Dual magnification digital image correlation based strain measurement in CFRP Laminates with open hole

CFRP laminates have received growing attention in engineering practice. In this paper, a dual magnification digital image correlation method is applied to measure the strain fields in a CFRP laminates plate containing a circular hole under tensile loading. Two lenses with different magnifications are used in the experiment. Digital images (5 μm/pixel and 1.3 μm/pixel) obtained thereafter are adopted to measure the strain distributions of the specimen. 5 μm/pixel images are firstly used to measure global deformations and determine strain-concentrated regions. Then, 1.3 μm/pixel images are used to measure the strain distributions in those strain-concentrated regions. The measured strain fields show a good agreement with results from a three-dimension elastic–plastic FEM simulation.