6.57. .
, . - .
. 63. () ()
1 - ( ); 2, 3 ; 4, 5 -
6.58. - , , (. 63).
30 , .
. , , .
, , .
, , . .
6.59. , , , , . . . , .
6.60. . , . (, , , )
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q . = k q,
q - . ;
k - , , :
k = 0,02 , f / l ≤ 1/6;
k = 0,024 ;
k = 0,01 f / l ≥ 1/3 ( 1/6 < f / l < 1/3 k ).
, .
q = (q ω - q . n)/ t,
q ω - , , ;
n - (, , , ) ;
t - .
6.61. , , ,
P = 0,01 V,
V - , .
6.62. , , ,
P = 0,015 qS ,
S - .
6.63. q .. , q . , , - .
. 64. ,
.
(. 64):
U 0 - ;
U - , ;
φ0 - ;
φ - ;
b, h - ( ) ;
l - ;
M - ( );
α = 7,02 h / l;
β - h 0 ;
γ = 0,7 + 0,3β; ψ = 0,3 + 0,7β; m = 60 M /(E'b 3); t = γ m /ψ.
:
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U 0 = l /600, 3 ;
U = l /1200, 1,5 ;
φ0 = 25×10-4 .
k = m 2/(α2βψ); S = 0,9αβ b 3/[ l 3(1 + t)].
. 65.
) ; )
q . = U + U 0 + c φ0, (54)
A = E'S (k - 1);
B = E'S (k + 0,5 t);
C = E'Sh [0,5γ k + m /(α2β)].
A ( ) , . q . . - U U 0.
A < 0, A = 0.
1. 18 6 18 ´ 42 . 210 ´ 1630 .
0,05 1,5 - . (. 65).
. , 6 , (. 66).
. 66. .
); )
, , , (. . 65). , . 67.
- .
1 2 g = 1,13 /2, g = 1,29 /2. - , n = 0,9.
IV 0 = 1,5 /2 P = 2,04 /2.
II c = 0,8 c 3 = -0,4 , n = 0,9. q ω = q 0 kcnn = 0,35×0,65×0,8×1,2×0,9 = 0,2 /2, q' ω = q 0 kc 3 nn = 0,35×0,65×(-0,4)×1,2×0,9 = -0,1 /2.
. , . , , (. . 66). :
P 1 = - R 1 = q ω l 1 h 12/(2×2 h 2) = 0,2×6×2,12/(2×2×1) = 1,32 ;
P 2 = - R 2 = q ω l 1 h 24/(2 h 3) = 0,2×5×9,62/(2×8,4) = 6,6 ;
P' 1 = q' ω l 1 h 12/(2×2 h 2) = -0,1×6×2,12/(2×2×1) = -0,66 ;
P' 2 = q' ω l 1 h 24/(2 h 3) = -0,1×6×9,62/(2×8,4) = -3,3 ,
l 1 - .
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. 67. (. . 65)
) ; )
, , , :
Q = n 2(P 2 + P' 2)/(2 n 1) = 2(6,6 - 3,3)/(2×5) = 0,66 ,
n 1 - ; n 2 - P 2.
.
q . = k q = 0,024×20 = 0,48 /,
q = (g + p) l 1 = (1,29 + 2,04)6 = 20 /;
k = 0,024 (. . 6.59). . 6.62
U = l /1200 = 18/1200 = 0,015 ;
U 0 = l /600 = 18/600 = 0,03 ;
φ0 = 25×10-4,
β = h 0/ h, = 1,19/1,63 = 0,73;
α = 7,02 h / l = 7,02×1,63/18 = 0,636;
γ = 0,7 + 0,3β = 0,7 + 0,3×0,73 = 0,92;
ψ = 0,3 + 0,7β = 0,3 + 0,7×0,73 = 0,81.
2- , II-35-80
R = 15 m × m × m × m /γ n = 15×1×1×1,2×0,8/0,95 = 15,1 ,
E' = 300 R = 300×15,1 = 4530 = 4,53×103 /2.
M = ql 2/8 = 20×182/8 = 810 ×.
m = 60 M /(E'b 3) = 60×8107(4,53×106×0,213) = 1,16;
k = m 2/(α2βφ) = 1,162/(0,6362×0,73×0,81) = 5,62;
S = 0,9αβ b 3/[ l 3(1 + γ m /ψ)] = 0,9×0,636×0,73×0,213/[183(1 + 0,92×1,16/0,81)] = 2,86×10-7,
:
A = E'S (k - 1) = 4,53×106×2,86×10-7(5,62 - 1) = 5,99 /2;
B = E'S (k - 0,5γ m /ψ) = 4,53×106×2,86×10-7(5,62 + 0,5×0,92×1,16/0,81) = 8,13 /2;
C = E'Sh [0,5γ k + m /(α2β)] = 4,53×106×2,86×10-7×1,63[0,5×0,92×5,62 + 1,16/(0,6362×0,73)] = 13,76 /.
(54), :
q . = AU + BU 0 + C - φ0 = 5,99×0,015 + 8,13×0,03 + 13,76×25×10-4 = 0,37 /.
q ., .
, , - (n - 2)/ t , n - , t - . , 0,37×3 = 1,11 ,
q .×3×(n - 2)/ t = 0,37×3×(8 - 2)/2 = 3,33 .
. . 67.
x , N = 3,99 .
N = 17,83 . l = 6,26 . 125 ´ 150 .
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λ = l /(0,29 h) = 6,26/(0,29×0,125) = 173 < 200
( II-25-80, . 14).
.
R
R = 14 m /γ n = 14×1,2/0,95 = 17,7 .
λ > 70
φ = 3000/λ2 = 3000/1732 = 0,1.
(6) II-25-80
N /(φ F) = 17,83×103/(0,1×125×150) = 9,51 < R = 17,7 .
. 68. 4 . . d = 12 .
T = 1,8 d 2 + 0,02 a 2 = 1,8×1,22 + 0,02×7,32 = 3,66 > 2,5 d 2 = 3,6 ,
T = 0,8 ad = 0,8×7,3×1,2 = 7 .
n = N /(Tn ) = 17,83/(3,6×2) = 2,5.
4 2 S 1 = 8,5 > 7 d. , (7) II-23-81:
N /(φ F) ≤ Ry γ/γ n.
. 68.
λ = 170/(0,29×4) = 146,6; φ = 0,352,
σ = 17,83×103/(0,352×4×90) = 140,7 < Ry γ/γ n = 220×0,95/0,95 = 220 .
, , d = 20 , t = 4 . (127) II-23-81:
Nbs = Rbs γ bFns /4 = 157,9×0,9×314×1 = 44,6 > 17,83 ,
F = 314 2 - ;
Rbs = 150/γ n = 150/0,95 = 157,9 ; γ b = 0,9; ns = 1;
N = R γ bdt /γ n = 340×0,9×20×4/0,95 = 25,8 > 17,83 .
, ,
N = 17,83cos 63 + 14cos 61,4 = 14,8 .
kf = 4 , (120) II-23-81
N /(btkfl ) ≤ R ω f γω f γγ/γ n.
N = 14,8 ; β t = 0,7; kf = 0,004 ; γω f = 0,85;
γ = 0,95; γ n = 0,95; R ω f = 185 ;
l = 14,8×103×0,95/(0,7×4×185×0,85×0,95) = 33,6 .
l = 80 . , , 4 .
N = N / n = 14,8/4 = 3,7 .
16 .
T = 2,5 d 2 = 2,5×162 = 6,4 > 3,7 .
T = 0,35 cd = 0,35×21×1,6 = 11,76 > 3,7 .
N / F . = 17,83×103/[(125 - 2×12)(150 - 4)] = 1,29 < R m /γ n = 7×1,2/0,95 = 8,8 .