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Раздел 6. Основные понятия. Раздел 7. Простейшие виды деформаций. Раздел 8. Сложное сопротивление. Раздел 9. Прочность при переменных и динамических напряжениях. Раздел 10. Устойчивость. Модуль 2. СОПРОТИВЛЕНИЕ МАТЕРИАЛОВ. М Е Х А Н И К А. - PowerPoint PPT Presentation
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- 34 17 : - 2.
6. -
2
1 :1.1
1.1 1.2 () 1.3 1.4 . . 2
- , 1.2 .
.
.
:
, , ; ; ; 1.3
1.4
() 1.5
()
1.6 (, , )
() 1.7 :-
() 1.8 ________________________________________________________
N - Q - . - - - .________________________________________________________
-
1.9 . .
,
22.1 2 2.1. . 2.2. . 2.3. . 2.4.
- (, ) 2.2
, : 2.3 ,
2.4 x y __________________________________________ (1 = 1 /2). (1 = 106 = 106 /2 =1 /2.
()
- 2.5
l - - 2.6 = l / l - ( ) = +
()
2.7 : - ( ) G -
2.8
7 - 2
3 :3.1. -3.2. - 3.3. -3.4. 3.1 2.
N:3.2
- 3.3
- 3.4 :
3.5
, 2 105 1 - 1051 - 1040,67 - 1051,6 - 1050,56 - 105
0,25 - 0,330,31 - 0,340,32 0,350,32 - 0,360,23 - 0,270,16 - 0,340,08 - 0,180,07 0
- 3.6 : = ,
: () -
3.7 max = Nmax/A []. l [l],
4 :4.1. 4.2. 4.3. 4.4. 4.5. , 4.6. . 4.1 2.
4.2
4.3 - ( ) - - ( ) - -
4.40,2 - -
4.5 > 10% = 1 - 5%
4.6 h < 3d
4.7 - ().
- , 4.8 - .
- - .
. 4.9[]=np / n - n : ( = ), : ( = ) n = 2...4, n = 4...6.
5 :5.1. 5.2. 5.3. 5.4. 5.1 2.
5.2 ,
5.3 Sxc= 0, Syc = 0 - ,
5.4 4
5.5 Ix = Ix + a2 A,
Iy = Iy + b2 A,
5.6u = Ix cos2 + Iy sin2 - Ixy sin2 ,
I = Ix sin2 + Iy cos2 + Ixy sin2 ,
5.7 - - u v, u = 0, u I max min.
6 :6.1. 6.2. . 6.3. 6.4. 6.5. 6.1 2. .
. 6.2 - , - ; = G ,G - , G = 8 104 G = E / [2(1 + )] :
. 6.3. :
. 6.4dQ = dAdQ = dA
. 6.5
. 6.6 W= d3/16 0,2 d3 W= 0,2 D3(1- 4)
. 6.7GI -
. 6.8
7 :7.1. 7.2. 7.3. 7.4. 7.1 2.
7.2 , -
7.3 Q : :
7.4 Q
7.5 M Q, N. . . M, Q N , . -
8 :8.1. 8.2. 8.1 2.
8.2 - , , , , - , , , . ( ) -
8.3 dz = d. = y/. =Ey /.
8.4 :
8.5 .
8.6 : (EIx) - =Ey /,
:
8.7 :
8.8
9 :9.1. 9.2. 9.1 2.
9.2 >> . : max , [] . : [] Wx
9.3 - , . >0 . - , .
>0 .
9.4
:
9.5 = Ix0 D = Ixy0 : : :
9.6 . : y0 = 0, 0 = 0, : yA = 0, yB = 0.
: :
9.7 : , () .. : .
2. f - 1.
3. , :
9.8 ( ) Af f ; yc f ; EIx . , . f .
- 8.
10 :10.1. 10.2. 10.3. 10.1 2. -
10.2 - , - 1, 2, 3, -
10.3
10.4 : 1 0, 2 0, 3 = 0,1 = x ; 2 = y ; 3 = 0 0:
10.5 :
1 0, 2 0, 3 0 max , 45 1 3 2
10.6 ,
- - ' xyzxyz
10.7 , , . , , [p] -
10.8 2. ( )
11 :11.1. 11.2. 11.1 2.
11.2 - , . :- , ( , , ); ( , , ).
11.3 Fx= Fsin ;
Fy= Fcos . x=Fyz=(Fcos )z;
My=Fxz=(Fsin )z. F : : , . Q
11.4 , : :
11.5 : : , :
12 :12.1. ()12.2. 12.3. 12.1 2.
12.2 () : : :N= Fz,Qx= Fx, = Fy z,Qy= Fy , My = Fx z
12.3 () N = F; = F yF; = F xF , : : :
12.4 :
11.5 :
9.
13 :13.1. 13.2. 13.1 2.
13.2 , , , . - -
13.3 ( )
( ) -
13.4 :
13.5 m = 0,= max= min; r = -1. m 0,max min;.min=0; m = = max/2; r = 0.
: -1 (0,4...0,5) ,
: -1 (0,25...0,5) 13.6
14 :14.1 , . 14.2 14.1 2.
14.2 , ,
,
,
14.3 - , , , . , - ,
14.4 , ( - , , ); ( ); ( ). - d
do = 6...10
14.5 , - ( = 1) ( ) -1 - ( , ). -1 - (, , .),
14.6 :n - , [n] = 1,5 4.
15 :15.1 15.2. 15.3. 15.1 2.
15.2 - . :
;
;
;
. :
15.3 - . :-
2. h >>15.4 : 1. h = 0
10.
16 :16.1. 16.2. 16.1 2.
16.2 - .
- , .
- . , , :
16.3 - Fk -
16.4 . n - = 2 4, Fk -
16.5 Imin "= .EIminy" = -Fk y. Fk / (EImin) = 2," + 2 = 0, = Asin x + Bcos x = -Fk y ; = 0, .. = 0 = 0. y = A sin x. = l = 0 = A sin l = 0 sin l = 0, l = n n = 1
16.5 (l)
17 :17.1. . 17.2. 17.3. 17.1 2.
_________________________________________________________________ 8_________________________________________________________________ 17.1. . 17.2. 17.3. 17.1
17.2 Imin /A, = i2min, - 100 - 80, - 60 :
17.3
17.4 : [] - ; - ( ) :