Advances in Rotorcraft Crashworthiness: Trends Leading to Improved Survivability

摘要

The optimal crashworthy design of an aircraft/rotorcraft utilizes a systems approach to provide the maximum level of protection for the occupants. Using this approach, the designer ensures that all of the separate safety systems in the aircraft work together to absorb the aircraft's kinetic energy and to decelerate the occupants to rest without causing injurious loading. In a crash of a rotary-wing aircraft, landing gear absorbs energy to reduce the impact velocity of the fuselage, either through crash attenuating shock struts or permanent deformation of a skid gear. The subfloor structure provides additional deceleration through stable crushing and plastic deformation. The seat completes the system by limiting high deceleration loads that could be transmitted to the occupant. The seat must also remain attached to the floor to prevent the occupant from becoming a projectile within the cabin. The restraints must function well during the primary and secondary impacts to minimize head strike potential and occupant flail. The floor should be designed as a primary structure to transfer load effectively between the seat and the subfloor. Finally, the fuselage cabin must be sufficiently stiff and strong to prevent intrusion of the overhead rotor transmission mass into the occupied space.