University of Florida/Eml4500/f08.qwiki/Lecture 6

The global force relationship is given by the equation $$F=KD$$, where $$F$$ is the resultant force matrix, $$K$$ is the global stiffness matrix, and $$D$$ is the global displacement matrix.

In matrix format,

$$ k^e = k^e \begin{bmatrix} (l^e)^2 & (l^e m^e) & -(l^e)^2 & -(l^e m^e) \\ (l^e m^e) & (m^e)^2 & -(l^e m^e) & -(m^e)^2 \\ -(l^e)^2 & -(l^e m^e) & (l^e)^2 & (l^e m^e) \\ -(l^e m^e) & -(m^e)^2 & (l^e m^e) & (m^e)^2 \end{bmatrix} $$