Computing Codes For Development Of Helicopter Crashworthy Structures And Test Substantiation

Helicopter crash protection is more and more considered as a design constraint for military helicopters and it also appears as a constraint for civilian helicopters as well. The helicopter structure is the basic element for this protection because it must be designed to participate in crash energy absorption while at the same time acting as a protective shell for the occupants. The distorted or crushed structure areas must be designed to absorb the energy and to limit the loads in the remaining structure in order to maintain the acceleration at level of pilots and passengers to a value tolerated by the human body. In order to cope with these design constraints, it is necessary that an accurate stress analysis prediction method be available together with a good knowledge of buckling and post buckling characteristics for elements subjected to large deformations. This paper will describe the main computing tools used by Aerospatiale Helicopter Division, as well as related qualification tests.