Coefficient of Restitution of Fiber-Reinforced Hydrogel Ball Impacts

The word hydrogel encompasses a variety of commercially relevant water-swollen, highly porous materials often utilized in pharmaceutical and food industries. In a variety of applications, hydrogels are mixed with other materials to form a composite, yet how such heterogeneous hydrogels respond to dynamic forces is not well understood. This study has sought to experimentally probe how millimetric fiber-reinforced hydrogel balls dynamically respond to impacts. High-speed imaging and dynamography were used in tandem to validate the dynamic response of sodium alginate hydrogels undergoing impact. The results demonstrate that the peak force follows Hertzian scaling with impact velocity for the parameter space tested (e.g., 0% cellulose and 10% cellulose), yet there is a divergence in the coefficient of restitution behavior between hydrogels with and without cellulose fiber reinforcement.