Experimental determination of Representative Volume Element (RVE) size in woven composites

In-Situ Observation of Lüders Band Formation in Hot-Rolled Steel via Digital Image Correlation

“…. The result of DIC analysis is sensitive to the DIC parameter [14], and, thus, three conditions of DIC analysis were used in the correlation operation: ① subset size, 9 pixels × 9 pixels (248 μm × 248 μm), step, 5 pixels (138 μm), ② subset size, 21 pixels × 21 pixels (579 μm × 579 μm), step, 5 pixels (138 μm), and ③ subset size, 41 pixels × 41 pixels (1.13 mm × 1.13 mm), step, 5 pixels (138 μm).…”

“…The 2D-DIC measurement was within the global elastic region in which applied stress ranged from zero to σ up.ys.ob . The result of DIC analysis is sensitive to the DIC parameter [14], and, thus, three conditions of DIC analysis were used in the correlation operation: Van Rooyen [5] believed that the local stress can be related to the local strain in terms of a basic stress-strain curve. Van Rooyen [4] suggested that the basic stress-strain curve can be obtained from the experimental stress-strain curve with Lüders deformation, as shown in Figure 3.…”

Verification of Continuum Mechanics Predictions with Experimental Mechanics

“…This must be done because while the woven composite analyzed in Refs. [21,22] had a fairly regular structure, the Al-SiC composite analyzed in this study has a highly heterogeneous structure where strain concentrations change by a great deal from one particle-matrix interface region to another.…”

“…The experimental mechanics-based approach adopted in this study for verifying the RVE concept is very general, while the technical literature usually focuses on determining the proper homogenization scheme as well as on the RVE shape and size to be used in specific homogenization-based computations on heterogeneous materials such as, for example, composite materials reinforced by fibers, random fibers, textures, or randomly distributed inclusions [15][16][17][18][19][20]. Regarding the specific application of optical methods to RVE analysis, it should be mentioned that digital image correlation was recently used for multiscale investigation on woven composites [21,22]. Following the classical approach of the literature, the length scale of the representative volume element (RVE) was estimated by comparing different window sizes where the average of the local strain pattern measured by DIC has to match macro-scale measurements.…”

“…The present study is some steps ahead of Refs. [21,22] because the concept of RVE will be framed in a very comprehensive context connecting image analysis, kinematics of deformation, the material's structure, the constitutive behavior, and failure mechanisms. This must be done because while the woven composite analyzed in Refs.…”