Department of Mechanics, Shanghai University, Shanghai 200444, People's Republic of China; Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai 200072, People's Republic of China.
Shanghai Institute of Applied Mathematics and Mechanics, Shanghai 200072, People's Republic of China.
J Mech Behav Biomed Mater. 2019 May;93:204-212. doi: 10.1016/j.jmbbm.2019.02.008. Epub 2019 Feb 11.
Natural biological composites such as bone, dentin, nacre and enamel exhibit anisotropic microstructures, giving rise to orientation-dependent mechanical properties. Although the mechanical properties of these materials have been studied extensively, there is limited progress on modeling the common features associated with the orientation-dependent plastic deformation of biological composites. In this study, we develop a continuum theory for elastic-viscoplastic deformations of anisotropic biological composites. The pressure-sensitive and plastically dilatant plastic flow is incorporated into the theory, and the plastic spin related to the kinematics of the underlying substructure during macroscopic plastic deformation is explicitly taken into account. A special set of constitutive equations are implemented in a finite element program. Furthermore, the material parameters have been calibrated and numerical simulations of elastic-plastic deformation in bone are performed. It is found that the theory can capture the major features of plastic deformation of biological composites. The numerical simulations are in good agreement with experiments, demonstrating that the model is capable of predicting the complex plastic deformation of bone.
天然生物复合材料，如骨骼、牙本质、珍珠层和牙釉质，具有各向异性的微观结构，从而产生与方向相关的机械性能。尽管这些材料的机械性能已经得到了广泛的研究，但在建模与生物复合材料的各向异性塑性变形相关的共同特征方面，进展有限。在这项研究中，我们开发了一种各向异性生物复合材料弹性-粘塑性变形的连续体理论。该理论中包含了压敏和塑性膨胀塑性流动，并且在宏观塑性变形过程中，明确考虑了与基础子结构运动学相关的塑性旋转。一组特殊的本构方程已经在有限元程序中实现。此外，对材料参数进行了标定，并对骨骼的弹塑性变形进行了数值模拟。结果表明，该理论能够捕捉生物复合材料塑性变形的主要特征。数值模拟与实验结果吻合较好，证明了该模型能够预测骨骼的复杂塑性变形。
