Control surface sizing and design through integrated MDO approach: Enhancing load alleviation while preserving handling quality criteria

ifasd2024 Tracking Number 25

As part of ongoing efforts for cleaner and more efficient aviation, this research introduces a novel Multidisciplinary Optimization (MDO) strategy for the weight optimization of High Aspect Ratio (HAR) wings involving active load alleviation. The study focuses on implementing a Load Alleviation Function (LAF) to reduce wingbox structural loads during manoeuvres or gust encounters by redistributing lift inboard using movable control surfaces [1]. Building upon previous work [2], this MDO process aims to redefine control surface sizing and positioning for an optimised load alleviation while preserving the primary goal of ensuring effective aircraft manoeuvrability. An HAR wing concept is an enabler for enhancing the aircraft performance, however it is typically heavier than its lower aspect ratio counterpart. Additionally, it leads to greater flexibility in the wing, directly influencing the efficiency of the control surface and potentially leading to control surface reversal phenomena. The challenge thus lies in defining a control surface concept to allow a weight reduction through load alleviation thanks to the an optimal position and size of control surfaces, while simultaneously satisfying certification criteria for aircraft manoeuvrability across a diverse set of flight scenarios, including failure cases such as engine or actuator failure. To achieve this, an MDO approach is being considered in this work, intended to cover relevant Loads conditions and Handling Quality (HQ) criteria considered for certification, covering also overall aircraft design considerations such as the detrimental effect on Horizontal Tail Plane (HTP) weight impacted by the tuning of the Loads Alleviation. The implemented MDO approach considers the following disciplines, static aeroelastic analysis, discrete tuned gust encounter, aircraft manoeuvre trimming, HTP load monitoring, control surface reversal analysis, handling qualities efficiency assessment, and its associated validation between classic wing concept versus high aspect ratio.