On the Evaluation of a Coupled Sequential Approach for Rotorcraft Landing Simulation

Abstract

Maximum loads acting on aircraft structures generally arise when the aircraft is undergoing some form of acceleration, such as during landing. Landing, especially when considering rotorcrafts, is thus crucial in determining the operational load spectrum, and accurate predictions on the actual health/load level of the rotorcraft structure cannot be achieved unless a database comprising the structural response in various landing conditions is available. An effective means to create a structural response database relies on the modeling and simulation of the items and phenomena of concern. The structural response to rotorcraft landing is an underrated topic in the open scientific literature, and tools for the landing event simulation are lacking. In the present work, a coupled sequential simulation strategy is proposed and experimentally verified. This approach divides the complex landing problem into two separate domains, namely a dynamic domain, which is ruled by a multibody model, and a structural domain, which relies on a finite element model (FEM). The dynamic analysis is performed first, calculating a set of intermediate parameters that are provided as input to the subsequent structural analysis. Two approaches are compared, using displacements and forces at specific airframe locations, respectively, as the link between the dynamic and structural domains.

Fiber Bragg Grating-Based Sensors and Systems

“…The reduced noise present in optical versus electrical strain gauges showed improved accuracy of the instantaneous strain measurement. D. Cristiani et al, presented a system for rotorcraft landing simulation [3]. The FBG sensors of a system were placed in the most loaded rotorcraft areas, namely the frames and the tail boom; thus, three arrays of strain-measuring sensors were available for a total of 48 sensors, two of which were designed for temperature compensation.…”

Numerical and experimental verification of an inverse‐direct approach for load and strain monitoring in aeronautical structures

“…HUMS is intended to monitor the health state of a structure and its consumed life, based on a series of permanently installed sensors 1–3 . In this framework, knowledge of the real load spectra 4 to which a structure is subjected during its service life and thus the associated strain and stress fields are mandatory for computing the consumed life and exploiting HUMS system data on real structures 5–7 . Thus, load monitoring is a requirement for aircrafts to promote the switch from the safe‐life design to the damage‐tolerant concept 8 since it allows continuous monitoring of the structure.…”