Metamodeling Approach for Wing Structural Sizing of Box-Wing Aircraft

This paper presents a predictive metamodel, built on a finite element method (FEM)-based design of experiment (DoE), developed for the structural design of a box wing. For this configuration, statistical or semi-empirical predictions are not available for the conceptual design. The aim, hence, is to develop a fast and reliable structural sizing model for the early stages of the aircraft design process. The proposed model can predict maximum stress and wing deflections for a wide range of combinations of wing design variables related to geometrical (e.g., aspect ratio, span, surface) and structural parameters (e.g., stringer thickness and shape, skin thickness). The metamodel, built by handling the information from an FEM-based DoE database, has been implemented into multidisciplinary design frameworks for the conceptual design of box-wing aircraft of different sizes and geometries. The tool proved to be effective for optimizing lifting system structure, considering wing structural mass as the objective function. The accuracy of the proposed metamodel is assessed by comparing the results of different box-wing structural solutions sized with both the DoE-based surrogate model and FEM analyses; the comparisons showed a good accuracy for the metamodel, with a maximum error on the estimation of structural mass below 4% and maximum Von Mises stress below 6%.