Zak28
Advanced Member level 2
Need to obtain natural oscillation frequency for several fr4 boards and other non PCB objects. Striking the objects emanates low frequency tone which dampens out rather quickly. The trouble with obtaining its frequency with condenser and other forms of acoustic microphones is their low frequency response does not dwell near natural frequency of objects and if there are mics which can pick up sub 80Hz accustics then those are likely very costly.
Calculating or or employing FEM to obtain their natural frequency isn't ideal since there are several objects I need to measure containing very dissimilar materials comprising the rigid body hence FEM isn't ideal for this. There might be something with infared reflective optics which might be able to carry this out however not sure if this is most simple and practical method. Perhaps a fine powder spread over the surface of object and an acoustic generator is varied until specific patterns appear. But this might not be accurate and its likely patterns will appear regardless of natural frequency. Would adhering a rather small super magnet so as to not distort the natural frequency of objects and picking up the oscillations with a nearby coil be a means to obtaining natural frequency of objects or are there specialty piezo or other pick ups made specifically for these purposes?
Calculating or or employing FEM to obtain their natural frequency isn't ideal since there are several objects I need to measure containing very dissimilar materials comprising the rigid body hence FEM isn't ideal for this. There might be something with infared reflective optics which might be able to carry this out however not sure if this is most simple and practical method. Perhaps a fine powder spread over the surface of object and an acoustic generator is varied until specific patterns appear. But this might not be accurate and its likely patterns will appear regardless of natural frequency. Would adhering a rather small super magnet so as to not distort the natural frequency of objects and picking up the oscillations with a nearby coil be a means to obtaining natural frequency of objects or are there specialty piezo or other pick ups made specifically for these purposes?
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