Improved design methods for crashworthy composite helicopter structures

The development and validation of new methods to simulate the crash response and energy absorption of composite airframe structures are described in this paper. The simulation methods were developed and demonstrated on representative crush element tests, then larger sub-elements. Final validation, as reported in this paper, was conducted using a structure representative of a helicopter fuselage frame complete with an energy absorbing sub-floor. Scaled instrumented structures were tested quasi-statically and dynamically. The numerical model developed in PAM-CRASH was capable of predicting the deformation modes and provided excellent agreement with the steady state crushing loads and energy absorption. The ability to predict the dynamic response of a composite frame section gives confidence that numerical models can be used to design the next generation of crashworthy helicopter structures using •virtual1 crash tests resulting in lighter, stronger, safer helicopters.