Analysis, Design, and Optimization of Noncylindrical Fuselage for Blended-Wing-Body Vehicle

A study toward finding an efficient noncylindrical fuselage configuration for a conceptual blended-wing-body flight vehicle is presented. A simplified two-dimensional beam-column analysis and optimization was used to demonstrate the problem of containing cabin pressure in such flight vehicles. Then a set of detailed finite element models of deep sandwich panel and ribbed shell construction concepts were analyzed and optimized. Generally these constructions with high bending stiffness but without curvature were found to be structurally efficient to a certain extent to withstand internal pressure and resultant compressive loads simultaneously. To attain additional structural efficiency, a set of multibubble fuselage configurations was developed for balancing internal cabin pressure load efficiently, through membrane stress in inner-stiffened shell and intercabin walls. An outer-ribbed shell was designed to prevent buckling due to external resultant compressive loads. Initial results from finite element analysis of a representative fuselage segment, using this stress separation concept, appear to be promising. This concept has some additional advantages. Distortion of aerodynamic surface due to cabin pressure is minimal. Availability of duct space above and below the main fuselage can be used for direct ventilation; these also provide structural redundancy in the event of a pressure leak as well as for improved crashworthiness. These concepts should be developed further to exploit their inherent structural efficiency. [PUBLICATION ABSTRACT]