% 无阻尼二自由系统固有频率的程序 20180401A
* p* K; A$ ]/ k, a: m5 gm1=100;m2=100;k1=200;k2=400;%
5 c% Z: Y6 @- W/ ]c1=0;c2=0;
7 Q4 b/ s0 y/ E, N @x0=[1;0];xd0=[0;0];tf=50;dt=0.1;
# K0 |( y7 A3 T! W0 o, M' OM=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];4 c2 T. P$ L* ^9 Q9 Q9 z
c=[c1+c2,-c2;-c2,c2];! W# t2 W! u, S+ m: G
A=[zeros(2,2),eye(2);-M\k,-M\c];
- R: v( t& I9 Z/ N) Gy0=[x0;xd0];
/ ^& i n7 E8 ?for i=1:round(tf/dt)+1" \ F1 a, n/ T( i& n" k0 _ Z6 N0 M
t(i)=dt*(i-1)
* w; g! ]+ \1 J! O& H3 p y(:,i)=expm(A*t(i))*y0;4 q( l( o' ]- H, D( v2 e& h
end
2 H% L. ]/ e" h& V4 V7 osubplot(2,1,1),plot(t,y(1, ),grid ! ^5 d$ Y" h% |. ?# B6 f, _( W
subplot(2,1,2),plot(t,y(2,),grid& z6 R9 r, g9 `6 _1 I0 m6 l
[p,lamda]=eig(A)% g, a+ q- C' l/ h. }
. I$ S6 s! I5 {
/ A' y! _9 V7 j% O# x* A5 p
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lamda =
& S# A9 l. o9 ]8 E Columns 1 through 2
' j5 D% d) \$ T; @/ ~ 0.000000000000000 + 3.020447918044219i 0.000000000000000 + 0.000000000000000i
3 a2 G! C7 [: ?$ {- t u& h 0.000000000000000 + 0.000000000000000i 0.000000000000000 - 3.020447918044219i7 b6 `1 h- x* y b+ X
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i5 s" i% W5 u" T% t2 @. ?
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
6 a& j9 }/ ]3 Y- m( b9 z' Y Columns 3 through 4
, D0 [& S- C- ? O1 ^3 T& T( O 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i. h$ ^0 a3 p6 F; M, P8 J- Y# C
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i4 X4 U/ ~. c: e* Y( V8 }4 |
-0.000000000000000 + 0.936426384924271i 0.000000000000000 + 0.000000000000000i) k8 p4 |: q& h* d: V; r
0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i
# ^5 N7 p v' q$ e/ V
* x O% q6 E& Z6 X' p, l& a( M. r1 d3 ?: R% N
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发表于 2018-4-16 19:41:12
