DYNAMIC STABILITY ANALYSIS OF THE GEOPHONE SPURIOUS FREQUENCY PHENOMENON

A geophone is a device for detecting vertical seismic waves. Based on its structure, a geophone is modelled in the present paper by a suspension system consisting of a coil suspended from the hull through six springs. The springs are in fact curved beams with one end rigidly attached to the hull and the other end attached to the coil. A dynamic stability analysis of the curved beams reveals the cause of the spurious frequency of the geophone: the horizontal excitation upon a curved beam in the horizontal plane under certain conditions may result in an out-of-plane dynamic buckling with drastic vibration, which causes a spurious signal output. Numerical results show the effects of some factors, such as the amplitude of the harmonically exciting velocity, the direction of the excitation with respect to the spring location and the eigenfrequencies of in-plane vibration of the curved beam, on the spurious frequency. Numerical results are compared with experimental data. (A)

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    Academic Press Incorporated

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  • Authors:
    • Ling, F H
    • Wang, W M
    • Mao, R J
  • Publication Date: 1990-5-22

Language

  • English

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Filing Info

  • Accession Number: 00606062
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1991 12:00AM