' .
. ' .
'. ' ( ) , . ' ( 37, ) :
σ = F /(δ b) ≤ [σ]', (55)
σ ; F , ';
δ, b ' , ;
[σ]' '.
37. 璺
' , , . [σ]' ' .
, , (Κσ ≤ 1,6). σ = 1
'. ' , ( 32, ), m = 0,7k.
', 38,
τ = F /(0,7k l) ≤ [τ]', (56)
τ ; F , '; k ; l ; [τ]' .
' l , ' ( 38) l = 2 l , ' ( 38) l = 2 l , ' ( 38) l = 0,28 l + 1,5 l . l ' .
38 璺
' 䳿 F ( 38) l = l 1 + l 2 (2). l 1 l 2 F, :
l 1 = l 2/(e 1 + e 2); l 2 = l 1/( 1 + 2).
' , 38, F . (τ F τ T ):
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τ F = F /(0.7kπd); τ T = FT / A = 2 T /(0,7kπd2); (57)
FT = 2 T / d, = 0.7kπ d.
' Μ ( 39), ( 39a ).
39. ,
, l b. τ M = M / W p, W p .
(l < b), , ( 39) 䳺 F = M / b. '
τ M = M /(0,7k lb) ≤ [τ]'. (58)
' ( 39), F 1 = F cos α, F 2 = F sin α, Μ = F 2 h.
, ( 39 )
, (59)
:
τ F 1 = F 1/(2∙0,7k l); τ F 2 = F 2/(2∙0,7k l); τ M = M /(0,7k lb).