Gradient elasticity length scale validation using static fracture experiments of PMMA and PVC

The use of gradient elasticity has been advocated in the past decades because of its ability to predict singularity-free stresses and strains around the tips of sharp cracks. However, identification and validation of the intrinsic length scales that appear in gradient elasticity is in a less advanced state, which hampers a more widespread use of gradient elasticity. In this short note, we provide validation of the gradient elasticity length scales for two polymers, namely PMMA and PVC, using static fracture experiments from the literature. The obtained length scales are in the order of magnitude of several tens of microns.