Tensile test of membrane materials using digital image correlation method

Digital image correlation method (DICM) is employed to measure the mechanical behavior of Precontraint 1202 Fluotop T2 membrane materials under biaxial loading conditions. in this study, shape functions in global coordinates are preferred, which is validated to determine large rigid body displacements as well as small strains more accurately. Creep tests are also carried out and the corresponding creep properties are analyzed. During the tests, images of the membrane surface are captured in real-time by a CCD camera. DICM is subsequently used to calculate strains by correlating the images recorded before and after deformations. Based on the results from DICM, modulus of elasticity, Poisson's ratio and creep curves are determined. Experimental results demonstrate the accuracy of the proposed method in evaluating the tension behavior of membrane materials, and prove the proposed method as a direct inspection tool and a practical alternative to the standard electrical measurements.