The tolerances to be applied to the 1.0g sine sweep have been
over-simplified so that the test conductor can determine compliance by
visually monitoring the RMS meter during the sweep. If a tolerance exceedance
is noted he must obtain qualitative data on the bandwidth and amplitude of the
exceedance in order to determine its effect on the random vibration test. This
will probably require that the sine sweep portion of the tape be rerun and a
plot of acceleration versus frequency made. With this plot the test conductor
can determine if a significant problem exists or whether the random test can
be performed. Guidelines for this evaluation are presented in Chapter 6. If a
problem with the vibration system is verified the test conductor must
troubleshoot the system to isolate and correct the problem. In order to
efficiently troubleshoot the system a reference tape should be made:
a. Side A of the tape will contain the tape deck frequency response data.
(Procedure outlined in Chapter 2 ).
b. Side B of the tape will contain a 1.0g (peak) sine frequency sweep of
the vibration system with the test article removed - fixture only.
(Procedure outlined in Chapter
The frequency response tape (reference tape side A) can be used to
verify performance of the tape deck without operating the shaker system. The
fixture-only sine sweep tape (reference tape side B) can be used to isolate
problems in the vibration system without subjecting the test article to
repeated sine sweeps during troubleshooting operations. This tape should be
recorded at the start of the program and retained as a troubleshooting aid for
the duration of the test program.