Deformation and fracture of echinoderm collagen networks

TL;DR

This study investigates the mechanical behavior of collagen networks from echinoderms, revealing non-linear stiffening and brittle fracture, with simulations aiding understanding and potential design of tunable bio-mimetic materials.

Contribution

It combines experimental analysis with numerical modeling to understand the deformation and fracture mechanics of echinoderm collagen networks, offering insights for bio-mimetic material design.

Findings

Collagen networks exhibit non-linear stiffening and brittle fracture.

Sample-to-sample variability in elasticity and fracture strength.

Numerical model successfully reproduces experimental macroscopic behavior.

Abstract

Collagen networks provide the main structural component of most tissues and represent an important ingredient for bio-mimetic materials for bio-medical applications. Here we study the mechanical properties of stiff collagen networks derived from three different echinoderms and show that they exhibit non-linear stiffening followed by brittle fracture. The disordered nature of the network leads to strong sample-to-sample fluctuations in elasticity and fracture strength. We perform numerical simulations of a three dimensional model for the deformation of a cross-linked elastic fibril network which is able to reproduce the macroscopic features of the experimental results and provide insights into the internal mechanics of stiff collagen networks. Our numerical model provides an avenue for the design of collagen membranes with tunable mechanical properties.