Semiflexible Filamentous Composites

TL;DR

This study models biopolymer networks with interconnected floppy and stiff filaments, revealing how the mechanical response depends on the fraction and connectivity of stiff components in three-dimensional simulations.

Contribution

It introduces a detailed 3D simulation framework to analyze stress distribution in composite filamentous networks with varying stiff and floppy filament ratios.

Findings

Non-percolated stiff inclusions are protected by floppy matrix at low fractions.

Percolated stiff networks dominate mechanical behavior at higher fractions.

Stress partitioning depends on the connectivity and fraction of stiff filaments.

Abstract

Inspired by the ubiquity of composite filamentous networks in nature we investigate models of biopolymer networks that consist of interconnected floppy and stiff filaments. Numerical simulations carried out in three dimensions allow us to explore the microscopic partitioning of stresses and strains between the stiff and floppy fractions c_s and c_f, and reveal a non-trivial relationship between the mechanical behavior and the relative fraction of stiff polymer: when there are few stiff polymers, non-percolated stiff ``inclusions`` are protected from large deformations by an encompassing floppy matrix, while at higher fractions of stiff material the stiff network is independently percolated and dominates the mechanical response.