Homogenized anisotropic micromechanical modeling and cyclic mechanical response of fiber network flexible composites

Fiber networks are widely used in soft-tissue repair owing to their excellent flexibility, breathability, moisture permeability, and structural versatility. During wound healing, they integrate with native tissue to form fiber network flexible composites (FNFCs), whose anisotropic cyclic stress softening and residual deformation critically influence therapeutic outcomes. However, previous studies have primarily focused on the theoretical models of flexible composites with simple fiber architectures, which are inadequate for capturing the cyclic mechanical behavior of FNFCs with highly complex mesostructures and hyper-visco-pseudoelastic properties. To address this limitation, we develop a homogenized anisotropic micromechanical model that couples a hyper-visco-pseudoelastic constitutive law for the soft matrix with a micromechanical homogenization framework, and implement it numerically. The model accurately predicts stress softening, residual deformation, and anisotropic responses during cyclic loading–unloading, and its validity is confirmed through cyclic experiments on knitted fabric flexible composites (KFFCs). By optimizing the knitted fabric architecture, we further demonstrate that the cyclic stress–strain responses of KFFCs can be closely matched to those of carotid artery tissue in both longitudinal and circumferential directions. Moreover, the model elucidates the governing role of helical fiber geometry in the cyclic mechanical behavior of FNFCs, identifying fiber crimp as a key parameter that controls reinforcement efficiency, stress softening, and residual deformation. These findings highlight the novelty and effectiveness of the proposed model and demonstrate its potential as a design tool for tailoring the biomechanical properties of fiber networks to improve soft-tissue repair.