DYNAMIC STRAIN-MEASUREMENT BY OPTICAL SPECKLE CORRELATION METHOD USING LCTV PANELS

A new noncontacting dynamic strain measurement technique using optical speckle correlation is presented. Two LCTV panels placed symmetricall y with respect to the incident laser beam are modulated with the initi al speckle patterns and used as shadow filters. Speckle movement can b e converted into light intensity variation. A strain wave excited unde r a shock loading through impact on an aluminum cantilever was measure d. The results agreed well with the strain wave monitored by an electr ical strain gauge.