Patent ID: 7780116

Claim:
A fuselage structure ( 2 ) of a rotary wing aircraft, comprising: vertical walls, comprised of transverse walls ( 18 B) and longitudinal walls ( 18 ); a cross-strut section member ( 21 ) joining the longitudinal walls ( 18 ) to the transverse walls ( 18 a ); and a cylindrical delaminating insert ( 26 ), having a frustoconical head, located at a base ( 21 A) of the section member ( 21 ), wherein each of the vertical walls comprises an intermediate arrangement ( 20 ) and two planar jackets ( 19 ) of composite material disposed on either side of the intermediate arrangement ( 20 ), wherein the intermediate arrangement of at least one of the vertical walls comprises a corrugated core ( 70 ) presenting corrugations extending along an axis (Z) substantially parallel to the planar jackets such that an energy-absorption capacity of the at least one of the vertical walls in an impact in a direction of the axis (Z) is increased, wherein a base of the at least one of the vertical walls includes a zone of weakness ( 45 ) where a thickness of the at least one vertical wall is reduced, wherein the corrugated core cooperates with the planar jackets to define cavities ( 61 ) shaped as portions of prisms of polygonal section with a cellular filler material ( 23 , 24 ) filling the cavities, and wherein the delaminating insert ( 26 ) has a central axis extending parallel to the axis (Z), the delaminating insert ( 26 ) being configured to cooperate with a material of the section member surrounding the delaminating insert ( 26 ) to delaminate the material upon the occurrence of the impact.