v2_002.m

美国辛辛那提大学的振动教材

% v2_002.m    
%
% This is a script file to illustrate the response 
% of an underdamped, critically damped and overdamped
% SDOF system to an initial displacement.
%            
% SDOF System
% Underdamped, critically damped overdamped response
% Figures for UC-SDRL-CN-20-263-662, Chapter 2
             
%**********************************************************************
% Author: Randall J. Allemang
% Date:	18-Apr-94
% Structural Dynamics Research Lab
% University of Cincinnati
% Cincinnati, Ohio  45221-0072
% TEL:  [phone]
% FAX:  [phone]
% E-MAIL: [e-mail]
%*********************************************************************
%
clear,clg
plt=input('Store plots to file (Yes=1): (0)');if isempty(plt),plt=0;end
mag=10; 
V=[-15,15,-15,15];
%
%     Overdamped Solution 
% 
lambda1=-2;
lambda2=-8;
t=linspace(0,4.0,201);
x=mag.*exp(lambda1.*t)+mag.*exp(lambda2.*t);
plot(t,x)
xlabel('Time(sec.)'),ylabel('Displacement'),grid
title('Overdamped SDOF System')
if plt==1,print -deps v2_002a.eps, end;
pause
clg
axis(V);
plot(real(lambda1),imag(lambda1),'*',real(lambda2),imag(lambda2),'*')
axis;
xlabel('Real Part of Complex Frequency')
ylabel('Imaginary Part of Complex Frequency'),grid
title('Overdamped SDOF System')
if plt==1,print -deps v2_002b.eps, end;
pause
clear x
lambda1=-5;
lambda2=-5;
x=mag.*exp(lambda1.*t)+mag.*exp(lambda2.*t);
plot(t,x)
xlabel('Time(sec.)'),ylabel('Magnitude'),grid
title('Critically Damped SDOF System')
if plt==1,print -deps v2_002c.eps, end;
pause
clg
axis(V);
plot(real(lambda1),imag(lambda1),'*',real(lambda2),imag(lambda2),'*')
axis;
xlabel('Real Part of Complex Frequency')
ylabel('Imaginary Part of Complex Frequency'),grid
title('Critically Damped SDOF System')
if plt==1,print -deps v2_002d.eps, end;
pause
clg 
clear x
lambda1=-5+j*10;
lambda2=-5-j*10;
x=mag.*exp(lambda1.*t)+mag.*exp(lambda2.*t);
plot(t,x)
xlabel('Time(sec.)'),ylabel('Magnitude'),grid
title('Underdamped SDOF System')
if plt==1,print -deps v2_002e.eps, end;
pause
clg
axis(V);
plot(real(lambda1),imag(lambda1),'*',real(lambda2),imag(lambda2),'*')
axis;
xlabel('Real Part of Complex Frequency')
ylabel('Imaginary Part of Complex Frequency'),grid
title('Underdamped SDOF System')
if plt==1,print -deps v2_002f.eps, end;
pause