FEA-based methods for optimising structure-borne sound radiation

Klaerner, Matthias; Wuehrl, Mario; Kroll, Lothar; Marburg, Steffen

doi:10.1016/j.ymssp.2016.07.019

Cited by 24 publications

(5 citation statements)

References 22 publications

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“…These often renders the parameter identification questionable if at all tractable, as demonstrated in previous works by the authors and others, see e.g. [23,4,15,5,20,12]. The presence of resonances and anti-resonances in the spectrum is not the only factor responsible for local minima.…”

Section: Introductionmentioning

confidence: 94%

Parameter estimation in modelling frequency response of coupled systems using a stepwise approach

Göransson

Cuenca

Lähivaara

2019

Mechanical Systems and Signal Processing

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This paper studies the problem of parameter estimation in resonant, acoustic fluid-structure interaction problems over a wide frequency range. Problems with multiple resonances are known to be subjected to local minima, which represents a major challenge in the field of parameter identification. We propose a stepwise approach consisting in subdividing the frequency spectrum such that the solution to a low-frequency subproblem serves as the starting point for the immediately higher frequency range. In the current work, two different inversion frameworks are used. The first approach is a gradient-based deterministic procedure that seeks the model parameters by minimising a cost function in the least squares sense and the second approach is a Bayesian inversion framework. The latter provides a potential way to assess the validity of the least squares estimate. In addition, it presents several advantages by providing invaluable information on the uncertainty and correlation between the estimated parameters. The methodology is illustrated on synthetic measurements with known design variables and controlled noise levels. The model problem is deliberately kept simple to allow for extensive numerical experiments to be conducted in order to investigate the nature of the local minima in full spectrum analyses and to assess the potential of the proposed method to overcome these. Numerical experiments suggest that the proposed methods may present an efficient approach to find material parameters and their uncertainty estimates with acceptable accuracy. arXiv:1808.04985v1 [physics.comp-ph]

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Section: Introductionmentioning

confidence: 94%

Parameter estimation in modelling frequency response of coupled systems using a stepwise approach

Göransson

Cuenca

Lähivaara

2019

Mechanical Systems and Signal Processing

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“…Since the optimized solution is strongly influenced by the investigated frequency, it is hard to obtain a solution holding the best for all the frequencies. In this case, a frequency‐based sum or integration of objective functions with weights is normally used . By dividing the frequency band [ f l , f u ] into n f intervals

false[f_{1}, f_{2}, …, f_{n_{f} + 1} false]

, we define the frequency‐averaged sound power as

W_{ave} = \frac{1}{f_{u} - f_{l}} true \sum_{n = 1}^{n_{f}} ([], normalΔ f_{n} W ((), f_{n}^{c})),

with

f_{n}^{c} = \frac{f_{n} + f_{n + 1}}{2} 1 ⩽ n ⩽ n_{f},

normalΔ f_{n} = f_{n + 1} - f_{n} 1 ⩽ n ⩽ n_{f} .

…”

Section: Numerical Examplesmentioning

confidence: 99%

Topology optimization of exterior acoustic‐structure interaction systems using the coupled FEM‐BEM method

Zhao

Chen

et al. 2019

Numerical Meth Engineering

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This paper presents an efficient topology optimization procedure for exterior acoustic-structure interaction problems, in which the coupled systems are formulated by the boundary element method (BEM) and the finite element method (FEM). So far, the topology optimization based on the coupled FEM-BEM still faces several issues needed to be addressed, especially the efficient design sensitivity analysis for the coupled systems. In this work, we contribute to these issues in two main aspects. Firstly, the adjoint variable method (AVM) formulations are derived for sensitivity analysis of arbitrary objective function, and the feedback coupling between the structural and acoustic domains are taken into consideration in the sensitivity analysis. Secondly, in addition to the application of fast multipole method (FMM) in the acoustic BEM response analysis, the FMM is now updated to adapt to the arising different multiplications in the AVM equations. These accelerations save considerable computing time and memory. Numerical tests show that the developed approach permits its application to large-scale problems. Finally, some basic observations for the optimized designs are drawn from the numerical investigations. KEYWORDS adjoint variable method, boundary element method, fast multipole method, finite element method, topology optimization INTRODUCTIONReducing the sound emission of machines, systems, and structures has become a key component of an engineer's work. An efficient tool for developing quiet structures consists in the topology optimization, which was originally developed in the field of structural mechanics. Many different topology optimization approaches exist including the homogenization method, 1-3 density-based methods, 4-6 the evolutionary structural optimization method, 7,8 and the level set method. 9,10 Due to their computational efficiency and conceptual simplicity, density-based methods, such as the isotropic material with penalization (SIMP) method, are most widely used. Many commercial finite element packages have adapted density-based 404

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“…The numerical tools of the Finite Element Method [6,7] and Boundary Element Method [8] have been applied extensively for modeling acoustic problems. Such numerical techniques are adopted stand-alone or in conjunction (hybrid methods) [9].…”

Section: Introductionmentioning

confidence: 99%

Vibroacoustic Assessment of an Innovative Composite Material for the Roof of a Coupe Car

et al. 2021

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The objective of this paper is the vibroacoustic evaluation of an innovative material for a sports car roof, aiming at replacing fiberglass composite materials. Such evaluation was carried out using numerical and experimental analysis techniques, with cross-comparison between the corresponding results. The innovative material under analysis is a composite material, with a thermoplastic polypropylene matrix and reinforcement made of cellulose fibers. In order to validate the virtual dynamic modeling of the new material, the inertance on different points of some sheets made of the material under analysis was evaluated by an in-house made experimental activity, performed in the CRF (Fiat Research Center) test room, and cross-compared with corresponding results from a numerical analysis performed with the MSC Nastran software. Then, a realistic model of the car roof of the Alfa Romeo 4C car, made with the new material, was implemented and analyzed from the vibroacoustic point of view. The mere switch to the new material, with no changes in the geometry/structure of the car roof, did not allow preserving the original values of static rigidity, dynamic rigidity, and configuration of modal shapes. For this reason, a geometric/structural optimization of the component was performed. Once the new geometry/structure was defined, a vibroacoustic analysis was carried out, checking for a possible coupling between the fluid cavity modes and the structure car body modes. Finally, the vibroacoustic transfer functions to the driver’s ear node were assessed, considering two different excitation points on the structure. The excellent damping capacity of the proposed material led to an improvement in the vibroacoustic transfer functions and to a reduction in the weight of the pavilion.

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FEA-based methods for optimising structure-borne sound radiation

Cited by 24 publications

References 22 publications

Parameter estimation in modelling frequency response of coupled systems using a stepwise approach

Parameter estimation in modelling frequency response of coupled systems using a stepwise approach

Topology optimization of exterior acoustic‐structure interaction systems using the coupled FEM‐BEM method

Vibroacoustic Assessment of an Innovative Composite Material for the Roof of a Coupe Car

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