Ground Vibration Testing of a Flexible Wing: A Benchmark and Case Study

Abstract

Beam-like flexible structures are of interest in many fields of engineering, particularly aeronautics, where wings are frequently modelled and represented as such. Experimental modal analysis is commonly used to characterise the wing’s dynamical response. However, unlike other flexible structure applications, no benchmark problems involving high-aspect-ratio flexible wings have appeared in the open literature. To address this, this paper reports on ground vibration testing results for a flexible wing and its sub-assembly and parts. The experimental data can be used as a benchmark and are available to the aeronautical and structural dynamics community. Furthermore, non-linearities in the structure, where present, were detected. Tests were performed on the whole wing as well as parts and sub-assembly, providing four specimens. These were excited with random vibration at three different amplitudes from a shaker table. The modal properties of a very flexible high-aspect-ratio wing model, its sub-assembly and parts, were extracted, non-linear behaviour was detected and the experimental data are shared in an open repository.

A Loewner-Based System Identification and Structural Health Monitoring Approach for Mechanical Systems

“…Tese SI methods can be divided into many categories, depending on the data domain (time or frequency) and the identifcation procedure (input-output or output-only). Input-output data are usually obtained by experimental modal analysis (EMA) [3], while output-only techniques are collected with operational modal analysis (OMA) techniques [4]. Recent advances have focused on frequency-domain techniques and EMA for the SHM of engineering systems [5][6][7].…”

The Accuracy and Computational Efficiency of the Loewner Framework for the System Identification of Mechanical Systems

“…The former is typical of operational modal analysis [2], the latter of experimental modal analysis (EMA) [3], the approach considered in this work. The modal parameters extracted from these EMA approaches can then be employed in a plethora of uses [4], such as structural health monitoring (SHM) [5] and model updating [6,7].…”

“…A complete theoretical exposition of the LF is available in [8], while the authors' implementation of the LF for modal analysis is outlined in full detail in [9], a comparative study is presented in [18] and a MATLAB tutorial given in [19].…”

Comparison of Aeroelastic Problems Calculation Methods Based on Numerical and Experimental Results

“…For the GVT, natural frequencies, mode shapes, structural damping coefficients and the generalized mass of the main vibration modes are sought. The GVT method is broadly recognized in the literature and has been used for various aircraft structures, from commercial civil airliners [3,4] to fighter aircrafts [5] and, more recently, unmanned aerial vehicles (UAVs) [6,7]. The full scale tests are becoming progressively imperative due to the 2 wide use of composite materials in the aeronautics industry, due to the advantages of the development of lighter yet stiffer airframe configurations with aeroelastic tailoring [8] and active load alleviation capabilities.…”