Finite-element simulation of in-plane tear propagation in the dissected aorta: Implications for the propagation mechanism
Finite-element simulation of in-plane tear propagation in the dissected aorta: Implications for the propagation mechanism
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DOI：
10.1002/cnm.3743
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发表时间：
2023-06-21
影响因子：
2.1
通讯作者：
Liu，Haofei
中科院分区：
文献类型：
--
作者：
Han，Han;Guo，Baolei;Liu，Haofei
计算机建模和数值模拟对于了解主动脉夹层的进展是必不可少的。然而，撕裂传播还没有得到正确的建模和模拟。用带双线性牵引力-分离律的内聚区方法模拟了同心分布弹性薄板间的平面内夹层传播。粘结元件的参数针对介质中三种界面损伤模式进行了校准，从而能够对平面内撕裂传播进行定量预测。采用理想的圆柱管状双层厚壁模型，分析了几何参数、载荷条件和残余应力对撕裂扩展的影响。虽然该模型能够模拟更深、更大的撕裂与较低的临界压力相关，但新的发现包括：(I)较大的轴向拉伸导致较低的临界压力；(Ii)较大的残余应力大小与较高的临界压力相关；(Iii)真腔与假腔之间的压差改变临界压力；(Iv)界面损伤在轴向以开口型为主，但在环向以剪切为主；(V)开口型损伤与较小的断裂能有关，这使得它比剪切模式和混合模式更容易扩展。(Vi)撕裂的变形形状与其几何特征和加载条件有关，通过两条途径调节临界压力：(A)变形形状与特定的损伤模式有关，影响临界压力；(B)变形形状直接通过几何约束调节临界压力。
Computer modeling and numerical simulation are essential for understanding the progression of aortic dissection. However, tear propagation has not been properly modeled and simulated. The in‐plane dissection propagation between concentrically distributed elastic lamellae is modeled using the cohesive zone method with a bilinear traction‐separation law. The parameters of cohesive elements are calibrated for the three modes of interfacial damage in the media, enabling quantitative predictions of in‐plane tear propagation. An idealized cylindrical tube‐shaped bilayer thick‐wall model of the aorta is employed to elucidate the influence of geometrical parameters, loading conditions and residual stress on the tear propagation. While the model is capable of replicating that deeper, larger tears are associated with lower critical pressure, new findings include: (i) Larger axial stretch leads to lower critical pressure; (ii) Increased magnitude of residual stress is associated with higher critical pressure; (iii) Pressure difference between true and false lumen alters the critical pressure; (iv) The interfacial damage is mostly opening mode in the axial direction, but shear‐dominated in the circumferential direction; (v) Damage due to the opening mode is associated with smaller fracture energy, which makes it easier to propagate than the shear and the mixed modes. (vi) The deformed shape of the tear, which is related to its geometrical features and loading conditions, modulates the critical pressure via two pathways: (a) deformed shapes are associated with specific modes of damage, which influences the critical pressure, and (b) deformed shapes modulate the critical pressure directly via geometrical constraints.