SCS9021 / 9022
Oberst method for Damping loss factor determination
When connected to the SCS 902A system, the Oberst set device allows the determination
of the Damping loss factor of material samples according to DIN standard. The
material sample is normally attached to a steel plate clamped to the top of
the Oberst device, it is then excited using an electromagnetic actuator driven
with random or impulse signals; sinusoid sweep is also available as standard
from the SCS 902A system.
The displacement parameters of the testing specimen are measured with a laser
transducer in order to avoid any mass loading on it and to guarantee precise
results. From the transfer function between excitation signal and displacement,
damping is calculated through a curve fitting procedure. The Oberst apparatus
is a very rigid stainless steel structure with rapid clamps adjustable for fixing
the specimen in various position; the laser transducer is movable along the
rod and the distance from the specimen is also adjustable.
The use of a laser transducer overcomes any problem concerning the nature of
the material under testing and it is also possible to use a non metallic support
plate, like fibber plate or others. As a device for the SCS 902A system, all
functions implemented in the PC based system can be applied to the case, including
mathematical functions, storing and reporting. The Oberst device ensemble for
the SCS 902A system is available as a separated set which can also be connected
with other acquisition and analysis systems.