On the applicability of digital image correlation method in extracting the higher order terms in stress field around blunt notches

•Determination of NSIFs of blunt notches by employing the experimental method of Digital Image Correlation.•Three different notch geometries including U, VO, and Keyhole are considered.•PMMA is used as test material and various notch opening angles are considered.•The over-deterministic scheme is adopted for calculating the coefficients of stress series from DIC results.•The important role of higher-order terms in the stress field of notched components is demonstrated.