X20 system modules • Other functions • X20CM4810
X20 system User's Manual 3.10
2085
Sensor positioning
To ensure optimal detection and measurement of frequencies propagating from a point of damage, sensor posi-
tioning plays an important role. The ideal position for mounting a sensor on a structure is often difficult to reach and
is not always necessary. Since sound waves propagate throughout the entire structure, the damage frequencies
are measured with varying intensity or amplitude (green arrow). If a flexible connection is used, a valid measure-
ment is no longer possible (red arrow).
Shaft
Elastic
coupling
Bearing A with
bearing damage
on the outer ring
Bearing B without
Motor
bearing damage
Figure 649: Suitable and unsuitable sensor attachments
4.26.2.4.2.2 Oscillations - Overview of measuring structure-borne sound
Oscillations
Mechanical oscillations
Oscillations are forms of movement that occur very frequently in nature. Harmonic oscillation is the third basic type
of form of movement alongside uniform movement and uniform accelerating movement. An oscillation or vibration
is a cyclical, i.e. repetitive simultaneous movement of a structure in its rest or equilibrium position.
Cycle duration T [s]
Am
pl
itu
de
Time
Figure 650: Illustration of a basic oscillation
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