Multiscale modeling of viscoelastic behavior in demineralized human trabecular bone

Bone is a hierarchical composite of inorganic and organic phases, with the former governing stiffness and strength, and the latter controlling toughness and post-yield behavior. The mechanical properties of the organic phase, particularly in demineralized trabecular bone, remain poorly understood, limiting insights into fracture mechanisms and scaffold design. In this study, we investigate the time-dependent viscoelastic behavior of human demineralized trabecular bone using an integrated approach combining stress-relaxation testing, micro-finite element simulations, and Raman spectroscopy at macro- and microscales. Multiscale equilibrium and instantaneous moduli were quantified and correlated with trabecular microarchitecture and collagen spectral markers. Our results reveal how collagen integrity and microarchitecture jointly govern viscoelastic behavior, providing a mechanistic link between tissue composition and macroscopic mechanical performance. These findings not only advance fundamental understanding of the organic matrix mechanics in trabecular bone but also establish a predictive framework for designing biomimetic scaffolds that replicate the native biomechanical and biochemical microenvironment.