充液管路和弹性板耦合的ISM-FEM混合计算方法

Hybrid ISM-FEM Computational Approach for Coupled Fluid-Filled Pipelines and Elastic Plates

摘要: 基于“十四方程”理论发展而来的阻抗综合法(ISM)具有物理清晰、求解迅速和精度高的特点，常应用于复杂充液管路系统的声振耦合求解。然而在充液管路系统与壳体耦合的实际工程应用中，难以单纯应用阻抗综合法求解。若采用有限元方法(FEM)求解，不仅需要大量计算资源，且难以厘清声振耦合传递的机制。本文以管路和弹性板的耦合系统为例，利用管路与弹性板耦合处力和位移等边界条件的连续性，给出一种阻抗综合法和有限元方法相结合的计算方法。求解了两种充液管路和弹性板耦合系统的响应，通过与FEM对比，验证本方法的正确性，并在此基础上分析了弯管以及管内流体对模型固有频率和振动响应的影响，为与壳体耦合的复杂充液管路的声振耦合传递提供一种高效且物理过程清晰的计算方法。

Abstract: Based on the “14 equations” theory, the impedance synthesis method (ISM) has the characteristics of physical clarity, quick solution and high accuracy, and is often applied to the acoustic and vibration coupling solution of complex liquid-filled pipeline systems. However, in practical, the liquid-filled pipeline is often coupled with the shell, and it is difficult to solve the problem by applying the ISM directly. If the finite element method (FEM) is used, it requires a lot of computational resources, and also makes it difficult to clarify the physical mechanism of the couplings. In this paper, taking the coupled pipeline and elastic plate as an example, utilizing the boundary conditions such as force and displacement at the couplings, a combined ISM and FEM method is proposed for the prediction of the coupled system. The method is verified by comparing with the FEM, and the influence of the elbow and the fluid in the pipe on the natural frequency and vibration response of the model is analyzed, so as to provide an efficient calculation method for the vibroacoustic transmission of the complex liquid-filled pipeline coupled with the shell structures.