内激励动力源作用下水-管-桥流激振动力学行为及耦合机制研究

Based on the point view of the multi-field coupling and dynamic boundary theory, the basic problems in the nonlinear dynamics and the coupling mechanism of long-span suspension bridge laying large pipeline under the water hammer excitation are focused on. .For investigation of excitation load characteristics, the double phase medium equivalent viscous-elastic artificial boundary, based on the view of power source, is carried on to construct the internal incentive model of water hammer. The multi-field coupling method is adopt to reveal the dynamic transfer behavior and coupling effect of the mechanical system combined water, pipe and bridge. And then, the boundary compatibility conditions of time-varying complex space force system are investigated to establish the whole time domain model via hybrid integration method. Furthermore, based on the momentum transfer of coupling transition zone, the spatial and temporal multi-scale coupling algorithm is built for large scale structure with slender pipe. .On structure response, the proposed model is put forword to analyze the response in time- and frequency- domains of the nonlinear coupled vibration system and, ultimately, to reveal the influence of coupling effect on the mechanical behavior and the disaster mechanism of the system. .This research pays more attention on the multi-disciplinary basic problems involving the fluid mechanics, the vibration mechanics and the impact dynamics, as well as the fluid-solid coupling theory. Research results are beneficial realization of theoretical sublimation from quasi-static analysis to dynamic analysis, and are important theoretical significance for revealing the dynamic coupling mechanism and catastrophic failure modes of the coupled pipe-bridge nonlinear mechanical system.

项目从多场耦合和动力边界理论的研究观点出发，聚焦大跨度悬索桥敷设大型输流管道在水锤激励下非线性动力学行为及耦合机制的基础科学问题。在荷载层面，采用动力源观点，考虑双相介质等效粘弹性人工边界构造内激励型水锤弹性波表征模式；在多场耦合层面，探索具有时变特性的复杂空间力系作用下的边界相容条件，揭示水管桥组合机械系统的力学传递行为及其动力耦合作用，建立基于混合积分方法的多物理场耦合整体时域模型；在多尺度算法层面，基于耦合过渡区动量传递建立大尺度结构匹配细长管道的时空多尺度耦合算法；在结构响应层面，研究非线性耦合振动系统的时域频域响应，分析共振失稳模式，最终揭示水锤激励下耦合动力效应对系统力学行为影响规律。课题研究涉及流体力学、流激振动、冲击波和流固耦合等多学科的基础问题，研究成果将实现对水管桥非线性系统从静力或拟静力分析到动力耦合分析的跨越和理论提升，对揭示其动力学耦合机制和灾变模式具有重要意义。

近年来，随着对海外岛屿资源的开发利用，大型产业如石油开采、港口等逐渐向外海延伸，采用跨海大桥连接外海岛屿，并在桥梁上敷设输水管道，不仅可解决岛屿上的淡水资源短缺问题，也是最为经济有效的供水模式和普遍性的管道敷设方式。但是，随着大跨度桥梁、柔性结构技术的不断创新发展，加之海岛用水需求的增加导致供水管道直径越来越大，水-管形成的配重和输水过程形成的动力作用对于桥梁结构以及水-管-桥系统的力学行为产生了显著影响。本课题以跨海大桥搭载输流管道系统作为研究对象，针对水-管-桥组合结构在水锤弹性波激励下非线性动力学行为及耦合机制的基础科学问题展开研究。在荷载层面，采用动力源观点，考虑双相介质等效粘弹性人工边界构造内激励型水锤弹性波表征模式，揭示了在水锤这种极端瞬态水力过程的动力源表征以及在激励下弹性和粘弹性输流直管、输流弯管的横向振动、轴向振动的振动特性和模态特性；在多场耦合层面，探索具有时变特性的复杂空间力系作用下的边界相容条件，建立了水-管-桥系统整体数值模型，完成了应力分析、模态分析及管道-箱型桥系统与管道内流场的耦合振动分析；在多尺度算法层面，基于耦合过渡区动量传递建立大尺度结构匹配细长管道的时空多尺度耦合算法；在结构响应层面，研究非线性耦合振动系统的时域频域响应，分析共振失稳模式，最终揭示水锤激励下耦合动力效应对系统力学行为影响规律。同时展开物理模型试验，通过大量的试验，完成了在水锤激励下，不同工况下，水-管道-桥系统物理模型的动力响应和频域分析。课题研究涉及流体力学、流激振动、冲击波和流固耦合等多学科的基础问题，研究成果将实现对水管桥非线性系统从静力或拟静力分析到动力耦合分析的跨越和理论提升，对揭示其动力学耦合机制和灾变模式具有重要意义。