Civil Engineering ETDs

Author

Yuanzhong Qiu

Publication Date

7-11-2013

Abstract

The characterization of cable damping is important for the stability and performance of structures deployed in space using cables. However, literature available for the analysis of carbon fiber cable damping and its effect on dynamical behavior of deployable space structure is scarce. The objective of this work is to examine the variation of cable damping involving different cable properties and the ambient environments through several carefully instrumented tests. An analytical model to predict damping based on internal forces and variable cable geometry is developed and compared with those of tests. An experimental set-up for the measurement of cable damping is described. Cables in different lengths (0.2032m, 0.3048m and 0.5080m), constructions (20.71turns/m, 41.42tutns/m and 62.13turns/m), temperatures (20\u2103 and 4\u2103) and air pressures (normal and vacuum) are tested under five different tensile forces (111.25N, 222.50N, 333.75N, 445.00N and 578.50N). In addition, the effect of sensor mass, the support and test apparatus on damping are investigated. The damping is identified by the half-power bandwidth' method and the 'logarithmic decrement' method. The results indicate that, typically, damping decreases as the length, tension and the number of turns of the tested cable increases. Also, temperature and air pressure contribute to the variation of damping. To explore the use of finite elements method (FEM) to simulate cable vibration and damping, the COMBIN14 and MASS21 elements in ANSYS13.0 are used. The finite element simulation results agree well with the test results on vibration frequency and time history response. This demonstrates that the selected elements are capable of modeling the dynamic response of cables using the Rayleigh damping constants. Using simplified mechanistic assumptions, an analytical approach is proposed to model cable damping. The proposed method and related issues are discussed considering numerical examples. It is shown that this method can predict the damping variation trend as observed in the tests of carbon fiber cables.'

Keywords

Damping, Vibration, Carbon fiber cable, Finite element method, Theoretical model, Deployable space structure

Document Type

Dissertation

Language

English

Degree Name

Civil Engineering

Level of Degree

Doctoral

Department Name

Civil Engineering

First Advisor

Maji, Arup

First Committee Member (Chair)

Maji, Arup

Second Committee Member

Gerstle, Walter

Third Committee Member

Ng, Percy

Fourth Committee Member

Ghosh, Ashok

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