Influence of Two-dimensional Bending on Flexible Electronic Sensors for Bendable and Wearable Applications

The effect of bending is one of the most important parameters to look up to, for any flexible and wearable device design. Often the performance of any flexible sensor depends on the extent and type of bending. In this direction, herein, we discuss a computational study based on a finite element method of two-dimensional bending of a flexible substrate to understand the stress development on the substrate. In this study, we have considered a 2mm thick sheet of polyether ether ketone (PEEK) polymer having a dimension of ($100\times 75\times 2$) mm as substrate material. Due to the outstanding mechanical, electrical and thermal properties of PEEK polymer, it is a very good candidate for the flexible electronic substrate. The mentioned substrate has been subjected to a tensile-compressive cyclic deformation of 20 mm from its axis. It was observed that the maximum surface stress of magnitude $9.07\times 10^{7}\ \mathrm{N}/\mathrm{m}^{2}$ is developed at the center of the substrate. However, the maximum stress developed at the edge is higher than that of the surface. Further, the fatigue analysis of the substrate shows that the substrate is stable for 9000 cycles of dynamic tensile or compressive bending. The computational analysis of bending in this case will be extremely helpful for the design and fabrication of flexible electronic sensors for various wearable applications.