Showing papers on "Dynamic Vibration Absorber published in 1977"

On the Dynamic Vibration Damped Absorber of the Vibration System

Abstract: Main purpose of this paper is to analyse the forced vibration prevention of the vibration system with positive or negative damping by the damped dynamic absorber. The cases treated in this paper are: the case I (the alternative exciting force of a constant magnitude is acting on the mass of the main system), the case II (the alternative exciting force, of which the magnitude is proportional to the square of its frequency, is acting on the mass of the main system), and the case III (the alternative displacement is given to the foundation of main system), It is explained how the spring constant and the damping factor of the dynamic absorber are desirably optimized to make the vibration effect minimum. The optimum values in the above cases are given by the convenient empirical formulae.

Implement for striking a ball

Abstract: This invention relates to means for suppressing vibration in implements which serve to strike the ball and comprise a striking surface, a hoop which encloses the striking surface, and a handle. The invention relates particularly to tennis rackets and aims at suppressing the high-frequency vibration which is excited by the impact of the ball. In these striking implements, at least two longitudinal or transverse strings or at least one longitudinal string and at least one transverse string are mechanically coupled to each other by a vibration absorber.

Static and Dynamic Performance of an Infinite Stiffness Hydrostatic Thrust Bearing

Abstract: A novel form of variable hydrostatic restriction is proposed which will automatically achieve a high, infinite or negative static stiffness over a substantial load range. The restrictor is formed between the bearing body and a spring mounted conical plug. The steady state performance is analyzed and design curves presented which are valid for any cone angle from zero, i.e., fixed clearance, to 90 deg which is the normal diaphragm restrictor. The dynamic response to forced sinusoidal vibrations is examined in conventional vibration analysis form and it is found that the restrictor system may be designed to act as a vibration absorber.

Motive vibration absorber

Abstract: PURPOSE:Mapping out obtaining the motive vibration absorber to be designed not to waste the energy in the course that when the body of inertia travels, the motive frictional resistance is remarkably diminished and the body of inertia irregularly hit the surface of the cylinder bulkhead.

Viscously Damped Dynamic Absorbers of Conventional and Novel Design.

Abstract: The behavior of dynamic vibration absorbers of conventional and novel design has been investigated experimentally and found to compare closely with prediction. The dynamic absorbers were employed to suppress the transmissibility at resonance across a 1‐df primary system. Initially considered was a dynamic absorber with a conventional mass‐spring‐dashpot configuration; the primary system was undamped. Subsequently considered were (1) so‐called dual dynamic absorbers, and (2) a single, nominally undamped absorber, or two such absorbers, attached to the primary system after it had been damped heavily. The dual absorbers—a conventional viscously damped absorber used in parallel with a less massive undamped absorber—introduced a pronounced transmissibility trough without the appearance of unwanted ’’compensating’’ peaks at lower and higher frequencies. The attachment of a nominally undamped absorber to the heavily damped primary system also introduced a pronounced trough without giving rise to compensating peaks. Further, the attachment of two such absorbers introduced pronounced troughs at two frequencies that could be varied independently of one another. Thus, the novel absorber systems considered here behaved as mechanical ’’notch’’ filters, providing at specific ’’low’’ frequencies a high degree of isolation that other passive systems cannot duplicate without exhibiting a marked loss in isolation at neighboring frequencies.

Vibration absorber for helicopter rotors - has sealed resonator boxes, mounted on hub with sloped sides forming track for high density metal ball

Abstract: The vibration absorber for vibrations in the plane of a helicopter rotor, consists of at least two resonators attached to the hub (2) of the rotor by a rigid support Each resonator is formed from two dished pieces (18, 19) which are secured together and sealed along side flanges to form an enclosure, inside which is trapped a metal, or metal alloy, ball (24) of high density The side walls of the dished pieces (27, 28) are sloped so that they form a track for the ball when it is subjected to centrifugal and vibrational forces