Enhancement of the measurement stability of conductive ink based sensor by topology optimization

As the conductive ink becoming mature in preparation and use, this smart material is gradually used in various industrial activities. Conductive ink can automatically change its resistance depending on the contact area, which can convert different mechanical signals into electrical signals for output. Nevertheless, the properties are affected by the substrate material on which the conductive ink is printed. A soft substrate will increase the non-linearity and result in a considerable error and unacceptable for the sensor. This paper presents an approach based on the topology optimization, the Solid Isotropic Material with Penalization (SIMP) method. To optimize the structure of the substrate, the compliance is minimized with certain constraints. The optimized structure is simulated by Comsol Multiphysics (version 5.5), and the mechanical property is tested. The measured results are fitted to obtain the relationship between stress and contact area. As a result of topology optimization, the substrate membrane's mechanical property in the piezoresistive sensor is improved, and the requirement of increasing the stability of detection is met. Meanwhile, the ability to respond to rapid loading does not lose. The results show that the method is beneficial to improve the mechanical property of the substrate. The topology optimization on the substrate has application value in piezoresistive sensors.