Composite stacking sequence optimization for aeroelastically tailored forward-swept wings

Abstract

A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite wings is presented. It exploits bend-twist coupling to mitigate aeroelastic divergence. The method proposed here is intended for estimating potential weight savings during the preliminary aircraft design stages. A structural beam model of the composite wingbox is derived from anisotropic shell theory and the governing aeroelastic equations are presented for a spanwise discretized forward swept wing. Optimization of the system to reduce wing mass is undertaken for sweep angles of -35 • to 0 • and Mach numbers from 0.7 to 0.9. A subset of lamination parameters (LPs) and the number of laminate plies in each pre-defined direction (restricted to {0 • ,±45 • , 90 • }) serve as design variables. A bi-level hybrid optimization approach is employed, making use of a genetic algorithm (GA) and a subsequent gradientbased optimizer. Constraints are implemented to match lift requirements and prevent aeroelastic divergence, excessive deformations, airfoil stalling and structural failure. A permutation GA is then used to match specific composite ply stacking sequences to the optimum design variables with a limited number of manufacturing constraints considered for demonstration purposes. The optimization results in positive bend-twist coupling and

Optimal Design of Plated/Shell Structures under Flutter Constraints—A Literature Review

“…It is interesting to note that the decrease of the aerodynamic critical pressure with the growth of the fiber orientations (the angle-ply configuration is considered) is almost insensitive to the form of boundary condition and the orthotropy ratio A lot of papers studied the influence of the fiber orientations, stacking sequences, and fiber mechanical properties on critical aerodynamic speed [21,[59][60][61][62][63][64][65][66][67][68]. Hertz et al [69] called the above process as aeroelastic tailoring, i.e., the design that makes use of the directional properties of fibrous composite materials in wing skins and orients these materials in optimum directions-see also References [70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. In different papers the dominant role of the bending stiffness D11 is observed.…”

Approximate static aeroelastic analysis of composite wings

“…In the simplest case the sole angle α defines the orientation of the multilayer over the total plane of the wing. For example, the blocks for stacking sequence could be (Liu et al , 2011; Bach et al , 2017): …”

“…A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite wings was presented in Bach et al (2017). The method exploits bend-twist coupling to mitigate aeroelastic divergence.…”

An aeroelastic optimisation framework for manufacturable variable stiffness composite wings including critical gust loads

“…In the structural design of aircraft wings, aeroelastic tailoring usually is used to introduce the beneficial coupling effects, e.g., wash-out twist, to passively alleviate the aerodynamic loads and thereby lead to the reduction of wing weight (Jutte and Stanford 2014). For composite aircraft wings, one way of aeroelastic tailoring is to elaborately design the stacking sequence of laminates, so that the wing stiffness can be tailored in desirable directions (Gasbarri et al 2009;Bach et al 2017;Bordogna et al 2020).…”