(. 3.3) . , , RA, RB A B. , , , , , , , . , , .
(. 3.3) :
S mB = 0, - RAl + P 1(l a 1) + P 2 a 2 = 0, ()
RA = [ P 1(l a 1) + P 2 a 2]/ l.
S mA = 0, RBl P 1 a 1 P 2(l a 2) = 0, ()
RB = [ P 1 a 1 + P 2(l a 2)]/ l.
() () , . :
S x = 0, HA HB = 0, HA = HB = H.
S mC = 0, RBl 2 P 2(l 2 a 2) HBf = 0, ()
HB = H = [ RBl 2 P 2(l 2 a 2)]/ f, :
(3.1)
(3.1) , (. 3.3). (3.1) , f.
(. 3.4, ) :
Mx = RAx P 1(x - a 1) P 2(x - a 2) Hy,
:
x = Mx - H ∙ y, (3.2)
(. 3.4, ) ( ). (3.2) . , . (3.1).
, . . 3.4, , , ∙ (3.1). . 3.4, .
Qx Nx . n n (. 3. 4, ) , :
Qx = (RA P 1 P 2)cosj x H sinj x,
Nx = + (RA P 1 P 2)sinj x + H cosj x.
, , , ; :
|
|
Qx = Qx cosj x - sinj x, (3.3)
Nx = Qx sinj x + H cosj x. (3.4)
, N > 0 .
(3.2) , , , , . .
(3.5)
= 0.
(3.5) . . 3. 5, .
3.1 , . 3. 6, m n. . :
, l = 12 , f = 4 .
.
1. :
S mA = q 6×3 + P∙ 9 RB 12 = 0. RB = 6 .
S mB = q 6×9 + P∙ 3 RA 12 = 0. RA = 10 .
H = MC / f = (RB 6 P∙ 3)/4 = 6 .
2. Q .
3. (3.2) , m n:
4. Qm Qn, (3.3)
Qm=Qm cosj m - H sinj m
:
;
,
, ,
, .
:
sinj n = - 0,555, cosj n = 0,832.
Q :
Qm = Qm cosj m - H sinj m = 4×0,832 6×0,555 = 0.
n Q , . :
.
QA = 10×0,6 6×0,8 = 1,2 ; QB = -6×0,66(-0,8) = 1,2 .
QC = - 2×1 = - 2 .
5. (3.4):
Nm = Qm sinj m + H cosj m = 4×0,555 + 6×0,832 = 7,218 ,
Nn = (-2)×(- 0,555) + 6×0,832 = 6,108 ,
Nn = (- 6)×(- 0,555) + 6×0,832 = 8,328,
:
NA = 10×0,8 + 6×0,6 = 11,6 ,
N = (-6)×(-0,8) + 6×0,6 = 8,4 .
1.
. | () | y () | tg φ | sinφ | cosφ | M | Q | Q ∙ cosφ | H ∙ sinφ | Q | Q ∙ sinφ | H ∙ cos φ | N | ||
A | 1.333 | 0.8 | 0.6 | 4.8 | 1.2 | 3.6 | 11.6 | ||||||||
m | 0.667 | 0.555 | 0.83 | 3.33 | 3.33 | 2.22 | 4.99 | 7.22 | |||||||
C | -2 | -2 | -2 | ||||||||||||
n () | -0.667 | -0.555 | 0.83 | -2 | -1.66 | -3.33 | 1.66 | -1.11 | 4.99 | 6.11 | |||||
n( ) | -0.667 | -0.555 | 0.83 | -6 | -4.99 | -3.33 | -1.69 | -3.33 | 4.99 | 8.33 | |||||
B | -1.333 | -0.8 | 0.6 | -6 | -3.6 | -4.8 | 1.2 | 4.8 | 3.6 | 8.4 |
|
|
6. 1 (. 3. 6).
3.2
, . 3. 7, , .
.
1. :
S mA = - q 12×18 - P∙ 3 + RB 24 = 0. R = 10,25 .
S mB = q 12×6 + P∙ 21 RA 24 = 0. R = 11,75 .
H = MC / f = (R ∙12 P∙ 9)/6 = 8.5 .
2. Q (. 3. 7, ).
3. (3.2), (3.3), (3.4) , .
(3.2)
Qk=Qk cosj k - H sinj k (3.3)
Nk = Qk sinj k + H cosj k (3.4)
2 , , m n. ( ), , .
2.
. | () | y () | sin φ | cos φ | M | Q | Q cosφ | H sinφ | Q | Q sinφ | H cos φ | N | ||
A | 0.707 | 0.707 | 8.5 | 11.75 | 8.31 | 6.01 | 2.3 | 8.31 | 6.01 | 14.32 | ||||
k( ) | 0.707 | 0.707 | 31.25 | 8.5 | 5.7 | 11.75 | 8.31 | 6.01 | 2.3 | 8.31 | 6.01 | 14.32 | ||
k( ) | 0.707 | 0.707 | 31.25 | 8.5 | 5.7 | 1.75 | 1.24 | 6.01 | -4.77 | 1.24 | 6.01 | 7.25 | ||
n( ) | 0.707 | 0.707 | 40.5 | 8.5 | -10.5 | 1.75 | 1.75 | 6.01 | -4.77 | 1.24 | 6.01 | 7.25 | ||
n( ) | 40.5 | 8.5 | -10.5 | 1.75 | 1.75 | 1.75 | 8.5 | 8.5 | ||||||
C | 8.5 | 1.75 | 1.75 | 1.75 | 8.5 | 8.5 | ||||||||
m () | 46.5 | 8.5 | -4.5 | -4.25 | -4.25 | -3.33 | -0.92 | 8.5 | 8.5 | |||||
m( ) | -0.707 | 0.707 | 46.5 | 8.5 | -4.5 | -4.25 | -3.0 | -6.01 | 3.01 | 3.0 | 6.01 | 9.01 | ||
B | -0.707 | 0.707 | 8.5 | -10.2 | -7.25 | -6.01 | -1.24 | 7.25 | 6.01 | 13.3 |
8, 12 15 2 (. 3.8).