Framework to Assess Effects of Structural Flexibility on Dynamic Loads Developed in Maneuvering Aircraft

Abstract

Sizing loads for major aircraft structural components are often experienced during dynamic maneuvers, several of which are described within the Federal Aviation Regulations as part of certification requirements. A simulation and analysis framework that permits such dynamic loads to be assessed earlier in the design process is an advantage for designers and aligned with the trend towards certification by analysis. Such a framework is demonstrated in this paper using the case of a business jet performing a longitudinal checked pitch maneuver. The maneuver is simulated with a six degree-of-freedom MATLAB/Simulink simulation model, using the aircraft aerodynamic characteristics, mass properties, and an adequate level of modeling for the flight control system and pilot control action. The effects of structural flexibility and deformation of the lifting surfaces and fuselage under maneuver loads are modeled by tracking a number of structural degrees-of-freedom for each. The modular nature of the simulation setup facilitates the assessment of multiple maneuvers, analysis of sensitivity to uncertainty, as well as the identification of the impact of structural flexibility through flexible versus rigid maneuver simulations.