大型渡槽的二维半流固耦合模型及其工程应用研究

发布时间：2018-03-12 09:14

本文选题：大型渡槽　切入点：流固耦合　出处：《华南理工大学》2014年博士论文　论文类型：学位论文

【摘要】：本文针对现有各类模型的局限性及存在的问题，提出了大型渡槽的二维半流固耦合模型。以简支U型渡槽为研究对象，采用二维半流固耦合模型进行了静力和动力数值计算分析，通过与三维模型计算结果进行对比分析，证明了该二维半流固耦合模型在渡槽的动、静力分析中均可获得较好的计算结果。通过对受到横向地震荷载的多跨联合大型渡槽进行流固耦合分析，研究了梁式渡槽槽身在横向地震荷载下的扭转效应。以支撑不等高的三跨大型梁式渡槽作为研究对象，研究了其在水平正交双向地震作用下的结构响应分析。本文进行了以下研究工作，并得到了一些有意义的结论：（1）提出大型渡槽的二维半流固耦合模型。大型渡槽的二维半流固耦合模型是在已有的大型渡槽的流固耦合建模方法的基础上，针对目前不同计算模型存在的缺陷，在流固耦合理论以及结构动力学理论的基础上，按照平面问题与空间问题相结合的方法，提出的一种更好的流固耦合模型。本模型可有效降低非线性流固耦合求解的方程自由度，使得运算效率极大地提高，适用于实际工程应用中的多跨联合渡槽大规模求解。（2）采用二维半流固耦合模型对大型渡槽进行了静力计算分析。以简支U型渡槽为研究对象，，采用二维半流固耦合模型进行了静力数值计算分析。本文提出的二维半流固耦合模型，在静力作用下，可很好地模拟三维渡槽结构的槽身以及支撑的位移以及内力，也可以很好地模拟三维渡槽结构的壳槽内内水压力，并可以很好地反映耦合作用的三维效应。因此，本文模型可以满足工程实践中渡槽静力计算的精度要求。合理地设置二维流固耦合片的数目可以达到良好的静力模拟效果。（3）采用二维半流固耦合模型对大型渡槽进行了动力计算分析。以简支U型渡槽为研究对象，在静力分析基础上，采用二维半流固耦合模型进行了动力数值计算分析。本文提出的二维半流固耦合模型，在动力作用下，可较好地模拟三维渡槽结构的槽身以及支撑的位移以及内力变化规律，也可以较好地模拟三维渡槽结构的壳槽内内水压力变化规律，并可以较好地反映耦合作用的三维效应。因此，本文模型可以满足工程实践中渡槽动力计算的精度要求；而且，本文提出的二维半流固耦合模型保持了较高的计算效率，便于工程利用。（4）对大型渡槽的槽身地震扭转效应进行了研究。针对渡槽两端支撑刚度的不同、支撑条件的差异是否会导致渡槽的槽身结构发生不利的扭转问题进行研究。在不同地震波激励作用下，支撑刚度差异对槽身跨端扭矩的影响程度不同，在工程分析中，需要考虑不同地震激励荷载的周期特性差异。在渡槽的设计中，对于简支梁式渡槽，用来设计整个槽身的控制条件一般可以采用跨中截面的内力。在地震过程中，由于跨中截面的应力最大，以跨中截面的内力作为控制条件来设计整个槽身是可以满足抗震要求的。（5）对大型渡槽槽身的水平双向地震响应进行了研究。以支撑不等高的三跨大型梁式渡槽作为研究对象，利用有限元分析软件ADINA，采用时程分析方法和流固耦合有限元计算方法，研究了其在水平正交双向地震作用下的结构响应。水平双向地震作用下，渡槽槽身的竖向位移和变形、竖向弯矩与横向地震动单独作用下的差别不大，受纵向地震动的影响较小。相比较纵向或横向地震动单独作用，在水平双向地震同时作用下，槽身截面最大主应力的增大较明显，因此，在进行槽身局部设计时，应该将水平双向地震作用纳入考虑。
[Abstract]:In this paper, aiming at the limitations of various kinds of models and existing problems, put forward the two-dimensional aqueduct of semi fluid solid coupling model. With the simple U type aqueduct as the research object, using a two-dimensional semi fluid solid coupling model of numerical calculation and analysis of static and dynamic, and the 3D model calculation results were analyzed to prove the two dimensional fluid solid coupling model in aqueduct dynamic, static analysis can get good results. Based on the lateral seismic loads by multi span large aqueduct of fluid solid coupled analysis of beam type aqueduct in the lateral torsion effect under earthquake loading. With the three span large aqueduct support unequal height as the research object, the research on the two directional horizontal earthquake under the orthogonal structure response analysis. This paper carried out the following research work, and obtained some meaningful conclusions:
(1) the large aqueduct half dimensional fluid solid coupling model. The two-dimensional aqueduct of semi fluid solid coupling model is based on solid coupling modeling method in large scale aqueduct existing flow, in order to overcome the disadvantages of different calculation models, based on fluid solid coupling theory and dynamic theory, according to the method plane and space combination, coupled with a better flow model. The proposed model can effectively reduce the nonlinear fluid solid coupling equation of degree of freedom, the operation efficiency is greatly improved, which is suitable for the actual project for solving large scale multi span combined with the aqueduct.
(2) using a two-dimensional semi fluid solid coupling model of static analysis of large aqueduct. The aqueduct simply supported U as the research object, using a two-dimensional semi fluid solid coupling model for numerical calculation and analysis of static. This paper proposed two dimensional semi fluid solid coupling model under static loads, and can well simulate the 3D aqueduct trough body and supporting the displacement and internal force, also can well simulate the internal water pressure tank shell 3D aqueduct structure, and can well reflect the three-dimensional effects of coupling. Therefore, this model can meet the requirements of aqueduct static calculation in engineering practice. The accuracy of setting reasonable number of two-dimensional solid flow the coupling piece can achieve good static simulation results.
(3) using a two-dimensional semi fluid solid coupling model is analyzed and calculated. Power of large aqueduct with simply supported U type aqueduct as the research object, based on the static analysis using a two-dimensional semi fluid solid coupling model is analyzed. The numerical model of two-dimensional semi solid coupling flow is proposed in this paper. Under the dynamic action that can simulate 3D aqueduct structure body and supporting the displacement and internal force variation, also can be used to simulate the change of water pressure of shell 3D aqueduct structure, and can better reflect the three-dimensional effects of coupling. Therefore, this model can meet the precision requirements of dynamic calculation of aqueduct engineering practice; moreover, the proposed two-dimensional semi fluid solid coupling model to maintain high computational efficiency, convenient for engineering use.
(4) the torsional effect of aqueduct earthquake on large-scale aqueduct is studied. Based on the two ends of the supporting stiffness is different, whether differences support conditions will result in the occurrence of adverse of torsion problem of aqueduct structure aqueduct. In different seismic excitations, the support stiffness difference of trough cross end torque degree in engineering analysis, the need to consider the difference characteristics of different seismic excitation loads. In aqueduct design, for simply supported beam aqueduct, used to control the condition of design of the aqueduct body can generally be used in force at the mid span section. During the earthquake, the cross section of the maximum stress. Control conditions to design the whole body can meet the seismic requirements in force at the mid span section.
(5) the level of large-scale aqueduct with bidirectional seismic response are studied. By three span large aqueduct support height as the research object, using finite element analysis software ADINA, using time history analysis method and fluid solid coupling finite element method to study the structure in the water levels orthogonal bidirectional earthquake the response of the two directional horizontal earthquake, deformation and vertical displacement of the aqueduct, the vertical bending moment and lateral vibration under the action of the individual difference, affected by the longitudinal earthquake. Compared to vertical or horizontal ground motion alone, at the level of bi-directional earthquake effect at the same time, the maximum principal body section the stress increases obviously, therefore, in the design of local body, should be the level of bidirectional earthquake into account.

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TV672.3

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