猪肝动态力学性能及本构模型研究

发布时间：2018-05-10 19:58

  本文选题：肝脏 + 动态力学性能　； 参考：《力学学报》2017年06期

【摘要】：在交通事故中,腹部器官常因冲击载荷作用而受到伤害,严重时甚至危及生命.肝损伤是腹部损伤中最为常见的一种,致死率很高,了解肝脏的动态力学性能对于事故中肝脏的损伤评估及防护设计有着重要的意义.从新鲜的猪肝组织中取肝实质部分制作试样,利用英斯特朗材料试验机对其进行两种加载率(0.004 s~(-1),0.04 s~(-1))和两种加载方向(垂直肝脏表面和平行于肝脏表面)的准静态压缩试验,并压缩至破坏.利用改进的分离式霍普金森压杆(split Hopkinson pressure bar,SHPB)实验装置沿平行于肝脏表面方向进行三种高应变率(1 300 s~(-1),2 400 s~(-1),4 500 s~(-1))的动态压缩试验.结果表明:所有应变率下的猪肝压缩应力应变曲线都呈非线性凹向上特征,初始阶段应力值很低,应变约30%后应力幅值显著增大;准静态压缩时,两种应变率(0.004 s~(-1),0.04 s~(-1))和两种加载方向下肝脏组织破坏应力和破坏应变等力学性能无显著不同,平均破坏应变为48%,平均破坏应力为0.45 MPa.高应变率下肝脏组织的流动应力明显高于准静态下的流动应力,表现出一定的率敏感性.采用Yeoh型超弹性本构模型描述猪肝组织准静态力学性能,基于黏超弹性模型理论,提出了一个能描述肝脏组织从低应变率到高应变率范围力学性能的率相关本构模型,该模型与实验结果有很好的一致性.
[Abstract]:In traffic accidents, abdominal organs are often injured by impact load, and even life-threatening. Liver injury is one of the most common abdominal injuries with high mortality. Understanding the dynamic mechanical properties of the liver is of great significance to the assessment and protection design of liver injury in accidents. Samples of liver parenchyma were taken from fresh porcine liver tissue, and quasi static compression tests were carried out in two loading directions (vertical liver surface and parallel to liver surface) with two loading rates (0.004 s-1) and two directions (vertical liver surface and parallel to liver surface). And compress to destroy. The dynamic compression tests of three kinds of high strain rate (1 300 sm ~ (-1) ~ (-1) C ~ (2 400) sm ~ (- 1) ~ (4 500) sm ~ (-1) have been carried out by using an improved split Hopkinson pressure barb experimental apparatus along the direction parallel to the surface of the liver. The results show that the stress-strain curves of porcine liver at all strain rates show a nonlinear concave upward feature, the initial stress values are very low, the stress amplitude increases significantly after about 30% strain, and the stress amplitude increases significantly under quasi-static compression. There was no significant difference between the two strain rates (0.004 s-1) and two directions of loading, such as failure stress and strain of liver tissue. The average failure strain was 48% and the average failure stress was 0.45 MPA. The flow stress of liver tissue at high strain rate was significantly higher than that at quasi static state, showing a certain rate sensitivity. Yeoh hyperelastic constitutive model was used to describe the quasi-static mechanical properties of porcine liver tissue. Based on the viscohyperelastic model theory, a rate-dependent constitutive model was proposed to describe the mechanical properties of liver tissue from low strain rate to high strain rate. The model is in good agreement with the experimental results.
【作者单位】： 合肥工业大学土木与水利工程学院;中国科学技术大学中国科学院材料力学行为和设计重点实验室;
【基金】：国家自然科学基金(11102206) 合肥工业大学博士专项科研基金(J2014HGBZ0178)资助项目
【分类号】：U467.14;U491.3
，

本文编号：1870659