A columnar multi-layer sliding triboelectric nanogenerator for water wave energy harvesting independent of wave height and direction

The ocean,with its highly variable and complex meteorological conditions,harbors enormous renewable resources.Triboelectric nanogenerators(TENGs),which possess unique advantages,show exciting prospects in water wave energy collection.How to design and optimize TENGs to cover all characteristic water wave energies and achieve efficient energy utilization is emergent.In this paper,we carefully designed and fabricated a columnar multi-layer sliding TENG(CMLS-TENG)that can harvest water wave energy independent of wave height and direction.Drive rods with a hollow acrylic spherical shell were introduced to deliver wave energy,ensuring that the CMLS-TENG can work in all directions from 0°to 360°.Based on the sliding structure,switching the optimized CMLS-TENG is independent of wave heights.The optimized CMLS-TENG can achieve a total power density of 730 mW/m^(3) at a wave height of only 4.8 cm regardless of wave direction,which can illuminate multiple light-emitting diodes(LEDs)to provide lighting and provide power to a watch and a hygrometer for temperature and humidity monitoring.This work provides new choices and hopes for the effective collection of full-range water wave energy.

Theoretical study of the electroactive bistable actuator and regulation methods

Dielectric elastomer actuators have attracted growing interest for soft robot due to their large deformation and fast response.However,continuous high-voltage loading tends to cause the electric breakdown of the actuator due to heat accumulation,and viscoelasticity complicates precise control.The snap-through bistability of the Venus flytrap is one of the essential inspirations for bionic structure,which can be adopted to improve the shortcoming of dielectric elastomer actuators and develop a new actuation structure with low energy consumption,variable configuration,and multi-mode actuation.Hence,in this paper,the structural design principles of electroactive bistable actuators are first presented based on the total potential energy of the structure.Following that,a feasible design parameter region is provided,the influence of crucial parameters on the actuation stroke,trigger voltage,and actuation charge are discussed.Finally,according to the coupling relationship between the bending stiffness and the bistable property of the actuator,the adjusting methods of bistable actuation are explored.A qualitative experiment was performed to verify the feasibility and correctness of the bistable design methodology and the actuation regulation strategy.This study provides significant theoretical guidance and technical support for developing and applying dielectric elastomer actuators with multi-mode,high-performance,and long-life characteristics.