-0,05 , . , , , .
, 32, :
Abn = Na /(2 Rbam) = 86580/(2×150×0,85) = 340 2,
m = 0,85 - .
d = 24 , Abn = 352 2. 200 , c = 200/2 - 50/2 = 75 .
, , :
M = c 3 Na /2 = 0,075×86,58/2 = 3,247 ×;
Qa = Na /2 = 86,58/2 = 43,29 .
100 ´ 10 36-1.
:
F = 2×10×100 = 2000 2; W = 2×10×1002/6 = 333,3×102 3; I = 2×10×1003/12 = 1666,7×103 4; S = 2×10×1002/8 = 25000 3; t = 10
σ = M / W = 3247000/33330 = 97,42 < Ry γ/γ n = 240×0,9/0,95 = 227 ;
τ = QS /(Jt) = 43290×25000/(1066,7×103×10) = 64,9 < Ra = 0,58 Ry γ/γ n = 0,58×227 = 132 .
.
kf = 8 , l ω = 100 .
Wf =2β fkfl ω2/6 = 2×0,7×8×1002/6 = 18667 3;
Ff = 2β fkfl ω = 2×0,7×8×100 = 1120 2;
σ f = M / Wf = 3247000/18667 = 173,9 ;
τ f = Q / Ff = 43290/1120 = 38,7 ;
= 178,2 < R ω f γω f γ/γ n = 185×1×1/0,95 = 195 .
, .
l = 50 + 10×2/2 = 60 , b = 60 .
, ,
M = Nal /(2×4) = 86580×60/(2×4) = 649,4×103 ×.
36-1
h = = 17,4 .
18 .
2. 18 , 3 (. 59). - 1,5 ´ 3 . - . - . 1 , /:
( ) g = 3,2 g = 3,55;
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q = 4,5;
q = q c 1 = 4,5×0,5 = 2,25
q 1 = q c 2 = 4,5×2,2 = 9,9,
c 1 c 2 f / l = 1/4 II-6-74, . 5.
, , b (. 60).
. 61. M = 101,7 ×, N = 69,7 .
. 59.
.
r = 7,31 .
. 60. () ; (, )
. 61.
h = 630 > l /30 = 18000/30 = 600 b = 140 a = 33 , rk = t - h /2 ≈ 7 rk / a = 7000/33 = 210 > 150.
II-25-80 . 7, 8, 9 m = 0,95; m = 1, m = 0,92, 2- γ n = 0,95.
R = R = 15 m m /γ n = 15×0,95×0,92/0,95 = 13,8 .
h / r = 0,63/7,31 ≈ 1/11 < 1/7
II-25-80, . 4.17 6.28
N / F + M / W = 69,7×102/8,8×104 + 108,1×106/9,25×106 = 12,5 < R = 13,8 ,
M = M /ξ = 101,7/0,94 = 108,1 ×.
, , II-25-80, . 4.17 6.27, ξ N 0 = 29 :
ξ = 1 - N 0/(φ FR ) = 1 - 29×103/(0,425×8,8×104×13,8) = 0,94;
φ = 3000/λ2 = 3000/842 = 0,425;
λ = l 0/(0,289 h) = 0,5 s /(0,289 h) = 0,5×30,8/(0,289×0,63) = 0,84;
s - .
h / b = 630/140 ≈ 4,5 .
. . , .
, , , .
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6.50. . h = 1/16 - 1/12 , b = h /4 - h /2.
.
, . 15 .
. 62.
1 - ( ); 2 -
6.51. .
6.52. , .
(. 62) e 0 = M / N, M = M /ξ.
e 0 ≤ h /6 , . 1 % .
e 0 > h /6 , Na, ,
Na = N (e 0 - h /2 + x /3)/(h 0 - x /3). (50)
x = h [(1 + h)/6 e 0]/2 - ,
h 0 = h a - . 62;
a - .
Fa ≥ Na / Ra, (51)
Ra - (, ).
6.53. . N 1 N 2
N 1 = bh 0 R [2(1 + T / A)] - T; N 2 = bhR /2,
T - , Ta T :
Ta = FaRa - ;
T - II-25-80 . 5.31,
T ≥ Na;
A = 20 FaR .
N ≤ N 1,
Ne ≤ (N + T)(h 0 - x /3), (52)
e = e 0 + ha - h /2;
B = 20 Fa (N + T)/(bT).
N 1 < N <N 2,
Ne ≤ (1/2) bx (h 0 - x /3) R , (53)
x = [ N - A + ]/(bR ).
6.54. x , (50) (51) Fa:
x 3 + x 2 + x + = 0,
= -2 Nb /3, = -2 Nb (e 0 - h /2);
= -80 NFa [ e 0 + (h 2 a)/2];
= 80 NFa [ e 0 + (h 2 a)/2](h a).
:
σ a = N (e 0 - h /2 + x /3)/[ Fa (h 0 - x /3)] ≤ Ra;
σ aFa ≤ Ta;
σ = 2 N (e 0 + h 0 - h /2)/[ bx (h 0 - x /3)] ≤ R .
6.55. , .
6.56. .
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