OPTICAL METHODS FOR MEASURING VIBRATION AND LOCAL DISPLACEMENT

Two optical methods are described to measure vibration and local displacement. In the first case a neutral wedge is connected to the moving object, in a way it changes the transparency in direction of the motion. A detector receives the transmitted light of a fixed light beam. The detector signal depends on the relative position of the light beam and the moved neutral wedge. The neutral wedge used is a neutral density optical glass the optical density of which changes linearly in one direction. In the second case a laser light beam is expanded by cylindrical lenses producing a light band. A detector unit records the intensity of the residual light when the band is crossed by a leading edge of a moving object. The detector signal is correlated to the position of the object. With both methods the range can be adjusted to the requirements of the problem. The resolution is in the sub-micron range depending on the beam geometry. The time resolutions extends up to 500 mhz depending on the detector circuity. The methods are easy to handle even in cases of difficult experimental conditions. (TRRL)

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  • Corporate Authors:

    Modino Press Limited

    Keswick House, 3 Greenway
    London N20 8EE,   England 
  • Authors:
    • EISENREICH, N
    • Kugler, H P
    • Liehmann, W
  • Publication Date: 1983-12

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Filing Info

  • Accession Number: 00385506
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jun 28 1984 12:00AM