Abstract
In real aircraft structures the comfort and the occupational performance of crewmembers and passengers are affected by the presence of noise. In this sense, special attention is focused on mechanical and material design for isolation and vibration control. Experimental characterization and, in particular, experimental modal analysis, provides information for adequate cabin noise control. Traditional sensors employed in the aircraft industry for this purpose are invasive and provide a low spatial resolution. This paper presents a methodology for experimental modal characterization of a front fuselage full-scale demonstrator using high-speed 3D digital image correlation, which is non-invasive, ensuring that the structural response is unperturbed by the instrumentation mass. Specifically, full-field measurements on the passenger window area were conducted when the structure was excited using an electrodynamic shaker. The spectral analysis of the measured time-domain displacements made it possible to identify natural frequencies and full-field operational deflection shapes. Changes in the modal parameters due to cabin pressurization and the behavior of different local structural modifications were assessed using this methodology. The proposed full-field methodology allowed the characterization of relevant dynamic response patterns, complementing the capabilities provided by accelerometers.
Highlights
In the past decades many efforts have been made in the aerospace industry to control and reduce the noise level inside aircraft
In the work reported in the current paper, the HS 3D-Digital image correlation (DIC) technique has been employed for the dynamic characterization of part of a front fuselage full-scale demonstrator (Figure 1) developed by Airbus Defence and Space in the frame of the Clean Sky/Green Regional Aircraft program, with partial funding by the European Union
This full-scale used forfor a comprehensive series of tests, including static static and structural fatigue tests, impact damage tolerance, as well as vibroacoustic tests. It was in and structural fatigue tests, impact damage tolerance, as well as vibroacoustic tests. It was in this this context that the potential of testing technology was evaluated for non-invasive context that the potential of HS 3D-DIC testing technology was evaluated for non-invasive structural structural dynamic testing, complementing using accelerometers
Summary
In the past decades many efforts have been made in the aerospace industry to control and reduce the noise level inside aircraft. By analyzing the peaks that maximize the response it is possible to estimate the natural frequencies and the damping ratios [12,13,24,25,26,27,28,29,30,31] Special interest presents those studies that employ image decomposition approaches [17,18,22,25,32,33] to reduce the full-field information to just a few shape descriptors [34,35,36,37]. In the work reported in the current paper, the HS 3D-DIC technique has been employed for the dynamic characterization of part of a front fuselage full-scale demonstrator (Figure 1) developed by Airbus Defence and Space in the frame of the Clean Sky/Green Regional Aircraft program, with partial funding by the European Union For this purpose, measurements using HS 3D-DIC from the inside of the demonstrator have been conducted in the passenger window area, built using a multi-material component. (a) Regional Aircraft MT2 cockpit demonstrator (a) and (b)test rig (b) developed
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