Deformation and Puncture of Synthetic Tissue Surrogates under Impact Loading

Penetration resistant textiles are used to protect vital organs from perforation and blunt trauma during a medium to high velocity event. Current standards measure the ability of protective to resist penetration from a standard threat propelled at impact energies up to 75 J. Fabric penetration, by the threat, represents a critical injury for the wearer. In order to better mimic real world physics, soft elastomers or foams are employed to replicate the compliance and viscoelasticity of tissue. In the case of a non-penetrating impact, little information may be gleaned about secondary injuries from blunt trauma. Better dynamic measurements on deformation and fracture properties of soft tissue surrogate materials under high energy, medium velocity indentation may lead to test methods for assessing non-critical injuries. In this work, an instrumented impactor is used to measure acceleration and force during impact of silicone and foam tissue surrogates at velocities up to 7 m/s and energies up to 90 J. High speed videography is utilized to quantify local strains, surface deflections, and initiation of fracture during impact. The effect of surrogate network structure and fracture toughness on dynamic response and the potential for assessment of soft tissue damage is presented.