, 䳿 , .
:
σ ≤ [σ] τ ≤ [τ], (1)
σ, [σ] ;
τ, [τ] , .
. . 4.1.
:
(. 4.1, ) σp = F/A ≤ [σ]; (2)
(. 4.1, ) σ = M/W0 ≤ [σ]; (3)
(. 4.1, ) τ = T/Wp ≤ [τ]; (4)
(. 4.1, ) σ = F/ A ≤ [σ ]; (5)
(, . 4.1, )
τ = F/A ≤ [τ]; (6)
F ; ; ; ( ); W0 ; Wp .
:
d
W0 = πd 3/32 ≈ 0,1d 3; W = πd 3/16 ≈ 0,2d 3;
b x h ( h )
W0 = bh2/6.
䳿 , () ,
(7)
, , . ' .
, , .
, ( , , .).
, ', . , , .
:
|
|
1. ( , ). . 4.2, q = F / ℓ.
ϳ .
, (8)
ZM , , ; ρ .
, (9)
1 2 ; μ1 μ2 .
(1 = 2 = μ1 = μ2 = μ), ZM
. (9)
( = 2,15105 ; μ = 0,3) ZM == 275 1/2.
( . 4.2, . 4.2, )
1/ρ = 1/ρ1 1/ρ2, (10)
ρ1 (ρ2 = ∞) ρ = ρ1.
(8) , . ρ1 ρ2 .
2. ( , ).
FH (. 4.2, ) .
, (11)
Z'M , ;
.
. (12)
,
(1 = 2 = μ1 = μ.2 = μ), Z'M
. (12)
Z*M = 1755 2/3.
. , , .
ϳ 䳿 . , . , , , ( , , ).
, , .
. 4.3 σ τ t.
|
|
. σmax σmin , σ R. σm :
σm = 0,5(σmax + σmin). (13)
σa :
σa = 0,5(σmax σmin). (14)
³ , ,
R = σmin/σmax. (15)
: (σm = σ; σ = 0; R = 1), (σm = 0; σ = σmax; R = 1) (σm = 0,5σmax; σ = 0,5σmax; R = 0) . .
³, . σR ( σ1, τ1 σ0, τ0 ).