Structural sizing and mass estimation of strut- and truss-braced wings: the effects of moderate to high aspect ratios and novel technologies

The aviation sector aims for more efficient and environmentally friendly novel transport aircraft. For this aim, sensitive and rapid conceptual or early preliminary design stage methods are vital to accurately analysing and comparing potential candidates. Thus, this PhD thesis presents a comprehensive, physics-based (quasi-analytical) structural sizing and mass estimation method for conventional and innovative aircraft wings. The method is unique due to its computational efficiency and ability to cover a wide spectrum of wings, ranging from moderate to ultra-high aspect ratios, accommodating new wing configurations such as strut- and truss-braced wings with composite or metallic materials, and incorporating emerging propulsion technologies such as hydrogen, electric and distributed propulsion systems. A key distinguishing feature of this study is the exclusive focus on the load-carrying structures of an aircraft wing: the wing boxes, struts, juries, and offsets. Validation was an integral part of the model's development, tested against data from 14 aircraft: 13 real aircraft with aluminium wing boxes and an aircraft with a high aspect ratio truss-braced wing and a composite wing box. The results show the model's high accuracy and correlation with actual wing group mass data, featuring an average error of -2.22% and a standard error of 1.74%. Simultaneously, the thesis offers comprehensive literature reviews and identifies significant gaps in the field. It provides thorough parametric and comparative studies to increase the credibility of the presented methods and investigate the effect of design decisions on the mass of the studied aircraft wings. Four hundred eighty-three loading cases are examined to detect the critical ones that drive the wing components' structural sizing. A reduced number of nine loading cases is introduced, reducing the computational time by thirtyfold. Furthermore, primary optimisation studies are conducted with the developed models for optimum strut-wing attachment and engine locations, considering different engine counts.