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Periodic structures such as metamaterials and phononic crystals hold potential as promising compact and lightweight solutions for noise and/or vibration attenuation in targeted frequency ranges. The performance of these structures is usually investigated by means of dispersion curves. The input for dispersion curve computations is often a finite element model of the corresponding unit cell. Nowadays, the vibration and noise attenuation of the periodic structures are generally tackled as separate problems and their performance is investigated with either structural or acoustic dispersion curves, respectively. Recently, vibro-acoustic unit cell models have come to the fore which can exhibit simultaneous structural and acoustic stopbands. However, the vibro-acoustic coupling inside the unit cell is usually not taken into account during the dispersion curve computations. To consider this coupling during their performance assessment, the computation of vibro-acoustic dispersion curves is required. Although these dispersion curves provide valuable information, the associated computational cost rapidly increases with unit cell model size. Model order reduction techniques are important enablers to overcome this high cost. In this work, the Bloch mode synthesis (BMS) and generalized BMS (GBMS) unit cell model order reduction techniques are extended to be applicable for 2D and 3D periodic vibro-acoustic systems. Through a verification case, the methodologies are shown to enable a strongly reduced dispersion curve calculation time while maintaining accurate predictions. At the time of verification: no ISSN/ISBN on the publisher's site. ispartof: Proceedings of ECCOMAS 2022 ispartof: ECCOMAS 2022, 8th European Congress on Computational Methods in Applied Sciences and Engineering location:Oslo, Norway date:5 Jun - 9 Jun 2022 status: published

ispartof: pages:1-15 ispartof: Proceedings of ISMA 2022 ispartof: ISMA 2022 location:Leuven status: published

In the search for lightweight and compact partitions with both favorable vibro-acoustic characteristics and load-carrying capacity, an increasing trend towards double-leaf panels with structural metamaterial cores is emerging. Generally, these partitions are designed and analyzed by only considering the attenuation along the structural path, disregarding the influence of the air inside. This work investigates the impact of the air in these partitions on their performance, which reveals that the acoustic path needs to be included during the design phase. ispartof: pages:562-563 ispartof: Proceedings of META 2022 pages:562-563 ispartof: META 2022, the 12th International Conference on Metamaterials, Photonic crystals and Plasmonics location:Torremolinos, Spain date:19 Jul - 22 Jul 2022 status: Published online

Due to the increasingly stringent noise exposure regulations as well as rising customer expectations, there is a growing need to incorporate, assess and improve the vibro-acoustic behavior of products in early design stages. In transportation industry, the current ecological trends towards electrification and light-weighting of vehicles also bring forth novel and formerly masked noise problems. Going beyond typical frequency domain analysis and providing an audible prediction of the radiated noise, can add an extra dimension for the design engineer to assess the expected noise characteristics, without the need for full-scale prototypes. In the context of gearbox noise, the current paper proposes combining timedomain drivetrain simulations with a frequency-domain vibro-acoustic finite element model of a gearbox housing to determine audible sound pressure responses for the assessment of di erent bearing input forces and housing design changes. To this end, simulated time-domain bearing force signals are filtered using vibro-acoustic frequency response functions obtained from free-field sound pressure responses for a unit point force excitation of the gearbox housing at a bearing location. The proposed method models the full chain from noise source to output and thus enables translating design changes into audible impressions of the resulting noise characteristics. Username and password needed to access proceedings User: daga-proceedings2022 Password: maultaschen ispartof: pages:515-518 ispartof: DAGA2022 conference proceedings pages:515-518 ispartof: DAGA location:Stuttgart date:20 Mar - 24 Mar 2022 status: published

Recently, the potential of metamaterials and phononic crystals to cope with conflicting requirements of obtaining lightweight structures with desirable noise and vibration properties has been demonstrated. These, often periodic, structures are commonly studied based on their representative unit cell of which the vibro-acoustic performance is examined by means of their wave propagation, visualized by dispersion curves. Typically, the unit cell is discretized using a finite element technique to capture the possibly complex geometry. This leads to a high computation cost for the dispersion curve calculation which can be strongly reduced by applying modal based model order reduction techniques such as the (generalized) Bloch mode synthesis. In this paper, the choice of the unit cell is shown to have an impact on the dispersion curve calculation time. Moreover, the efficiency of (generalized) Bloch mode synthesis strongly depends on the unit cell choice. The highest reduction in computation time is accomplished when the number of boundary degrees-of-freedom is limited. ispartof: Journal of Vibration and Acoustics vol:144 issue:2 status: Published online

ispartof: pages:1-9 ispartof: Proceedings of the 26th International Congress of Mechanical Engineering pages:1-9 ispartof: COBEM 2021 26th International Congress of Mechanical Engineering location:Virtual Conference (Brazil) status: Published online

ispartof: pages:1323-1332 ispartof: Proceedings of Euronoise pages:1323-1332 ispartof: Euronoise 2021 location:Madeira, Portugal - Online date:25 Oct - 27 Oct 2021 status: Published online

Metamaterials have recently emerged and shown potential as lightweight and compact noise and vibration solutions. By adding or embedding resonant structures to or in a flexible host structure on a sub-wavelength scale, stop bands can be created, which enable frequency ranges of strong vibration and noise attenuation. These often periodic structures are typically analyzed using infinite periodic structure theory, based on a representative unit cell model. The stop bands in metamaterials are generally analyzed by means of dispersion curves. For complex unit cell models, however, this rapidly becomes computationally expensive. Therefore, in this work, model order reduction is applied to finite element unit cell models for stop band predictions. In view of designing metamaterials for a targeted frequency range, the reduced order modeling approach is next introduced in a design optimization routine. The results show that the reduced order models for stop band predictions enable substantial gains in metamaterial analysis and fast metamaterial design optimization. ispartof: pages:2487-2501 ispartof: Proceedings of ISMA 2020 pages:2487-2501 ispartof: International Conference on Noise and Vibration Engineering - ISMA 2020 location:Leuven, Belgium date:7 Sep - 9 Sep 2020 status: published

This paper presents a hybrid unit cell method to predict sound transmission and sound absorption properties of arbitrary two-dimensional periodic structures, combining the advantages of the Wave Based Method and the Finite Element Method. The planar periodic structure, represented by its unit cell, is modelled by the Finite Element Method and the acoustic pressure field in the semi-unbounded acoustic domains is represented using the Wave Based Method. The Finite Element Method allows to include geometrical details and any combination of governing physics in the unit cell. The Wave Based Method applies dedicated approximation functions that inherently satisfy the acoustic Helmholtz equation, the Sommerfeld radiation condition and the Bloch-Floquet periodicity conditions. The dynamic fields described within both frameworks are coupled using a direct coupling strategy. The method is validated for an infinite porous plate, modelled as an equivalent fluid, with periodic, rigid, circular inclusions and is shown to be a promising tool for the analysis of complex periodic structures. No ISBN/ISSN. ispartof: pages:184-187 ispartof: Proceedings of MEDYNA 2017: 2nd Euro-Mediterranean Conference on Structural Dynamics and Vibroacoustics pages:184-187 ispartof: MEDYNA location:Sevilla date:25 Apr - 27 Apr 2017 status: published

ispartof: "EMVeM" Energy efficiency Management for Vehicles and Machines pages:173-189 ispartof: pages:173-189 status: published

Recently, locally resonant metamaterials have shown great potential for noise and vibration control engineering. Understanding the influence of damping is important, as it impacts the performance of these materials. Damping is included in a unit cell modelling technique, the results are studied and are in agreement with earlier findings and measurements. ispartof: pages:138-139 ispartof: The 12th International Conference on Mathematical and Numerical Aspects of Wave Propagation Book of Abstracts pages:138-139 ispartof: International Conference on Mathematical and Numerical Aspects of Wave Propagation location:Karlsruhe date:20 Jul - 24 Jul 2015 status: published