基于结构声强法的机匣振动能量传递特性

为了分析在转子不平衡力激励作用下机匣上纵波、剪切波、扭转波以及弯曲波所携带的瞬态与稳态振动能量的分布规律和传递特性，将结构声强法拓展成矩阵的形式应用到航空发动机领域。建立了转子不平衡力作用下的双转子-支承-机匣耦合模型，通过由有限元工具和自编译程序组建的计算系统，求解并可视化了在高低压转子不平衡力激励作用下机匣瞬态与稳态的总结构声强场以及不同类型振动波的结构声强场。此外，通过运动方程推导并分析了结构声强与结构振动特性之间的内在物理关系。结果表明，机匣上纵波振动能量穿过法兰边后沿其周向传递，而剪切波和扭转波所携带的振动能量则可以穿过法兰边沿机匣轴向传递；支板上的振动能量首先以弯曲波的形式传递到机匣上，振动能量在机匣上沿主要路径传递过程中会发生不同类型振动波相互转换的现象；结构声强通过结构的动能变化率、应变能变化率以及阻尼耗散等能量参数与结构振动特性产生内在物理联系，对结构振动的控制本质上就是对振动能量流的控制。研究结论可为航空发动机机匣以及整机减振提供一定理论指导。

Vibration energy transmission characteristics of casing based on structural intensity method

To analyze the distribution rules and transmission characteristics of instantaneous and steady vibration energy carried by longitudinal wave, shear wave, twist wave, and flexural wave on the casing subjected to the rotor unbalanced forces, the structural intensity method is extended into a matrix form and applied to the field of aero-engines. The dual rotor-support-casing coupling model subjected to the rotor unbalanced forces is established. The calculation system consisting of the finite element tool and the in-house program is used to compute and visualize the instantaneous and steady structural intensity fields of the casing for these different types of vibration waves. Moreover, the relationship between the structural intensity and the general vibration characteristics is derived and analyzed from the basic motion equation. The results show that the longitudinal wave vibration energy of the casing passes through the flange and then transmits along the circumferential direction, and the vibration energy carried by the shear wave and the twist wave can be transmitted through the flange and then transmits along the axial direction on the casing. Second, the vibration energy of the support is first transmitted to the casing in the form of the bending wave, and the vibration energy is converted into different types of vibration waves during the transmission along the main path on the casing. Third, the structural intensity generates an intrinsic physical connection between the structure vibration characteristics by the energy parameters such as the kinetic energy change rate, the strain energy change rate, and the damping dissipation. The control of the structure vibration is essentially the control of the vibrational energy flow. The conclusions can provide some guiding significance for the vibration attenuation of the casing and the whole aero-engine.