Potential Limits of Load Alleviation in Reducing the Structural Mass of a Long-Range Transport Configuration

Abstract

Load alleviation technologies on transport aircraft have been more widely researched in the past years. If the load alleviation functions are considered in the aircraft design process already, the resulting structural mass of the aircraft can be reduced. With more and more aggressive load alleviation functions, however, aspects such as material fatigue, failure cases and high-lift loads - which are commonly neglected in the early design stages - might become sizing relevant, and the initially expected potential of mass reduction might not be achievable. In this work, the three mentioned aspects are investigated and evaluated, ultimately regarding their influence on the wing box mass. With the applied fatigue model, results show that for the reference long-range transport configuration made of composite materials, the fatigue aspect does not become sizing relevant. Furthermore, the considered failure cases with defective load alleviation functions - and the assumed reduced safety factor according to the certification specifications - do not show any influence on the wing box mass. With the inclusion of high-lift load cases, however, a fraction of the expected mass reduction through load alleviation is neutralized. The more extensive the load alleviation functions are, the more mass reduction potential is neutralized due to the high-lift loads.