A versatile constitutive model for load-carrying soft biological tissue should incorporate salient microstructural deformation mechanisms and be able to reliably predict complex non-linear viscoelastic behavior. The advancement of treatment and rehabilitation strategies for soft tissue injuries is inextricably linked to our understanding of the underlying tissue microstructure and how this defines its macroscopic material properties. Towards this long-term objective, we present a generalized multiscale constitutive framework based on a novel description of collagen, the most mechanically significant extracellular matrix protein. The description accounts for the gradual recruitment of undulated collagen fibrils and introduces proteoglycan mediated time-dependent fibrillar sliding. Crucially, the proteoglycan deformation allows for the reduction of overstressed fibrils towards a preferential homeostatic stress. An implicit Finite Element implementation of the model uses an interpolation strategy towards collagen fiber stress determination and results in a memory-efficient representation of the model. A number of test cases, including patient-specific geometries, establish the efficiency of the description and demonstrate its ability to explain qualitative properties reported from macroscopic experimental studies of tendon and vascular tissue.

用于承载软生物组织的通用本构模型应包含显着的微观结构变形机制，并能够可靠地预测复杂的非线性粘弹性行为。软组织损伤治疗和康复策略的进步与我们对底层组织微观结构的理解以及这如何定义其宏观材料特性密不可分。为了实现这一长期目标，我们基于对胶原蛋白的新描述提出了一个广义的多尺度本构框架，胶原蛋白是机械上最重要的细胞外基质蛋白。该描述解释了起伏的胶原纤维的逐渐募集，并引入了蛋白多糖介导的时间依赖性纤维滑动。至关重要的是，蛋白多糖变形允许将过度应力的原纤维减少到优先的稳态应力。模型的隐式有限元实现使用插值策略来确定胶原纤维应力，并导致模型的记忆有效表示。许多测试案例，包括患者特定的几何形状，建立了描述的效率，并证明了它能够解释从肌腱和血管组织的宏观实验研究报告的定性特性。