, . .
1- () , 2- () = 1, . , (13)
(4.1)
: D ¾ ; , Qp, Np ¾ , ; 1, Q 1, N 1 ¾ , , (), ( = 1, m = 1); EI, EA, GA ¾ , () ; m ¾ , ; l ¾ .
.
( (4,1)) . :
(4.2)
, (), (4,1) .
(4.3)
, (, ), .
4.2. (. ) (. 4.9) .
. 1. . (. 4.9, ):
2. (. ) = 1, . . 1- (. 4.9, )
3. , (4.2):
+ D , =1.
4. (. ) (. 4.9, ) 2 :
2 = m = 1.
5. 2- :
, ( ) m = 1, . . .
|
|
4.3. 3 (. 4.10). = const.
. :
(5.3)
1. Np . (. 4.10, ). . :
RA = RB = 1.5 P= 9 .
1 5 ,
N 12 = N 56 = - 1.5 P = - 9 ,
N 13 = N 35 = 0.
4 N 34 = P.
, 2 (. 5.3). (sina = 0.6, cosa = 0.8)
S y = 0,
- P N 12 N 23sina = 0.
S x = 0
N 24 + N 23cosa = 0. N 24 = - 5 ∙ 0.8 = - 4 .
N 36 = N 23 = 5 , N 46 = N 24 = - 4 .
2. , ( 4.10,). .
RA = RB = 0.5 P= 0, 5.
1 5
N 12 = N 56 = 0,5, N 13 = N 35 = 0.
4 N34 = 0.
2 (. 5.4).
S y = 0, N 12 N 23sina = 0.
, S x = 0, N 24 + N 23cosa = 0.
N 24 = .
N 36 = N 23 = 5 , N 46 = N 24 = - 4 .
(4.3) .
Np () | li | Np∙ ∙ li | ||
1-2 | - 9 | - 0,5 | 1.5 | 6,75 |
1-3 | ||||
2-3 | 5/6 | 2.5 | 10.42 | |
2-4 | - 4 | - 4/6 | 5.33 | |
3-4 | - 6 | 1.5 | ||
3-5 | ||||
3-6 | 5/6 | 2.5 | 10.42 | |
4-6 | - 4 | - 4/6 | 5.33 | |
5-6 | - 9 | - 0,5 | 1.5 | 6,75 |
S | 45.01 |
, 3 D3 = 45.01/ EA.
, , , (4.2) , . (4.4).
. (4,4)
: 1 (. 4,13), ( ) w p , . , .
, EI = const S (. 4.13)
S = .
2 : 2 = ∙ tga,
S = .
,
S =
- , 0, . .
S = tgα∙w ∙x 0. , 0tga = yc. , S
S = w∙
. 1925 .
, (. 4.14) (4.2)
. (4.5)
(4.5) 1905 . -.
, , (4.6):
|
|
, (4.6)
a, b, c, d ¾ l (. 4,15); e, f ¾ .
4.4 (. 4.16, ) C . .
. 1 2 .
1. .
Mx= 0 = 0,
. 4.16, .
2. 1- - (. 4.16, ) 1 (. 4.16, ).
3. 1 (4,6). ( 2).
4. 2- - (. 4.16, ) 2 (. 4.16, ).
5. 2
, . , , , . . .
4.5 (. 4.17, ) D, . .
. q, i, i.
Q, (. 4.17, ). ( , , ). 1 1=1, , 2 2=1, D. (. 4.17, ).
:
d D (4.4), ¾ (4.6).
. 4.17, , .
4.6 D (. 4.18, ). .
. 1. (. 4.18, ). , .
S mA = 0, - P ∙3 + RB ∙3 = 0, RB = 10 .
S m = 0, - ∙3 + RB ∙1 = 0, B = 10/3 .
S m = 0, - P ∙3 + R ∙3 = 0, R = 10 .
S m = 0, - ∙3 + R ∙2 = 0, = 20/3 .
: S = 0.
2. 1 , D (. 4.19, ).
S mA = 0, - P ∙3 + RB ∙3 = 0, RB = 1.
S m = 0, - ∙3 + RB ∙1 = 0, B = 1/3 .
S m = 0, - P ∙3 + R ∙3 = 0, R = 1 .
S m = 0, - ∙3 + R ∙2 = 0, = 2/3 .
1 . 5.11, .
1 ,
|
|
,
( EI = 4 EI ), :
4 D 28,3%.
, .
5.
1. . . . . .: . ., 2000. 416 .
2. . ., . . . .: . ., 1986. 607 .
3. . ., . ., . . . .: , 1984. 210 .
4. . . . . . . 1972. 488 .
5. . . . . .: , 1986. 520 .
6. . ., . ., . . . .: . , 1996. 541 .
7. . . . . .: . , 1995. 572 .
8. . . .. . . ., . , 1993, 116 .
-
- .
( ). , , 2071256, 256. , , .
4 (210297), .
. , .
, , , , . . . , .
1