The design area for a sizing optimization must be a shell type of structure, that is, shell or plate elements. The shell thicknesses of the most typical modeling shell elements are supported as design variables. The mesh should be uniform in element size. Only single layered shells are supported. Contact in the design area is also allowed. Geometrical nonlinearities are not supported. Constitutive nonlinear modeling is only allowed outside the design area (for example, a nonlinear spring). | |||||||