ABSTRACT
Data driven hyperelasticity is a promising approach for the constitutive modeling of rubberlike materials. It enables direct use of experimental data for the construction of the stress-strain response without need of a specific analytical expression for the strain energy density function. In this study, we propose distinct kinematic approaches to hyperelastic response of rubberlike materials, e.g. invariant, principal stretch based formulations, respectively (Dal, Açkgöz, & Badienia 2021). The partial derivatives of the strain energy density functions are replaced with appropriate B-spline interpolations with a set of control points are implemented for various multiaxial loading scenarios such as uniaxial tension, pure shear, and (equi)biaxial tension deformations. In addition, the convexity requirement is enforced into the spline interpolation in order to ensure a convex and stable constitutive response. The data sets of Treloar and Kawabata are used in order to demonstrate the performance of the the proposed data driven approach.
