Operational measurement of frequency response functions

McGee, R.; Elliott, A.; Meggitt, J.; Smith, J.

Abstract

A common problem that arises during modal testing is the inability to directly excite degrees-of-freedom to obtain frequency response functions (FRFs). It has been shown previously that reliable reproduction of FRFs via indirect excitation is difficult. This issue led to further investigation into the reconstruction of FRFs, with the most successful method arising called the ’Round-trip’ method. In one arrangement, the round-trip identity can be used to determine the point receptance between two components, by replacing local excitations with remote ones. This original formulation requires three receptance terms to be measured. Depending on the combination two of these terms represent either a velocity or force transmissibility, which may be determined operationally. This alternative formulation called the ’Operational Round-trip’ method, leaves just one receptance term to be measured via modal testing. Presented in the paper is an experimental example demonstrating the application of the Operational Round-trip method. Furthermore, an investigation into the sensitivity of the approach when either the velocity or force transmissibility is analysed.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: 10th Convention of the European Acoustics Association Forum Acusticum 2023
• Acceptance Date: Aug 7, 2023
• Online Publication Date: Jan 17, 2024
• Deposit Date: Feb 21, 2024
• Publicly Available Date: Feb 21, 2024
• Journal: Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.61782/fa.2023.1265