Constitutive modeling of rate-dependent stress-strain behavior of human liver in blunt impact loading
Constitutive modeling of rate-dependent stress-strain behavior of human liver in blunt impact loading
复制标题
DOI：
10.1007/s10439-008-9555-3
复制
发表时间：
2008-11-01
影响因子：
3.8
通讯作者：
Dupaix, Rebecca B.
中科院分区：
文献类型：
--
作者：
Sparks, Jessica L.;Dupaix, Rebecca B.
了解肝脏在高应变率载荷条件下的力学变形行为有助于制定车辆安全措施，以减少钝性肝损伤的发生。本研究的目的是建立钝冲击载荷下人类肝脏应力-应变行为的本构模型。采用落塔法对12个未经防腐处理的人肝脏进行了冲击试验，获得了实验应力和应变数据。先前为非晶聚合物的有限应变行为开发的本构模型适用于模拟观察到的肝脏行为。模型的单元包括与线性弹簧平行的非线性弹簧和非线性阻尼器。该模型捕捉了冲击载荷下肝脏应力-应变行为的三个特征：(1)相对刚性的初始模量，(2)与速率相关的屈服或转向粘性“流动”行为，以及(3)大应变下的应变硬化。采用材料的六种性能来定义本构模型。本研究代表了聚合物力学概念的新应用，以理解高应变率载荷下人体肝组织的速率依赖大应变行为。该研究的应用包括产生损伤的肝脏或腹部撞击事件的有限元模拟。
An understanding of the mechanical deformation behavior of the liver under high strain rate loading conditions could aid in the development of vehicle safety measures to reduce the occurrence of blunt liver injury. The purpose of this study was to develop a constitutive model of the stress-strain behavior of the human liver in blunt impact loading. Experimental stress and strain data was obtained from impact tests of 12 unembalmed human livers using a drop tower technique. A constitutive model previously developed for finite strain behavior of amorphous polymers was adapted to model the observed liver behavior. The elements of the model include a nonlinear spring in parallel with a linear spring and nonlinear dashpot. The model captures three features of liver stress-strain behavior in impact loading: (1) relatively stiff initial modulus, (2) rate-dependent yield or rollover to viscous "flow" behavior, and (3) strain hardening at large strains. Six material properties were used to define the constitutive model. This study represents a novel application of polymer mechanics concepts to understand the rate-dependent large strain behavior of human liver tissue under high strain rate loading. Applications of this research include finite element simulations of injury-producing liver or abdominal impact events.