Loudness scattering due to vibro-acoustic model variability

Oliveira, L.; Silva, Maíra Martins da; Sánchez, Jaime Alberto Mosquera; Gonçalves, Luiz Augusto Martin

doi:10.1590/s1678-58782012000600009

Cited by 8 publications

(5 citation statements)

References 10 publications

(10 reference statements)

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“…It is possible to use any one-sided projection-based MOR method for second-order systems to generate a projection basis V as in (21) and then split and augment this basis to obtain Q V in (24). Alternatively, some MOR techniques exist that immediately produce a projection matrix which has the structure of Q V. Substructuring techniques such as component mode synthesis are a popular choice of MOR method for vibro-acoustic systems, often paired to a FE model in u p formulation [34,38,39]. The structural and acoustic domains are then considered as two separate 'components' of the full coupled system, and individual projection bases are constructed for each of these domains, which lead to a global projection matrix with the same structure as Q V. The insights gained in this section allow us to prove that these methods are in fact stability-preserving.…”

Section: P F S;r D V T S F S F A;r D V T a F A K C;r D V T S K C V Amentioning

confidence: 99%

Stability‐preserving model order reduction for time‐domain simulation of vibro‐acoustic FE models

Walle

Naets

Deckers

et al. 2016

Numerical Meth Engineering

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This work proposes novel stability-preserving model order reduction approaches for vibro-acoustic finite element models. As most research in the past for these systems has focused on noise attenuation in the frequency-domain, stability-preserving properties were of low priority. However, as the interest for timedomain auralization and (model based) active noise control increases, stability-preserving model order reduction techniques are becoming indispensable. The original finite element models for vibro-acoustic simulation are already well established but require too much computational load for these applications. This work therefore proposes two new global approaches for the generation of stable reduced-order models. Based on proven conditions for stability preservation under one-sided projection, a reformulation of the displacement-fluid velocity potential (u ) formulation is proposed. In contrast to the regular formulation, the proposed approach leads to a new asymmetric structure for the system matrices which is proven to preserve stability under one-sided projection. The second approach starts from a displacement-pressure (u p) description where the system level projection space is decoupled for the two domains, for which we also prove the preservation of stability. Two numerical validation cases are presented which demonstrate the inadequacy of straightforward model order reduction on typical vibro-acoustic models for time-domain simulation and compare the performance of the proposed approaches. Both proposed approaches effectively preserve the stability of the original system. formulation is that it results in a real dynamic stiffness matrix for undamped frequency-domain simulations and in a real eigenvalue problem for the computation of the undamped modes. It is the standard formulation used in most commercial FE tools for coupled vibro-acoustic analysis [10].One of the major drawbacks of element-based methods is their computational cost, which scales unfavourably with increasing problem size and frequency, restricting the overall practical applicability. In order to accurately describe the wave-like spatial character of the variables, the use of locally defined and low-order shape functions imposes minimum requirements on the number of elements used per wavelength and therefore limits the maximum element size for a given wavelength [11]. The highest frequency of interest determines the smallest wavelength present in the model, which in turn dictates the maximum element size. Because of the three-dimensional nature of acoustics, the number of elements in the model grows rapidly with increasing problem size or equivalently with decreasing element size (and thus also with increasing frequency). In order to alleviate the problems associated with computational costs, one can turn to model order reduction (MOR) techniques to reduce the number of DOFs for a desired accuracy [12]. For coupled vibro-acoustic problems, the advantages of MOR have already been demonstrated in frequency-domain analysis [10,13,14]. I...

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Section: P F S;r D V T S F S F A;r D V T a F A K C;r D V T S K C V Amentioning

confidence: 99%

Stability‐preserving model order reduction for time‐domain simulation of vibro‐acoustic FE models

Walle

Naets

Deckers

et al. 2016

Numerical Meth Engineering

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“…Since the mock-up is airborne-sealed, plant variations due to changes in the acoustic domain are mostly avoided [81]. Hence, a single measurement of the acoustic control plant was carried out before each experimental run, just to account for long-term environmental changes (air temperature and humidity).…”

Section: Dynamics Of the Acoustic Plantmentioning

confidence: 99%

Multiple target sound quality balance for hybrid electric powertrain noise

Mosquera-Sánchez

Sarrazin

Janssens

et al. 2018

Mechanical Systems and Signal Processing

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“…The proposed mock-up, depicted in Fig. 1, represents the structural transfer paths on a vehicle, as noise and vibration issues in this industry are critical for product development and often stimulate research for analysis and control techniques [8][9][10][11]. The top assembly represents the powertrain, connected to the chassis via three mounts, that can vary in flexibility, and capable of transmitting vibration to the full system via the inertial shaker which is considered part of the active system.…”

Section: Introductionmentioning

confidence: 99%

Combining classical and component-based TPA for equivalent load identification

Melo

Oliveira

2020

J Braz. Soc. Mech. Sci. Eng.

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The transfer path analysis (TPA) has become a rather standard tool for solving noise and vibration problems, as it helps understanding the mechanisms responsible for the generation and transmission of those quantities. By better understanding the intricate role of multiple sources and propagation paths, it is possible to diagnose and propose effective modifications that would addresses such issues at specific target locations. Although originally an experimental approach, hybrid methods that include modeled subsystems have been proposed, which allow the assessment of key system features even at stages prior to the construction of full physical prototypes. However, in classical TPA, the operational forces are characteristics of the complete system, which implies that, with each modification in one subsystem, it is necessary to redo all the tests for the correct determination of target functions. For this reason, in recent years, interest has been renewed in the development of faster and simpler techniques for analyzing energy transfer paths, which offer a compromise between workload and accuracy. More specifically, a set of methods called component-based TPA is highlighted, which consists of characterizing the excitation of a source through a set of equivalent forces (or even interface velocities) inherent only to the active subsystem. In this way, the responses at target locations on the passive subsystem could be calculated using these equivalent loads and the dynamics of the complete system, obtained numerically, experimentally or under a hybrid framework. This work presents a critical analysis of the component-based TPA methods and proposes the combined use of these methods with a classical TPA approach in the process of determining equivalent forces of the active subsystem. This set of equivalent forces, combined with the passive subsystem dynamics, allows the prediction of the vibrational behavior of the full assembly at targeted locations, without the need for a full experimental analysis of the assembled system. As the case study presented here consists of a modular academic setup, it allows the qualitative assessment of the method in distinct assembly boundary conditions, in which the subsystems are connected via rigid or flexible joints.

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Loudness scattering due to vibro-acoustic model variability

Cited by 8 publications

References 10 publications

Stability‐preserving model order reduction for time‐domain simulation of vibro‐acoustic FE models

Stability‐preserving model order reduction for time‐domain simulation of vibro‐acoustic FE models

Multiple target sound quality balance for hybrid electric powertrain noise

Combining classical and component-based TPA for equivalent load identification

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