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Equation of motion (5) when using (4), (8) in matrix form

σ

= C

ε

D

T,

ε

= BU

,

Can be transformed into the following form:

LU

GΘ +

λ

MV = 0

.

(11)

Here

L

,

G

,

M

— element matrices, and

V

— vector of rate values at

mesh points.

Elements of matrices in (8)–(11) are calculated in the following way:

L

e

=

Z

Ω

B

T

CB

dr dz,

G

e

=

Z

Ω

B

T

DB

dr dz,

M

e

=

Z

Ω

ρ

NN

T

dr dz.

Matrices

C

,

D

,

B

depend on physical properties of the material and

the form of interpolation functions

C =

E

(1 +

ν

)(1

2

ν

)

 

1

ν ν ν

0

0

0

ν

1

ν ν

0

0

0

ν ν

1

ν

0

0

0

0 0 0 1

/

2

ν

0

0

0 0 0 0 1

/

2

ν

0

0 0 0 0

0 1

/

2

ν

 

,

D =

(1

2

ν

)

[1 1 1 0 0 0]

T

,

B = [B

1

. . .

B

m

]

,

B

i

=

 

N

i

∂r

0

0

N

i

r

n

N

i

r

0

0

0

N

i

∂z

nN

i

2

r

1

2

N

i

∂r

N

i

r

0

0

1

2

N

i

∂z

n

N

i

2

r

1

2

N

i

∂z

0

1

2

N

i

∂r

 

,

(

i

= 1

, . . . , m

)

.

ISSN 0236-3933. HERALD of the BMSTU. Series Instrument Engineering. 2015. No. 2

33