Asked by Ben Newton
on 28 Oct 2019

%ben newton swansea university 956205

k = 997.584; %stiffness, units = N/m

m = 10.692; %mass, units = kg

xo = 0.026844; %initial displacement, units = m

vo = 0:0.001:5; %initial velocity, units = m/s

t = 0.735; %time, units = s

x = 0.0852; %dispacement, units = m

c = 36.84; %damping coefficient, units = kg/s

wn = sqrt(k/m); %natural frequency, units = rad/s

ccrit = 2*sqrt(k*m); %critical damping coefficient, units = kg/s

zeta = c/ccrit; %damping ratio, no units

wd = wn*sqrt(1 - zeta^2); %damped natural frequency, units = rad/s

A = sqrt((vo+zeta*wn*xo).^2 + (xo*wd)^2/wd^2);

phi = atan((xo*wd)./vo+zeta*wn*xo); %phase angle, units = radians

x@time = A.*exp(-zeta.*wn.*t)*sin((wd.*t)+phi);

%everythings fine up until the last line, gives the error using * inner matrix dimensions must agree

all matrices used are the same shape an size etc and .* has been used

but i still get the error message

please help

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## 3 Comments

## Guillaume (view profile)

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## Stephen Cobeldick (view profile)

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## Rena Berman (view profile)

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