Innovative Structural Concepts for Deep-Winged Large Transports

Future deep-winged large transport aircraft would challenge the conventional approach to aircraft structural design. The tremendous size of deep-winged transports offers new latitudes to rethink structural configurations which efficiently meet the escalated structural demands. Conventional aircraft wing structures comprise a multitude of elements, only some of which make major structural contributions. Inefficient load paths are used in conventional designs to transfer wing structural forces to the fuselage; the susceptibility to local and global structural instabilities further undermines the efficiency of conventional structures. As a result, the working stresses in today’s aircraft wing structures are relatively low, only about 10% of the tensile strength of high-performance fibers. A new structural concept is proposed here for achieving improved levels of structural efficiency through: (i) replacement of the multitude of semi-structural and structural elements with a streamlined, multi-functional structure that is capable of mobilizing optimum load paths and effectively resisting structural instabilities for achieving higher levels of efficiency; (ii) Optimal use of the prestressing technique to effectively exploit the high tensile strength of advanced fibrous materials towards improvement of structural efficiency; and (iii) streamlined transfer of wing structural forces to the fuselage by mobilizing the efficient structural performance of fuselage under hydrostatic pressure using the wing prestressing tendons, which also benefit the fuselage performance under cabin pressure. The main thrust of the proposed Phase I research is to validate and quantify the gains in structural efficiency and safety resulting from application of the proposed structural concept to deep-winged transport aircraft. The Phase I research will: (i) identify viable ranges for the primary design variables of the proposed structural concept, and establish optimum sets of design variables with existing and emerging selections of materials; (ii) experimentally verify the optimum design with existing selections of materials; (iii) assess the competitive position of the new structural concept versus conventional designs; and (iv) devise and validate strategies for improving the competitiveness of the new concept.