% 无阻尼二自由系统固有频率的程序 20180401A
! a9 l* z a" r* @$ ], f: im1=100;m2=100;k1=200;k2=400;%
5 G' H- Z: G& m! |c1=0;c2=0;
" X5 V: [. @- Z! n9 l- U, ax0=[1;0];xd0=[0;0];tf=50;dt=0.1;
2 I1 i& }$ Q7 H: L* L: OM=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];
$ q1 i7 O+ I, [+ t/ f* Uc=[c1+c2,-c2;-c2,c2];3 m1 h( q# ?/ z. ?$ ~' D
A=[zeros(2,2),eye(2);-M\k,-M\c];# |7 Q2 X$ h+ ~9 K @
y0=[x0;xd0];
4 _1 _4 I7 f* x) g ffor i=1:round(tf/dt)+15 ?- W) \) x" _! c* w9 V3 }
t(i)=dt*(i-1)0 ]3 w, s; u6 z+ \4 h
y(:,i)=expm(A*t(i))*y0;
9 g& z% g" X, J a9 ?end
6 T. y( w! b, j# d# q2 G q7 K' Y7 w7 ?subplot(2,1,1),plot(t,y(1, ),grid * O6 b+ x5 i5 r6 V
subplot(2,1,2),plot(t,y(2,),grid0 E0 R0 f' Z# o& E& G
[p,lamda]=eig(A)3 ]# z" ^/ q6 G- C( A' U: m
& @$ ]8 J# \4 e0 S
( _! `3 a0 ?8 j) O$ A& X3 X& v, d
7 }$ L, r0 u5 Z3 n
& [8 s C$ A, [/ T( W% M* Alamda =
* a3 y" C' h8 @ Columns 1 through 2 j" u% y7 d- a7 g4 Z
0.000000000000000 + 3.020447918044219i 0.000000000000000 + 0.000000000000000i4 x3 Y! N; a p7 r
0.000000000000000 + 0.000000000000000i 0.000000000000000 - 3.020447918044219i
2 e* C6 j4 {# a 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i3 B4 g; G8 U, T/ u; H7 k1 }
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i2 M2 g' E o' Y
Columns 3 through 43 E! ^" o" F: d! C/ v- Y% K2 ~
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
- w2 s7 }- n% ^4 u! p" T 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
6 o# a6 `; u6 U$ d -0.000000000000000 + 0.936426384924271i 0.000000000000000 + 0.000000000000000i4 n$ Z# B. u) I r3 V1 R
0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i+ a' \' p' j5 X) o
' m' w5 r% `. `" K" r2 x# p, q
4 K# L) ]1 g W- c
0 ^* U+ E2 J$ k) E
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发表于 2018-4-16 19:41:12
