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An innovative composite fuselage concept for light aircraft has been developed to provide improved crash protection. The fuselage consists of a relatively rigid upper section, or passenger cabin, including a stiff structural floor and a frangible lower section that encloses the crash energy management structure. The development of the fuselage concept is described including the fabrication of a 60-in. diameter full-scale fuselage section that is manufactured using a composite sandwich construction. Drop tests of the fuselage section were performed at 372-in/s vertical velocity for both 0°- and 15°-roll impact attitudes to evaluate the crashworthy features of the fuselage design. The experimental data are correlated with analytical predictions from a crash simulation developed using the nonlinear, explicit transient dynamic finite element code, MSC/DYTRAN.

In support of crashworthiness studies on composite airframes and substructure, an experimental and analytical study was conducted to characterize size effects in the large deflection response of scale model graphite-epoxy beams subjected to impact. Scale model beams of 1/2, 2/3, 3/4, 5/6, and full scale were constructed of four different laminate stacking sequences including unidirectional, angle ply, cross ply, and quasi-isotropic. The beam specimens were subjected to eccentric axial impact loads which were scaled to provide homologous beam responses. Comparisons of the load and strain time histories between the scale model beams and the prototype should verify the scale law and demonstrate the use of scale model testing for determining impact behavior of composite structures. The nonlinear structural analysis finite element program DYCAST (DYnamic Crash Analysis of STructures) was used to model the beam response.