Tuned dynamic absorbers (TDA) find use, in particular, for attenuating tonal vibration export produced by the moving components of cryogenic cooler. For the best performance, the resonant frequency of TDA needs to be essentially equal the driving frequency; accurate frequency match is favorably achieved by minimizing the cooler induced vibration by adjusting the driving frequency. For the best performance, the design of TDA needs to ensure minimum damping ratio; this is achievable by using planar flexural bearings having zero friction anchoring features.
Accurate evaluation of effective mass, damping ratio and frequency is needed for TDA characterization during development and manufacturing. This data may be also important for the dynamic modelling. The authors are exploring the express method requiring no physical access to the proof mass of TDA. In this approach, the TDA is mounted upon the low frequency vibration mounted rod, the dynamic properties of TDA are then evaluated using the frequency response function – local accelerance – captured on the above rod using accelerometer, instrumented modal hammer and dual-channel signal analyzer. The authors are presenting the TDA design, outcomes of full-scale experimentation on dynamic properties evaluation and attained performance.
a SemiConductor Devices POB 2250, Haifa 31021, Israel
b Loughborough University, Epinal Way, Loughborough, LE11 3TU, UK
c Israel Ministry of Defense, Kirya, Tel Aviv, 64734, Israel