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Vibration Isolation Characteristics of a Modified Gough-Stewart Platform with the Top Platform Filled with Damping Particles

Ahmad, N and Ranganath, R and Poomani, D and Ghosal, A (2022) Vibration Isolation Characteristics of a Modified Gough-Stewart Platform with the Top Platform Filled with Damping Particles. In: 5th International and 20th National Conference on Machines and Mechanisms, iNaCoMM 2021, 9 December 2021 - 11 December 2021, Jabalpur, pp. 243-256.

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Official URL: https://doi.org/10.1007/978-981-19-3716-3_19

Abstract

In this paper, we consider a modified Gough-Stewart platform (MGSP) where two groups of three legs meet at two concentric circles on both top and bottom platforms.The geometry of the MGSP is chosen such that all the first six natural frequencies are equal for a typical payload mounted on the top platform.Additionally, in the top platform, made up of an aluminum honeycomb sandwich, the empty cells of the honeycomb core are filled with damping particles (DPs) to introduce passive damping in the system and to limit the resonance responses.A finite element model (FEM) of the MGSP is developed to quantify the performance in terms of frequency response functions (FRF), resonance peaks, and the damping introduced by the damping particles.The FEM model of the MGSP is combined with the discrete element model (DEM) of the damping particles to compute the effect of the particles on the overall dynamics and damping behavior of the platform.The effect of DPs on the transfer function is evaluated by solving the equations of motion of the DPs and the FEM model of the MGSP simultaneously.Finally, the FRF between the bottom platform and the mass center of the payload is computed for assessing the effectiveness of DPs, the transfer functions between the base excitation and mass center of the payload with respect to four inputs—sine swept inputs applied separately at the base of the platform—were computed for 25%, 50%, 75%, and 93% fill fractions.The peaks at resonances progressively decrease as the fill fraction was increased.For all the modes, it was seen that the damping introduced by damping particles results in the splitting of the modes and the formation of anti-resonance at resonance peaks.The damping introduced by the particles is more effective in longitudinal direction where there is a reduction from 25 to 8 with increasing fill fractions from 25 to 93%.The cross-axis transfer functions also seen to come down from 98 and 10 to 75 and 5 along the X-axis and Y-axis, respectively.

Item Type: Conference Paper
Publication: Lecture Notes in Mechanical Engineering
Publisher: Springer Science and Business Media Deutschland GmbH
Additional Information: The copyright for this article belongs to Springer Science and Business Media Deutschland GmbH
Keywords: Equations of motion; Finite element method; Frequency response; Honeycomb structures; Resonance; Transfer functions, At resonance; Finite-element model modeling; Frequency response functions; Gough-Stewart platform; Mass centers; Modified stewart platform; Multi-axis vibration control; Multi-axis vibrations; Particle impact damping; Resonance peak, Damping
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 01 Dec 2022 05:31
Last Modified: 01 Dec 2022 05:31
URI: https://eprints.iisc.ac.in/id/eprint/77878

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