Modelling of micro-particles perforations into human tissue surrogate: Numerical and analytical aspects

Investigating high-speed microparticle impact responses into soft tissue is essential to several fields like medicine and transdermal delivery of pharmaceuticals. Various simulants such as ballistic gelatin, rubber, and polymers have been developed to replace the biological body in experimental investigation, considering the practical and ethical issues. The synthetic polymer SEBS gel (styrene-ethylene-butylene-styrene) interests some scientists in recent years because it involves several benefits like environmental stability, reproducibility, mechanical consistency, transparency, and biofidelic ability to reproduce human soft tissue behavior. A few experiments have been performed on the penetration of SEBS gel. But its physical behavior under high-velocity impact, especially in micro-scale, is yet to be investigated. As the earliest meshless method, Smoothed Particles Hydrodynamics (SPH) has been identified to have a great potential in simulating extremely large deformation. This study employs a numerical model by the SPH method to investigate the response of the SEBS gel under micro-penetration, combined with an elastic-hydrodynamic constitutive law. The range of Young's modulus is firstly described for the SEBS gel under micro-impacts, which is validated against experimental data. Supplementally, the suitability of three types of analytical models depending on fitting coefficients is also discussed for micro penetrations into soft tissue. (C) 2021 Elsevier Ltd. All rights reserved.