Structural Optimization of a Hat-Stiffened Panel Using Response Surfaces

Abstract

This paper describes a design study for structural optimization of an upper cover panel of a typical passenger bay of a blended wing body transport airplane. For these type of airplane the structure that obtained a common consent among designers is a sandwich structure. However unresolved issues of sandwich structures, like core crushing, might prevent their employment and suggest the study of an alternative all composite structure. A hat-stiffened laminated composite panel concept is considered as an alternative to the sandwich configuration. The initial geometry of the hat stiffener configuration is determined with the PANDA2 program by restricting the design to uniform axial properties. Because of pressure loading, a more efficient design has variable properties. Such designs are obtained by combining the STAGS finite element program with the optimization program in the Microsoft EXCEL spreadsheet program using response surfaces. Buckling and stress response surfaces are constructed from multiple STAGS analyses and are used as optimization constraints. The optimization conducted with the response surfaces results in considerable weight savings compared to the uniform cross-section design, albeit at the 2 expense of a more complex design. Moreover, after the initial optimization cycles are performed a subdomain of the design space is identified where simple approximate analyses, such as Euler-Bernulli beam theory and Kirchhoff plate theory applied to laminated composites, can be used to predict the behavior of the structure.

Extended fractal branch and bound method for optimization of multiple stacking sequences of stiffened composite panel

“…Only the interaction of the two kinds of stacking sequences of the laminates is dealt with here. Vitali et al have optimized these dimensions of the hat-stiffened panel [15]. The present study adopts the same dimensions of the hat-stiffened panel as shown in the research of Vitali et al As the loading condition of the present study is different from the research of Vitali et al, these dimensions are not the exact optimum but are used as reference data for the maximization of the buckling load.…”

Generatrix shape optimization of stiffened shells for low imperfection sensitivity

“…To release the computational burden caused by the large number of iterations, surrogate models have been successfully utilized in the optimization of stiffened panels [26][27][28].…”

Pressure Testing of a Minimum Gauge PRSEUS Panel

“…While later studies have continued to address HWB flying characteristics, including noise and propulsion issues, recent years have seen an increased focus on the structural performance of the HWB. [3][4][5][6][7][8] This increased focus is due to the fact that structures technology still does not yet satisfy the expected structural capabilities required to facilitate HWB aircraft.…”

“…Several sizing and optimization studies have been conducted on HWB-like structures. 3,4,6,7 Of particular importance is the response of the non-circular HWB structure subjected to internal pressure, where double bending curvature (center and edges of the panel bending in opposite directions) is experienced by the pressurized panel that results in large local stresses that drive the panel design. This phenomenon is discussed in Refs.…”