Improved strain transfer model for flexible sensors based on non-uniform distribution of shear stress in each layer

Abstract

The assumption of linear stress distribution for flexible sensors results in inaccurate strain transfer assessment because of low elastic moduli and thick layers, and the coating further constrains the deformation of the sensitive layer. A novel strain transfer model based on non-uniform distribution of shear stress is proposed to accurately characterize the strain of sensitive layer. The quadratic shear stress distribution is derived to calculate the strain transfer coefficient of each layer, replacing the linear attenuation of the shear stress. The average relative displacement of the sensitive layer was obtained through Hooke's law, thereby introducing the shear stress at the contact interface between the coating and the sensitive layer. Numerical simulations and experiments demonstrate that the substrate of the sensors is the primary factor causing strain transfer loss and the proposed model can accurately reflect the strain of the sensitive layer.