On the use of dynamic vibration absorbers to counteract the loss of sound insulation due to mass-spring-mass resonance effects in external thermal insulation composite systems

Abstract

One of the common ways to increase the energy performance of existing buildings is to add a thermal insulation layer to their façade elements, which in turn is covered by a thin protecting cement plaster. Such an arrangement is commonly known as External Thermal Insulation Composite System (ETICS). This article studies the effect of an ETICS implementation induced mechanical resonance mechanism, which results in a loss of performance in the sound insulation spectrum. A mitigating approach is proposed, which is based on an array of dynamic vibration absorbers that were designed to counteract the decrease of the sound reduction index. Using a wavenumber domain approach combined with unit cell FEM-modelling employing Bloch-Floquet boundary conditions, numerical predictions are presented for the sound reduction index. A number of different dynamic vibration absorber designs were tested on a silicate cement brick wall in a transmission loss facility. The predictions are in good agreement with experimental data obtained by classical, microphone based acoustic isolation measurements and laser Doppler vibrometry.

Acoustic team at the Faculty of Civil Engineering, STU Bratislava, Slovakia

“…It is well known that ETICS used for improving of thermal insulation of buildings does not always help to improve the acoustic insulation as well. Researchers prepared theoretical case study, which helps in understanding the relationship between thermal and acoustic performance in building envelopes [2][3]. The team performs both, laboratory measurements as well as theoretical calculations and simulations of building constructions performance also aimed at the low-frequency sound insulation.…”

Assessment of the effectiveness of mounting the aircraft piston combustion engine on a test stand

“…The issues of vibration isolation of systems require further detailed studies and empirical research, especially in the context of the development of materials engineering, regarding e.g. : nanoparticles and composite structures [3,6], coating on fiber insolation of thermal and vibration processes [10,21], external composite systems [25], acoustic metamaterials for low-frequency broadband vibration and sound insulation [31,32], composites structures studied for specified boundary conditions [34].…”

On the Determination of Acoustic Properties of Membrane Type Structural Skin Elements by Means of Surface Displacements

“…Sci. 2021, 11, 10357 3 of 23 dynamic vibration absorbers the significant local control of low-frequency noise can be achieved [24][25][26][27].…”