Crashworthy design and energy absorption mechanisms for helicopter structures: A systematic literature review

Helicopters are versatile aircraft that can perform numerous missions such as ground surveillance, rescue missions, air ambulance, fire-fighting etc. However, helicopter crashes sometimes occur owing to technical failures or human errors. Accordingly, the crashworthy design of helicopters has always remained a top priority to prevent catastrophic structural failure and significant casualties. The crashworthy performance of helicopters can be immensely improved with well-designed energy absorption materials or structures. This paper presents a systematic literature review on crashworthy design and energy absorption mechanisms for helicopter structures. Firstly, the historical development of aircraft crashworthiness investigation at various periods over the past few decades is presented. Then, some typical energy absorbing components such as rings, tubes, honeycombs, corrugated structures and emerging energy absorbers are introduced to act as the major structural elements for the crashworthy design of helicopters. After that, an emphasis is placed on the dynamic behavior and energy absorption of typical helicopter structures such as the landing gear, subfloor, full-scale airframe, helicopter crashworthy seats, fuel tank and helicopter blade. In addition, representative helicopter crash scenarios such as bird strike, water impact and the impact response and injury of the occupants are described. Finally, the crashworthy evaluation criteria of helicopter structures are summarized in this paper. This article is intended as a comprehensive literature review of crashworthy design and impact protection of helicopter structures.