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Amplitudes or seat to head transmissibilities calculation? i wrote a code based on some already optimized parameters to calculate amplitude ratios but curve is not matching can any one help me to find out where is the mistake

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veeresh g
veeresh g on 13 Sep 2019
Commented: veeresh g on 17 Oct 2019
clc
clear all
%This is the programme with parameterssuggested by the somaye
m1=5.5 ;m2= 20;m3=4.17;m4= 9.337 ;m5=15.853 ;m6= 5.807;
k1=49340 ;k2=20000;k3=10000;k4=134400 ;k5=2916 ;k6=146640;k7= 68064;
c1=2475 ;c2=330 ;c3=200;c4= 250;c5=316;c6=3252.9;c7=1606.3;
M=[m1 0 0 0 0 0 ;0 m2 0 0 0 0; 0 0 m3 0 0 0;0 0 0 m4 0 0;0 0 0 0 m5 0;0 0 0 0 0 m6];
K=[k1+k2+k7 -k2 0 0 -k7 0; -k2 k2+k3 -k3 0 0 0; 0 -k3 k3+k4 -k4 0 0; 0 0 -k4 k4+k5 -k5 0;-k7 0 0 -k5 k5+k6+k7 -k6; 0 0 0 0 -k6 k6];
C=[c1+c2+c7 -c2 0 0 -c7 0; -c2 c2+c3 -c3 0 0 0; 0 -c3 c3+c4 -c4 0 0; 0 0 -c4 c4+c5 -c5 0;-c7 0 0 -c5 c5+c6+c7 -c6; 0 0 0 0 -c6 c6];
W = 2*pi*[0.5 0.63 0.8 1 1.25 1.6 2 2.5 3.15 4 5 6.3 8 10 12.5 16 20];% Experimental frequency range in radians
p=zeros(17,1);
x=zeros(17,1);
x1=zeros(17,1);
q=zeros(17,1);
y=zeros(17,1);
y1=zeros(17,1);
r=zeros(17,1);
z=zeros(17,1);
z1=zeros(17,1);
[rows columns] = size(W);
for i=1:columns % Retriveing number of frquencies
A= (-W(i)^2*M+j*W(i)*C+K);
B=[k1 c1; 0 0; 0 0; 0 0;0 0;0 0];
a = [1.01 1.01 1.01 1.02 1.03 1.06 1.08 1.1 1.16 1.29 1.45 1.23 1.01 0.96 0.86 0.71 0.63]; % Experimental results of seat to head transmissibility.
% b1= abs([0 0 0 0 0 1]*inv(A)*B*[1; j*W(i)]); % Analytical calculation of seat to head trasnmissibility.
%
% p(i)= abs(b1);
% x(i)= (p(i)- a(i)); % Difference between analytical and experimental STHT values.
% x1(i)= (x(i)^2); % square of the Errors.
end

Accepted Answer

darova
darova on 13 Sep 2019
These matrices look like symmetric except:
>> C-C'
ans =
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 316 0
0 0 0 0 0 0
0 0 -316 0 0 0
0 0 0 0 0 0
>> (K-K')/1000
ans =
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 2.9160 0
0 0 0 0 0 0
0 0 -2.9160 0 0 0
0 0 0 0 0 0
2.jpeg
Giving only 6th root?
b1= abs([0 0 0 0 0 1]*inv(A)*B*[1; j*W(i)]); % Analytical calculation of seat to head trasnmissibility.

  19 Comments

veeresh g
veeresh g on 17 Oct 2019
do u have idea of optimization techniques.. iam trying to optimize some parameters with fire fly algorithm but unable to minimize the error..can u help me out how to choose parameters range

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