Simple full-field method for the elastic characterization of orthotropic composite plates

A speckle shearing interferometer with a simple setup is designed and tested for full-field characterization of the elastic properties of isotropic and orthotropic composite plates. The technique is straightforward and provides comparable results obtained by standard methods. The proposed method has the advantages of being noncontact and full field in nature. Beam specimens cut from the plate were loaded under the standard four-point bending configuration. Gradients of bending deformation are measured by the speckle shearing interferometer directly. Curvature of each bended beam is calculated from the slope of the fitted line of the gradient data. The elastic moduli and Poisson's ratios of the plate material are determined from the curvature of the beam specimens. Comparing the present approach to other full-field techniques reported in literature that are mostly based on deformation measurement of a specimen subjected to a complicated load field, the present method is much easier to apply, and the image analysis procedure is much simpler.