Mohsenizadeh, Navid (2010-08). Simulation Methodologies for Satellite Solar Array Dynamics. Master's Thesis. Thesis uri icon

abstract

  • The purpose of the present thesis is to furnish diverse studies on the dynamic
    response of satellite solar arrays. The term flexible structure or, briefly, structure has
    different interpretations and definitions, depending on source and on application. The
    solar array studied in the present thesis has flexible sub-structures and undergoes large
    deformations.
    Structural dynamics is an important basis of many engineering studies associated
    with engineering structures, such as design, construction, and control. It generally
    consists of two functions, i.e. free vibration analysis (modal analysis) and response
    analysis (steady-state and transient analysis).
    The thesis starts with introducing the solar array considered for our study and
    then continues with several structural analyses, including nonlinear pre-stressed static
    analysis, pre-stressed modal analysis, nonlinear full transient analysis and Fast Fourier
    Transform study on the transient response.
    The purpose of static analysis is to obtain the configuration of the array under
    implementing static loads. Modal analysis provides the natural frequencies and mode
    shapes which are the intrinsic dynamic properties of the structure. Transient analysis is used for evaluating the mechanical behavior of the structure. It gives relations between
    the intrinsic properties of structure and the external excitations. Transient analysis under
    different types of inputs will be used to track physical quantities like displacement,
    rotation, stress, and strain during specific satellite maneuvers. Pointing error will be
    introduced as a measure of accuracy of Sun tracking maneuver. It will be computed as a
    postprocessing step on the transient displacement results. To improve the pointing error
    which will consequently result in higher energy generating performance, two other
    staggering type input profiles are proposed for each orbit, GEO and LEO. Pointing error
    and vibration response under the proposed inputs are obtained to determine the
    efficiency of the new inputs. After a comparison, it will be shown that the proposed
    inputs are more efficient in the Sun tracking solar array maneuver.
    At the end, a novel approach in performing mode-superposition transient analysis
    using modal effective mass tables is introduced. Since it is very common among
    engineers to assume the first 10 percent or 20 percent of the mode shapes when mode-superposition
    method is preferred to obtain the transient response, this novel approach shows that even
    smaller numbers of mode shapes can be assumed to perform this type of analysis and
    still obtain acceptable results, only if the assumed modes contain the majority of the
    modal effective mass in a specific direction, depending on the loading condition.

publication date

  • August 2010