兔胸主动脉在冻结状态下的断裂方式及其断裂判据的实验探讨  

Experimental Study on the Fracture Mode and Crack Criterion of Frozen Rabbit Aorta

作　　者：胥义[1] 华泽钊[1] 周国燕[1] 

机构地区：[1]上海理工大学低温医学与食品冷冻研究所,上海200093

出　　处：《中国生物医学工程学报》2007年第4期573-577,共5页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金重点项目(50436030);上海理工大学博士启动基金(X642);上海市重点学科(T0503)

摘　　要：采用动态力学分析仪(DMA)研究温度、降温速率以及低温保护剂对冻结状态下兔胸主动脉的断裂方式的影响,并探讨其在冻结状态下断裂判据的确定方法。研究结果表明:均以5℃/min降温,主动脉在20℃时的轴向拉伸断裂方式表现为典型的韧性断裂,而温度达到-50℃或-80℃时,其断裂方式表现为典型的脆性断裂,其抗断裂能力随着温度降低而快速减弱;分别采用20℃/min和5℃/min降温到-50℃时,对主动脉的断裂方式影响不大,但对其抗断裂能力稍有影响;采用10%(V/V)二甲亚砜(DMSO)作低温保护剂,其断裂方式为典型的韧性断裂,抗断裂能力显著强于未经DMSO处理的血管;血管周向的抗断裂能力明显大于轴向,这可以解释为何主动脉血管冻存过程裂纹扩展方向一般与轴向垂直的现象。With Dynamical Mechanics Analysis （DMA）, the effect of temperature, cooling rate and cryo-protective agent on the fracture modes of frozen rabbit aorta was investigated, and the determining method for crack criterion of frozen rabbit aorta was also discussed. The results showed that： with temperature decreasing, the fracture modes of frozen rabbit aorta were transformed from typical ductile fracture to typical brittle fracture, and its resist-fracture ability weakened remarkably from - 20℃ to - 80℃. The cooling rate exhibited little effects on the fracture modes when cooled to - 50 ℃, the resist-fracture ability of frozen rabbit aorta was stronger when the samples were pretreated at a higher cooling rate. Due to the hydration action of dimethyl sulphoxide （ DMSO）, the rabbit aorta permeated by 10% （V/V）. DMSO presented typical ductile fracture when cooled to -50℃, so its resist-fracture ability was enhanced obviously. The peripheral resist-fracture ability is higher than the axial one, which gave explanation of why the cracks of frozen rabbit aorta often present perpendicularly to the axial direction of rabbit aorta.

关 键 词：兔胸主动脉 冻结 韧性断裂 脆性断裂 断裂判据 

分 类 号：R318[医药卫生—生物医学工程]