% 无阻尼二自由系统固有频率的程序 20180401A- f' n" D0 r) Z1 C6 }: D2 t0 {
m1=100;m2=100;k1=200;k2=400;%
, n7 c* N+ \2 h% q1 S Dc1=0;c2=0;6 O: i% c$ L/ g
x0=[1;0];xd0=[0;0];tf=50;dt=0.1;
; h7 l( f7 y# h2 `. e) \- m' H+ EM=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];& r- @$ `0 j4 V
c=[c1+c2,-c2;-c2,c2];
. t- S7 k: f9 o3 OA=[zeros(2,2),eye(2);-M\k,-M\c];
8 x* x% y7 ` @+ By0=[x0;xd0];
8 u/ U8 m& @6 L a: V- u% _for i=1:round(tf/dt)+1" F5 Y4 @3 }. A0 V! x2 Q. S
t(i)=dt*(i-1)6 L# |# O1 \6 F3 k& w; Y
y(:,i)=expm(A*t(i))*y0;
# c; H2 z& [1 y6 n7 E; M3 q" gend$ l; f% h$ Q- t
subplot(2,1,1),plot(t,y(1, ),grid
% n! X1 T2 P; f8 W9 bsubplot(2,1,2),plot(t,y(2,),grid
! ^6 b% c6 C! A2 B5 I[p,lamda]=eig(A)
% }& a7 L p% k8 z) \
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# o" l) |# P/ i* V4 f( Ilamda =
7 T3 d7 v' S5 ^0 ?7 F Columns 1 through 26 E! ]& U9 U1 Z$ o. t9 W+ j
0.000000000000000 + 3.020447918044219i 0.000000000000000 + 0.000000000000000i
& f- x5 D; Z7 K! F3 k; l l 0.000000000000000 + 0.000000000000000i 0.000000000000000 - 3.020447918044219i% M+ q2 E, j# L) o9 P, l& b# C
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
/ ?0 }2 Q0 B, Z4 s" Z7 A, m 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i6 l0 n0 F2 @, I4 D
Columns 3 through 4& ?& G/ |$ ~* K, `9 ^/ N/ i
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i v/ z2 T! [$ r( A" s& g
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i; Z I: A% w. |: m$ y0 i) m
-0.000000000000000 + 0.936426384924271i 0.000000000000000 + 0.000000000000000i
% }4 S& d* W7 B 0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i* v3 F& C6 q4 t( q
2 B9 B/ ]3 z! J; K
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8 L: \4 s' C- d" s5 \# ?2 m$ c% e' b' V0 t# z/ u' m7 t4 p0 U2 @
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发表于 2018-4-16 19:41:12
