Holographic interferometry -- a unique and versatile new method of nondestructive testing (HNDT) -- is now available for industrial design and quality-control purposes. Coherent laser light is used in recording and reconstructing three-dimensional images and interference fringe patterns. HNDT can quickly, accurately, and reliably detect hidden flaws in tires, rubber-to-metal bonds, metal-to-metal bonds, and other objects of interest to automotive engineers responsible for design and testing. Through mild stressing (heat, pressure, creep, vacuum, vibration, etc.) of the test object, well below its elastic limit, subsurface anomalies are manifested in the form of minute surface displacements. These displacements, as small as a few microinches, are easily apparent in holographic interferograms, clearly indicating the location, size, and shape of a variety of common anomalies.
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