Creating a smooth and wide attenuation band in the transmissibility of beam vibration using a neutraliser

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© 2026 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license. http://creativecommons.org/licenses/by/4.0/This paper investigates how a single vibration neutraliser can be attached to a beam to create a wide frequency range in which vibration transmission is reduced. This range, termed the smooth wide attenuation band (WAB), is defined as the region where the displacement transmissibility across the beam is below unity and exhibits no peaks or troughs. The concept is motivated by similar behaviour observed in mono-coupled periodic rods. The primary aim of the study is to identify the physical mechanisms responsible for the formation of the WAB and to establish an effective approach for tuning the neutraliser. Using the receptance method, with the beam modelled using its vibration modes, it is shown that the formation of a WAB requires specific conditions. The neutraliser must be placed at a nodal point of the beam and be tuned such that the real part of its dynamic stiffness is equal and opposite to the mass-like receptance of the beam at the corresponding natural frequency. The analysis shows that the WAB results from a degenerate mode condition in which two vibration modes of the combined beam–neutraliser system coincide in frequency. Numerical simulations indicate that attaching the neutraliser at the nodal point nearest to the end of the beam which is excited, produces a wider WAB and greater reduction in transmissibility than using the nodal point near the opposite end. These findings, which are supported by experimental validation, provide new physical insight into the WAB phenomenon on a beam.

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