https://onlinelibrary.wiley.com/doi/pdf/10.1002/nme.1620171214

Concepts and applications of finite element analysis, 2nd edn, by Robert D. Cook, Wiley, New York, 1981. No. of Pages: 531. ISBN 0-471-03050-3. Price: £22.35 ($40·20)

The main objectives of the study are: (1) identification of potential passive damping concepts for slender tubular structural members with rotational and translational end springs under natural and forced-free vibrations; (2) evaluation of damping efficiencies of the various damping concepts; and (3) evaluation of the suitability of a theoretical finite difference analysis by comparison to the experimental results for the case of natural vibrations. Only member flexural an translation motion is considered. The natural vibration study is conducted on the seven damping concepts and for only one specific initial deflection. The most suitable of the seven dampers is further investigated under forced-free vibrations. In addition only one set of end springs is used for all of the experiments. The results show that passive damping provides a possible approach to structural vibration reduction.

https://ntrs.nasa.gov/api/citations/19910007098/downloads/19910007098.pdf

Passive damping concepts for tubular beams with partial rotational and translational end restraints

Potential passive damping concepts for use in space structures are identified. The effectiveness of copper brush, wool swab, and silly putty in chamber dampers is investigated through natural vibration tests on a tubular aluminum member. The member ends have zero translation and possess partial rotational restraints. The silly putty in chamber dampers provide the maximum passive damping efficiency. Forced vibration tests are then conducted with one, two, and three damper chambers containing silly putty. Owing to the limitation of the vibrator used, the performance of these dampers could not be evaluated experimentally until the forcing function was disengaged. Nevertheless, their performance is evaluated through a forced dynamic finite element analysis conducted as a part of this investigation. The theoretical results based on experimentally obtained damping ratios indicate that the passive dampers are considerably more effective under member natural vibration than during forced vibration. Also, the maximum damping under forced vibration occurs at or near resonance.

https://ntrs.nasa.gov/api/citations/19880017309/downloads/19880017309.pdf

David W. Mykins

Papers

Experimental and theoretical investigation of passive damping concepts for member forced and free vibration