A finite nonlinear hyper-viscoelastic model for soft biological tissues.

Area of Science:

• Biomechanics
• Materials Science
• Computational Modeling

Background:

• Soft tissues exhibit complex nonlinear, rate-dependent mechanical properties.
• Existing models (hyperelastic, standard linear solid, quasi-linear) inadequately capture finite strain and time-dependent behaviors.
• Thermodynamic inconsistencies exist in current convolution integral-based finite viscoelastic models.

Purpose of the Study:

• Develop a novel three-dimensional finite hyper-viscoelastic model for soft tissues.
• Ensure the model's approach is consistent with the laws of thermodynamics.
• Incorporate a nonlinear function to account for strain and strain rate-dependent viscosity variations.

Main Methods:

• Formulated a thermodynamically consistent finite hyper-viscoelastic constitutive model.
• Integrated a nonlinear viscosity function dependent on strain and strain rate.
• Validated the model by simulating experimental data from various soft tissues.

Main Results:

• The developed model accurately replicated experimental soft tissue stress-strain data.
• Simulation results showed excellent agreement with experimental findings (R² ≥ 0.99).
• The model demonstrated versatility across different soft tissue types.

Conclusions:

• The proposed finite hyper-viscoelastic model offers a thermodynamically consistent and accurate approach for soft tissue biomechanics.
• This model effectively captures the nonlinear, time-dependent, and finite strain responses of soft tissues.
• The findings pave the way for more reliable computational modeling in soft tissue engineering and analysis.