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Izpit 5. 9. 2005
Dinamika in stabilnost
L1 =3;
m1 = 2000;
EI1 = 1 10^8;
L2 =5;
m2 = 5000;
EI2 = 4 10^8;
v1
@x_
D:=
A1 x3
6
+A2 x 2
2
+A3 x +A4;
v2@x_D := B1 x36
+B2 x2
2+ B3 x + B4;
Dolocitev konstant
resitve = Solve@8v2@0D ==0, v2@L2D ==0, v2''@L2D ==0,v2 '@0D ==
v1 '@L1D, v2''@0DEI2 == v1''@L1DEI1,v1@0D == 0, v1'@0D ==0, v1@3D
1
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kg = Pukl0
L1
v1 '@xDv1 '@xD x739 Pukl
1960
Sestava posplosene togosti
k = EI10
L1
v1''@xDv1''@xD x + EI20
L2
v2''@xDv2''@xDx2050000000
63
Sestava posplosene mase
m = m10
L1
v1@xDv1@xDx +m20
L2
v2@xDv2@xD x + m2 L228079200
1029
Lastna frekvenca
!!!!!!!!!!!!k m
N@%D% 2 Pi1750$%%%%%%%%%%%%%%%%%%%%41
105297
34.532
5.49594
Izracun kriticne uklonske sile
Solve@k kg == 0, PuklD99Pukl 574000000000
6651==
N@%D88Pukl 8.63028 107
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precna1 = obtezba1x +C1C1 2000
ikjj23 x3
252
41 x4
3024
y{zz 2
moment1 = precna1x + C2C2 + C1 x
2875 x4 2
63+
1025 x5 2
189
zasuk1 = moment1 EI1x + C3
C3 +C2 x + C1 x
2
2
575 x5 2
63
+ 1025 x6 2
1134
100000000
w1@x_D = zasuk1x + C4C4 + C3 x + C2 x
2
200000000+ C1 x
3
600000000 23 x
6
2
1512000000+ 41 x
7
2
31752000000
obtezba2 = 2 m2 v2@xD 5000
ikjj 5 x
28
3 x2
56+
x3
280
y{zz 2
precna2 = obtezba2x +D1D1 5000
ikjj5 x2
56
x3
56+
x4
1120
y{zz 2
moment2 = precna2x + D2D2 + D1 x
3125 x3 2
21+
625 x4 2
28
25 x5 2
28
zasuk2 = moment2 EI2x + D3
D3 +D2 x + D1 x
2
2
3125 x4 2
84
+ 125 x5 2
28
25 x6 2
168
400000000
w2@x_D = zasuk2x + D4D4 + D3 x +
D2 x2
800000000+
D1 x3
2400000000
x5 2
53760000+
x6 2
537600000
x7 2
18816000000
V= m2 L2 2 v1@L1D25000 2
e24 za racunalniske vaje.nb 3
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resitve = Solve@8w1@0D 0, w1'@0D 0, w2@0D 0, w2@L2D 0,w2''@L2D
0, w1'@L1D w2 '@0D,w1''@L1DEI1 w2''@0DEI2, w1'''@L1DEI1 V
