1. Local stiffness matrix and deformation matrix (3d linear bar element formulation)
[kL, B, T, kG] = stiffbar3d(E, A, L, dircos, ne)
Modulus of elasticity [ne x 1]
Cross-sectional Area [ne x 1]
Bar length [ne x 1]
Direction cosines [ne x 3]
Number of elements [1 x 1]
Local stiffness matrix [ne*2 x 2]
Deformation matrix [ne*1 x 2]
Coordinates Transformation matrix [ne*2 x 6]
Global stiffness matrix [ne*6 x 6]