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1. Gil G. Valdez
ARC- 3203
Acoustic Building Systems and Technologies
A deep understanding of sound transmission through complex structures,
characterized by numerous interfaces and surfaces forms the base of our work on
building systems and technologies. Our extensive knowledge in building acoustics
is applied to the development of novel modeling and characterization methods
of conventional and lightweight building components and their connections
(with special attention for wood construction) aiming at the acoustical
optimization of products and designs. In addition, we support companies in the
experimental assessment of the acoustical performance of their products and
building solutions in our well-equipped labs, which are accredited for sound
transmission and sound absorption measurements.
Acoustic Performance of Engineered Materials
Possesses extensive knowledge on the modeling of wave propagation in
solids and of fluid structure interaction (FSI). We use analytical and numerical
modeling to better understand the processes that govern the propagation of
elastic waves in solids with complex geometries and the exchange of energy at
interfaces. The models lead to engineered materials represented by periodic
arrangements of features in space (metamaterials, phononic crystals),
aperiodically microstructured materials (such as inspired by quasicrystals) or other
complex, inhomogeneous materials, such as foams, or compacted granular
materials. We experimentally verify and complement our models using scanning
laser vibrometry, impedance analysis as well as our acoustic measurement set-
ups. This combination of models and experimental insights improves the properties
of everyday structures and achieves novel functionalities.
Sound Generation of Environmental Noise Sources
Along with our long experience in the development of sound propagation
models, we have a strong focus on experimental characterization and modelling
of the sound generation of environmental noise sources such as road traffic,
railway, aircraft, shooting or wind turbine noise. Our capability to establish
detailed, physically based models is indispensable for engineering models, but in
particular also for auralization, as the ear is unforgiving.
These capabilities are used to develop sound source models
for environmental noise exposure assessment, and to acoustically optimize noise
sources and noise abatement procedures, to minimize noise impact.
Road Traffic Noise
We study the complex process of rolling noise generation in road vehicles,
investigate experimental methods to describe pavement properties and
determine the accuracy of different measurement concepts. Our theoretical
understanding in combination with large measurement datasets is the basis for
formulating road traffic sound source models, like the recently
published sonROAD18.

2. Railway Noise
With our sophisticated finite-element-models, we simulate the process of
rolling noise generation by predicting vibrational modes of track superstructure
and wheel and by modelling the radiation of air-borne sound as well as low-
frequent vibrations transferred to the underground. Our profound knowledge is
used to develop targeted optimizations of track components like rail pads,
sleepers or under sleeper pads.
Aircraft Noise
For physically-based aircraft noise modelling, our next-generation
program sonAIR comprises a separate engine and airframe noise model
describing in detail the sound emission and directivity as a function of flight
configuration (power setting and aeroplane configuration, i.e., flaps, slats and
landing gear).
Shooting Noise
We established and constantly update a large database of acoustic
properties of civil and military weapon systems, which is used in our shooting
noise model sonARMS. The emission data including a detailed description of the
corresponding directivity pattern is either based on own source measurements
or derived from theoretical approximations based on the explosive charge,
projectile dimensions and ballistics.
Virtual Acoustics
What will a future transportation system or urban space sound like? The
technique of auralization – the acoustical counterpart to visualization – allows to
artificially create listening experiences of new designs. As part of our
comprehensive approach, we will create acoustic virtual realities allowing us to
include sound perception in the design process, communicate our research to
stakeholders and intuitively present noise solutions. Our group advances the
auralization models for urban outdoor and indoor sceneries considering complex
propagation geometries and material properties, for example of road surfaces,
facades and building constructions. Good quality auralization requires a detailed
understanding of sound generation, sound propagation, acoustic measurement
techniques, signal processing, electro-acoustics and psychoacoustics. We
operate our laboratory facility AuraLab and use recent virtual reality technologies
like headsets. We actively shape the scientific advances in virtual acoustics and
participate in interdisciplinary and international research projects.