Polyurethanes are applied as artificial skin materials for medical simulators. There is a difference between human skin and artificial skin for simulators with respect to “puncture resistance.” Based on comments from medical doctors who perform puncture procedures in clinical sites, puncturing human skin is expressed as “low needle resistance,” whereas the artificial skin for simulators is expressed as “high needle resistance.” It is possible to practice medical procedures with a more realistic sensation if the artificial skin’s puncture resistance is brought closer to that of the human skin. In this study, sensory evaluations via needle suturing and quantitative evaluation via measuring devices were performed to clarify the relationship between the puncture resistance force and physical properties of three artificial skin samples for a suture training model made of polyurethanes. The composition and molecular structures of the materials were confirmed using Fourier transform infrared spectroscopy and nuclear magnetic resonance. The puncture resistance force measurements showed that Regina’s artificial skin: MODEL A was the lowest in three samples. Additionally, we discovered that low Young’s modulus and the amount of plasticizer contributed to the decreasing puncture resistance of MODEL A. This study proposes methods to combine sensory evaluation by humans and experimental data of the materials for the suture training model.

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This study aims to improve the penetration of fluid resin from top to bottom of a sandwich composite with common single double-sided square deep-groove foam core and multi-axial fibre-stitched fabric-skin layer in vacuum-assisted resin infusion moulding (VARIM). Through common cutting and drilling, six kinds of composite slot hole structures were designed based on their vertical and horizontal deep grooves, surface grid shallow grooves, and vertical cylindrical deep holes as unit structures. Optimisation and comparative analysis of the composite slot structures were then conducted based on the amount of fluid resin that penetrated the slot structure, total area of the seepage hole section, and time required for the fluid resin pass through the orifice, among others. The composite slot hole structure (No. III) was determined as the optimised slotted hole structure based on the comparative analysis of the penetration of fluid resin from top to bottom in the VARIM manufacture process and reinforcement effect of the resin structure on the sandwich composites, where the points for comparison were the optimised design composite slot hole (No. III) and common single double-sided square deep-slot (No. i) resin/foam cores. For the sandwich composite with the composite slot (No. III), the total area of the seepage hole section from top to bottom of the composite was larger by approximately 10 dm², the flow velocity of fluid resin in the pore quadrupled, the time for the fluid resin to pass through the orifice was significantly shorter, and the flat compression and shear strength of the composite improved by 47% and 85%, respectively.

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