Stretch-induced shear deformation in periodic soft networks

Abstract The bio-inspired periodic network design with unit lattice constructed by wavy filamentary microstructures displays potential applications in the fields of bio-integrated devices and tissue engineering, due to its reproduction of the J-shaped mechanics curve that typically observed in biological soft materials. An obvious macroscopic shear deformation can be induced during the uniaxial tension of such kind of periodic soft network materials, which is an important issue for practical application, since that mechanical matching between the network material and target biological tissue is essential for conformal adhesion, while such unusual shear behavior is rarely observed in conventional biological materials. For quantitative evaluation, a theoretical model for nonlinear mechanics of periodic soft network materials is developed and then validated by finite element analysis (FEA) and experiments. The results present a hook-shaped characteristic curve for the shear deformation, whose mechanism is explained via the analysis of microscopic deformation of lattice structure. Based on this model, several factors are taken into account to investigate their effects on the shearing behavior, including horseshoe geometrical parameters, interconnect configuration and lattice topology. The results could provide potential guidelines for the design and optimization of such periodic soft network materials.