A viscoelastic nonlinear compressible material model of lung parenchyma - Experiments and numerical identification
A viscoelastic nonlinear compressible material model of lung parenchyma - Experiments and numerical identification
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DOI：
10.1016/j.jmbbm.2019.02.024
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发表时间：
2019-06-01
影响因子：
3.9
通讯作者：
Wall, Wolfgang A.
中科院分区：
文献类型：
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作者：
Birzle, Anna M.;Wall, Wolfgang A.
为了描述和预测健康和疾病状态下肺的力学行为，表征肺实质的材料特性是必不可少的。因此，我们的目标是确定的粘弹性本构行为的活肺实质，特别关注的非线性，可压缩，和频率依赖的材料特性。为了量化大鼠肺实质的粘弹性材料行为实验，我们进行了不同频率的单轴拉伸试验，包括整个范围的生理频率，结合全场位移测量（共120个测试30个样品的5只大鼠）。通过这些实验测量，我们确定了适用于大三维变形的两种粘弹性材料模型的材料参数，即，标准线性固体模型和分数粘弹性模型。我们的目标是确定一组描述整个生理频率范围的材料参数;因此，我们使用了耦合逆分析，该分析同样包含对一个样本进行的所有不同拉伸试验。该模型最适合描述粘弹性、非线性、活鼠肺实质的可压缩材料行为为应变能函数psi = 356.7Pa（I-1 - 3）+331.7Pa（I-3（-1.075）-1）+71.05 Pa（J（-2/3）I-1 - 3）（3）+5.766 Pa（I-3（1/3）-1）（6）结合分数粘弹性模型（τ = 0.06454 s，α = 0.5378，β = 1.856）。该材料模型被验证为描述肺实质的复杂的非线性和可压缩的粘弹性材料行为，并可用于整个生理频率范围的有限元模拟。基于该模型，将来可以更可靠地量化自主呼吸和人工呼吸过程中肺组织的应力和应变。
Characterizing material properties of lung parenchyma is essential in order to describe and predict the mechanical behavior of the lung in health and disease. Hence, we aim to identify the viscoelastic constitutive behavior of viable lung parenchyma with a particular focus on the nonlinear, compressible, and frequency-dependent material properties. To quantify the viscoelastic material behavior of rat lung parenchyma experimentally, we performed uniaxial tension tests with different frequencies, including the whole range of physiological frequencies, in combination with full-field displacement measurements (a total of 120 tests on 30 samples of 5 rats). By means of these experimental measurements, we identified the material parameters of two viscoelastic material models applicable to large three-dimensional deformations, i.e., the standard linear solid model and the model of fractional viscoelasticity. Our aim is to identify one set of material parameters that describes the whole range of physiological frequencies; therefore, we utilized a coupled inverse analysis, which equally incorporates all different tensile tests performed on one sample. The model most suitable for the description of the viscoelastic, nonlinear, and compressible material behavior of viable rat lung parenchyma is the strain energy function psi = 356.7 Pa(I-1 - 3) + 331.7 Pa(I-3(-1.075) - 1) + 71.05 Pa(J(-2/3) I-1 - 3)(3) + 5.766 Pa(I-3(1/3) - 1)(6) in combination with the model of fractional viscoelasticity (tau = 0.06454 s, alpha = 0.5378, and beta = 1.856). This material model was validated to describe the complex nonlinear and compressible viscoelastic material behavior of lung parenchyma and can be utilized in finite element simulations of the whole range of physiological frequencies. Based on this model, it will be possible to quantify the stresses and strains of lung tissue during spontaneous and artificial breathing more reliable in the future.