Holographic method of photoelastic stress analysis
Abstract
Abstract TO DETERMINE THE PATTERN OF STRESS (OR STRAIN) DISTRIBUTION IN A MEMBE UNDER STRESS A TRANSPARENT MODEL OF A MEMBER IS FORMED AND A FIRST EXPOSURE HOLOGRAM OR PHOTOGRAPHIC RECORD OF THE INTERFERENCE PATTERN BETWEEN COHERENT LIGHT PASSED THROUGH THE MODEL AND LIGHT DIRECTLY FROM THE COHERENT SOURCE IS MADE. THE MODEL IS THEN STRESSED AND A SECOND EXPOSURE IS RECORDED ON THE SAME HOLOGRAM. AFTER DEVELOPING, THE HOLOGRAM IS APPROPRIATELY ILLUMINATED TO PROVIDE A VISUAL RECONSTRUCTION OF THE OBJECT WITH FRINGE LINES VISIBLE WHICH CONSTITUTE THE INTERFERENCE PATTERN BETWEEN THE LIGHT RAYS EMANATING FROM THE OBJECT DURING THE TWO EXPOSURES. THESE FRINGES MAY ALSO BE VIEWED AS THE INTEFERENCE PATTERN BETWEEN THE LIGHT WHICH RECONSTRUCTS THE IMAGES OF THE OBJECT AS SEEN DURING THE TWO EXPOSURES. THESE FRINGE PATTERNS CONTAIN INFORMATION RELATING TO BOTH THE LOCUS OF LINES WHEREIN THE DIFFERENCE BETWEEN THE PRINCIPAL STRESS IS CONTANT AND THE LOCUS OF LINES WHEREIN THE SUM OF THE PRINCIPAL STRESS IS CONSTANT.
Inventors
- 👤 Robert Powell
- 👤 Joseph Der Hovanesian
Bibliographic Details
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