Showing papers on "Dynamic Vibration Absorber published in 1970"
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01 Jan 1970
TL;DR: In this article, the authors proposed a new design concept for a tunable damper (damped vibration absorber), which is used for increasing the dynamic stability and thus cutting performance of a vertical milling, drilling, and boring machine with a long overhung quill.
Abstract: SUMMARY The paper proposes a new design concept for a tunable damper (damped vibration absorber). The spring rate of the device is changed by utilizing the non-linear stiffness characteristic of plastic elements. The purpose of the damper is to eliminate chatter of the machine tool by self-optimizing selection of the proper value of damper tuning. The principles for the selection of optimal values of tuning are obtained by analog computer simulation of regenerative chatter. The damper is used for increasing the dynamic stability and thus cutting performance of a vertical milling, drilling, and boring machine with a long overhung quill. Results of cutting tests are presented, illustrating the degree of chatter elimination obtained by the use of the damper.
10 citations
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TL;DR: In this paper, the Fourier transform and impedance (FT&IM) method is used to measure the spectrum of a shock wave at the interface of a machine and an equipment.
Abstract: A theoretical study of the characteristics of a shock spectrum which is measured in a shock test of equipment is presented. For this purpose, the machine and the equipment are represented by two systems connected in series; an upper and a lower bound of the spectrum of the shock motion at the interface of the two systems are found using the Fourier transform and impedance method. The spectrum is shown to be affected by the characteristics of both systems. It is demonstrated that in a system containing negligible damping, hills would occur in the spectrum at the resonant frequencies of the combined system, whereas valleys (spectrum dips) would appear in the neighborhood of the fixed-base resonant frequencies of the equipment. The possible effects of damping and of the variation in the characteristics of the system on the phenomenon are also discussed. The results support, at least in the case of systems with low damping, the current design practice of the Navy in which an envelope of a group of the dips of measured spectra is used in creating a design spectra for similar equipment. The analysis developed here would also be useful in understanding the behavior of vibration absorber and other shock phenomena.
2 citations
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20 May 1970
TL;DR: A vibration absorber is a mass attached through rubber spring means 15 to a vibrating system, e.g. an overhead transmission line as mentioned in this paper, the mass having its centre of gravity offset from the effective centre of spring suspension P so that the mass has at least two coupled modes of vibration at distinct frequencies.
Abstract: 1,192,355. Vibration absorber. METALASTIK Ltd. 20 June, 1967 [6 July, 1966], No. 30252/66. Heading F2S. A vibration absorber comprises a mass 14 attached through rubber spring means 15 to a vibrating system, e.g. an overhead transmission line 11, the mass having its centre of gravity offset from the effective centre of spring suspension P so that the mass has at least two coupled modes of vibration at distinct frequencies. The mass is non-symmetrical about at least one of the three planes H.T.V. mutually at right angles and each containing the centre of gravity of the mass.
1 citations