% 无阻尼二自由系统固有频率的程序 20180401A, P; f, T4 B `7 z* Q
m1=100;m2=100;k1=200;k2=400;%
1 Y# Z2 y+ U0 F- t" b8 P+ m2 u% Zc1=0;c2=0;$ ]. \ ^! F: o' P/ W6 i
x0=[1;0];xd0=[0;0];tf=50;dt=0.1;+ \0 u, k3 [& n) F- n0 A# U8 ]
M=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];! M' v2 E5 M/ y. s
c=[c1+c2,-c2;-c2,c2];7 [- w' f; k# S2 _7 |
A=[zeros(2,2),eye(2);-M\k,-M\c];
. s2 H5 m7 s" S( ~- ?y0=[x0;xd0];. ^/ s" a3 D' E" f6 [# {/ B& S l
for i=1:round(tf/dt)+1
k4 f& L: T6 i; A& z7 y t(i)=dt*(i-1)2 j; I5 ^7 a" k- ^" _' {" h
y(:,i)=expm(A*t(i))*y0;
3 X J' h5 j; `5 J; }5 gend
! K$ U0 l: l1 ?& S8 I: Csubplot(2,1,1),plot(t,y(1, ),grid - ]! o+ h9 o. Z8 G! ~8 c
subplot(2,1,2),plot(t,y(2,),grid
& r' l! m+ q8 u& O[p,lamda]=eig(A). c+ s- Q, H7 i0 o' J1 ^7 I$ Y8 l/ D
; l) Z1 F$ S r: d2 H1 n1 X+ ]
& c! q; {# T5 t! E5 q& Q
9 K; P( \" C: Z. Z/ e3 d5 H# D" v4 [- Y; q/ S# x# F+ n8 f5 \
lamda =
+ [) y7 S& o. f! j N$ U- Q Columns 1 through 27 j& m1 ~" P* D2 ^7 u& @
0.000000000000000 + 3.020447918044219i 0.000000000000000 + 0.000000000000000i
/ O+ I( N6 R+ k, t: l. [) A m) Z 0.000000000000000 + 0.000000000000000i 0.000000000000000 - 3.020447918044219i; l1 V% Q/ L: Q( ]
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i' j6 `, t' ?5 y, i" h" d0 T) n! N
0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
3 Y6 B. M' r* F& t Columns 3 through 4
) Q/ T' |+ g9 ^& A* R1 |8 T2 W2 ` 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i
+ e$ W, J0 L. T6 M& I) q8 Z 0.000000000000000 + 0.000000000000000i 0.000000000000000 + 0.000000000000000i! }! Q; z0 P7 q
-0.000000000000000 + 0.936426384924271i 0.000000000000000 + 0.000000000000000i' V6 K+ b0 u& n
0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i1 M+ E5 z- V5 B
) t. \& [: A+ _4 B8 Z" C
5 Y3 }! A1 `9 n# v; y7 d! r
. Q+ I4 c/ ?3 ~" b% Q. n3 ]" i5 i3 K& {) N
|
发表于 2018-4-16 19:41:12
