软材料输流管道的大变形理论建模、动力学机理及其磁调控方法

与硬材料输流管相比，软材料输流管刚度很低，其动力学行为通常会表现出大变形、强非线性等特征。以往工作在理论建模和动力学分析方面存有明显不足。本项目围绕软材料输流管的流致振动问题，拟开展以下工作：1）从软材料非线性本构关系出发，考虑流体与管道的耦合作用力，分别基于绝对节点坐标法和精确几何描述法，发展软材料输流管大变形的动力学理论模型；2）在确定管道静平衡位置的基础上，求解系统的广义特征值问题，揭示软材料管在静平衡位置附近的振动特性和稳定性机理；3）应用现代非线性动力学分析方法，研究软材料管在失稳后的非线性动态响应规律；4）利用“磁调控”思想和动力学控制理论，提出软材料输流管稳定性和大变形振动行为的新的调控方法。本项目的理论研究成果和实验测试数据将深化人们对输流管大变形动力学行为的认识和理解，进一步完善输流管动力学与控制的理论体系，为前沿科技领域软材料输流管的分析与设计提供理论基础和技术储备。

Compared with hard pipes conveying fluid, pipes made of soft materials have relatively lower stiffness, and hence their dynamical behavior would display some unexpected characteristics including large deformation and strong nonlinearity. From previous studies, it is noted that there were considerable unresolved problems in the theoretical modelling and dynamic analysis in this dynamical system. This project focuses on the following aspects. 1) Considering the nonlinear constitutive relation of soft materials and the coupling force between the pipe and internal fluid flow, the dynamic theoretical model for large deformation of soft pipes conveying fluid is developed based on the absolute coordinate method formulation as well as the geometrically exact description. 2) On the basis of determining the static equilibrium position of the soft pipe, the generalized eigenvalue problem of the system is solved to reveal the vibration characteristics and stability mechanism of the soft pipe around the static equilibrium position. 3) The nonlinear dynamic responses of soft pipes after instability are studied by using modern nonlinear dynamic analysis methods. 4) Using the idea of ‘magnetic adjustment’ and control theoreis of dynamics, a new control method for the stability and large-amplitude behavior of the soft pipe conveying fluid is developed. The obtained theoretical results and experimental data of this project can deepen people’s understanding of the dynamical behavior of large-deformation responses of pipes conveying fluid. This study can also improve the theory of dynamics and control of pipes conveying fluid, and further provide theoretical basis and technical reserve for the analysis and design of soft pipes conveying fluid possibly used in the field of cutting-edge science and technology.