4.11. - N . M M = M + N f , f - M N .
, ( ) , f = f /(1 - N / N ), f = M / N , f = M /(N - N ),
M = M + N M /(N - N ) = M [1 - N /(N - N )] = M /(1 - N / N ) = M /ξ,
N -
ξ = 1 - N / N = 1 - N /(φ0 R F ).
(30) II-25-80 φ (8) II-25-80 φ = 3000/λ2 . φ (30) ξ = 1 - λ2 N /(3000 R F ).
-
M = , (10)
Mi - M
(11)
,
1 + N /(N i 2 - N ) = 1/(1 - N / N i 2) N / N = 1 - ξ,
M = (12)
M = β M /ξ,
β = (ξ/ M) (13)
,
i = 1 1 - (1 - ξ)/ i 2 = ξ, i ≥ 3 1 - (1 - ξ)/ i 2 ≈ 1,
(13)
β = (M 1/ M) + ξ (14)
M 1/ M = m, ,
(1/ M) = 1 - m,
(14)
β = m + ξ(1 - m). (15)
16
α = 1,62 | α = 0,81 | α = 1,22 | α = 2,44/(3 - 4 2/ l 2) | α ≈ 1 |
m = 2/π | m = 4/π | m = 8/π2 | m = 4 l sin (a π/ l)/(π2 ) | m = 32/π3 |
M M = β M /ξ, , , ,
M = M /(K ξ), (16)
K = αξ(1 - α) ξ, .
K β. m α (. 16), β K α ≈ 1/ m; K ≈ 1/β. α K , 3 % α 1,5 % - .
4.12. C K , , λ = l / r, λ = l /(2 r) N ξ ξ.
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l - , ;
r - .
. 5.
. 6.
α ≠ 1 α ≠ 1, (32) II-25-80
M = M /(K ξ) + M /(K ξ). (17)
, C K , .
C K . 5, α α . 16. , , , C K (. 6.)
4.13. , , . M
M = . (18)
N .
. 6
M = - M 1/(K 1ξ) + M 2(l /2 - x)/(K 2ξ l /2) + Mx /(K ξ),
M 1 = (M + M)/2, M > M; M 2 = (M - M)/2;
Mx = qx (l - x)/2;
(31) II-25-80 . 16,
K 1 = 0,81 + 0,19ξ; K 2 = 1,62 - 0,62ξ; K ≈ 1;
ξ = 1 - λ2 N /(3000 R F); ξ = 1 - λ2 N /(3000 R F);
λ = l / r = 2λ.
4.14. - , , . - , , . μ0 (. . 4.21 II-25-80).
i - j
Mi = mi (β M 0 j + KjM 0 i)/[2(KiKj - β2)]; (19)
Mj = mj (β M 0 i - KiM 0 j)/[2(KiKj - β2)].
i j i - :
(20)
(19) (20) :
M 0 - : . 17.5; - . 17.6.
( . -, . 2, ., 1973 .);
mi ( j ) = μ i ( j ) l /(EJ) - (μ - , );
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Ki (j) = 0,5 mi (j) + α,
α, β, - , N - ( . -, ., 1960, . 16.30).
m . mi ( j ) = 5,4 mi ( j ) = 9,9 , μ0.
4.15. - , , .
, - . , , ( ). . 17.3.4 ( . -, . 2, ., 1973). ( ) ( ) rk , , . 17.7 .
17.3.4 [ , . . 5.8.1 ( -, ., 1960 .)]. , , i -
Ki , i -1 = - ri,i -1/(ri,i -1 + ri , i +1);
Ki,i +1 = - ri,i +1/(ri,i -1 + ri , i +1),
()
μ = β/α,
r - ( ), :
α, β, - .. (. . -. ., 1980, . 16.30).
i - j l () M i M j, N , .
, . ( i - ) x
M x = A sin (vx / l) + B cos (vx / l) + C, (21)
A = A + Σ A ;
B = B + Σ B ;
C = Σ C ;
( , ; - ).
A , B C , . 17. A B
A = (M i - M j cos v)/sin v;
B = M i,
.
A, B, C . , .
17
x ≤ Kl | x > Kl | ||
A | ql 2cos2 θ(1 - cos v)/(v 2 sin v) | Pl cos θ sin [(1 - K) v ]/(v sin v) | - Pl cos θ sin (Kv)/(v tg v) |
B | ql 2cos2 θ/ v 2 | Pl cos θsin (Kv)/ v | |
C | - ql 2cos2 θ/ v 2 |
4.16.
x 1 = 0
x = l ψ/ v, (K = 2, 3, ), (22)
ψ = arcsin (A / M) + (K - 2)π;
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M = S (B) ;
. 7.
x 0 ≤ x ≤ l. x < 0 x = 0, x > l x = l. x , A, B C. , , , x .
, x , ,
x = x ,
x - .
M (21) x = x (22).
i - j .
. 1 - 2 . 7. EJ = 1600 ×2.
. A, B, C .
v ,
= = 1,5; v 2 = 2,25; sin v = 1; cos v = 0,0707; tg v = 14,1.
K 1 = x 1/ l = 1/3, K 2 = x 2/ l = 2/3.
sin [(1 - K 1) v ] = 0,841; sin (K 1 v) = 0,479;
sin [(1 - K 2) v ] = 0,479; sin (K 2 v) = 0,841,
cos θ = 1.
A = (M 1 + M 2cos v)/sin v = (-9 + 7×0,0707)/1 = -8,5 ×;
B = M 1 = -9 ×.
A, B, C, , .
1.
Σ A = ql 2cos2 θ(1 - cos v)/(v 2sin v) + P 1 l cos θsin [(1 - K 1) v ]/(v sin v) + P 2cos θsin [(1 - K 2) v ]/(v sin v) = 13×32×12(1 - 0,0707)/(2,25×1) + 5×3×1×0,841/(1,5×1) + 5×3×1×0,479/(1,5×1) = 61,52 ×;
Σ B = ql 2cos2 θ/ v 2 = 13×32×12/2,25 = 52 ×;
Σ C = - ql 2cos2 θ/ v 2 = -13×32×12/2,25 = -52 ×.
2.
Σ A = ql 2(1 - cos v)cos2 θ/(v 2sin v) - P 1 l cos θsin (K 1 v ]/(v tg v) + P 2 l cos θsin [(1 - K 2) v ]/(v sin v) = 13×32(1 - 0,0707)12/(2,25×1) - 5×3×1×0,479/(1,5×14,1) + 5×3×1×0,479/(1,5×1) = 52,77 ×;
Σ B = ql 2cos2 θ/ v 2 + P 1 l cos θsin (K 1 v)/ v = 13×32×12/2,25 + 5×3×1×0,479/1,5 = 56,79 ×;
Σ C = - ql 2cos2 θ/ v 2 = -13×32×12/2,25 = -52 ×.
3.
Σ A = ql 2(1 - cos v)cos2 θ/(v 2sin v) - P 1 l cos θsin (K 1 v)/(v tg v) - P 2 l cos θsin (K 2 v)/(v tg v) = 13×32(1 - 0,0707)12/(2,25×1) - 5×3×1×0,479/(1,5×14,1) - 5×3×1×0,841/(1,5×14,1) = 47,39 ×;
Σ B = ql 2cos2 θ/ v 2 + P 1 l cos θsin (K 1 v)/ v + P 2 l cos θsin (K 2 v)/ v = 13×32×12/2,25 + 5×3×1×0,479/1,5 + 5×3×1×0,841/1,5 = 65,2 ×;
Σ C = - ql 2cos2 θ/ v 2 = -13×32×12/2,25 = -52 ×.
A, B, C
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C = Σ C = -52 × .
:
x 1 = 0. , , ,
ψ2 = arcsin (A / M) = arcsin (53,02/68,3) = 0,889,
x 2 = ψ2 l / v = 0,889×3/1,5 = 1,78 > x 1.
. ψ2, , ,
ψ2 = arcsin (A / M) = arcsin (44,27/65,14) = 0,747.
x 2 = ψ2 l / v = 0,747×3/1,5 = 1,494 .
,
x 1 < x 2 < x 2.
ψ3 , , ,
ψ3 = arcsin (A / M) + π = arcsin (44,27/65,14) + 3,14 = 3,89.
,
x 3 = ψ3 l / v = 3,89×3/1,5 = 7,78 > x 2.
, ,
ψ3 = arcsin (A / M) + π = arcsin (38,89/68,3) + 3,14 = 3,75
x 3 = 3,75×3/1,5 = 7,5 > l.
, x 3 = l.
x 2:
M 2 = A sin (vx 2/ l) + B cos (vx 2/ l) + C = 44,27 sin (1,5×1,494/3) + 47,79cos (1,5×1,494/3) - 52 = 13,15 ×.
, (M 1 = M 1 = -9 × M 3 = M 3 = -7 ×) .
M 2 = M 2 = 13,15 ×.