-
(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 . ;