汽车碰撞事故中钝性主动脉损伤可能发生在心脏跳动周期的任何时刻，然而不同生理阶段的血流动力学特性对安全带约束载荷作用下主动脉力学响应的影响仍缺乏深入了解。本文基于心脏-主动脉系统有限元模型，建立了具有生理特性的流固耦合模型，并对其进行了血流动力学仿真可靠性验证。在此基础上，采用分步建模的策略构建了安全带约束载荷作用下的胸廓包覆内脏器官流固耦合模型，通过改变左心室运动位移和主动脉出口压力边界条件实现了心脏收缩期不同生理阶段（收缩初期、中期和末期）的数值模拟分析。研究结果表明，安全带约束载荷下心脏收缩中期主动脉具有较高的损伤风险。在心脏快速射血期阶段，0.12 s时刻下的主动脉弓区域的应变值峰值为0.148，较收缩初期和末期分别增加9.4%和6.1%；降主动脉出口处的血液压力在0.08 s时刻达到了峰值137.33 mmHg，较收缩初期和末期分别高出14.7%和9.6%。研究所建立的安全带约束载荷作用下胸廓包覆内脏器官的流固耦合模型能够模拟复杂载荷环境下主动脉的血流动力学响应，可为生理状态相关的主动脉损伤机制分析提供技术参考。

Blunt aortic injury in vehicle crash accident may occur at any moment of the cardiac cycle. However, the influence of hemodynamic characteristics at different physiological stages on the aortic mechanical response under seatbelt restraint loading remains insufficiently understood. This study developed a physiologically characteristics fluid-structure interaction (FSI) model based on a heart-aorta finite element system and validated its hemodynamic simulation reliability. On this basis, a stepwise modeling strategy was employed to establish a thorax-enclosed visceral organs FSI model under seatbelt restraint loading. Numerical simulation analysis of different physiological stages of the heart during systole (early, mid, and late) was achieved by changing the left ventricular motion displacement and aortic outlet pressure boundary conditions. The results indicated that during the rapid ejection phase (mid-systole), there was a higher risk of aortic injury under seatbelt restraint loading. During the rapid ejection phase, the aortic arch region exhibited a peak strain of 0.148 at 0.12 s, representing 9.4% and 6.1% increases compared to early-systole and late-systole phases, respectively. The peak blood pressure at the outlet of the descending aorta reached 137.33 mmHg at 0.08 s, which was 14.7% and 9.6% higher than that in the early and late systole, respectively. The established thorax-viscera integrated FSI model under seatbelt restraint loading demonstrated the capability to simulate hemodynamic responses of the aorta under complex loading conditions, providing a technical reference for analyzing physiological state-dependent aortic injury mechanisms.