MATLAB: Dot Operations in MATLAB

dot operations in matlab

format compact;

t = 0: 0.1: 2.0; % time in seconds

m = 0.709; % Mass of capsule in Kilograms

F = 62.9 – 60; % Force in Newtons

v0 = 0; % Initial velocity is zero

acc = F./m % Acceleration in meters/second

x = t.*v0 + acc.*t.^2 % Position in meters

v = v0 + t.*acc; % Velocity in meters/second

a = 2.*(v.*t – x)/t.^2 % Acceleration in meters/square second

Table = [t', x', v', a'];

fprintf ('\n');

disp (' Time,s Position,m Velocity,m/s Acceleration,m/s2');

fprintf ('%9.2f s%10.2f m%10.2f m/s%15.3e m/s2 \n', Table')

why calculation for a is wrong?

Best Answer

a = 2.*(v.*t - x)./t.^2 
           %     ^---- missed it

Related Solutions

MATLAB: Projectile motion with drag. Im not sure what Im doing wrong here but it tells me the matrix dimensions must agree however I thought that if I use .* it can multiply a scalar and a vector together

Perhaps you need to index all vectors by i

p(i) = p(i-1) + Vel.*t - AccDrag.*(t^2);

Vel and t are vectors, so try

p(i) = p(i-1) + Vel(i).*t(i) - AccDrag.*(t(i)^2);

AccDrag is a 3 element vector. I'm not sure which of the 3 values you want to use.

MATLAB: Plotting Displacement, Velocity and Acceleration vs. Time

function Myfunction()
%% @ Jeanette M. Sarra, CE 165
%Newmark-Beta Method
%% Given Values
clear all;
clc;
close all;
elcentro = load('elcentro.dat') ;           % load the Seismic data
t = elcentro(:,1);          %time values
Ag = elcentro(:,2);         %acceleration values
g = 9.81;                   %acceleration due to gravity
Dt = 0.02;                  %time step
m = 1;                      %mass
xi = 0.02;                  %damping ratio
endp = 31.18;               %terminating value of t
tn = 0:Dt:31.18;
T = 1;                      %Period
%% Solver
omega = 2*pi/T;
k = (omega^2)*m;     %stiffness
c = 2*m*omega*xi;    %damping coefficient
%parameters
gamma = 1/2;
beta = 1/6;
u(1) = 0;               %displacement initial condition
v(1) = 0;               %velocity initial condition
a(1) = 0;               %acceleration initial condition
keff = k +gamma*c/(beta*Dt) + m/(beta*Dt*Dt);
A = m/(beta*Dt)+gamma*c/beta;
B = m/(2*beta)+(Dt*c*((0.5*gamma/beta)-1));
u0 = u;
v0 = v;
a0 = a;
%loop for every time step
u_t1 = zeros(1,length(t)) ; u_t1(1) = u0 ; 
v_t1 = zeros(1,length(t)) ; v_t1(1) = v0 ; 
a_t1 = zeros(1,length(t)) ; a_t1(1) = a0 ; 
for i = 2:(length(t)-Dt)
    DF = -m*g.*(Ag(i+1)-Ag(i));
    [t,u,v,a] = Newmark(t,A,B,DF,Dt,keff,u0,v0,a0,gamma,beta);
    u_t1(:,i) = u(:,1)';
    v_t1(:,i) = v(:,1)';
    a_t1(:,i) = a(:,1)';
    
    u0 = u;
    v0 = v;
    a0 = a;
    t0 = t;
end
umax = max(abs(u_t1));
vmax = max(abs(v_t1));
amax = max(abs(a_t1));
fprintf('\n-------NEWMARK BETA METHOD-------\n');
fprintf('\nMaximum Response of a SDOF System\n\n');
fprintf('Maximum Displacement = %f\n',umax);
fprintf('Maximum Velocity     = %f\n',vmax);
fprintf('Maximum Acceleration = %f\n',amax);
%% Plotting the Figures for Response
figure(1)
plot(tn,u_t1);
title('Displacement Response')
xlabel('Period(sec)');
ylabel('Displacement (m)');
% Save picture


saveas(gca,'Displacement2.tif');
figure(2)
plot(tn,v_t1);
title('Velocity Response')
xlabel('Period(sec)');
ylabel('Velocity (m/s)');
% Save picture
saveas(gca,'Velocity2.tif');
figure(3)
plot(tn,a_t1);
title('Acceleration Response')
xlabel('Period(sec)');
ylabel('Acceleration (m/s^2)');
% Save picture
saveas(gca,'Acceleration2.tif');
end
%% Function for Newmark-Beta
function [t,u,v,a] = Newmark (t,A,B,DF,Dt,keff,u0,v0,a0,gamma,beta)
DFbar = DF + A*v0+B*a0;
Du = DFbar/keff;
Dudot = gamma*Du/(beta*Dt)-((gamma*v0)/beta)+ Dt*a0*(1-0.5*(gamma/beta));
Dudotdot = Du/(beta*Dt*Dt)-v0/(beta*Dt)-a0/(2*beta);
u = u0+Du;
v = v0+Dudot;
a = a0+Dudotdot;
t = t+Dt;
end

Best Answer

Related Solutions

MATLAB: Projectile motion with drag. Im not sure what Im doing wrong here but it tells me the matrix dimensions must agree however I thought that if I use .* it can multiply a scalar and a vector together

MATLAB: Plotting Displacement, Velocity and Acceleration vs. Time

Related Question