He Jiasheng, Zhong Weijian
School of mechanical and electrical engineering, Wuhan Institute of Technology, Wuhan 430200, P.R.China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2021 Dec 25;38(6):1097-1102. doi: 10.7507/1001-5515.202106077.
Atherosclerotic plaque rupture is the main cause of many cardiovascular diseases, and biomechanical factors play an important role in the process of plaque rupture. In the study of plaque biomechanics, there are relatively few studies based on fatigue fracture failure theory, and most of them mainly focus on the whole fatigue propagation process from crack initiation to plaque rupture, while there are few studies on the influence of crack on plaque rupture at a certain time in the process of fatigue propagation. In this paper, a two-dimensional plaque model with crack was established. Based on the theory of fracture mechanics and combined with the finite element numerical simulation method, the stress intensity factor (SIF) and related influencing factors at the crack tip in the plaque were studied. The SIF was used to measure the influence of crack on plaque rupture. The results show that the existence of crack can lead to local stress concentration, which increases the risk of plaque rupture. The SIF at the crack tip in the plaque was positively correlated with blood pressure, but negatively correlated with fibrous cap thickness and lipid pool stiffness. The effect of the thickness and angle of lipid pool on the SIF at the crack tip in the plaque was less than 4%, which could be ignored. This study provides a theoretical basis for the risk assessment of plaque rupture with cracks.
动脉粥样硬化斑块破裂是许多心血管疾病的主要原因，生物力学因素在斑块破裂过程中起重要作用。在斑块生物力学研究中，基于疲劳断裂失效理论的研究相对较少，且大多主要关注从裂纹萌生到斑块破裂的整个疲劳扩展过程，而对于疲劳扩展过程中某一时刻裂纹对斑块破裂的影响研究较少。本文建立了含裂纹的二维斑块模型。基于断裂力学理论并结合有限元数值模拟方法，研究了斑块中裂纹尖端的应力强度因子（SIF）及相关影响因素。用SIF来衡量裂纹对斑块破裂的影响。结果表明，裂纹的存在会导致局部应力集中，增加斑块破裂风险。斑块中裂纹尖端的SIF与血压呈正相关，但与纤维帽厚度和脂质池刚度呈负相关。脂质池厚度和角度对斑块中裂纹尖端SIF的影响小于4%，可忽略不计。本研究为含裂纹斑块破裂风险评估提供了理论依据。
