Here is a part of an ingenious function for storing shear force on a beam, in an array.

This is a code implemented in Matlab, it is part of a group of 15 functions that I created to solve a problem of calculation of beams, particularly solid and bored axes. This function is for the treatment of the vector of shear forces, through a numerical integration by the triangle method of the elastic equation with main inputs, the distributed loads and the point forces.

All the functions and the example program are in a toolbox available for download in Matlab.

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Function definition:

function [Q, V] = cortante (l, f, q, qt, qt2)
    k = 1000;    % Number of sample points
    Long = l(length(l))*k;
    Q = zeros(1,Long+1);     %vector of distributed loads
    Qaux = zeros(1,Long+1);  %vector of distributed load with slopes
    i=0;  j=0;   last=0;     % i: counter of pointst, j: counter of             critical points, last: final value

Cycle to fill the shear force vector:

while i<Long
   if i==l(j+1)*k        %Rutine to evaluate when program found a    critical point
   j = j+1;
   last = Qaux(i+1);
   end
   if qt(j+1) < qt(j)
      m = (qt(j+1)-qt(j))/(l(j+1)-l(j));   % slope of distributed load
      Qaux(i+2) = m*((i/k)-l(j));   %Qaux is a rect line
   elseif qt2(j+1) > qt2(j)
      m2 = (qt2(j+1)-qt2(j))/(l(j+1)-l(j));
      Qaux(i+2) = last + m2*((i/k)-l(j));
   else
      Qaux(i+2) = 0;            %if there isn't slope, then save vector
   end
   Q(i+2) = q(j);
   i = i+1;
end