MEASUREMENT OF POISSON RATIOS FOR YELLOW-POPLAR

Longitudinal/tangential, longitudinal/radial, tangential/radial, and r adial/tangential Poisson's ratios for yellow-poplar (Liriodendron tuli pifera) were determined using the white light speckle technique in exp erimental mechanics called the Digital Image Correlation Technique (DI CT). Average values were found to compare well with other literature v alues where available; however, DICT allowed for calculation of Poisso n's ratios from multiple measurements spanning the entire specimen rat her than from one or two points per specimen. It was further discovere d that for yellow-poplar, Poisson's ratio is not a constant during the loading process, but decreases with increasing load.