AEROLASTIC LOADS MODELING FOR COMPOSITE AIRCRAFT DESIGN SUPPORT

Abstract

The mathematical modeling of maneuvering flexible aircraft is in “constant evolution”. Previously the limitations of hardware and numerical techniques in terms of computing time needed for large scale problem solving forced the engineers to make several far reaching approximations in the mathematical modeling of aircraft dynamics. However, the ongoing reduction in computational cost resulting from the decreasing cost of hardware and the increasing efficiency of numerical techniques allows todays engineers to simulate efficiently not only simple models based on rigid-body flight mechanics but also complex models incorporating many of the details associated with the trinity of flight dynamics, controls and aero-elasticity. Current aircraft development like the emergence of high-altitude and long-endurance Unmanned Aerial Vehicles (UAVs) with very high aspect ratio flexible wings, subject to large wing de- flections and rigid-body perturbations in flight, has opened a new paradigm in the modeling and simulation of highly flexible aircraft, requiring inclusion of the structural nonlinearities, both geometry and material related, in the mathematical model [1,2,3]. However, it is not the objective of the current research to focus on large geometric perturbations characterizing the flight of these specialized aircraft. The aim is to develop a linear model, considering only the small perturbations around the steady state condition, that allows the analysis of elastically tailored composite aircraft, both business jets [4] and large civil transport airplanes [5]. Although such a linear model is only valid close to the steady state condition, it can be used in many cases to support compliance finding to loads related aviation requirements found in FAR/CS part 23 and part 25, applicable to light and large aeroplanes respectively