Modelling and characterisation of the dynamic behaviours of silicone-based composite skin simulant with short polyethylene fibres and bioactive glass particles

Abstract

The field of medical injury prediction and impact biomechanics in relation to skin and its simulant materials has traditionally focused on quasi-static properties while overlooking the time-dependent behaviour strain rate sensitivity due to the challenges associated with dynamic events. In the present study, silicone-based composites reinforced with short polyethylene fibres and bioglass particles, previously identified as promising bio-integrative skin simulants, were characterised under the intermediate and high strain rates for short durations and viscoelastic behaviours for extended durations. The integration of reinforcements led to an enhancement in the compressive modulus, which elevated as the strain rate increased. Specifically, the composite with 3% reinforcement subjected to high strain rate loading exhibited a compressive modulus up to 9 times greater than that of the same material under quasi-static loading. It was found that the composites with 3% reinforcement exhibited similar dynamic behaviours to those measured in human and animal skins. Furthermore, the finite element modelling of a representative volume element of the developed composite was conducted to explore the necessity of incorporating blood vessels and pressure in numerical modelling. The results indicated that the influence of blood vessels on the viscoelastic responses of the skin simulant was more significant at high oscillated frequencies. However, the impact of blood vessels was relatively small, as evidenced by less than a 15% difference in response between models with and without blood channels under both quasi-static and harmonic loadings. Systematically characterised for the first time in both experiment and modelling, these composite skin simulants successfully emulated the dynamic properties of the human skin, offering a wide range of potential applications.