Nonlinear viscoelastic effects in oscillatory shear deformation of brain tissue
Nonlinear viscoelastic effects in oscillatory shear deformation of brain tissue
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DOI：
10.1016/s1350-4533(01)00101-1
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发表时间：
2001-11-01
影响因子：
2.2
通讯作者：
Crandall, JR
中科院分区：
文献类型：
--
作者：
Darvish, KK;Crandall, JR
采用两种非线性本构模型来描述脑组织的动态粘弹性行为。牛脑组织的小圆盘形样品进行了测试，在简单的剪切使用强迫振动（0.5至200赫兹）与有限的振幅（高达20%拉格朗日剪切应变）。样品响应简单，双，和三次谐波输入，以确定其特征的非线性高达三阶。提出了一个拟线性粘弹性模型来描述空间非线性。提出了一个具有乘积形式多重遗传积分的完全非线性粘弹性模型来描述空间和时间的非线性。完全非线性模型在高频（44 Hz以上）下表现出优越性。在有限应变下，线性复模量表现出不可恢复的渐近应变条件化行为。在先前发表的研究中观察到的不一致性和神经组织功能衰竭的阈值被证明与这种应变调节效应有关。(C)2002年妇女平等研究所。爱思唯尔科技有限公司版权所有。
Two nonlinear constitutive models were used to describe the dynamic viscoelastic behavior of brain tissue. Small disc-shaped samples of bovine brain tissue were tested in simple shear using forced vibrations (0.5 to 200 Hz) with finite amplitudes (up to 20% Lagrangian shear strain). The samples response to simple, double, and triple harmonic inputs was determined in order to characterize the nonlinearities up to the third-order. A quasilinear viscoelastic model was proposed to describe the spatial nonlinearity. A fully nonlinear viscoelastic model with product-form multiple hereditary integrals was proposed to describe the spatial as well as the temporal nonlinearities. The fully nonlinear model demonstrated superiority at high frequencies (above 44 Hz). Under finite strains, the linear complex modulus showed nonrecoverable asymptotic strain conditioning behavior. Discrepancies observed in previously published studies and the threshold of functional failure of the neural tissue were shown to be related to this strain conditioning effect. (C) 2002 IPEM. Elsevier Science Ltd. All rights reserved.