無(wú)阻尼二自由系統(tǒng)固有頻率的程序

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% 無(wú)阻尼二自由系統(tǒng)固有頻率的程序 20180401A
m1=100;m2=100;k1=200;k2=400;%
9 A# |( k1 U6 ?$ u/ |c1=0;c2=0;
7 a7 c& s5 b# S. T+ zx0=[1;0];xd0=[0;0];tf=50;dt=0.1;
3 N  x" l& S4 [M=[m1,0;0,m2];k=[k1+k2,-k2;-k2,k2];
c=[c1+c2,-c2;-c2,c2];
A=[zeros(2,2),eye(2);-M\k,-M\c];
/ n) ^6 M5 F$ }$ e# p9 o5 Cy0=[x0;xd0];
for i=1:round(tf/dt)+1
* \" c; Y' J3 u    t(i)=dt*(i-1)
    y(:,i)=expm(A*t(i))*y0;
end
  z/ Y6 j% p( @4 o* isubplot(2,1,1),plot(t,y(1,),grid  
$ K  B, l& Z1 n% g& F! E8 i/ ^  a9 ]* Xsubplot(2,1,2),plot(t,y(2,),grid
[p,lamda]=eig(A)

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lamda =
* {( J/ V5 e: m  Columns 1 through 2
  0.000000000000000 + 3.020447918044219i  0.000000000000000 + 0.000000000000000i
1 p* j0 ?0 T9 D: x0 T5 d  0.000000000000000 + 0.000000000000000i  0.000000000000000 - 3.020447918044219i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
+ \- D' _) n4 k# u# v2 v6 o  Columns 3 through 4
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
  0.000000000000000 + 0.000000000000000i  0.000000000000000 + 0.000000000000000i
8 D; Q. _6 l, G9 Z6 v, D) T$ @ -0.000000000000000 + 0.936426384924271i  0.000000000000000 + 0.000000000000000i
* F2 A, a: W. J. }6 R1 ~+ }  0.000000000000000 + 0.000000000000000i -0.000000000000000 - 0.936426384924271i
4 T# [& B/ X" V, k5 F/ G

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鴻鵠重工

代碼中有個(gè)笑臉是啥意思，此處應(yīng)該是什么代碼？