Method for Quantifying Percentage Wood Failure in Block-Shear Specimens by a Laser Scanning Profilometer

    Volume 2, Issue 8 (September 2005)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 22 June 2005

    Page Count: 10


    Scott, CT
    General Engineer, Research Engineer, Project Leader, Physical Science Technician, and Student, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI

    Hernandez, R
    General Engineer, Research Engineer, Project Leader, Physical Science Technician, and Student, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI

    Frihart, C
    General Engineer, Research Engineer, Project Leader, Physical Science Technician, and Student, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI

    Gleisner, R
    General Engineer, Research Engineer, Project Leader, Physical Science Technician, and Student, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI

    Tice, T
    General Engineer, Research Engineer, Project Leader, Physical Science Technician, and Student, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI

    (Received 4 October 2004; accepted 23 February 2005)

    Abstract

    A new method for quantifying percentage wood failure of an adhesively bonded block-shear specimen has been developed. This method incorporates a laser displacement gage with an automated two-axis positioning system that functions as a highly sensitive profilometer. The failed specimen is continuously scanned across its width to obtain a surface failure profile. The laser is then moved incrementally along the length of the specimen and repeatedly scanned to obtain a three-dimensional digital profile of the surface. This digital profile can then be reconstructed and analyzed with appropriate software. Special algorithms are used to quantify percentage wood failure and degree of wood failure (depth of wood failure) and to recognize various surface anomalies, such as bondline voids. This paper presents exploratory data on several different types of wood failures and correlates these measurements to the visual inspections of skilled evaluators. The device is very sensitive to most observed failures, particularly those with deep wood failure. However, shallow failures close to the bondline can be problematic. The algorithms allow a “roughness” tolerance to be specified to characterize these surfaces. This new method will be useful for automating measurement of wood failure in block-shear specimens with good precision and repeatability.


    Paper ID: JAI12957

    DOI: 10.1520/JAI12957

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    Author
    Title Method for Quantifying Percentage Wood Failure in Block-Shear Specimens by a Laser Scanning Profilometer
    Symposium Advances in Adhesives, Adhesion Science, and Testing, 2004-10-06
    Committee D14