Evaluating Plastic Deformation and Damage as Potential Mechanisms for Tendon Inelasticity Using a Reactive Modeling...

Area of Science:

• Biomechanics
• Materials Science
• Cellular Biology

Background:

• Inelastic behaviors like softening are key in tendon degeneration and tendinopathy.
• These behaviors are often linked to plastic deformation or molecular damage, but the primary cause remains unclear.

Purpose of the Study:

• To evaluate plastic deformation and damage as mechanisms of tendon inelasticity.
• To utilize a novel reactive inelasticity model (RIE) for this evaluation.
• To compare the efficacy of RIE-based models for plastic deformation and damage in fitting experimental tendon data.

Main Methods:

• Developed two material models within the RIE framework: one for plastic deformation, one for damage.
• Fit both models to published rat tail tendon tensile test data.
• Quantified inelastic effects and compared model performance across loading, relaxation, unloading, and reloading phases.
• Validated models using independent ramp-to-failure stress-strain curve data.

Main Results:

• Both the plastic deformation and damage models successfully fit the experimental data.
• The models also accurately predicted independent validation data.
• Results did not conclusively favor plastic deformation or damage as the dominant mechanism.

Conclusions:

• The reactive inelasticity model (RIE) shows promise as a framework for studying tendon inelasticity.
• Distinguishing between plastic deformation and damage in tendons requires novel experimental approaches.
• Understanding these mechanisms is crucial for addressing tendinopathy and degeneration.