Annual Report 2016 - Mechanical Engineering

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205 Vibroacoustics of Vehicles and Machines
Vibroacoustics of Vehicles and Machines
Vibroacoustics, acoustics of vehicles, experimental acoustics, computational acoustics (FEM/BEM), structural
dynamics and structure-borne sound, uncertainty quantification, damage detection, acoustic porous materials
Research
structures, acoustic radiation damping
may be of a similar or even higher mag-
nitude than other damping mechanisms.
The first project is directed to investigate
such cases and to provide mathematical
formulations which allow one to consider
acoustic radiation damping in a pure-
ly structural model although the actual
physics would require a coupled struc-
tural acoustic model. The second project
focuses on the damping modeling in
wearing joints and systems involving fric-
tion-induced vibrations. While vibrations
usually decay with time owing to damping,
friction-induced instabilities cause positive
n The year 2016 was a unique opportunity for the Chair of Vibroacoustics
of Vehicles and Machines, founded on 1st July 2015, to extend its activi-
ties in research, establishment of test facilities and teaching. The prompt
emphasis was on new horizons in research by developing new models
adopting real engineering vibroacoustic problems. The Chair collaborated
closely with partners from diverse national and international universities
and industry in 2016 to ensure research opportunities. This allows us to
develop our newly established Chair not only in research and teaching,
but also to find new funds to employ new staff members.
Phone +49.89.289.55121
Contact
Prof. Dr.-Ing.
Steffen Marburg
Fig. 1: Developing more efficient
numerical FEM vibracoustic mod-
els for car engine and transforma-
tion unit (BFS project)
Fig. 2: The impact of damping uncertainty on the
frequency response function (FRF) of fiber-reinforced
composite structures
The research activities of the Chair in
2016 covered a range of topics in com-
putational vibroacoustic problems and
developing new algorithms in numerical
acoustic problems, uncertainty quantifi-
cation in structural vibroacoustic analysis,
aeroacoustics and room acoustics. The
efforts to approach more realistic vi-
broacoustic models for complex machines
and structures have been also continued
via ongoing BFS and DFG projects. The
endeavor on achieving practical and more
efficient models for FEM vibroacoustic
simulations of entire car engine and trans-
formation unit lead to new completion (see
Fig. 1). The developing novel numerical
uncertainty quantification methods in
engineering and science in this year yield
to new horizons. The so-called non-sam-
pling based stochastic analysis has been
adopted for vibroacoustic analysis of fib-
er-reinforced composites having random
fiber orientations and damping parameters
(cf. ref. 8 and Fig. 2). The investigations
on modeling of exterior acoustic problems
using the infinite finite element method
(IFEM) achieved new perspectives (see
Fig. 3).
In addition to ongoing projects, this year
two new projects, funded by DFG, have
been defined to develop new strategies
for modeling and realization of the struc-
tural damping. Concerning lightweight