Rectification of stress by fiber networks: manifestation of non-linear screening through self-organized buckling.

Abstract

Force transmission at large length scales is crucial for such biological functions as cell motility and morphogenesis. The networks that transmit these forces are malleable, patterned by active forces generated at the microscale by biological motors. In this paper we explore a simple model of a non-linear fiber network which has only two modes of deformation, but exhibits diverse mechanical phases with distinct large-scale response, tuned by the strength of a microscopic force dipole. We demonstrate, <i>via</i> numerical simulations, that the network is remodeled by organized patterns of buckling. In addition, we use a mechanical screening theory of applied forces to extract an effective parameter that characterizes the spatial response of the stress field. This parameter shows strong variations that accompany changes in the buckling pattern. The emergent behavior at large length scales indicates that the medium screens out the details of the force dipole.