Stress–strain curves of combined porcine liver tissue sample compression and elongation from (Journal of Biomechanics 47 (2014) 2430–2435): (a) Mean values of experimental data, standard deviations from mean values are indicated with horizontal bars; (b) Median values of experimental data; (c) Simulation using the 5-constant Mooney-Rivlin model with parameters calculated by inverse finite element method; and (d) Simulation using the 5-constant Mooney–Rivlin model with parameters calculated by curve fitting.
For modeling and simulating soft tissue indentation, it is important to consider both compression and elongation stress-strain data, as tissue deformation is influenced by both its compressive and tensile characteristics.
An alternative to the Mooney-Rivlin model is a combined logarithmic and polynomial model originally proposed in (Medical & Biological Engineering and Computing 42 (2004) 787-798). The combined logarithmic and polynomial model is superior to the 5-constant Mooney-Rivlin model as the constitutive model for simulation of soft tissue indentation.