SRS primary positive and negative
SRS primary positive and negative
(OP)
I'm having a hard time wrapping my head around the concept of a primary positive and negative SRS responses. What is physically happening to produce these waveforms? How are they derived?





RE: SRS primary positive and negative
The object is vibrating, that produces the waveform. By measuring acceleration versus time the SRS can be derived. The shock response spectrum (acceleration versus frequency) is derived from the fourier transform of acceleration versus time data. Fourier transforms are the means to go from the time to frequency domains.
Hope that helps.
RE: SRS primary positive and negative
Jim Kinney
Kennedy Space Center, FL
RE: SRS primary positive and negative
Can you elaborate on that further? Are you talking about the effect of the shock on the accelerometer?
RE: SRS primary positive and negative
I should have said accelerometer problems. Both of these problems add low frequency energy to the wave form, and will show up with the velocity shifting (DC) or continuing to increase as the transient dies out. High pass filtering (5-10Hz) will sometimes get rid of the DC offset. The continuous change in velocity will require some kind of trend removal (wavelets work quite well), and may also remove some parts of the waveform that you really need. As such, manipulating the data is a last resort if you can't retest (ie. flight data reduction).
Jim Kinney
Kennedy Space Center, FL
RE: SRS primary positive and negative
I've been told a good rule of thumb is that a difference of 3dB between the + and the - was acceptable. Does this sound about right?
RE: SRS primary positive and negative
Jim Kinney
Kennedy Space Center, FL