Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation
Elastic Characterization of Transversely Isotropic Soft Materials by Dynamic Shear and Asymmetric Indentation
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DOI：
10.1115/1.4006848
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发表时间：
2012-06-01
影响因子：
1.7
通讯作者：
Bayly, P. V.
中科院分区：
文献类型：
--
作者：
Namani, R.;Feng, Y.;Bayly, P. V.
软质各向异性材料的力学表征是一个根本性的挑战，因为在软物质中施加机械载荷的困难和需要联合收割机从多个测试的信息。提出了一种基于动态剪切试验（DST）和非对称压痕相结合的横观各向同性软材料线弹性特性表征方法。该程序被证明是通过表征一个几乎不可压缩的横观各向同性的软材料。通过在高场磁体（B = 11.7 T）中聚合纤维蛋白原和凝血酶溶液的混合物获得具有受控各向异性的软凝胶;所得凝胶中的原纤维主要平行于磁场排列。使对齐的纤维蛋白凝胶在两个正交方向上经受动态（20-40 Hz）剪切变形。剪切储能模量为1.08 +/-0. 42 kPa（平均值+/-标准dev.）对于平行于主纤维方向的平面中的剪切，为0.58 +/-0.21kPa;对于各向同性平面中的剪切，为0.58 +/-0.21kPa。通过大纵横比的矩形尖端使凝胶缩进，平行或垂直于横向各向同性平面的法线对齐。对齐的纤维蛋白凝胶出现刚性时，缩进与垂直于主导纤维方向的矩形尖端的长轴。采用三维非对称压痕数值模拟的方法，研究了压痕刚度方向差异与材料参数之间的关系。这种方法使一个不可压缩的，横观各向同性的，线性弹性材料的一套完整的参数的估计。[DOI电话：10.1115/1.4006848
The mechanical characterization of soft anisotropic materials is a fundamental challenge because of difficulties in applying mechanical loads to soft matter and the need to combine information from multiple tests. A method to characterize the linear elastic properties of transversely isotropic soft materials is proposed, based on the combination of dynamic shear testing (DST) and asymmetric indentation. The procedure was demonstrated by characterizing a nearly incompressible transversely isotropic soft material. A soft gel with controlled anisotropy was obtained by polymerizing a mixture of fibrinogen and thrombin solutions in a high field magnet (B = 11.7 T); fibrils in the resulting gel were predominantly aligned parallel to the magnetic field. Aligned fibrin gels were subject to dynamic (20-40 Hz) shear deformation in two orthogonal directions. The shear storage modulus was 1.08 +/- 0. 42 kPa (mean +/- std. dev.) for shear in a plane parallel to the dominant fiber direction, and 0.58 +/- 0.21 kPa for shear in the plane of isotropy. Gels were indented by a rectangular tip of a large aspect ratio, aligned either parallel or perpendicular to the normal to the plane of transverse isotropy. Aligned fibrin gels appeared stiffer when indented with the long axis of a rectangular tip perpendicular to the dominant fiber direction. Three-dimensional numerical simulations of asymmetric indentation were used to determine the relationship between direction-dependent differences in indentation stiffness and material parameters. This approach enables the estimation of a complete set of parameters for an incompressible, transversely isotropic, linear elastic material. [DOI: 10.1115/1.4006848]