3D printing composite material flexible strain sensor based on auxetic structure and preparation method thereof

Abstract

The invention relates to a 3D printing composite material flexible strain sensor based on an auxetic structure and a preparation method thereof, the flexible strain sensor structure comprises a sensing element embedded in one side of an elastic film, and the other side of the elastic film is printed with an auxetic structure support; according to the preparation method, size parameters of each structure of the sensor are designed according to an application scene, then composite materials used by each structure are prepared respectively, the sensor structure is obtained through integrated printing forming of multi-material 3D printing equipment, and finally the flexible strain sensor is obtained through high-temperature curing. According to the invention, the tension-expansion structure support reinforced by the composite material enables the flexible strain sensor to generate a stronger expansion effect in the transverse direction when the flexible strain sensor is stretched in the longitudinal direction, thereby improving the strain sensitivity and reliability of the sensor; and multiple materials are integrally formed by using a 3D printing process, so that the manufacturing process is greatly simplified, and the manufacturing cost is reduced.

Description

technical field [0001] The invention relates to the technical field of flexible strain sensors, in particular to a 3D printed composite material flexible strain sensor based on an auxetic structure and a preparation method thereof. Background technique [0002] Flexible strain sensors have broad application prospects in wearable sensing devices, soft robots, and shape monitoring of large deformation structures. Traditional sensor materials such as metals and semiconductors are difficult to apply to the manufacture of flexible strain sensors due to their brittleness and low strain range; however, piezoresistive sensing composites based on elastic polymers can overcome the original sensor The disadvantage of the material is that in the process of tensile strain, the conductive network formed by the internal nano-fillers is broken and reorganized, and then the resistance increases macroscopically. However, composite flexible strain sensors still face two problems. [0003] On...

AI Technical Summary

Problems solved by technology

[0005] At present, there are some precedents of auxetic structure strain sensors, such as Chinese patent (CN201910746851.3, name: high sensitivity and large tensile strain sensor based on auxetic structure and its application), which relies on the auxetic structure to realize the flexible strain sensor Sensitivity is improved, but it does not realize integrated 3D printing, which leads to complicated manufacturing process

In addition, the stiffness of the auxetic structure affects the Poisson's ratio of the sensor film, which is very important for the improvement of sensitivity. There are literatures (F.Clemens, et al., 2D Printing of Piezoresistive Auxetic Silicone SensorStructures[J].IEEE Robotics and Automation Letters, vol.6, no.2, Apr.2021.) mixed silica powder into the material for printing the auxetic structure to improve the structural rigidity and greatly improve the sensitivity, but the addition of silica increased the The material is brittle, and cracks are prone to appear after repeated stretching, and the reliability is insufficient

Images