Influencing Parameters on Tensile Modulus Characterization of Unidirectional Composite Laminates Using Digital Image Correlation Technique

Digital image correlation as a well-established strain measurement technique is commonly employed for material characterization purposes. however, several parameters should usually be decided by users to attain accurate results with minimum processing time while there are few definite recommendations for the selection of these parameters. in the present study, the optimum setting of digital image correlation parameters is examined in order to minimize the processing time and sensitivity to the selection of parameters, and practical directions are advised to improve the efficiency of the technique. the performance of a typical analysis for the derivation of strain field and measurement of tensile modulus of a unidirectional carbon/epoxy composite laminate subjected to monotonic loading is experimentally assessed. the influence of setting parameters on the accuracy of measurement and the computational time required for the process is examined. the mutual influence of these parameters is also analyzed and discussed. comparison of results shows the sensitivity of outputs to the selection of investigating parameters i.e. subset radius, subset spacing, and region of interest. the results show that an efficient gain from the maximum available region of digital images reduces the sensitivity of the analysis to these parameters. moreover, the error introduced to the results is slightly increased by the increase of subset spacing while this influence can be diminished by enlarging the subset radius.