Romain Rumpler

• PhD
• Researcher at KTH Royal Institute of Technology

This paper proposes an inverse method to characterize wave and energy propagation in curved structures, addressing the challenges of accurately obtaining dispersion curves, wavenumber space, and damping loss factors caused by their complex dynamics. The proposed method, Generalized Algebraic K-Space Identification (GAKSI) technique, is developed wi...

The assessment of the exposure to road traffic noise pollution and of associated health conditions is usually based on energy-average noise levels. However, the number of noise events to which an individual is exposed has proven essential to the prediction of annoyance and sleep disturbance. Unfortunately, no standard method has been adopted for th...

Wave-based structural identification for real honeycomb sandwich structures has become an important research focus. However, most existing wave-based identification methods suffers from experimental uncertainties and a limited frequency range of applicability. To this end, we present a new wave-based structural identification framework, which inclu...

Road-traffic flow parameters are a critical input to urban noise pollution evaluation frameworks such as CNOSSOS-EU. The accuracy and resolution of the traffic flow improves the quality of the noise exposure assessment. Highly resolved traffic flow within an urban network is difficult to reliably measure or predict. The quality and availability of...

Noise pollution is a major health and well-being concern, being associated with, e.g., sleep disturbance, annoyance, and cardiovascular diseases. Road traffic is, by far, the largest contributor to this noise pollution in urban areas. With the growing electrification of cars in developed countries, it is commonly believed that road traffic noise po...

Road traffic noise is one of the major sources of environmental noise and has been shown to increase risk of adverse health effects. For this reason, noise mapping is an efficient tool to assess and monitor city-wide noise levels in accordance with the Environmental Noise Directive (END). To relate these noise levels to the associated health effect...

The tuning of the low frequency sound absorption of open-cell anisotropic porous materials is studied in the form of an optimisation problem. Using modelling based on micro-structural representations of the anisotropic elasticity, the dynamic viscous drag forces and cell porosity, a physically meaningful dependence between these quantities is ensur...

Parametric model order reduction by matrix interpolation allows for efficient prediction of the behavior of dynamic systems without requiring knowledge about the underlying parametric dependency. Within this approach, reduced models are first sampled and then made consistent with each other by transforming the underlying reduced bases. Finally, the...

This study introduces an agent-specific assessment method of traffic noise exposure in agent mobility simulations. The assessment is achieved through a combination of an energy-based noise exposure impact assessment using noise exposure cost, and the state-of-the-art traffic noise prediction tool NoiseModelling coupled with the activity-based agent...

With prospective applications ranging from improving the understanding of the daily and seasonal dynamics of noise exposure to raising public awareness of the associated health effects, dynamic noise mapping in real time is one of the next milestones in environmental acoustics. The present contribution proposes a methodology for near-real-time dyna...

This paper proposes a methodology in traffic noise assessment, whose objective is to combine microscopic traffic simulations and noise calculation methods with macro-level, systemic noise impact assessment models. This combination, referred to as the vehicle-specific noise exposure cost (NEC), provides a per-vehicle contribution to the overall nois...

Improvements in noise mapping techniques and smart cities infrastructure have fostered the development of new ways to evaluate traffic noise exposure. An example of one such outcome is the noise exposure sensitivity map, which quantifies the noise exposure potential of a road network as a function of the vehicle type, the prevailing background nois...

This paper proposes an impedance-based design methodology for cylindrical sandwich shells, with the aim to improve the sound transmission loss properties near the ring and coincidence frequency regions. The approach enables to systematically address the poor acoustic performance, characteristic of these problematic frequency regions, while retainin...

The dynamic behaviour of a novel anisotropic cellular micro-structural geometry derived from the basic symmetric Kelvin cell is discussed for varying relative density. The cells are arranged in a cubic array and the dynamic response is studied in a classical seismic mass setup using beam elements to represent the ligaments of the cell. The eigenfre...

The Environmental Noise Directive (2002/49/EC) requires all European Union Member States to produce strategic noise maps using a common assessment methodology: CNOSSOS-EU. The reliability of CNOSSOS-EU railway noise evaluation is dependent on the input vehicle and track transfer functions. The CNOSSOS-EU default database contains the currently avai...

Responses to COVID-19 altered environmental exposures and health behaviours associated with non-communicable diseases. We aimed to (1) quantify changes in nitrogen dioxide (NO 2), noise, physical activity, and greenspace visits associated with COVID-19 policies in the spring of 2020 in Barcelona (Spain), Vienna (Austria), and Stockholm (Sweden), an...

Responses to COVID-19 altered environmental exposures and health behaviours associated with non-communicable diseases. We aimed to (1) quantify changes in nitrogen dioxide (NO2), noise, physical activity, and greenspace visits associated with COVID-19 policies in the spring of 2020 in Barcelona (Spain), Vienna (Austria), and Stockholm (Sweden), and...

Road traffic is a major source of environmental noise pollution in urban areas. While strategic noise maps are widely used to identify the critical areas and propose mitigation plans, more specific tools are needed to evaluate the impact from traffic noise such as overall population exposure or anticipated impact from specific vehicles in varying s...

In the recent years, our team has been working to identify key aspects of anisotropy on porous media. More than just characterising their anisotropic properties, we're interested in generating cellular media with completely designed anisotropic properties. The results of these studies have partly been published and more are to come. In this present...

Traffic is a major source of environmental noise pollution in urban areas. The present contribution focuses on a methodology designed to assess the impact of the noise generated by individual vehicles on a city's population using NoiseModelling, an open-source library implementing the CNOSSOS-EU model, capable of producing environmental noise maps....

In this workshop we will share our teaching and learning experiences in the Sound and Vibration track at KTH, with emphasis on the challenges we are facing with practical activities in pandemic times while ensuring the quality of education remains unaffected. These are tangible challenges faced currently by higher education institutions worldwide,...

Sweden stands out among the other European countries by the degree of restrictive measures taken towards handling the 2019 coronavirus outbreak, associated with the CoViD-19 pandemic. While several governments have imposed a nationwide total or partial lockdown to slow down the spread of the virus, the Swedish government has opted for a recommendat...

A locally resonant metamaterial curved double wall is proposed and studied. The aim is to improve the sound insulation by introducing a metamaterial design targeting a narrow frequency band region associated with characteristic frequencies of curved double walls, thus enabling an overall improvement of sound insulation properties in a broader frequ...

Previously reported measurements of uniaxial compression of such materials have shown an intriguing loss of stiffness in the regions close to the boundaries. The present contribution attempts to further investigate if these effects may be modelled by assuming a local alteration of the microstructure in these regions close to the boundaries resultin...

The present contribution reports part of the study conducted in the context of the CIVITAS ECCENTRIC European project, focused on the investigation of the conditions for silent deliveries in the city of Stockholm, Sweden. In particular, the methodology and results associated with measurements performed in 2019 are presented, in order to evaluate th...

Sweden stands out among the other European countries by the degree of restrictive measures taken towards handling the 2019 coronavirus outbreak, associated with the CoViD-19 pandemic. While several governments have imposed a nationwide total or partial lockdown in order to slow down the spread of the virus, the Swedish government has opted for a re...

Simple geometric distortions applied to the isometric Kelvin cell structures, (the tetrakaidecahedron), are shown to result in equivalent materials with anisotropic Hooke's tensors. The equivalent material models are estimated using a recently published inversion method where the 21 independent elastic constants of the Hooke's tensor are identified...

This paper proposes an inverse estimation method for the extraction of the equivalent, static elastic, Hooke's tensor. The inversion is based on a fitting of the displacements, obtained from a combination of static compression and shear traction loads, on the faces of a sample specimen. An equivalent, homogenised material model is found by varying...

Effective treatment of unbounded domains using artificial truncating boundaries are essential in numerical simulation, e.g. using the Finite Element Method (FEM). Among these, Perfectly Matched Layers (PML) have proved to be particularly efficient and flexible. However, an efficient handling of frequency sweeps is not trivial with such absorbing la...

Locally resonant metamaterial flat panels have proved to potentially exhibit extraordinary sound transmission loss properties when the resonance frequency of the resonators is tuned to the coincidence frequency region. Whether this technique is also effective to address the ring frequency effect for curved panels is investigated in this paper. For...

This paper presents applications of an inverse method for the design and characterisation of anisotropic elastic material properties of acoustic porous materials. Full field 3D displacements under static surface loads are used as targets in the inverse estimation to fit a material model of an equivalent solid to the measurement data. Test cases of...

A new design for locally resonant metamaterial sandwich plates is proposed in this paper for noise insulation engineering applications. A systematic method to tune the resonance frequency of local resonators is developed in order to overcome the coincidence phenomenon. This method, based on an impedance approach, additionally explains the ability t...

Several Padé-based computational methods have been recently combined with the finite element method for the efficient solution of complex time-harmonic acoustic problems. Among these, the component-wise approach, which focuses on the fast-frequency sweep of individual degrees of freedom in the problem, is an alternative to the projection-based appr...

In order to increase the robustness of a Padé-based approximation of parametric solutions to finite element problems, an a priori estimate of the poles is proposed. The resulting original approach is shown to allow for a straightforward, efficient, subsequent Padé-based expansion of the solution vector components, overcoming some of the current con...

Two heavy trucks have been operated in Stockholm city center during night time for e period of one and a half years. New technology has been tested: one the trucks was an electric hybrid with zone management and one was a PIEK certified biogas truck. The two trucks have been operated in different delivery schemes: on dedicated and one consolidated....

An innovative configuration of an acoustic sandwich structure is proposed in this paper, which uses the locally resonant structures to generate stopbands in desired frequency regions and hence to increase the sound transmission loss of the panel. Effects of different types of resonators, including the mounting techniques, are investigated. The meth...

Several Padé-based computational methods have been recently combined with the finite element method for the efficient solution of complex time-harmonic acoustic problems. Among these, the component-wise approach, which focuses on the fast-frequency sweep of individual degrees of freedom in the problem, is an alternative to the projection-based appr...

Fiber composites are widely used for space applications such as antennas, solar panels and spacecraft support structures. This paper presents a combined electromagnetic and acoustic analysis of a triaxial carbon fiber weave structure, designed for ultra lightweight reflector antennas in satellite communication systems. The electromagnetic and acous...

The direct point by point swept solution of the discretised Helmholtz equation over a broad frequency range can become computationally expensive for large systems when fine frequency increments are required. Approaches involving reduced-order models using Padé-or waveform-based methods such as the well conditioned asymptotic waveform evaluation (WC...

In this work, a solution strategy based on the use of Padé approximants is investi- gated for efficient solution of parametric finite element problems such as, for example, frequency sweep analyses. An improvement to the Padé-based expansion of the solu- tion vector components is proposed, suggesting the advantageous a priori estimate of the poles...

In this work, a solution strategy based on the use of Padé approximants is investigated for efficient solution of parametric finite element problems such as, for example, frequency sweep analyses. An improvement to the Padé-based expansion of the solution vector components is proposed, suggesting the advantageous a priori estimate of the poles of t...

Most engineering applications involving solutions by numerical methods are dependent on several parameters, whose impact on the solution may significantly vary from one to the other. At times an evaluation of these multivariate solutions may be required at the expense of a prohibitively high computational cost. In the present paper, an adaptive app...

In this work, a solution strategy is investigated for the resolution of multi-frequency structural-acoustic problems including 3D modeling of poroelastic materials. The finite element method is used, together with a combination of a modal-based reduction of the poroelastic domain and a Padé-based reconstruction approach. It thus takes advantage of...

Analysis of three-dimensional sound propagation in porous elastic media with the Finite Element (FE) method is, in general, computationally costly. Although it is the most commonly used predictive tool in complex noise control applications, efficient FE solution strategies for large-size industrial problems are still lacking. In this work, an origi...

This thesis presents efficient finite element solutions of poro-elasto-acoustic coupled problems using modal-based approaches adapted to non conservative problems, combined with an interpolation method in frequency, based on Padé approximants. The performance of the proposed methods and their combination is demon-strated on several 1D to 3D coupled...

Analyses involving structural-acoustic finite element models including three-dimensional modelling of porous media are, in general, computationally costly. While being the most commonly used predictive tool in the context of noise and vibrations reduction, efficient solution strategies enabling the handling of large-size multiphysics industrial pro...

Analyses involving structural-acoustic finite element models including three-dimensional modeling of porous media are, in general, computationally costly. While being the most commonly used predictive tool in the context of noise and vibrations reduction, efficient solution strategies enabling the handling of large-size multiphysics industrial prob...

Structural-acoustic finite element models including three-dimensional (3D) modeling of porous media are generally computationally costly. While being the most commonly used predictive tool in the context of noise reduction applications, efficient solution strategies are required. In this work, an original modal reduction technique, involving real-v...

In this work, an efficient solution strategy is investigated for the resolution of multi-frequency structural-acoustic problems including 3D modelling of poroelastic materials. The finite element method is used, together with a combination of a modal-based reduction of the poroelastic domain and a Padé-based reconstruction approach. It thus takes a...

In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under time- harmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is u...

In this work, a modal reduction, based on real-valued modes, is used to improve the computational efficiency of Finite Element problems including 3D modelling of sound absorbing poroelastic materials. A mode selection procedure is proposed and tested in order to downsize the basis including only the most significant contributions. The results are p...

This work deals with numerical computation of structural-acoustic applications including dissipative interfaces, in the context of structure-borne noise reduction. It focuses on the need to propose efficient solution strategies for costly finite element modelling. As such, a restrained-interface component mode synthesis is applied to the conservati...

During the last decade, porous materials have been widely used in order to reduce noise for interior domain in the transports industry. During the design process, several detailed structural-acoustic analyses need to be performed. However, modelling vibroacoustic problems introducing dissipative interfaces such as porous materials can lead to prohi...

Résumé — La modélisation d'un problème vibro-acoustique en présence de matériaux absorbants pour la réduction du bruit conduit généralement à un nombre très important de degrés de liberté, notamment pour décrire précisément le comportement du milieu poreux qui dépend de la fréquence. Afin de réduire les temps de calcul, ce travail propose d'utilise...

OF PAPER During the last decade, porous materials have been widely used in order to reduce noise for interior domain in the transports industry. During the design process, several detailed structural-acoustic analyses need to be performed. However, modelling vibroacoustic problems introducing dissipative interfaces such as porous materials can lead...