Deformation Characterization of Multi-Morphology Composite Cellular Hyperelastic Structure under Biaxial Tension: Analytic Approaches for Sensor Applications

As a preliminary study to develop an effective stretchable sensor, we implemented multi-morphology cellular structures in the gauge area of a biaxial tensile specimen to obtain the desired biaxial mechanical behaviour. A numerical parametric study was conducted by considering the unit cell geometries, four biaxial tension conditions, and three groups of unit cells. The parametric study reveals that a multi-morphology composite cellular (M 2 C 2 ) specimen with compliant unit cells near the centre and stiff unit cells along the border of the gauge area shows high linearity between the force and displacement relationships and high compliance. M 2 C 2 specimens optimised using the Bayesian optimisation process share similar geometric patterns found in the parametric study and show enhancements in linearity and compliance up to 40.4 % and 65.6 %, respectively, compared with those of a conventional solid specimen.