tdofpz3x3_rlocus.m

振动仿真 vibration simulation using matlab and ansys!

	echo off
%	tdofpz3x3_rlocus.m		plotting locus of poles/zeros of z11 for tdof
%   model for range of damping values.

	clf;

	clear all;

%	using Matlab's pzmap function with the "tf" form using num/den
%	to define the numerator and denominator terms of the different
%	transfer functionx

%	assign values for masses, damping, and stiffnesses

	m1 = 1;
	m2 = 1;
	m3 = 1;
	k1 = 1;
	k2 = 1;

%	define vector of damping values for c1 and c2

	cvec = [0 .2 .4 .6 .8 1.0 1.1 1.05 1.1 1.15 1.16];

	for cnt = 1:length(cvec)

	c1 = cvec(cnt);
	
	c2 = cvec(cnt);
	
%	define row vectors of numerator and denominator coefficients

	den = [(m1*m2*m3) (m2*m3*c1 + m1*m3*c1 + m1*m2*c2 + m1*m3*c2) ...
	       (m1*m3*k1 + m1*m3*k2 + m1*m2*k2 + m2*c1*c2 + m3*c1*c2 + ...
	        m1*c1*c2 + k1*m2*m3) ...
		   (m3*c1*k2 + m2*c2*k1 + m1*c2*k1 + m1*c1*k2 + m3*c2*k1 + m2*c1*k2) ...
		   (m1*k1*k2 + m2*k1*k2 + m3*k1*k2) 0 0];

	z11num = [(m2*m3) (m3*c1 + m3*c2 + m2*c2) (c1*c2 + m2*k2 + m3*k1 + m3*k2) ...
			  (c1*k2 + c2*k1) (k1*k2)];

	z21num = [(m3*c1) (c1*c2 + m3*k1) (c1*k2 + c2*k1) (k1*k2)];

	z31num = [(c1*c2) (c1*k2 + c2*k1) (k1*k2)];

	z22num = [(m1*m3) (m1*c2 + m3*c1) (m1*k2 + c1*c2 + m3*k1) ...
			  (c1*k2 + c2*k1) (k1*k2)];

%	use the "tf" function to convert to define "transfer function" systems

	sysz11 = tf(z11num,den);

	sysz21 = tf(z21num,den);

	sysz31 = tf(z31num,den);

	sysz22 = tf(z22num,den);

%	use the "pzmap" function to map the poles and zeros of each transfer function

	[p11,z11] = pzmap(sysz11);

	[p21,z21] = pzmap(sysz21);

	[p31,z31] = pzmap(sysz31);

	[p22,z22] = pzmap(sysz22);

%	plot poles and zeros of z11

	subplot(1,1,1)
	plot(real(p11),imag(p11),'k*')
	hold on
	plot(real(z11),imag(z11),'ko')
	title('Poles and Zeros of z11 for range of damping values c1 and c2')
	xlabel('Real')
	ylabel('Imag')
	axis([-3 1 -2 2])
	axis('square')
	grid on

	end

	hold off