NEW VIDEO-OPTICAL METHOD FOR WHOLE-FIELD STRAIN MEASUREMENTS.

Abstract:

A new method for measuring entire two-dimensional strain fields in either transparent or opaque solids is described. The method consists of applying strippable film grids to the specimen and recording their deformation during mechanical testing in 35-mm photographs. The photographs are analyzed point by point in an optical diffractometer that is interfaced to a computer with a video camera and a video digitizer. By determining the precise locations of first-order diffraction peaks for deformed grids and comparing with the results for the undeformed grid, we obtain all four components of the in-plane deformation tensor: longitudinal and transverse strains, shear strain, and rigid-body rotation. The method is illustrated with results for a center-cracked aluminum tensile panel. Full-field images were obtained on a grid of 21 by 21 points, each corresponding to a 3-mm square on the specimen. Optically determined strains agreed well with electrical strain gage results.

Año de publicación:

1986

Keywords:

Fuente:

scopus