Coupled Rotor-Fuselage Analysis with Finite Motions Using Component Mode Synthesis

Abstract

This paper is concerned with the modeling of a rotor-fuselage system undergoing large angle maneuvers. The behavior of the elastic fuselage will be represented by a modal approximation, thereby greatly reducing the computational cost of the simulation. In this work, a floating frame approach is used. The total motion of the fuselage consists of the superposition of the rigid body motions of the floating frame and of elastic motions that are assumed to remain small. The proposed formulation makes use of a component mode synthesis technique that leaves the analyst free to choose any type of modal basis and simplifies the connection of the fuselage to other rotorcraft components. The proposed formulation is independent of the finite element analysis package used to compute the modes of the fuselage. It is also shown that in the absence of elastic deformations, the formulation recovers the exact equations of motion for a rigid body.

Active Vibration Control of Helicopter Maneuvering Flight Using Feedforward‐Robust Hybrid Control Based on Reference Signal Reconstruction

“…Currently, the elastic beam structure model has been widely used in helicopter vibration response analysis [30]. As is shown in Figure 6, a free-free finite element beam model built by ANSYS is regarded as the simplified helicopter fuselage [31].…”

Experimental investigations on active control of multifrequency helicopter vibrations using discrete model predictive sliding mode control

“…First, an ACSR system is established based on a free-free elastic beam structure which can be used to simulate a helicopter in flight effectively. 6,7 The system, which utilizes the LMS-DMPSMC control strategy, is successfully tested by choosing highly efficient d 33 -multilayer piezoelectric stacks as the actuator and taking the acceleration response at the observed point as the control object. The lowfrequency steady-state harmonic vibration, similar to the fuselage structural response produced by the main rotor, is excited by an electromagnetic shaker.…”

Model Reduction Methods for Rotor Dynamic Analysis: A Survey and Review

“…However, these bladed disk models that include only structural damping are nonrotating and are not analyzed with a full rotor-dynamic system. Bauchau et al [54] modeled a coupled rotor-fuselage undergoing large maneuver angles using Herting's transformation as opposed to the Craig-Bampton method. This analysis was done to study the coupling of a fuselage and rotor system in one dynamic analysis for transient analysis of maneuvers and was found to show good agreement; despite of the level of complexity, the rotor system is unclear.…”

“…3D solid rotor models have been used to look at complex disk geometries, attached component connections, and their response, to accurately model gyroscopics and nonlinear effects not captured in a linear formulation [20,35,[37][38][39][40][48][49][50][51][52][53], looking at large coupled rotor-structural systems [54,55], global and large scale modeling of rotating turbo machine assemblies [20], and modeling of fluid structural coupling effects of disks in rotating machines [56]. However, these models can easily reach high orders of dimensionality as seen in [50] where a bladed disk model, with no rotor or bearings, can easily reach 150000+ DOF in a turbo machine or jet engine.…”