STP1318

    New Applications of the Interferometric Strain/Displacement Gage

    Published: Jan 1997


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    Abstract

    The Interferometric Strain/Displacement Gage (ISDG) is an established laser-based technique that measures the relative displacement between two gage points on a specimen surface. The gage points are reflective markers illuminated with a low-power He-Ne laser to form interference patterns that are monitored with a computer-controlled system. Features of the technique are short gage length (50 – 300 μm) and no mechanical contact. Two new applications of the ISDG are described in this paper. The first is the measurement of strain on metal microspecimens that are 3 mm long with cross-sections typically 0.3 mm square. Details of the test procedure and results from 52 tests conducted as part of an ASTM-sponsored cross-comparison test are summarized. The second is strain measurement on 3.5 μm thick polysilicon film specimens; this capability has enabled measurement of the Young's Modulus and the tensile strength of this material which is used in microelectromechanical systems (MEMS).

    Keywords:

    interferometry, lasers, microspecimens, polysilicon, thin films, weldments, MEMS


    Author Information:

    Sharpe, WN
    Decker Professor and ChairJohns Hopkins University, Baltimore, MD

    Yuan, B
    Graduate Student, Johns Hopkins University, Baltimore, MD


    Paper ID: STP11889S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP11889S


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