Biomechanical material characterization of the equine accessory carpal bone: a constitutive modeling

Mechanical properties of hard and soft tissues are fundamental for the quantitative characterization of biological materials. In particular, the determination of biomechanical material parameters from experimental data is essential for accurate mechanical description and for the implementation of finite element method (FEM) studies. Therefore, this study focuses on the identification of fundamental material parameters of the equine accessory carpal bone (ACB, n = 8) based on uniaxial compression (force-to-failure) tests. Isotropic incompressible hyperelastic material models (Yeoh, Ogden, Demiray, and Neo-Hookean) were applied to describe the stress-strain behavior. In addition, Young’s modulus was determined from the linear region of the stress-strain curves. The coefficient of determination (R²) ranged from 0.90 to 0.99. Among the tested models, the two-parameter Ogden model provided the best fit. The mean values of the stress-like material parameter μ, the dimensionless parameter α, and Young’s modulus were 1.89 ± 0.55 MPa, 2.61 ± 0.15, and 7.38 ± 2.44 MPa, respectively. Future work will focus on extending the model to account for anisotropic behavior by incorporating the structural characteristics and loading direction of the ACB.