitude free vibration analysis of shear deformable FGM shallow arches on nonlinear elastic foundation.

In fact, porous materials appear around us and play in many areas of life such as fluid filtration, insulation, vibration dampening, and sound absorption. In addition, porous materials have high rigidity leading to the ability to work well in harsh environments. In recent years, porous materials have been researched and applied along with other materials to create new materials with the preeminent properties of component materials. Porous functionally graded (PFG) is one of the outstanding materials among them and has research works such as: Gao et al. [17] researched about dynamic characteristics of functionally graded porous beams with interval material properties. Dual-functional porous copper films modulated via dynamic hydrogen bubble template for in situ SERS monitoring electrocatalytic reaction are proposed by Yang et al. [18]. Foroutan et al. [19] investigated nonlinear static and dynamic hygrothermal buckling analysis of imperfect functionally graded porous cylindrical shells. Li [20]

presented nonlinear vibration and dynamic buckling analyses of sandwich functionally graded porous plate with graphene platelet reinforcement resting on Winkler–Pasternak elastic foundation. Li [21] carried out experimental research on dynamic mechanical properties of metal tailings porous concrete. Transient [22] published response of porous FG nanoplates subjected to various pulse loads based on nonlocal stress-strain gradient theory. Esmaeilzadeh and Kadkhodayan [23] researched about dynamic analysis of stiffened bi-directional functionally graded plates with porosities under a moving load by dynamic relaxation method with kinetic damping. Vibration analysis of magneto-electro-elastic heterogeneous porous material plates resting on elastic foundations are studied by Ebrahimi et al [24]. Arshid and Khorshidvand [25] presented free vibration analysis of saturated porous FG circular plates integrated with piezoelectric actuators via differential quadrature

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method. Micro temperature-dependent FG porous plate: Free vibration and thermal buckling analysis using modified couple stress theory with CPT and FSDT are researched by Shojaeefard [26]. Demirhan and Taskin [27] investigated bending and free vibration analysis of Levy-type porous functionally graded plate using state space approach.

The proposed method used in this study is the third-order shear deformation theory and the effect of the thermal load has been applied in a number of case studies such as Zhang [28] published nonlinear bending analysis of FGM beams based on physical neutral surface and high order shear deformation theory. Reddy and Chin [29] investigated thermo-mechanical analysis of functionally graded cylinders and plates. Modeling and analysis of FGM rectangular plates based on physical neutral surface and high order shear deformation theory is presented by Zang [30]. In [31], Thon and Bélanger presented EMAT design for minimum remnant thickness gauging using high order shear horizontal modes. Dynamic analysis of composite sandwich plates with damping modelled using high order shear deformation theory are carried out by Meunier and Shenoi [32]. Cong et al.[33] investigated nonlinear dynamic response of eccentrically stiffened FGM plate using Reddy’s TSDT in thermal environment. Stability of variable thickness shear deformable plates—first order and high order analyses are gave by Shufrin and M. Eisenberger [34]. In [35], Stojanović et al showed exact closed-form solutions for the natural frequencies and stability of elastically connected multiple beam system using Timoshenko and high order shear deformation theory. A high order shear element for nonlinear vibration analysis of composite layered plates and shells are proposal by Attia and El-Zafrany [36]. Khoa et al [37] observed nonlinear dynamic response and vibration of functionally graded nanocomposite cylindrical panel reinforced by carbon nanotubes in thermal environment. In [38], Allahyari and Asgari found that thermo-mechanical vibration of double-layer graphene nanosheets in elastic medium considering surface effects; developing a nonlocal third order shear deformation theory. Wang and Shi [39] presented a refined laminated plate theory accounting for the third order shear deformation and interlaminar transverse stress continuity.

From the literature review, the authors often used the high order shear deformation theory to investigate the nonlinear static, nonlinear dynamic or nonlinear vibration of FGM or plate porous funcationally graded (PFG). For the nonlinear dynamic and vibration of PFGCP has not carried out.

Therefore, in order to observe the nonlinear dynamic and vibration of PFGCP under mechanical load and thermal load, using the Reddy’s high order shear deformation theory and Ahry’ function are proposaled in this paper. The natural frequency of PFGCP is obtained by using cylindrical panel fourth- order Runge-Kutta method. Besides, the effect of geometrical ratio, elastic foundations: Winkler foundation and Paskternak foundation, the material properties and distribution type of porous on the modeling will be shown.

2. Theoretical formulation

Fig.1 show a PFGCP resting on elastic foundations included Winkler foundation and Pasternak foundation in a Cartesian coordinate system x y z, , , with

xy - the midplane of the panel

z- the thickness coordinator, h/ 2 z h/ 2. a- the length

b- the width

h- the thickness of the panel.

R- the radius of the cylinderical panel.

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Fig. 1. Geometry of the PFGCP on elastic foundation.

The volume fractions of metal and ceramic, V_m and V_c, are assumed as [25] with using a simple power-law distribution:

( ) 2 ; ( ) 1 ( ),

2

N

c m c

z h

V z V z V z

h

  

   

(1) in which the volume fraction index N, subscripts m and c stand for the metal and ceramic constituents, respectively.

The material properties of PFGCP with prosity distribution are given as Porosity – I:

   

( ), ( ), ( ) , ,

, , 2 , , ,

2 2

m m m

N

cm cm cm m c m c m c

E z z z E

z h

E E E

h

   

      



  

      

(2)

Porosity – II:

   

( ), ( ), ( ) , ,

2 | |

, , 1 2 , , ,

2 2

m m m

N

cm cm cm m c m c m c

E z z z E

z h z

E E E

h h

   

      



    

         

(3)

with

, , , ,

cm c m cm c m cm c m cm c m

E E E       K K K (4) and in this paper, the Poisson ratio ^

 

^z can be considered constant ( )z v.

a. Porosity - I b. Porosity - II

Fig. 2. The porosity distribution type.

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2.1. Governing equations

By using the Reddy’s high order shear deformation theory (HSDT), the governing equations and the dynamic analysis of PFGCP are determined.

The train-displacement relations taking into account the Von Karman nonlinear terms as [10,29,33]:

0 1 3

0 2

0 1 3 3 2

0 2

0 1 3

; ,

x x x x

xz xz xz

y y y y

yz yz yz

xy xy xy xy

k k

z k z k z k

k k k

   

 

     

 

   

 

     

 

          

       

       

       

(5)

With

2

0 1

2

0 1

1 2

1 ; ;

2

x

x x

y

y y

xy xy

x y

u w w

x R x x

v w k

y y k y

u v w w k

y x x y y x



 



  

        

     

    

          

          

           

     

             

2 2 3

2 3

1 2

3

2

0 2 1

0 2

w ,

2 w

; 3 ,

w w

x

y y

xy

x y

xz xz

x x

yz yz

y y

w

x x

k

k c

y y

k

y x x y

c k

x k x

y y



 

  



 

   



 

 

 

 

  

     

     

 

       

  

       

 

         

         

         

(6)

in which

2 1 4 / 3 , _x, _y c  h  

x, y

  - normal strains,

xy - the in-plane shear strain,

xz, yz

  - the transverse shear deformations , , w

u v - the displacement components along the x y z, , directions, respectively

x, y

  - the slope rotations in the

 

^{x z}^, ^and

 

^{y z}^, planes, respectively.

The strains are related in the compatibility equation [27, 28]:

(6)

2 0 2 0 2

2 0 2 2 2 2

2 2 2 2 2

w w w 1 w

y xy .

x

y x x y x y x y R x

 

 ^ ^  

    

     

          (7)

The effect of

temperature will be descirbed in Hooke

's law

for a

PFGCP as

:

   

, 2[( , ) , (1 ) (1,1)],

1

, , , , ,

2(1 )

x y x y y x

xy xz yz xy xz yz

E T

E

        



     



    



 

(8)

in which T is temperature rise.

The force and moment resultants of the PFGCP can be obtained with equations of stress components along with thickness of PFGCP as:

   

 

/ 2

3 / 2

/ 2

2 / 2

, , 1, , ; , , ,

, (1, ) ; , ; , .

h

i i i i

h h

i i j

h

N M P z z dz i x y xy

Q R z dz i x y j xz yz





 

  



(9)

Replacing Eqs. (3), (5) and (8) into Eq. (9) gives:

         

     

         

     

 

0 0 1 1

1 2 4 2 3 5

2 3 3

4 5 7

0 0 1 1

1 2 4 2 3 5

2 3 3

4 5 7

1 2

, , , ,

, , 1 ,

1 , , (1 ) , ,

, , , ,

, , 1 ,

1 , , (1 ) , ,

, , 1 , ,

2(1 )

x y x y

x x x

x y a b c

y x y x

y y y

y x a b c

xy xy xy

E E E E E E k k

N M P

E E E k k

E E E E E E k k

N M P

E E E k k

N M P E E E

  

  

  

  



    

 

         

    

 

         

 

     

0 1 3

4 2 3 5 4 5 7

0 2

1 3 3 5

0 2

1 3 3 5

, , , , ,

, 1 , , ,

2(1 )

, 1 , , ,

2(1 )

xy xy xy

x x xz xz

y y yz yz

E E E k E E E k

Q R E E E E k



 

   

 

 

    

 

    

(10)

with



1 2 3 4 5 7



^{/ 2}



² ³ ⁴ ⁶



/ 2

, , , , , 1, , , , , ( ) ,

h

E E E E E E z z z z z E z dz







/ 2 3 / 2

( , , ) (1, , ) ( ) ( ) ( ) ,

h

a b c

h

z z E z z T z dz



   



 (11)

and the coefficients E i_i(  1 5,7) are give in Appendix.

From Eq. (10), The inverse expression are obtained:

(7)

0 1 3 0 1 3

2 4 2 4

1 1

0 1 3

2 4

1

1 1

; ,

1 2(1 ) .

x x y x x a y y x y y a

xy xy xy xy

N N E k E k N N E k E k

E E

N E k E k E

   

 

   

               

 

     

(12)

The equations of motion are [26] based on HSDT:

2 2 3

0 2 1 2 1 3 2

2 2 3

0 2 1 2 1 3 2

2 2 2

2 2

1 2 2 1 2

w , w ,

w w w

2

2 w w

x xy x

xy y y

y y

x x

x xy y

xy y

x

N N u

I J c I

x y t t x t

N N v

I J c I

x y t t y t

Q R

c N N N

x y x y x x y y

P P

c P k k

x x y y x



    

   

     

    

   

     

   

             

    

          

2

2 2

2 4 4

2

0 2 0 1 6 2 2 2 2

3 3

1 3 2 2 4 2 2

2 2

1 2 1 2 2 2 1

w

w w w w

2

,

y

x y

xy xy

x x x

x x

N q

y R

I I c I

t t x t y t

u v

c I J

x t y t x t y t

M P

M P u

c Q c R J K c J

x y x y t t



 



   

  

 

 

   

         

        

           

   

             

3

4 2

2 2 3

1 2 1 2 2 2 1 4 2

w , w ,

xy y xy y y

y y

x t

M M P P v

c Q c R J K c J

x y x y t t y t





 

             

(13)

where

/ 2

 

/ 2

, (i 0,1,2,3,4,6),

h

i i

h

I  z z dz









2

1 2, 2 2 2 1 4 1 6, 2 3 ,1

i i i

J  I c I_ K  I c I c I c  c

(14)

and the coefficients I i_i(  0 4,6) are noted in Appendix, and k1 - Winkler foundation modulus

k2- Pasternak foundation model

q- an external pressure uniformly distributed on the surface of the plate

 - damping coefficient.

The stress function ^{f x y t}



^{, ,}



is introduced as

(8)

2 2 2

2 , 2 , .

x y xy

f f f

N N N

y x x y

  

   

    (15)

Replacing Eq. (15) into the two first Eqs. (13) yields

2

2 3

1 3 1

2 2 2

0 0

w ,

x c I

J u

t I t I x t



     

    (16a)

2 2 3

1 3 1

2 2 2

0 0

w .

y c I

J v

t I t I y t



  

  

   

(16b) By substituting Eqs. (16) into the Eqs. (13) and Eqs. (13) can be rewritten

2 2 2

2 2

2 2 2

1 2 2 1 2 2 2

2 2

2 4 4

1 3 2

0 2 0 1 6 2 2 2 2

0

4 1

w w w

2

w w

2 w

w w w w

2

y y

x x

x xy y

xy y y

x

Q R

c N N N

x y x y x x y y

P P N

c P k k q

x x y y x y R

I I c I c I

t t I x t y t

J c



   

             

      

               

  

   

          



3 3

1 3 1 1 3 1

2 4 1 2

0 0

y ,

J I c x J I c

I x t J c I y t

 ^

    

 

     

   

(17a)

2

2 3

1 3 1 1

1 2 2 2 1 4 2

0 0

w ,

xy xy

x x x

x x

M P

M P J c I J

c Q c R K c J

x y x y I t I x t

        

   

           

            (17b)

2 2 3

1 3 1 1

1 2 2 2 1 4 2

0 0

w .

xy y xy y y

y y

M M P P J c I J

c Q c R K c J

x y x y I t I y t



              (17c)

Substituting Eqs. (12) and (15) into the equation (7), we have:

4 4 4 2 2 2 2

4 2 2 4 2 2

1

1 w w w

2 .

f f f

E x x y y x y x y

         

         

    (18)

The system of motion Eqs. (17) is rewritten as Eq.(19) by replacing Eq. (6) into Eq. (10) and then into Eqs. (17):

       

²

11 12 13 0 2 0

2 2 4 4 3 3

1 3 2 1 3 1 1 3 1

1 6 2 2 2 2 4 1 2 4 1 2

0 0 0

w w

w w, 2

w w

,

x y

L L L P f q I I

t t

c I J I c J I c

c I J c J c

I x t y t I x t I y t

  

 

 

     

 

          

             

(19a)

     

¹² ² ^{1 3} ¹ ³

21 22 23 2 2 1 4 2

0 0

w _x _y J ^x c I J w ,

L L L K c J

I t I x t

  ^ ^^  ^ ^ ^

         

(19b)

(9)

     

¹² ² ^{1 3} ¹ ³

31 32 33 2 2 1 4 2

0 0

w _x _y J ^y c I J w ,

L L L K c J

I t I y t

  ^ ^^  ^ ^{ }

         

(19c)

and the L i_ij



 1 3,j 1 3



and P are noted in Appendix.

In next section, in order to determined nonlinear dynamical analysis of PFGCP using the third order shear deformation theory, the Eqs. (18)-(19) are used along with boundary conditions and initial conditions

2.2. Boundary conditions

In order to determined nonlinear dynamical analysis of PFGCP, the edges of the PFGCP are simply supported and immovable (IM) and boundary conditions are [27, 28]:

0 0

w 0, 0, ,

w = 0, 0, ,

y x x x x

x y x y y

u M P N N at x a

v M P N N at y b



      

      (20)

in whichN_x₀,N_y₀ are forces along the x and y axis.

Wiht the boundary condition (20) and In order to solve Eqs. (18) and (19), the approximate solutions can be written as [26]:

   

w , , W sin sin ,

, , cos sin ,

, , sin os ,

x x

y y

x y t t x y

x y t t xc y

 

  



 

(21) with

m , n

a b

 

   and m n, 1,2,...are the numbers of half waves in the direction x y, , W, _x, _y - the amplitudes which are functions dependent on time.

The stress function is defined as:

 

1

 

2

 

0 ² 0 ²

1 1

, , cos 2 cos 2 ,

2 ^x 2 ^y

f x y t A t xA t y N y  N x (22a)

with

2 2

1 1

1 2 ; 2 2 .

32 32

E E

A  W A  W

 

  (22b)

2.3. Nonlinear dynamical analysis

In ordet to obtain Eqs. (23), Eqs. (21) and (22) are replaced into the Eq. (19) after that applying Galerkin method:



² ²



³ ²

11 0 0 12 13 1 2 2 2 0

2 2

2 2 2 2

16 W W

+ 2

,

x y x y

x y

l N N W l l n W q n I

mn t t

m n

a t b t

  



 

 

 

          

   

   

 

 

(23a)

2 2

21 22 23 1 2 2 2

W,

x

x y

l W l l m

t a t

 ^{ }   ^

     

  (23b)

(10)

2 2

31 32 33 1 2 2 2

W _x _y ^y n W,

l l l

t b t

 ^{ }   ^

     

  (23c)

Where

2

1 3 1 1

1 2 2 1 4

0 0

; c I J

K J c J

I I

      ,

 

² ²

11 1 1 3 2 3 1 5

2 2 2 2 2 2

2 2

1 4

7 1 2

2

1

1 3 3

2(1 )

+ 1,

1

m n

l E c E c E c E

a b

c m n E m n m

E k k

a b E a b a R

 



    



    

           

             

                 

 

¹ ³ ² ⁴ ⁴²

12 1 1 3 2 3 1 5 2 5 1 7

1 1

2 2

2 4 4

1 2 5 1 2 7

1 1

1 3 3

2(1 ) 1

1 1

1 1 1 1 ,

c E E E

m m

l E c E c E c E E c E

a a E E

E E E m n

c E c E

v E E a b

 

 

   

  

  

 

                 

       

                

 

¹ ³ ² ⁴ ⁴²

13 1 1 3 2 3 1 5 2 5 1 7

1 1

2 2

2 4 4

1 2 5 1 2 7

1 1

1 3 3

2(1 ) 1

1 1

1 1 1 1 ,

c E E E

n n

l E c E c E c E E c E

b b E E

E E E

v v m n

c E c E

E E a b

 

 

 

   

  

 

                 

      

               

4 4

1

1 ,

16

E m n

n a b

 

    

      

2 2

2

2 3

2 0 1 6

0

I m n ,

n I c I

I a b

 

 

     

         

   

2 2 2

1 1 4 2 4

21 2 1 7 5

1 1

1 1 3 2 3 1 5

2 2 2 2

2 2 4 2 4

22 2 3 1 5 1 7

1 1 1

1 +

1 3 3 ,

2(1 )

1 1

1 2(1 ) 2

c m m n c E E E

l c E E

a a b E E

m E c E c E c E

a

E E E E

m n

l E c E c E

a b E E E

  







 

 

     

            

      

          

                  

   

 

1 1 3 2 3 1 5

2 2

2

2 2 4 2 4

23 3 1 5 1 7

1 1 1

1 3 3 ,

2(1 )

1 2 ,

2 1

E c E c E c E

E E E E

l mn E c E c E

ab E E E











      

    

           

(11)

 

2 2

2

1 4 2 4

31 2 1 7 1 5 1 1 3 2 3 1 5

1 1

2 2

2

2 2 4 2 4

32 3 1 5 1 7

1 1 1

2

33 2

1 3 3 ,

1 2(1 )

1 2 ,

2 1

1 1

1 2(1

c n E E E m n n

l c E c E E c E c E c E

b E E a b b

E E E E

l mn E c E c E

v ab E E E

l n

b

   

 





 

     

                  

    

           

 

      

 

2 2 2

2 2 4 2 4

3 1 5 1 7

1 1 1

1 1 3 2 3 1 5

) 2

1 3 3 ,

2(1 )

E E E E

m E c E c E

a E E E

E c E c E c E





            

        

       

 

      

In order to investigate the effect of thermal load on the PFGCP. The modeling are simply supported and immovable in all edges. In other words, boundary conditions of case stud is u0(on x0,a) and

v0 (ony0,b), and and is satisfied equations as [10, 29]:

0 0 0 0

0, 0.

b a a b

u v

dxdy dxdy

x y

   

 

 

⁽²⁴⁾

With Eqs. (6) and (12) along with (15), Ep (25) is determined as:

   

2

2 1 4

, , , , ,

1 1 1 1

2

2 1 4

, , , , ,

1 1 1 1

1 1

2 ,

1 1

2 .

a

yy xx x x x x xx

a

xx yy y y y y yy

E c E

u w w

f vf w

x E E E R x E

E c E

v w

f vf w

y E E E y E

 

          

  

 

        

  

(25)

In order to obtain Eqs. (26), Eqs. (21) and (22) are placed into Eq. (25) then the obtained result are replaced into Eq. (24) we have:

       

  

2 2

0 2 2 2 1 4 1 4

2 2 2

1 2

4

1 1

8 1 ,

a

x x y

N E c E v c E v W

v mn v

E v W

v

   



 

  

            

 



(26a)

       

  

2 2

0 2 2 2 1 4 1 4

2 2 2

1 2

4

1 1

8 1 .

a

y x y

N E c E v c E v W

v mn v

E v W

v

   



 

  

            

 



(26b)

Putting Eqs. (26) into the Eq. (23). We obtain:

l₁₁+ mp a æ èç

ö ø÷

2

+ np b æ èç

ö ø÷

æ 2

èçç ö

ø÷÷ F_a 1-v é

ë êê

ù û

úúW+l₁₂F_x+l₁₃F_y+l₁₄F_xW+l₁₅F_yW+ l₁₆W²+l₁₇W³

+ 16

mnp²^q⁼ⁿ²

¶²W

¶t² +2e^I₀^¶^W

¶t +r₂^mp a

¶²F_x

¶t² +r₂ⁿp b

¶²F_y

¶t² ,

(27a)

2 2

21 22 23 1 2 2 2

W,

x

x y

l W l l m

t a t

 ^{ }   ^

     

  (27b)

(12)

2 2

31 32 33 1 2 2 2

W _x _y ^y n W,

l l l

t b t

 ^{ }   ^

     

  (27c)

with

 

2 2

2 1 4

14 2 2

4

1 ,

m n

E c E v

a b m

l mn v a

 



    

      

 

 

2 2

2 1 4

15 2 2

4

1 ,

m n

E c E v

a b n

l mn v b

 



    

     

 

 

4 2 2 4

1 4

16 2 2

4 2

1 ,

c E v

l mn v

   



 

  

 

4 2 2 4

1

17 1 2 2 ,

8 1

E m m n n

l n v

a a b b

v

   

        

             

The Eqs. (27) are used to dertermine dynamic analysis of PFGCP with suported by elastic foundations along with the effect of temperature with the appearance of the coefficient _a.

In order to obtain the natural frequencies

 

^ of PFGCP, solving determinant of matrix (28) with linear coefficients taken from Eqs. (27) along with q0. The obtained results are three natural frequencies, the smallest value will be selected.

2 2

2 2 2

11 2 12 2 13 2

2 2

21 2 22 1 23

2 2

31 2 32 33 1

1

0.

m n a m n

l n l l

a b v a b

l m l l

a

l n l l

b

      

   

     

        

  

 

(28)

3. Numerical results and discussion

In this paper, consider PFGCP is under the influence of a uniformly distributed load on the surface with equations in the harmonic function q Q sint with Q is the amplitude of uniformly excited load.

Besides, the fourth-order Runge-Kutta method is used to solve equations (27) and the material properties of the component material are given as [40]:

9 2 3 6 1

380 10 / , 3800 / , 7.4 10 , 10.4 / ,

70 10 / , 2702 / , 23 10 , 204 / ,

0.3,

o

c c c c

o

m m m m

E N m kg m C K W mK

v

 

 

     



(13)

3.1. Natural frequency

In order to verify the reliability of the used method, the numerical results of this paper will be compared with the published results of Duc et al [40]. In the Duc author's paper, the used method is high order shear deformation for FGM plate. In order to obtain the highest accuracy of the comparison results, the modeling of this paper was brought to the same format as the modeling in Duc’s paper by R = infinity. The comparison results of the free natural frequency are shown in Table 1. It can be seen that the results of both papers are not much different. It verifies that the used method is reliable.

Table 1. Comparison of natural frequency

 

^s^¹ of PFGCP with other paper with same conditions as

/ 1, / 20, 1

a b a h N .



k k1; 2





GPa m GPa m^{/ ;} ^.



^^T

 

^o^C Natural frequency

 

^s^¹

Duc et al [40] Present study

 

^0;0 ⁰⁵⁰ ^1941.73^1570.25 ¹⁹²²¹⁵²²

105 1015.19 1082



^0.25;0



⁰⁵⁰ ^2303.00^1999.79 ²³⁴¹¹⁹⁹⁸

105 1601.28 1687



^0.25;0.02



⁰⁵⁰ ^2779.46^2533.92 ²⁷⁹⁰²⁵⁷⁶

105 2232.86 2293

The natural frequencies

 

^s^¹ of PFGCP with the influence of index N, modes



^{m n}^,



along with

1 2

/ 1, / 20, 0, 0

a b a h k  k  ,  T 100^oC and using type 2 of porosity distribution. We can see that the natural frequencies will raise when modes



^{m n}^,



increase in which index N is constant. In contrast, when index N increase in which modes



^{m n}^,



is constant, the natural frequencies increase. Form equation (1), it can be explained that index N = 0 corresponding to isotropic uniform panel is made from ceramic materials, N = 1 is the case when the ceramic and metal components are distributed linearly over the thickness of the structure wall and when N increase, the volume ratio of the metal component in the structure increases.

Table 2. The natural frequencies

 

^s^¹ of PFGCP with the influnece of index N, modes



^{m n}^,



along with

1 2

/ 1, / 20, 0, 0, / 400

a b a h k  k  R h and  T 100^oC. N



^m ^1,¹ⁿ ¹





 



^m ^1,²ⁿ ³





 



^m ^1,³ⁿ ⁵





 



^m ^3,⁴ⁿ ⁵





 



^m ^5,⁵ⁿ ⁵





 

0.5 2702 11175 27051 34564 48871

1 2434 9766 24060 30838 43767

3 2251 8817 21037 26808 37785

5 2172 8505 20218 25719 36137

12 2080 8174 19369 24594 34440

∞ 1629 6195 14636 18610 26149

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Table 3 shows the natural frequencies

 

^s^¹ of PFGCP with the influnece of ratio a b/ , elastic foundation, porosity distribution type along with a h/ 20,N  1, T 100^oC,

( , ) (1,1), /m n  R h400. It can easily see that the natural frequencies increase when ratio /a b raises as well as when modeling is supported by elastic foundations. Furthermore, the comparison of the effect between type 1 of porosity distribution and type 2 of porosity distribution are shown in table 3. The effect of type 2 of porosity distribution on the natural frequencies is smaller than the effect type 1 of porosity distribution.

Table 3. The natural frequencies

 

^s^¹ of PFGCP with the influnece of ratio a b/ , elastic foundation

( , )m n (1,1), /R h400 a h/ 20,N  1, T 100^oC.



k k1; 2



<