Stress heterogeneities in sheared type-I collagen networks revealed by Boundary Stress Microscopy.
Disordered fiber networks provide structural support to a wide range of important materials, and the combination of spatial and dynamic complexity may produce large inhomogeneities in mechanical properties, an effect that is largely unexplored experimentally. In this work, we introduce Boundary Stress Microscopy to quantify the non-uniform surface stresses in sheared collagen gels. We find local stresses exceeding average stresses by an order of magnitude, with variations over length scales much larger than the network mesh size. The strain stiffening behavior observed over a wide range of network mesh sizes can be parameterized by a single characteristic strain and associated stress, which describes both the strain stiffening regime and network yielding. The characteristic stress is approximately proportional to network density, but the peak boundary stress at both the characteristic strain and at yielding are remarkably insensitive to concentration.
Department of Physics and The Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA.
Richard C
RC
Arevalo
Department of Physics and The Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA.
Pramukta
P
Kumar
Department of Physics and The Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA.
Jeffrey S
JS
Urbach
Department of Physics and The Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, DC, USA.
Daniel L
DL
Blair
D000818:Animals; D024042:Collagen Type I / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D051381:Rats; D012212:Rheology; D013314:Stress, Mechanical
D024042:Collagen Type I; D005782:Gels