Microflown PU based Source Path Contribution Analysis

PU mini arrays offer a fast and single transducer solution for a fully fledged
broad banded analysis, even whilst driving a car. Until recently, for lower
frequency analysis, either accelerometers or a scanning laser vibrometer were
used. Fixation of accelerometer takes time and causes a mass load. A non
contact scanning laser vibrometer requires a line of sight for the beam which is
not always possible, thus still requiring accelerometers to be used. Acoustic
particle velocity equals the structural velocity in the acoustic near field, and
thus the normal structural velocity can be measured fast and everywhere
without a mass load!
For higher frequencies, sound intensity methods based upon a pair of sound
pressure transducers were used that are susceptible to reflections.
In order to overcome this problem, anechoic conditions were created in the
cabin by putting damping foam in, causing a mass load. For each panel to be
measured, the foam was removed, the radiated sound intensity measured, and
the foam put back in place again, a time consuming task.
PU probes are not susceptible to reflections, and thus the use of damping foam
is no longer required. Saves time, avoids mass load effects, and, above all,
allows testing under realistic driving conditions!
In order to determine the transfer path, reciprocity measurements are often
used. The pressure signal of the PU probe can be used as the receiver from the
volume velocity source.
Thus, PU probes offer the true single transducer solution!

Category:

Science & Technology

Tags:

• Microflown
• pu
• p-p-
• accelerometers
• laservibrometer
• interior
• noise
• transfer
• path
• particle
• velocity