7.
, , . (. . 2) , ().
● .
, [1]:
● 1- ;
● 2- (acrc 1 ≤ 0,2 ), ();
● 3- (acrc 1≤0,4 ) (crc 2≤0,3) .
, , .
1- γf>l ( ), 2- 3- γf=l.
1- , (, ), . 2- 3- . 3- .
. , (0,65...0,85)Rbp (. 3.4).
■ . - 1, , , , Rbt,ser. ( ) (σspσloss)γsp+2aRbt,ser. (σ8+σ9)+2aRbt,ser.
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● . , N , Ncrc:
σs=εsEs = εbtuEs=(Rbt,ser/ v tEb)Es = 2aRbt,ser; v t = 0,5;
, , .
. 7.1.
● . , crc, :
, (. 7.1, )
,
Wred ; Wred=Ired/y0; Ired , ; y0 , .
crc, , : M1, 0, 2, 0 Rbt,ser:
M1 . , (. 7.1, ).
(7.4) (7.7)
r=Wred/Ared (. 7.1, ); rp , () .
2 , , Rbt,ser. . (. 7.1, )
Wpl , Wpl = Wredψ, ψ , [1], ψ = 1,75. (7.8) (7.9) (7.6),
■ .
γb4 , [1]; σmt , , (4.30) .
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■ . γf = l II - . . , Δbt crc (. 7.2):
. 7.2.
Δas εsm lcrc,
εsm=ψsεs, ψs , ,
εs σs .
, . -
d ; η , ; μ .
(7.15) (7.14),
, 1,5 crc, (7.16). , crc, , (7.16), , :
δ , δ=1, δ = 1,2; φl , , ; φl = 1, φl=1,5; η , η = 1, η = 1,3; μ , μ<0,02; σs S ( ) : - σs=N/As, as = (NP)/(Asp+As), σs=M/(Asz), σs=[MP(zesp)]/[(Asp+As)z]; z ; esp Sp .
, , , . , , . 2- crc1 (7.17) . 3- crc crc3
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acrc1 acrc2:
crc2 , crc1, cr2, acrc3 (7.17) .
● , . . , . [1],
σsw :
Q Qb1 (4.47), Rbt Rbt,ser; φb4 0,8; d w ; μ w =A sw /bs.
■ () . 2- (, ) , . , ; . .
, :
● , ,
osp ; as , , (7.17);
● . σb 0,5 . σb
(3.10) (3.11); r=Wred/Ared.
, , - , . [1] , , (4.29) 0,5 .
.