ANALYTICAL CRASH SIMULATION OF 3 COMPOSITE FUSELAGE CONCEPTS AND EXPERIMENTAL CORRELATION

The DYnamic Crash Analysis of STructures (DYCAST) crash analysis code was used to simulate the vertical impact response of two fuselage sect ions of the all-composite Lear Fan 2100 General Aviation aircraft. One fuselage section was tested in the unmodified condition, with the exi sting rigid subfloor in place. The second fuselage section was modifie d by replacing the rigid subfloor with an energy absorbing subfloor Th e DYCAST analysis results for both the unmodified and modified Lear Fa n fuselage sections agreed well with the experimental data. The DYCAST analyses predicted the type and location of damage to the sections us ing a simple ultimate strain failure model. Experimental results from the Lear Fan testing program were used in the development of DYCAST mo dels of three fuselage design concepts. The first fuselage concept is typical of conventional design and consists of a composite frame-reinf orced fuselage shell with a stiff subfloor. The second fuselage concep t is a retrofit of the previous design in which the rigid subfloor is replaced with a composite energy absorbing subfloor, The third fuselag e concept is are innovative design which features a stiff ''inner'' fu selage intended to provide a protective shell surrounding the occupant s, with a frangible ''outer'' shell which encapsulates an energy absor bing subfloor. The DYCAST models of the three fuselage concepts were a nalyzed for the same impact and loading conditions. A comparison of th e response of the simulated occupant indicates a 25% reduction in vert ical acceleration for the retrofit fuselage concept and a 50% reductio n in vertical acceleration for the innovative third fuselage concept w hen compared with the conventional fuselage concept.