. 5.5:
.5.5.
R = ξ * Rb * γb2 = 1,2 * 46*104 * 0,9 = 49,7*104 /2;
R ;
ξ γb2 ;
Rb ( 7,5: Rb = 46 /2).
A = N / R = 80.061,8 / 49,7*104 = 1611,5*10-4 2;
L = A / B = 1611,5*10-4 / 0,42 = 0,38 .
420420 (A = 0,1764 2).
, , , :
g = N / A = 80.061,8 / 0,1764 = 45,4*104 /2.
:
1.) , :
Mx = g * a2 / 2 = 45,4*104 * (0,08)2 / 2 = 14,5*102 *;
2.) , 3 :
2 = a2 / b2 = 0,078 / 0,22 = 0,3545;
β2 =0,02382 + 0,1*2 + 0,0185*22 = 0,02382 + 0,1*0,3545 + 0,0185*0,35452 = 0,0616;
Mx = β2 * g * h2 = 0,0616 * 45,4*104 * 0,222 = 13,5*102 *;
3.) , 4 :
3 = b3 / a3 = 0,22 / 0,215 = 1,02;
α3 = -0,0218 + 0,08155*3 0,009516*32 = -0,0218 + 0,08155*1,02 0,009516*1,022 = 0,0517;
Mx = α2 * g * a32 = 0,0517 * 45,4*104 * 0,2152 = 10,9*102 *.
:
δ ≥ (6 * Mmax / (Ry * γc))1/2 = (6 * 1450 / (25*106 * 1))1/2 = 0,019 .
δ = 20 .
. - , , , : ∅24 .
, :
kf = 1,2 * δmin = 5,4*10-3 * 1,2 = 6,48*10-3 .
kf = 6 .
lw = 0,25 * N / (βf * kf * Rwf * γc) = 0,25 * 80062 / (1,1 * 6*10-3 * 18,5*106 * 1) = 0,16 .
lw = 180 . h = 200 .
.
, , (. .5.6).
.5.6. .
a = = 0,264 ;
l = (L - ) / 2 = (0,42 0,264) / 2 = 0,078 ;
g = g * / 2 = 45,4*104 * 0,42 / 2 = 9,5*104 /2;
= g * l2 / 2 = 9,5*104 * 0,0782 / 2 = 289,0 *;
= g * (l + a / 2)2 /2 0,25 * N * a / 2 = 9,5*104 * (0,078 + 0,264 / 2)2 / 2 0,25 * 80062 * 0,264 / 2 = 547,3 *;
:
= δ * h = 0,02 * 0,2 = 0,004 2;
W = δ * h2 / 6 = 0,02 * 0,22 / 6 = 1,3*10-4 3;
( = ; Q = 0):
σ = / W ≤ Ry * γc;
σ = 547,3 / 1,3*10-4 = 4,2*106 /2 ≤ 25*106 * 1 = 25*106 /2;
.
( = ; Q = 0,25*N):
|
|
|
σ = / W = 289,0 / 1,3*10-4 = 222,3*104 /2;
τ = Q / = 0,25*N / = 0,25*80062 / 0,004 = 500,4*104 /2;
σ = (σ2 + 3 * τ2)½ ≤ 1,15 * Ry * γc;
σ = ((222,3*104)2 + 3 * (500,4*104)2)½ = 8,9*106 /2 ≤ 1,15 * 25*106 * 1;
.
