This paper describes an optimization methodology giving simultaneously the optimal
spatial material distribution and the optimal material orthotropy distribution in a
two-dimensional space. The spatial material distribution is parametrized by a density
variable that defines the presence or absence of material. A general orthotropic
material is parametrized by the polar invariants of the elasticity tensor. The criterion
is the compliance that measures the global structural stiffness. The numerical
procedure iterates successively between local minimizations and finite element
calculations. Thanks to the polar method, the local minimizations are solved
explicitly providing analytical solutions. An optimization of a beam shows the
effectiveness of the method in finding concurrently the optimal shape and the optimal
material.
Keywords
topology optimization, SIMP, polar method, distributed
orthotropy, material design