【作者】 何建涛；

【导师】 刘云贺；

【作者基本信息】 西安理工大学 ， 结构工程， 2007， 硕士

【摘要】 大型渡槽流体-固体动力耦合是一个极其复杂的多学科交叉的研究课题,涉及流体和固体两种性质不同的介质,致使其研究非常困难,至今在理论、计算方法和工程应用上,还存在缺陷和不足。另外,由于很多工程领域都涉及到流固动力耦合问题,所以有必要对这一课题进行更加深入的研究。本文探讨了计入流体的粘性、大幅(非线性)晃动影响,不可压缩粘性流体与弹性体的三维动力耦合问题,分析了流体、固体接触界面的运动状态,给出了其运动和动力边界条件,即位移一致性和作用力平衡条件。对流固耦合系统进行离散化处理,推导了其有限元控制方程,并给出了相应的时间积分方法,通过储液池的算例验证了其正确性。利用前述三维流固动力耦合模型探讨了工程界比较关心而又没有很好验证的地震作用下大型渡槽顺槽向流固动力耦合问题。结果表明,考虑顺槽向流体影响后渡槽结构地震响应有所降低,说明工程实践中不考虑其影响是安全的。另外,对实际工程中广泛采用的附加质量模型与Housner简化模型的适用性和精度进行了探讨。地震响应计算结果表明,这两种模型与本文给出的流体固体动力耦合分析方法相比结构大部分部位的结果偏于保守。通过对比附加质量模型和流固耦合分析方法的结构自振频率和振型发现,两者非常接近,说明采用附加质量模型进行渡槽结构的动力特性分析是满足工程要求的。作为工程应用,本文以南水北调中线穿黄薄腹梁渡槽结构为研究对象,采用前述流固耦合分析方法对其进行了静、动力分析,并和实际工程采用附加质量模型的计算结果进行了对比研究。结果表明,两种方法渡槽结构的位移和应力结果具有相同的变化规律,只是在具体数值上附加质量模型略大于流固耦合分析方法,但是总体上差别不大,对于实际应用来说这种差别可以忽略,所以附加质量模型用于大型渡槽的抗震设计是合理可行的,同时也说明了本文流固耦合分析方法的正确性。更多还原

【Abstract】 The fluid-structure dynamic coupling of large-scale aqueduct is a very complicated problem which is relative to a good many disciplines. Because it involves two mediums—fluid and solid which have completely different characteristic, it is very difficult to study and there are still many shortcomings in the fields of theory, computing method and application. However, it is always met in engineering. Therefore, it is necessary for us to study the problem deeply.Considering the influence of fluid’s viscosity and large amplitude slosh (nonlinear slosh), the 3-dimension coupling system composed of uncompressible viscous fluid and ideal elastic structure is studied in this paper. The moving state of the interface between the fluid and the structure is analyzed, and the boundary’s moving condition (i.e. displacement compatibility) and dynamic condition (i.e. traction equilibrium) are given. The fluid-structure coupling system is divided into elements, finite element method equations are deduced and corresponding time integration methods are given. The fluid-structure dynamic coupling analysis method is proved correct by the water tank’s example.The flow direction’s fluid-structure dynamic coupling problem of large-scale aqueduct under the effect of earthquake which is concerned but not well validated in engineering is discussed using the forenamed fluid-structure dynamic coupling model. The results show that when considering fluid’s influence in the flow direction the seismic response of aqueduct structure decreases slightly. Therefore, it is safe without considering the influence in actual engineering. In addition, the applicability and accuracy of additional mass model and Housner model which are widely used in actual engineering are studied. The seismic response results show that most parts’results of structure computed using these two models are conservative comparing with the fluid-structure dynamic coupling analysis method. By contrasting aqueduct structure’s self-vibration frequencies and mode shapes between the additional mass model and the fluid-structure dynamic coupling analysis method, it can be found that these two method’sresults are very close, so adopting the additional mass model to analyze aqueduct structure’s dynamic property can meet engineering’s requirement.As engineering application, this paper discusses the static and dynamic response of the thin shell aqueduct in the middle line of South-to-North Water Diversion Project using the fluid-structure dynamic coupling analysis method which is given in this paper and the additional mass model which is adopted in the project. By contrasting the two method’s results it can be found that there are nearly same trends in the changes of aqueduct’s displacement and stress and the additional mass model’s values are larger slightly than the fluid-structure coupling analysis method’s, but the difference is not significant which can be neglected in actual application. Therefore, it is reasonable and feasible to adopt the additional mass model in large-scale aqueduct’s seismic design. And the results also show the fluid-structure coupling analysis method’s correctness.更多还原