Response of Composite Fuselage Sandwich Side Panels Subjected to Internal Pressure and Axial Tension
The results from an experimental and analytical study of two composite sandwich fuselage side panels for a transport aircraft are presented. Each panel has two window cutouts and three frames and utilizes a distinctly different structural concept. These panels have been evaluated with internal pressure loads that generate biaxial tension loading conditions. Design limit load and design ultimate load tests have been performed on both panels. One of the sandwich panels was tested with the middle frame removed to demonstrate the suitability of this two-frame design for supporting the prescribed biaxial loading conditions with twice the initial frame spacing of 20 inches. A damage tolerance study was conducted on the two-frame panel by cutting a notch in the panel that originates at the edge of a cutout and extends in the panel hoop direction through the window-belt area. This panel with a notch was tested in a combined-load condition to demonstrate the structural damage tolerance at the design limit load condition. Both the sandwich panel designs successfully satisfied all desired load requirements in the experimental part of the study, and experimental results from the two-frame panel with and without damage are fully explained by the analytical results. The results of this study suggest that there is potential for using sandwich structural concepts with greater than the usual 20-in.-wide frame spacing to further reduce aircraft fuselage structural weight. in the airframe industry. Structural trade studies for
Fuselage response simulation of stiffened panels using a pressure-box test machine
Analytical results for a reference shell and a stiffened composite panel tested in a pressure-box test machine are presented. These results are compared with one another to assess the ability of a pressure-box test machine to simulate the shell stress state in the damaged and undamaged panel. Tests are conducted on the undamaged panel with 18.2 psig internal pressure and the damaged panel with 8.85 psig of internal pressure to evaluate some of the panel design conditions. The panel was ukimately pressurized to 15.5 psig internal pressure load condition. Comparison of the experimental results for the damaged and undamaged panel with the analysis results is good. For the damaged panel test. damage initiated at a notch tip at approximately 6.5 psig of internal pressure. The failure modes included fiber breakage. extensive delamination and fiber splitting at the graphite-epoxy and fiberglass interply interface. This damage zone grew in a stable manner until the test was discontinued at 15.5 psig of internal pressure. The experimental results indicate that the panel satisfied the design conditions.
RIP - General Purpose Interactive Display at HHIRF
RIP is a general purpose interactive code for display and analysis of data acquired with the Holifield Heavy Ion Research Facility (HHIRF) accelerators at Oak Ridge National Laboratory. The HHIRF data acquisition system includes a version of RIP for on-line display of one-and two-dimensional histograms on color graphic terminals and hard copy on color printer/plotters. General features of the program and interactive techniques will be described.