The interphase joining tendon to bone plays the crucial role of integrating soft to hard tissues, by effectively transferring stresses across two tissues displaying a mismatch in mechanical properties of nearly two orders of magnitude. The outstanding mechanical properties of this interphase are attributed to its complex hierarchical structure, especially by means of competing gradients in mineral content and collagen fibers organization at different length scales. The goal of this study is to develop a multiscale model to describe how the tendon-to-bone insertion derives its overall mechanical behavior. To this end, the effective anisotropic stiffness tensor of the interphase is predicted by modeling its elastic response at different scales, spanning from the nanostructural to the mesostructural levels, using continuum micromechanics methods. The results obtained at a lower scale serve as inputs for the modeling at a higher scale. The obtained predictions are in good agreement with stochastic finite element simulations and experimental trends reported in literature. Such model has implication for the design of bioinspired bi-materials that display the functionally graded properties of the tendon-to-bone insertion.

肌腱与骨骼的相间连接在整合软组织和硬组织方面起着至关重要的作用，通过有效地跨两个组织传递应力，显示出近两个数量级的机械性能不匹配。这种界面的出色机械性能归因于其复杂的层次结构，特别是通过不同长度尺度上矿物质含量和胶原纤维组织的竞争梯度。本研究的目标是开发一个多尺度模型来描述肌腱到骨骼插入如何获得其整体力学行为。为此，通过使用连续介质微观力学方法对从纳米结构到细观结构水平的不同尺度的弹性响应进行建模，预测了界面的有效各向异性刚度张量。在较低尺度上获得的结果可作为较高尺度建模的输入。获得的预测与文献中报道的随机有限元模拟和实验趋势非常一致。这种模型对设计仿生双材料具有重要意义，该双材料显示了肌腱到骨插入的功能分级特性。