, 6- : Qx, Qy, Nz, Mx, My, Mz.
:
1) (Nz ≠ 0),
2) (Mx ≠ 0 My ≠ 0),
3) (Mx ≠ 0, Qy ≠ 0 My ≠ 0, Qx ≠ 0),
4) (Qx ≠ 0 Qy ≠ 0).
. , . , .
(. 3.1). , , :
- ,
- , .
l Oxyz, , z .
, α Oy (. 10.1).
, , .
Oy Ox Mx = cosα l = cosα, = sinα ( Oy) My = sinα l = = sinα.
, .
σ = σ(Mx) + σ(My) = (Mx / Jx) y + (My / Jy) x = M [(cosα/ Jx) y +(sinα/ Jy) x ]. (10.1)
, . (10.1) σ = 0 , M ≠ 0, :
y = - (sinα/ Jy)/(cosα/ Jx) x = - tgα (Jx/Jy) x,
tgβ = tgα (Jx/Jy), (10.2)
:
y = - tgβ x. (10.3)
. 10.1 |
α |
z |
, .
, Jx ≠ Jy, β ≠ α, .
(. 10.2).
, (7.1) :
|max = (Mx / Wx) + (My / Wy) ≤ [ ].
y = cosα = sinα (. 8.3):
|
|
fx = (l 3)/(3 EJy); fy = (yl 3)/(3 EJx).
Oyz :
tgγ = (fx / fy) = tgα (Jx/Jy) = tgβ,
.
γ |
+σ() |
σ() |
α |
. 10.2 |
+ |
- |
β |
+ |
- |
σmax |
, 10.1, , , , (. 10.3).
Oy Oz. z Nz = z σ(N) = N / F, y Mx = y l, σ(Mx) = (Mx / Jx) y.
z |
. 10.3 |
α |
z |
:
σ = σ(N) + σ(Mx) = N / F + (Mx / Jx) y.
, (. 10.4).
σmax = N / F + Mx / Wx;
σmin = N / F - Mx / Wx.
, , , .
:
|max = N / F + Mx / Wx ≤ [ ].
. 10.4 |
σ(Mx) |
σ(N) |
σmax |
+ |
+ |
+ |
σmin |
- |