We present a formulation in order to evaluate the stiffness and shear
stresses in orthotropic composite beams, with any complex cross-sectio
nal shape. The method generates two-dimensional partial differential p
roblems defined on the cross-section. Based on these formulations a co
mputer program has been developed and verified by means of comparisons
with analytical solution and computed results derived of three-dimens
ional discretization.