Fracture of elastomeric materials across length-scales: experiments and nonlocal continuum modeling

In this work, we investigate the fracture behavior of elastomeric materials across a wide range of length-scales using experiments and nonlocal continuum modeling. Specifically, we conducted precisely controlled desktop-scale mode-I tension tests for notched specimens made of photo-curable elastomers with various notch lengths. We clearly observed the size-dependent fracture behavior in the material, i.e., the macroscopic rupture stretch increases significantly as the notch length (or the specimen size) decreases. We also make use of a nonlocal continuum mechanics-based phase-field approach to model the fracture process in the materials subjected to large stretch; the nonlocal gradient-damage theory was numerically implemented for use in a finite element solver for coupled, nonlinear boundary value problems for fracture in elastomers. Our numerical simulation was found to be able to capture the main features of the size-dependent fracture in the materials revealed in experiments. Furthermore, using both experiments and gradient-damage theory-based numerical simulations, we address the transition from the flaw-sensitive to the flaw-insensitive fracture behavior strongly associated with the nonlocal nature of underlying physics in the fracture processes in elastomers.