Discontinuous Displacement/Strain Measurement Using Mesh Based Digital Image Correlation

In this paper, a method for evaluating discontinuous displacement and strain distributions using digital image correlation is proposed. A finite element mesh based digital image correlation method is utilized for measuring displacements taking into account displacement and strain discontinuities. Then, smoothed displacements are obtained and strains are computed from the measured displacements using finite element mesh again. Discontinuous strains can be obtained by the proposed method using a split finite element mesh. The effectiveness is validated by applying the proposed method to displacement and strain measurement of a triaxially woven fabric composite that has a lot of free boundaries, displacement measurement around a crack, and displacement and strain measurement around an interface in the dissimilar materials. Results show that the discontinuous displacement and strain distributions can be obtained by the proposed method. It is expected that the proposed method can be applied to experimental evaluation of various structures and members including displacement and strain discontinuities such as free boundaries, cracks and interfaces.