.


:




:

































 

 

 

 


)




-

(6.3)

γN - , /1/;

γN = 0.95 - , ;

γN = 0.95-0.25β0 - , c;

-

(6.4)

γM = 0.95 - 1 ;

γM = 1 - 2-3 ;

- -

(6.5)

γM= γM N/(ARyo)<0.6

γM= γM N/(ARyo)≥0.6

 

) :

- - ,

 

(6.6)

-

(6.7)

- -

(6.8)

(6.6)(6.8):

Nu , ,

(6.9)

Mu(Mux, Muy) ,

(6.10)

c- , , :

 

(6.11)

 

 

Rso . (6.9) (6.10)

,

(6.12)

Aot

(6.13)

Arc, Art , , , (. 3);

yoc, yot, yrc, yrt , Mu(Mux, Muy); (. 3);

α , (Ryr) (Ry)

(6.14)

γM γN (6.9) (6.10) :

γN = 0,95 , ;

γN =0,95-0,1(α+β-1) , ;

γM =0,95 ;

γM =0,95-0,2β(α-1) ;

γM=0,95-0,1(α +β-1) .

(6.7) , - (6.5).

200×20 600x10 = 400 . ∆ = 600 . (.4). Ry0 = 260 , Ryr= 345 .

 

:

- 0 = 140 2;

- I0 = 94880 4;

- Wxo = 2965 3.

 

/2;

= 337 > Ryo = 260 .

 

-

0m = Mxo/Wxo = 40000/2965 = 13.49 /2;

β0= 0max/Ryo = 134.9/260 = 0,52,

.. β0 < 0.8, .

 

.

1- - (.4,).

-250×14 .

) .

, 4,

rc = 0;

Art = 25-1.4 = 35.0 2.

α

α = Ryr/Ryo = 345/260 = 1.32.

= 0.5[Ao-α(Arc-Art)] = 0.5[140-1.32(0-35.0)] = 93.1 2;

A0t = - = 140 - 93.1 = 46.9 2.

 

(-) (0-0)

= (Aoc-Aot)/2tw= (93.1 - 46.9)/2-1.0 = 23.1 < 0.5hw.

 

:

- ..

= [2∙20∙31+(30-23.1)∙0.5∙ (30+23. 1) ∙ 1. 0] /93.1 =15.29 ;

 

- ..

yot = [2∙20∙31+(30+23.1) ∙0.5∙ (30-23.1) ∙1]/46.9=30.35 ;

 

- .. = 32.7 .

 

 

Mux = [Aocyoc+Aotyot+α(Arcyrc *Artyrt)]RyoγM =

[93. 1∙ 15. 29+46, 9∙ 30, 35+1, 32(0+35.0∙32. 7)] ∙ 26∙ [0, 95-0, 2∙ 0, 52*

*(1,32-1)] = 103895 = 1039 .

 

γM = 0,95-0,2 0(-1).

.. u = 1039 > = 1000 , .

 

) .

( )

0 = 25∙1.4∙32.7/(140+35) = 6.54 .

 

I = 94880+6.542∙140+(32.7-6.54)2∙25∙1,4 = 124820 4.

 

32.7+6.54

( )

3

.. m=314,4 > Ryo = 260 , . = 1.

2- - (.4,). - 250×6.

)

Arc=Art=15 2; yrt=yrt=32.3 ;

=Aot =70 2; =yot=30.25 .

 

,

Mux = (2∙70∙30.25 + 1.32∙2∙15∙32.2) ∙26∙0.95 = 136198 ;

u = 1362 > = 1000 .

 

.

) .

 

 

= 0+ r =85 2;

I = 94880 + 2-15-32.2 = 126179 4.

m=∙m/I = 100000∙32/126179 = 25.4 /2.

.. m = 254<Ry0 =260, .

, 2- , 1- .

, , . . , ..

 

7. /1,4/

, , . f0 k .

(7.1)

mf- ,

(7.2)

η - , 73 /1/.

(7.3)

λ - .

(7.4)

f- , N0 (.5);

ψ0 - , :

0=N0/A0≤π2E/λ2

 

f;

Ryo - .

N0 , 0 = 1.

, . :

- l0 = 5.4 ;

- 261 - . : 0 = 35.3 2, W0 = 312 3, h = 257.6 , tw = 5.6 , b = 120 , tf =8.5 ;

- N = 400 ;

- , N0 = 270 ;

- Ryo = 250 .

f= 60 δ = 1.2 . .

 

.

Ksw=0.25 . 5.1.

, ,

.73 /1/

mf<5 Af/Aw= 0.75,

.74 /1/: .

- , .

.. 25%, , = 0.9,

, .

 

8. /1,4/

, , , , .

= 0,8.

= 0,9, /1/ .

(8.1)

N - ;

- ;

Ry,red - () ;

- .

 

, ,

 

(8.2)

(8.3)

(8.4)

(8.5)

- , , ;

- , , .

:

(8.6)

- ;

Kw - , , Kw = 0.5, , Kw = 1, .

(8.7)

0

(8.8)

- (.5).

( 0=0) 0 :

(8.9)

m0 - , .8.1;

W0 - .

 

 

8.1

           
0,03 0,08 0,14 0,23 0,36 0,54

;

.

:

(8.10)

- ,

(8.11)

:

(8.12)

- , , , ;

- , ,

(8.13)

.

, , , .

, ,

(8.14)

- , : = 1 ; - ( - , - );

V - , ( - );

- ;

- i - , ;

- , - . ; - , i - , ; u - : , , u = 1,5; , =0,5, u = 0,7; , , , u = 1.

 

.

 

. 6. 0 = 23,3 2; W0 = 218,4 4; I0 = 2813 4; i0 = 10,99 ; Ryo = 250 , Ryr = 300 .

N10, , .5. r = - 10,9 2.

.

, .

 

.

:

- ( )

 

-

 

, .

 

(.5)

 

 

;

, (. .5.8 /1/)

- (.5)

 

..

 

.. ,

 

yi +, .. .

-

-

= 0 = 7.02 . -, .. N kw = 1, .

ef,max=1.53

.75 /1/

, .

 

.

 

9. , /2,6,8/

: , , (.6).

 

1) .

2)

(9.1)

hor - ,

( - ).

 

(9.2)

Rsr, Asr,- .

 

2) .

 

(9.3)

1 . ;

 





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