高速直升机采用了前行桨叶、降旋翼转速、尾推等技术来实现高速飞行，其中共轴刚性双旋翼、变转速传动系统、高功率输出尾推桨所构成的耦合系统给传统直升机扭振分析带来了新的挑战。针对高速直升机多模式复杂耦合扭振系统，提出了一种基于传递矩阵法的新建模策略。相比较于传统有限元方法建模策略，该方法无需对传动链进行当量化处理，也不需要基于哈密顿原理推导系统的整体控制方程，根据系统的拓扑结构即可直接写出系统的控制方程。此外，通过引入分叉虚铰链单元，将任意拓扑结构的传动链都解耦成多条相互独立的链式传动链，从而进一步显著降低了建模难度。最后基于该方法研究了高速直升机不同工作模式下的耦合扭振动力学。

High-speed helicopters use technologies such as advancing blade， reduced rotor rotation speed， and auxiliary propeller to achieve high-speed flight. The coupled system formed by coaxial rigid dual-rotor， variable speed drive train system， and high-power output tail propeller brings new challenges to traditional helicopter torsional vibration analysis. Firstly， a new modeling strategy based on the transfer matrix method is innovatively proposed to address the problem of complex multi-mode coupling torsional vibration system of high-speed helicopters. Compared to the modeling strategy of conventional finite element method， the present method does not require the equivalent processing of the drive train system， nor does it require the derivation of the overall governing equations based on Hamilton’s principle. System governing equations can be directly obtained according to the topology structure of the system. In addition， a virtual geared branch element is innovatively introduced to decouple the topology of the drive train system into multiple independent chain systems， further significantly reducing the difficulty of modeling. Finally， the coupled torsional vibration dynamics of high-speed helicopters under different working conditions is studied based on the proposed method.