In many industrial applications, such as in the automotive and
machine building industry, there is a continuous push towards
lightweight materials motivated by material and energy savings.
This increased use of lightweight materials, however, can strongly
compromise the Noise, Vibration and Harshness (NVH) performance of
the final products. Especially in times where the NVH performance
not only receives a higher legislative attention, but also becomes
a commercial differentiator, this also represents a key point of
attention for designers and directs research activities towards new
experimental and numerical techniques to accurately predict the NVH
performance of lightweight systems as early as possible in the
design process.
The presented work discusses novel measurement setup,
specifically developed for examining the vibro-acoustic behavior of
lightweight structures. The test stand consists of a concrete
cavity of 0.83 m₃. At its front wall, test specimens of variable
size and thickness can be inserted. This test setup allows applying
both acoustic and structural excitation. Among others it allows the
evaluation of vibro-acoustic Insertion Loss (IL) over a wide
frequency range taking into account the effect of acoustic cavity
modal loading, as is often the case in real life applications of
the tested materials such as for vehicle trimming.
The particular shape of the cavity also allows for the use of
efficient simulation techniques for steady-state numerical
analysis. The Wave-Based Method (WBM) has shown a superior
computational efficiency as compared to the classical element-based
techniques for problems of moderate geometric complexity, making
mid-frequency analysis feasible. The combination of the highly
efficient WBM and the novel test setup enables in situ material
characterization, both for internal acoustical problems as well as
for transmission cases.