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Design of Dry Friction Damper to Reduce Vibration Impacts to Circuit Cards at Critical Frequencies

Kovtun Igor, Goroshko Andrii, Petrashchuk Svitlana

Advances in Science and Technology. Research Journal

2024

Vol. 18, no 2

78--87

The paper is focused on providing strength and stiffness for circuit cards exposed to vibration at critical frequencies. Since the dry friction damping is more effective than viscous damping and in case when application of viscous dampers is restricted by electronic package design the dry friction damper is proposed to be embedded to design of enclosure case in order to reduce oscillation amplitudes of circuit cards at critical frequencies. Dry friction damper produces dissipative forces – non-elastic resistance forces due to friction in kinematic pairs undergoing oscillations. The mathematical model has been developed for estimation of maximal dynamic stress and deflection in critical cross-section of circuit card with embedded dry friction damper at critical frequencies. Developed mathematical model specifies minimal limit value for stiffness of dry friction damper, which is used in engineering calculations to determine its geometric parameters. Design of dry friction damper is introduced by semi-elliptical beam with rectangular profile. The effectiveness of dry friction damper to reduce dynamic stress and deflection in circuit cards has been analytically proved and experimentally testified.

Dry friction damper for supercritical drive shaft

Perkowski W.

Journal of KONES

2016

Vol. 23, No. 4

389--396

In this article the construction and mathematical model of a dry friction damper with radial gap, designed for dumping flexural vibrations of a supercritical propulsion shaft (developed previously during design works made in Institute of Aviation on propulsion system for an ultralight IS-2 helicopter), while passing through the resonance is presented. Some results of mathematical and numerical analyses of such a system (supercritical shaft + damper) behaviour are also presented – among other things, very distinctive behaviour of the shaft, while passing through resonance, is shown. From a theoretical point of view, it is interesting that certain range of damper parameters, obtained in the course of numerical analysis, lead to chaotic vibrations of the system (they were also observed in practice). From a practical point of view, it will be interesting that the article shows a way how to create a dimensionless (and therefore general) parameters of the system: supercritical shaft and friction damper and also simple engineering methodology for selection of suitable (for the correct operation of the shaft) damper parameters depending on the parameters of the shaft, developed during series of analyses. The practical aspect of the problem seems to be particularly important, as the supercritical propulsion shaft equipped with a friction damper can be very structurally simple, light and inexpensive, and still it is not widely used, probably because of certain doubts aroused in the constructors by the term: “resonant vibrations”.