Search

The Norwegian Public Roads Administration is reviewing the possibility of using floating bridges as fjord crossings. The dynamic behaviour of very long floating bridges with novel designs are prone to uncertainties. Studying the dynamic behaviour of existing bridges is valuable for understanding the in-situ performance. We present a case study of the Bergsøysund Bridge, a 840 m long floating pontoon bridge located in Norway. An extensive monitoring system is installed on the bridge, including a network of accelerometers. A finite element model of the bridge is established. Using the measured acceleration output and recently developed Kalman filter based methods (a joint input-state (JIS) estimation algorithm and a dual Kalman filter (DKF)), we estimate accelerations at unmeasured locations. It is shown that the estimated response from the DKF agrees well with direct reference measurements. For the JIS, numerical instabilities in the estimates occur due to ill-conditioning of the matrices used in the system inversion.

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

Resonant metamaterials are a lightweight noise insulation solution due to their tunable stop band effect. In previous works, the authors have shown how resonant metamaterials can be manufactured and fully integrated into a thermoformed twin sheet panel. This work shows an design optimisation procedure for the resonant structure of the metamaterial panel, based on its modal effective mass. Additionally, foam is added in the core of the panel, to achieve high noise insulation performance at the high-frequency range, which is deteriorated by the slits introduced to create the resonant structures. Two panels are designed, targeting single and double stop bands. Their insertion loss is experimentally evaluated, showing a pronounced noise insulation performance at the stop band targeted frequency, and no loss of noise insulation in the high-frequency range thanks to the foam addition. Therefore, this work shows that resonant metamaterials can be designed through optimisation and work in synergy with classical solutions while keeping a lightweight design. ispartof: pages:2513-2524 ispartof: Proceedings of ISMA 2020 pages:2513-2524 ispartof: International Conference on Noise and Vibration Engineering - ISMA 2020 location:Leuven - Belgium date:7 Sep - 9 Sep 2020 status: accepted

In this paper, we are investigating the capabilities of both classical system identification and modern machine learning (time regression neural networks) to derive predictive black-box models which can predict the wheel center loads (WCLs) by making use of either the road disturbances acting on the wheel-patch or strain measurements on the suspension components. The WCLs are very important for the durability analyses of a vehicle and their direct measurement requires the use of expensive force transducers. Thus, predictive black-box models can augment data sets by predictions of the WCLs when multiple vehicles need to be tested and where it is infeasible to instrument dedicated transducers in each vehicle. As identification techniques to be used to derive those black-box models, the linear ARX model, the polynomial nonlinear state space (PNLSS) method, and the time regression neural networks (NNs) will be reviewed and benchmarked using experimental data measured on a McPherson suspension test rig.

ispartof: pages:2351-2366 ispartof: Proceedings of ISMA 2020 - International Conference on Noise and Vibration Engineering and USD 2020 - International Conference on Uncertainty in Structural Dynamics pages:2351-2366 ispartof: ISMA 2020 - International Conference on Noise and Vibration Engineering location:Leuven, Belgium date:7 Sep - 9 Sep 2020 status: published

The aim of the paper is to introduce a case study for nonparametric nonlinear assessment using a toolbox illustrated on a small, battery-operated road vehicle. The toolbox (Simplified Analysis for Multiple Input Systems, SAMI) is based on the Best Linear Approximation framework of multiple input, multiple output systems which provides a user-friendly interpretation of the measurement data by extracting the user relevant information by splitting up the classical coherence function of the FRF measurements into noise, nonlinearity and transient parts. By the use of the proposed toolbox, a less experienced user will be able to 1) nonparametrically assess the system under test, 2) to tell whether the underlying system is linear or not, and 3) to tell how much is the gain by the use of an advanced nonlinear framework. The proposed toolbox addresses the questions related to the semi-automatic processing of MIMO measurements with respect to the whole process from the design of experiment to the nonparametric analysisof the frequency response functions. The toolbox has been tested with simulations and real-life industrial measurements.

ispartof: ISMA2020 ispartof: ISMA2020 International Conference on Noise and Vibration Engineering & USD2020 International Conference on Uncertainty in Structural location:Virtual date:7 Sep - 9 Sep 2020 status: Published online

ispartof: pages:685-695 ispartof: Proceedings Of International Conference On Noise And Vibration Engineering (ISMA2020) / International Conference On Uncertainty In Structural Dynamics (USD2020) pages:685-695 ispartof: International Conference On Noise And Vibration Engineering (ISMA2020) / International Conference On Uncertainty In Structural Dynamics (USD2020) location:KU Leuven, Dept. Werktuigkunde date:7 Sep - 9 Sep 2020 status: published

ispartof: pages:1-16 ispartof: Online Proceedings of ISMA2020 pages:1-16 ispartof: International Conference on Noise and Vibration Engineering 2020 location:Leuven, Belgium date:7 Sep - 9 Sep 2020 status: Published online

Double panel partitions with a foam core suffer from a poor sound transmission loss at the mass-spring-mass resonance frequency. This paper investigates the use of vibro-acoustic resonant metamaterials as a solution to improve the acoustic insulation performance for this vibro-acoustic problem while adding only 8% of mass to the complete double panel. To design the metamaterial, unit cell analysis is applied to calculate dispersion curves and predict the stop band behaviour, while the sound transmission loss is predicted with Heckl’s model extended with the equivalent dynamic mass of the metamaterial. The dynamic mass is obtained from the dispersion curves analysis, which allows to take into account complex and realizable resonator geometries. The designed metamaterial double panel is realized and its experimentally measured insertion loss shows a strong improvement around the mass-spring-mass resonance of the original double panel. The predicted insulation performance agrees well with the measured performance, validating the proposed method. ispartof: pages:3111-3123 ispartof: Proceedings of ISMA 2018 pages:3111-3123 ispartof: International Conference on Noise and Vibration Engineering - ISMA 2018 location:Leuven, Belgium date:17 Sep - 19 Sep 2018 status: published

In many mechanical applications, a design optimization is performed on the frequency response functions of the mechanical system. In this work, a novel model reduction technique is explored for the parametric analysis of the frequency response functions of dynamical mechanical systems. This approach entails two novel aspects. First, a super-local reduced order basis is introduced which allows models of much lower order compared to models obtained with single, frequency independent reduced order basis approaches. Secondly, a novel hyper-reduction scheme is introduced which selects a subset of the considered, discrete frequency domain and computes the corresponding interpolation matrix. During the online phase, the full frequency domain response is reconstructed by interpolating between these sampled frequency lines. The proposed approach is validated numerically on an academic mass-spring-damper system and shows promising results. ispartof: pages:2461-2468 ispartof: Proceedings of the International Conference on Noise and Vibration Engineering (ISMA2018) and the International Conference on Uncertainty in Structural Dynamics (USD2018) pages:2461-2468 ispartof: ISMA 2018 International Conference on Noise and Vibration Engineering location:Leuven, Belgium date:17 Sep - 19 Sep 2018 status: published

In order to fully exploit available computer aided engineering (CAE) models for modern mechatronic systems they need to be merged with measurement data in order to obtain reliable Digital Twins. These Digital Twins are evolving to become instrumental assets that accompany the product throughout its lifetime, enabling virtual quality assurance, virtual sensing and model-based control. However, in mechatronics, the typical CAE design models are relatively expensive physics based models which cannot be directly used throughout the entire lifecycle as Digital Twins. Model order reduction approaches for these nonlinear dynamic applications allow to reduce the computational cost sufficiently for use in a Digital Twin setting. This work gives an overview of nonlinear dynamics engineering applications in modern mechatronics products design, and demonstrates the role of (novel) MOR techniques in the design engineering process. ispartof: pages:2415-2429 ispartof: Proceedings of the International Conference on Noise and Vibration Engineering (ISMA2018) and the International Conference on Uncertainty in Structural Dynamics (USD2018) pages:2415-2429 ispartof: ISMA 2018 International Conference on Noise and Vibration Engineering location:Leuven, Belgium date:17 Sep - 19 Sep 2018 status: published

© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. This paper presents an experimental study of the aeroacoustic characteristics of Helmholtz resonators. The two-port characterization technique is applied to compute the scattering properties of the resonators from measured pressure spectra. The onset of aeroacoustic instabilities is investigated using an acoustic power balance based on the linear scattering matrix formulation. The influence of the grazing flow velocity on the aeroacoustic instability onset is discussed. Additionally, the effect of the orifice dimensions is analyzed with two different configurations. The results offer a valuable database for the validation of computational techniques for the prediction of whistling onset in duct systems. ispartof: pages:601-611 ispartof: https://www.isma-isaac.be/ pages:601-611 ispartof: ISMA2018 location:Leuven date:17 Sep - 19 Sep 2018 status: Published online

Non-deterministic methods such as the random field approach suffer from the curse of dimensionality from computational burden of industrially sized models. The computational complexity increases at high dimensions due to increased time complexity of eigenvalue computations, leading to the Karhunen-Loéve series expansion becoming intractable. This makes the corresponding propagation routines to become inviable. A novel methodology is proposed for efficient propagation of a random field by tackling this problem from the discretization perspective. The method uses a twin-model that efficiently discretizes a random field on a coarse mesh grid using a KL expansion, which is then propagated on a high-dimensional grid of the Finite Element model. A two-dimensional model of moderate-dimensionality with 10000 elements is used to illustrate the numerical efficiency of this approach through a convergence study focusing on the resolution of the twin-model when applied in a dynamic analysis. The method is also well suited for higher dimensions. ispartof: pages:5111-5123 ispartof: Proceedings of International Conference on Uncertainty in Structural Dynamics pages:5111-5123 ispartof: International Conference on Uncertainty in Structural Dynamics location:Leuven, Belgium date:17 Sep - 18 Sep 2018 status: Published online

© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. This paper proposes a method for the indirect measurement of wheel center loads which makes use of a suspension flexible multibody model and strain measurements on the suspension components. Wheel center loads are the loads acting at the center of the vehicle wheels and due to the interaction with the road. Those loads are the principal cause of damage to the vehicle structural integrity and hence are very important for durability analyses, but their direct measurement requires the use of expensive and intrusive dedicated measurement devices. By reusing available design simulation models and common sensors, the proposed method thus represents an appealing alternative to the direct measurement approach. After the presentation of the method, which is based on an augmented extended Kalman filter to perform the information fusion, validation results on a McPherson suspension test rig are reported. ispartof: pages:325-339 ispartof: Proceedings of ISMA2018 pages:325-339 ispartof: International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics location:Leuven, Belgium date:17 Sep - 19 Sep 2018 status: Published online

© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. Component-based TPA is a relatively new TPA approach that allows to characterize a structureborne source component independently from the receiver structure (as opposed to classical TPA) and to predict its behavior when coupled to different receivers. This approach would allow to frontload the development process and considerably increase the flexibility during the design process. However, there are a number of challenges affecting its applicability, such as a proper modelling of the coupling degrees of freedom at the interface, the difficulty to access the interface connection points and the conditioning of the equations. A number of innovative methods were developed to address these issues, that will be investigated by means of measurements on a laboratory test bench. A systematic analysis will be performed through which the accuracy and applicability of the component-based TPA will be analyzed and assessed. ispartof: pages:4131-4145 ispartof: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics pages:4131-4145 ispartof: ISMA 2018 - International Conference on Noise and Vibration Engineering location:Leuven, Belgium date:17 Sep - 19 Sep 2018 status: published