Investigation of viscous damping terms for a timoshenko beam

Brandi N. McPherson, George A. Lesieutre, Jeffrey L. Kauffman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Data cabling has become a significant portion of a spacecraft's dry mass and can no longer be neglected in structural dynamics models. At higher-frequency modes, the cable dynamics can interact with the bus structure to which they are attached, affecting the over- all dynamics of the spacecraft. Experimental testing has shown an increased damping ratio for cabled versus non-cabled structures, indicating the need for a spacecraft dynamics model that accurately includes the effects of data cable damping. Previous work has modeled cables as shear beams with structural and proportional damping terms. Structural damping models have a tendency to overestimate system damping in higher-frequency modes, while proportional damping results in unrealistic frequency-dependent damping. A time-domain viscous damping model reecting the frequency-independent nature of spacecraft cables is desired. The addition of viscous damping in the form of a “geometric-based” term produced nearly frequency-independent damping in Euler-Bernoulli beams and a similar result in shear beams. This work investigated the effects of a geometric-based damping term in the Timoshenko beam equations. Ten damping terms were included in a Timoshenko beam finite element model and categorized as motion-, rotation-, and strain-based damping. This research shows two trends of modal damping dominated by bending or shear, with no single damping term producing frequency-independent modal damping. The damping results provide further insight into the creation of a frequency-independent damping model.

Original languageEnglish (US)
Title of host publicationAIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
Edition210049
ISBN (Print)9781624105326
DOIs
StatePublished - Jan 1 2018
EventAIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018 - Kissimmee, United States
Duration: Jan 8 2018Jan 12 2018

Publication series

NameAIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018
Number210049

Other

OtherAIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018
CountryUnited States
CityKissimmee
Period1/8/181/12/18

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanics of Materials
  • Architecture

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  • Cite this

    McPherson, B. N., Lesieutre, G. A., & Kauffman, J. L. (2018). Investigation of viscous damping terms for a timoshenko beam. In AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials (210049 ed.). (AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2018; No. 210049). American Institute of Aeronautics and Astronautics Inc, AIAA. https://doi.org/10.2514/6.2018-0456