Whole Field 3D Internal Strain Distribution in a Composite Beam Under Three-Point Bent

Abstract

In this paper we present a new technique that can map the whole field 3D information of internal deformation of composites. The technique, called Digital Volumetric Speckle Photography (DVSP) is an extension of the 2D version developed by the senior author and his colleagues in 1993 called Digital Speckle Photography (DSP) or Computer Aided Speckle Interferometry (CASI). DVSP requires the use of an X-ray Micro CT to record a volume image of the object. Appropriate algorithm using 3D FFT is developed to process the data. As a demonstration we apply the technique to mapping the internal strain field of a composite beam under three-point bending load. Strain distribution in three transverse sections and two longitudinal sections of the beam are fully mapped. It should be noted that the technique can calculate the strain field in any section of the specimen and as many sections as needed. It is a truly whole field technique.