Gaur Piyush, Chawla Anoop, Verma Khyati, Mukherjee Sudipto, Lalvani Sanjeev, Malhotra Rajesh, Mayer Christian
Department of Mechanical Engineering, Indian Institute of Technology, New Delhi 110016, India.
All India Institute of Medical Sciences, New Delhi, India.
J Mech Behav Biomed Mater. 2016 Jul;60:603-616. doi: 10.1016/j.jmbbm.2016.02.031. Epub 2016 Mar 17.
Motor vehicle crashes (MVC׳s) commonly results in life threating thoracic and abdominal injuries. Finite element models are becoming an important tool in analyzing automotive related injuries to soft tissues. Establishment of accurate material models including tissue tolerance limits is critical for accurate injury evaluation. The diaphragm is the most important skeletal muscle for respiration having a bi-domed structure, separating the thoracic cavity from abdominal cavity. Traumatic rupture of the diaphragm is a potentially serious injury which presents in different forms depending upon the mechanisms of the causative trauma. A major step to gain insight into the mechanism of traumatic rupture of diaphragm is to understand the high rate failure properties of diaphragm tissue. Thus, the main objective of this study was to estimate the mechanical and failure properties of human diaphragm at strain rates associated with blunt thoracic and abdominal trauma. A total of 23 uniaxial tensile tests were performed at various strain rates ranging from 0.001-200s(-1) in order to characterize the mechanical and failure properties on human diaphragm tissue. Each specimen was tested to failure at one of the four strain rates (0.001s(-1), 65s(-1), and 130s(-1), 190s(-1)) to investigate the effects of strain rate dependency. High speed video and markers placed on the grippers were used to measure the gripper to gripper displacement. Engineering stresses reported in the study is calculated from the ratio of force measured and initial cross sectional area whereas engineering strain is calculated from the ratio of the elongation to the undeformed length (gauge length) of the specimen.The results of this study showed that the diaphragm tissues is rate dependent with higher strain rate tests giving higher failure stress and higher failure strains. The failure stress for all tests ranged from 1.17MPa to 4.1MPa and failure strain ranged from 12.15% to 24.62%.
机动车碰撞事故（MVC）通常会导致危及生命的胸腹部损伤。有限元模型正成为分析汽车相关软组织损伤的重要工具。建立包括组织耐受极限在内的精确材料模型对于准确的损伤评估至关重要。膈肌是呼吸最重要的骨骼肌，具有双穹顶结构，将胸腔与腹腔分隔开。膈肌创伤性破裂是一种潜在的严重损伤，根据致伤机制的不同呈现出不同形式。深入了解膈肌创伤性破裂机制的一个主要步骤是了解膈肌组织的高应变率失效特性。因此，本研究的主要目的是估计与钝性胸腹部创伤相关应变率下人体膈肌的力学和失效特性。总共在0.001 - 200s⁻¹的不同应变率下进行了23次单轴拉伸试验，以表征人体膈肌组织的力学和失效特性。每个试样在四个应变率之一（0.001s⁻¹、65s⁻¹、130s⁻¹、190s⁻¹）下测试至失效，以研究应变率依赖性的影响。使用高速摄像机和放置在夹具上的标记来测量夹具之间的位移。该研究报告的工程应力由测量力与初始横截面积的比值计算得出，而工程应变由试样伸长量与未变形长度（标距长度）的比值计算得出。本研究结果表明，膈肌组织具有应变率依赖性，较高应变率试验给出更高的失效应力和更高的失效应变。所有试验的失效应力范围为1.17MPa至4.1MPa，失效应变范围为12.15%至24.62%。
