Abstract:A spherical crown self-powered compressive strain sensing structure is designed for the demand of flexible wearable devices for compressive strain sensing. Nylon cloth and silicone are used as positive and negative friction materials respectively. The design strategy of heterogeneous silicone materials is adopted to realize the compression variability of the friction contact area. The self-powered compressive strain sensing principle is elucidated. The multi-nozzle silicone direct writing 3D printing technology is adopted to fabricate the self-powered compressive strain sensing structure. The influence of spherical crown size and compressive strain on output electrical performance of sensing structure is investigated. The experimental results show that the output signal of the maximum compressive strain is increased by the increasing of the height of supporting spherical crown. Furthermore, the open-circuit voltage, short-circuit transferred charge, and short-circuit current are positively correlated with the compressive strain. When the compressive strain increases from 7% to 35%, the peak open-circuit voltage increases from 5.3 V to 22.2V. At the same time, the sensing structure shows good durability and stability. Finally, a self-powered sensing insole is designed using the spherical crown compressive strain sensing structure, which shows a good application effect in monitoring gait and plantar pressure distribution. This study provides a new idea and a new way for the design and manufacturing of multi-material wearable flexible self-powered compressive strain sensing structures.