  This article proposes a novel computational modeling approach for
short-ranged molecular interactions between curved slender fibers undergoing
large 3D deformations, and gives a detailed overview how it fits into the
framework of existing fiber or beam interaction models, either considering
microscale molecular or macroscale contact effects. The direct evaluation of a
molecular interaction potential between two general bodies in 3D space would
require to integrate molecule densities over two 3D volumes, leading to a
sixfold integral to be solved numerically. By exploiting the short-range nature
of the considered class of interaction potentials as well as the fundamental
kinematic assumption of undeformable fiber cross-sections, as typically applied
in mechanical beam theories, a recently derived, closed-form analytical
solution is applied for the interaction potential between a given section of
the first fiber (slave beam) and the entire second fiber (master beam). This
novel approach based on a pre-defined section-beam interaction potential (SBIP)
requires only one single integration step along the slave beam length to be
performed numerically. In terms of accuracy, the total beam-beam interaction
potential resulting from this approach is shown to exhibit an asymptotically
consistent angular and distance scaling behavior. In addition to elementary
two-fiber systems, carefully chosen to verify accuracy and asymptotic
consistence of the proposed SBIP approach, a potential practical application in
form of adhesive nanofiber-grafted surfaces is studied. Involving a large
number of helicoidal fibers undergoing large 3D deformations, arbitrary mutual
fiber orientations as well as frequent local fiber pull-off and
snap-into-contact events, this example demonstrates the robustness and
computational efficiency of the new approach.
