Modal couping effects in the free vibration of elastically interconnected beams

Joshi, A and Upadhya, AR (1987) Modal couping effects in the free vibration of elastically interconnected beams. Journal of Sound and Vibration, 117 (1). pp. 115-130. ISSN 0022-460X

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    Abstract

    The problem of free vibration of a uniform beam elastically interconnected to a cantilevered beam, representing an idealized launch vehicle aeroelastic model in a wind tunnel, is studied. With elementary beam theory modelling, numerical results are obtained for the frequencies, mode shapes and the generalized modal mass of this elastically cou pled13; system, for a range of values of the spring constants and cantilevered beam stiffness and inertia values. The study shows that when the linear springs are supported at the nodal points corresponding to the first free-free beam mode, the modal interaction comes primarily from the rotational spring stiffness. The effect of the linear spring stiffness on the higher model modes is also found to be marginal. However, the rotational stiffness has a significant effect on all the predominantly model modes as it couples the model13; deformations and the support rod deformations. The study also shows that though the variations in the stiffness or the inertia values of the cantilever beam affect only the13; predominantly cantilever modes, these variations become important because of the fact that the cantilevered support rod frequencies may come close to, or even cross over, the13; predominantly model mode frequencies. The results also bring out the fact that shifting of the support points away from the first mode nodal points has a maximum effect only on the first model mode.

    Item Type: Journal Article
    Additional Information: Copyright to this article belongs to Academic Press Limited.
    Uncontrolled Keywords: Modal couping;Free vibration;Elasticity interconnected; Cantilevered beam;Spring stiffness
    Subjects: ENGINEERING > Structural Mechanics
    Division/Department: Structures Division, Structures Division
    Depositing User: M/S ICAST NAL
    Date Deposited: 31 Oct 2006
    Last Modified: 24 May 2010 09:51
    URI: http://nal-ir.nal.res.in/id/eprint/3047

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