How rate-based stretchability of soft solids controls fracture morphology in dynamic conical puncture

Puncture is a primary failure mechanism occurring in soft materials and biological tissues when subjected to impact and dynamic deep indentation. While many studies on puncture mechanics focus on the energies and forces associated with fracture, most of the existing models only capture qualitatively experimental measures at low rates and lack strong predictive power for the dynamic crack growth and its material basis. In this work, we employ a novel experimental framework to investigate the relationship between the fracture morphology and rate-based ultimate properties during dynamic puncture of soft and stretchable materials using a conical tool. We discover a scaling relationship between the tangents of the half cusp angles of the undeformed crack and the puncture tool, which gives a constant ratio whose magnitude depends on the combination of the effective strain rate in the material during puncture, and the visco-hyperelastic constitutive response of the material. Our theoretical prediction for the relationship between tensile stretch at failure and strain rate shows a close agreement with the experimental results determined from dynamic conical puncture tests. These findings, combined with two further case studies, confirm the feasibility of postmortem puncture damage characterization as a new tool for extracting ultimate stretch in complex soft biomaterials and biological tissues under dynamic/impact loading.