a structure particularly suited for use in aerospace industries comprising a base plate , a cover plate , and an orthogonally corrugated core including a pair of core plates formed of a superplastic alloy interposed between the base plate and the cover plate , in sandwiched relation therewith and bonded thereto , each of the core plates being characterized by a plurality of protrusions comprising square - based , truncated pyramids uniformly aligned along orthogonally related axes perpendicularly bisecting the legs of the bases of the pyramids and alternately inverted along orthogonally related planes diagonally bisecting the pyramids , whereby an orthogonally corrugated core is provided .