Crack Propagation Versus Fiber Alignment in Collagen Gels: Experiments and Multiscale Simulation

Area of Science:

• Biomaterials Science
• Computational Mechanics
• Tissue Engineering

Background:

• The mechanical properties and failure behavior of collagenous tissues are significantly influenced by their fiber organization.
• Predicting tissue failure under complex in vivo loading conditions computationally remains a challenge.

Purpose of the Study:

• To apply a multiscale model of collagen gel mechanics to predict failure in double-notched gels.
• To compare the failure behavior of aligned versus isotropic collagen gels computationally and experimentally.

Main Methods:

• A multiscale computational model of collagen gel mechanics was employed.
• Double-notched gels (aligned and isotropic) were subjected to tensile testing.
• Computational predictions were compared with laboratory experimental results.

Main Results:

• Aligned gels exhibited a greater tendency to fail by connecting the two notches compared to isotropic gels.
• The transition point for failure mode shifted significantly with fiber alignment.
• Model predictions for failure type strongly correlated with experimental outcomes (Fisher's exact test, p < 0.05).

Conclusions:

• The multiscale modeling approach accurately predicts failure modes in collagenous materials.
• Fiber organization critically influences tissue failure, as demonstrated in this model system.
• This strategy holds potential for predicting the failure of native and engineered tissues under various conditions.