paper_plot_freq_shift.m

% PAPER_PLOT_FREQ_SHIFT Compute and plot the frequency vs. load mass plot
%
% Generate data

% Copyright 2006, The MathWorks, Inc.

masses = [ 1 2 4 5 20 22 24 26 28 30 ];
data = paper_generate_freq_shift( masses , 'fea_cantilever_body' );
m=data(:,1);
T=data(:,2);
f=1./T;
omega=2*pi*f;
omega2=omega.^2;
omega2_inv = 1./omega2;

%
% Plot
%
figure;hold off;
subplot(2,1,2);plot(m,f,'r.')
subplot(2,1,1);plot(m,omega2_inv,'r.')
[p,S] = polyfit(m,omega2_inv,1)
hold on;
mp=min(m):0.01:max(m);
plot(mp,polyval(p,mp),'b-');

k=5.54e4;
M=1.35; %kg
alpha = p(2) * k / M
freefreq = sqrt( 1./p(2) ) / (2 * pi)


f2 = f.^2;
f2_inv = 1./f2;
figure;
plot(m,f2_inv,'r+'); hold on;
[p,S] = polyfit(m,f2_inv,1)
mp=min(m):0.01:max(m);
plot(mp,polyval(p,mp),'b-');
xlabel('mass [kg]');
ylabel('T_m^2 [sec]');
title('Load Mass Dependence of Oscillation Frequency')

freefreq=1/sqrt(p(2))