Hi, I am trying to capture the matrix results x as it loops through the For loop so that I can plot. Please see code below, thank you much for the help.
k = [1.750,-0.750,0;-0.750,1.250,-0.500;0,-0.500,0.500] %stiffness matrix in kip/in
m = [0.075,0,0;0,0.075,0;0,0,0.050] %mass matrix in kip
c = [0.00369,0,0;0,0.01481,0;0,0,0.01914] %damping matrix
tdelta = ((2*pi)/1.64)/pi
dt = 0.50
a_0 = 1/(dt)^2
a_1 = 1/(2*dt)
a_2 = 2 * a_0
a_3 = 1/a_2
[m_hat] = a_0*m + a_1*c %effective mass
x_ndt = zeros(3,1);
x_mdt = zeros(3,1);
F = zeros(3,1);
x = zeros(3,1);
xdot = zeros(3,1);
xddot = zeros(3,1);
for i = 1:1:5
h = i/i
if i == 1 %i = 1 is at t = 0
F(:,h) = [2;1;0.66667] %initial force vector
x(:,h) = [0;0;0] %initial displacment
xddot_0 = inv(m)*(F - c*xdot + k*x);
x_ndt = x - dt*xdot + a_3*xddot %x_ndt is x_-dt
x_mdt(:,h) = inv(m_hat)* F
xdot(:,h) = [0;0;0] %initial velocity
xddot(:,h) = inv(m)*(F - c*xdot + k*x)
else
x_ndt(:,h) = x
x(:,h) = x_mdt
F(:,h) = F - (k-a_2*m)*x - (a_0*m-a_1*c)*x_ndt
x_mdt(:,h) = inv(m_hat)* F
end
end
plot(i,x)
