Finite element simulation of swelling-induced crack healing in gels

Finite element simulations have been conducted to study the evolution of stress fields at the crack tip and the crack opening around the crack tip with time for a gel subject to mode I loading. It is found that the stress singularity at the crack tip is eliminated by the swelling of the gel when the solvent is applied at the crack tip. The swelling of the gel also heals the crack tip and the new crack tip generated by swelling does not have a stress singularity. This crack healing process is also verified by experiments and the strain field is measured by digital image correlation. This crack healing mechanism seems to provide a useful means to improve the mechanical integrity of gels and self-healing in general.