In this paper, an energy based method is proposed to determine the opt
imal orientation of orthotropic materials under static loading. Instea
d of assuming that the strain or stress fields are fixed with respect
to orientational variables, the dependency of strain and stress fields
on material orientation is explored by introducing an energy factor i
n the inclusion model. From the derivations, the strain based method a
nd the stress based method can be recovered and their limitations are
discussed. Numerical examples from these methods are presented and com
pared.