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In the present article, a fully three-dimensional human annulus fibrosus model is developed by considering the regional variation of the complex structural organization of collagen network at different scales to predict the regional anisotropic multiaxial damage of the intervertebral disc. The model parameters are identified using experimental data considering as elementary structural unit, the single annulus lamellae stretched till failure along the micro-sized collagen fibers. The multi-layered lamellar/inter-lamellar annulus model is constructed by considering the effective interactions between adjacent layers and the chemical-induced volumetric strain. The regional dependent model predictions are analyzed under various loading modes and compared to experimental data when available. The stretching along the circumferential and radial directions till failure serves to check the predictive capacities of the annulus model. Model results under simple shear, biaxial stretching and plane-strain compression are further presented and discussed. Finally, a full disc model is constructed using the regional annulus model and simulations are presented to assess the most likely failed areas under disc axial compression. The damage in annulus soft tissues is a complex multiscale phenomenon due to a complex structural arrangement of collagen network at different scales of hierarchical organization. A fully three-dimensional constitutive representation that considers the regional variation of the structural complexity to estimate annulus multiaxial mechanics till failure has not yet been developed. Here, a model is developed to predict deformation-induced damage and failure of annulus under multiaxial loading histories considering as time-dependent physical process both chemical-induced volumetric effects and damage accumulation. After model identification using single lamellae extracted from different disc regions, the model predictability is verified for various multiaxial elementary loading modes representative of the spine movement. The heterogeneous mechanics of a full human disc model is finally presented. [Display omitted] [ABSTRACT FROM AUTHOR]

• We develop biomimetic designs of the human annulus fibrosus. • We propose lattice structure with specially designed octagonal cells patterns. • We introduce hydrogel as matrix reinforced by polylactide fibers. • We model hydrogel time-dependent response in relation to polylactide features. • We show a perfect replication of the natural annulus unusual transversal response. Intervertebral disc hernia and dysfunctions are the most common health problems that affect humans. For this reason, the need of disc prosthetics, and especially annulus fibrosus replacements, is becoming increasingly mandatory and urgent. In the present paper, we present a novel bio-inspired hydrogel-based replacement system with rational mechanically mimetic designs of human annulus fibrosus. The new system consists of hydrogel-based lattice structure with octagonal cells separated by polylactide fibers reinforced hydrogel-based sheets. The mechanics of the new designs may be rationally controlled by tailoring microstructure, in terms of polylactide fibers orientation and hydrogel intrinsic viscosity, and mesostructure in terms of cell walls/sheets thickness. The new designs are successfully compared to the natural annulus fibrosus mechanics in terms of nonlinear stiffness and transversal behavior while considering regional dependency. The impressive biomimetic capabilities of the proposed hydrogel-based lattice structure allow foreseeing the possibility of designing personalized disc prosthetics by advanced 3D printing technologies. [Display omitted] [ABSTRACT FROM AUTHOR]