Considerations on the Use of Digital Image Correlation in Mechanical Testing for Material Characterization

A brief retrospective of the literature shows the use of the Digital Image Correlation (DIC) method especially in tensile or bending tests. The main objective of this research is determination of the shear properties for a polylactic acid (PLA) of type Biofusion, by using the DIC method in shear tests carried out on the V‐notched specimens. The attention is focused on different ways concerning the image processing, with effects on accuracy of the shear properties. The in‐plane shear modulus is calculated by processing the data in two different ways: (1) averaging the shear strains measured at various points located in the notch plane, in the area near the midpoint between the notches; (2) using the virtual strain gauge positioned midway between the notches to measure directly the shear strain. Although the two methods led to small differences concerning the in‐plane shear modulus of elasticity, the virtual strain gauge led to a decrease in the degree of dispersion of the results for the specimens tested. Statistical processing of the results showed that stdev is reduced by approximately 16.4 %. The shear strength is also reported. The failure areas of the shear specimens are also analysed by using a digital stereomicroscope.