: ; . , , , .
. , , .
. ' ε η φ (. 21.19).
φ :
φ = Ft /(Fl + F2) = Ft/(2F0) = σt /2σ0. (21.27)
F0, Ft, .
, . 21.19, .
Ft, F0, φ 0 φ0, . Ft ,
φ > φ . φ0 φ ( ).
φ0. φ η . η= 0,97...0,98, η = 0,94...0,96.
, . , . ³ φ /φ : 1,15...1,30; 1,25...1,40; 1,35...1,50; 1,50...1,60.
φ0, , : 0,6; 0,5; 0,7.
φ0 Fto F0 ( , σto 0, ):
Fto = 2 F0 φ. (21.28)
F0 . F0 Fto, , , F0 . F0 σ0, .
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.
, (. . 21.16). , 1
= ν / l ≤ [] (21.29)
v , /; 1 , .
:
[]= (5... 6) 1 ;
[]= (12... 15) 1 .
(21.29) , . ϳ , .
:
σmmax N = σmN N0 (21.30)
σmax ; N ; σN N0 = 107; .
h, , , ( ),
N = 3600 n h v, (21.31)
v , :
v = 1 u = 1; v = 0,8 u = 1,5; v = 0,6 u = 2; v = 0,5 u = 3.
ϳ (21.31) (21.30), :
h = 107 (σN/σmax)m /(3600 n v). (21.32)
(21.18). (21.32) , .
1284.289 2000 .
, (. 21.21). , , . .
, , (u ≤ 12), 0,92...0,98, .
, . (. 21.21). , , .
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: m = /π, ; h = 0,6; s = m; 2β= 50 40; = + 1 ; / = πmz, z . , : 2; 3; 4; 5; 7 10. ̳ : zt = 16...20 (2...5) ; = 20...26 = (7...10) .
ij d1 = mz1; d2 = mz2.(21.40)
da1 = d1 2∆;da2, = d2 2∆, (21.41)
0,3...0,4 ∆ = 0,6 , 0,65...0,80
∆ = 1,3 . ̳ : f = (0,25... 0,40) = (0,25...0,35) .
² ײ