液固耦合及桩土相互作用下的LNG储罐振动特性及其抗震性能

发布时间：2018-03-28 12:36

本文选题：LNG储罐　切入点：液固耦合　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：由于全球能源问题，天然气将成为21世纪消费量增长最快的能源，而液化天然气（Liquefied Natural Gas简称LNG）为天然气的长距离输送提供了方便、可行的方法。全容式LNG储罐是目前国际上LNG接收站常用的结构形式，其作为特种结构，一旦遭到地震破坏，不仅威胁人类的生命财产安全，而且对生态环境的危害也十分巨大。因此，针对LNG储罐的动力特性及其地震作用响应分析是LNG储罐设计的一项重要内容。本文根据实际LNG储罐工程实例，利用有限元软件ANSYS建立160000m3的LNG储罐精细化模型，主要针对以下几个方面展开研究工作： 1、以ANSYS有限元软件为研究平台，建立了160000m3大型LNG储罐的精细化模型，确定了相应的单元类型、网格尺寸、边界条件及材料参数等；给出了预应力及非预应力钢筋在有限元模型中的实现方式及液-固耦合方法的建模方式。 2、为获得大型全容式LNG储罐的自振特性，利用直接耦合法对液体单元和罐体结构进行流固耦合约束，采用缩减法进行储罐振动特性分析，获得了空罐、正常工作时满液位以及满液位泄露、半液位泄露四种工况下钢制内罐与预应力混凝土外罐的振动特点和振动周期；分析了液体与罐体相互作用时，液体对罐体结构振动特性的影响及其规律，掌握了预应力、罐内气压和底板约束数量等参数对外罐结构振动特性的影响规律。 3、选取El-Centro、Taft以及人工地震动对LNG储罐结构进行地震响应分析，得到储罐结构在不同工况、地震动施加方向的结构响应，总结了储罐的响应特点、结构的受力不利部位，并确定了地震动在结构上的最不利施加方向；计算了考虑地震动作用参与的最不利荷载组合，，通过与静力荷载效应的对比，得出了地震作用对于LNG结构混凝土外罐占主导地位的结论。 4、利用Winkler地基梁假设，考虑LNG储罐结构基础的桩土相互作用，获得了结构桩土相互作用下的振动特性；采用Deepsoil场地地震反应计算软件，分析不同类型土层在峰值加速度为220gal的El-Centro和Taft地震动作用下的地震响应；利用各土层的地震反应分析结果，计算桩-土-结构在地震动作用下的响应，对比总结了不同工况、液位、场地土以及桩土相互作用等条件下LNG储罐混凝土外罐地震响应特点。
[Abstract]:As a result of global energy problems, natural gas will become the fastest growing energy source in the 21st century, while liquefied natural gas (LNG) will provide convenience for long-distance transportation of natural gas. As a special structure, as a special structure, once destroyed by earthquake, it not only threatens the safety of human life and property. Therefore, the analysis of dynamic characteristics and seismic response of LNG tanks is an important content in the design of LNG tanks. In this paper, according to the actual LNG tank engineering example, the finite-element software ANSYS is used to establish the refined model of 160000m3 LNG storage tank, and the research work is mainly carried out in the following aspects:. 1. Based on the ANSYS finite element software, the fine model of 160000m3 large LNG storage tank is established, and the corresponding element types, mesh size, boundary conditions and material parameters are determined. The realization mode of prestressed and unprestressed steel bar in finite element model and the modeling method of liquid-solid coupling method are given. 2. In order to obtain the natural vibration characteristics of large full-capacity LNG tank, the direct coupling method is used to constrain the fluid-solid coupling between the liquid unit and the tank structure, and the reduction method is used to analyze the vibration characteristics of the tank, and the empty tank is obtained. The vibration characteristics and vibration period of steel inner tank and prestressed concrete external tank under four working conditions, full liquid level, full liquid level leakage and half liquid level leakage, are analyzed, and the interaction between liquid and tank body is analyzed. The influence of liquid on the vibration characteristics of tank structure and the influence of prestressing force pressure in tank and the number of bottom plate restraint on vibration characteristics of external tank structure are grasped. 3. El-Centroy Taft and artificial ground motion are selected to analyze the seismic response of LNG storage tank structure. The structural response of the storage tank structure in different working conditions and the direction of ground motion is obtained. The characteristics of the response of the storage tank and the unfavorable position of the structure are summarized. The most unfavorable applied direction of the ground motion in the structure is determined, and the most unfavorable load combination considering the earthquake action is calculated, which is compared with the static load effect. It is concluded that seismic action dominates the concrete tank with LNG structure. 4. Using the Winkler foundation beam hypothesis and considering the pile-soil interaction of the LNG storage tank structure foundation, the vibration characteristics of the structure pile-soil interaction are obtained, and the seismic response calculation software of the Deepsoil site is used. The seismic response of different soil layers under the action of El-Centro and Taft ground motion with peak acceleration of 220gal is analyzed, the response of pile-soil-structure under ground motion is calculated by using the seismic response analysis results of each soil layer, and the different working conditions are compared and summarized. The seismic response characteristics of LNG storage tank concrete outer tank under the condition of liquid level, site soil and pile-soil interaction.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU352.11;TE972

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