柱网横向加密的汽机弹簧隔振基础抗震性能研究

发布时间：2018-05-17 20:59

本文选题：弹簧隔振基础 + 凝汽器　；参考：《北方工业大学》2017年硕士论文

【摘要】：随着汽轮发电机的装机容量的增大,支撑汽轮机的基础结构也变得复杂。以往的大型电厂汽机基础的柱列多为两列,但由于装机容量的进一步增大,汽轮机的设备和扰力都大幅度地增加,于是出现了局部将柱列改为四列的设计方案。由于结构形式的变化,传统的设计方法不能保证机组在地震发生时仍安全运行,需做特殊研究。本文以2×1100MW汽轮发电机弹簧隔振基础为原型,设计建造了柱网横向加密的四列柱汽机弹簧隔振基础的1:8缩尺模型,进行了以下研究工作:一、通过多点激振试验,得到了该汽机弹簧隔振基础的动力特性,包括自振频率、振型以及阻尼比。特别是得到了凝汽器的低阶典型振型,为更准确地分析凝汽器的动力响应创造了条件。通过在ABAQUS软件中建立该弹簧隔振基础的数值模型以及同等条件的非隔振模型,对比两种结构的动力特性,充分说明了弹簧隔振器对改善结构动力特性的重要作用。二、通过锤击法对结构横梁进行动刚度测试,得到各轴承座处在25Hz土5%频率范围内的动刚度曲线。三、通过7度多遇烈度、基本烈度及罕遇烈度的拟动力试验,获取结构的地震响应。其中包括:顶板的速度时程、加速度时程、恢复力时程、位移时程;柱头、凝汽器及其他关键位置的位移时程;钢筋的应变时程以及裂缝分布与开展等。结果表明:各轴承座的动刚度值均大于4×106kN/m,满足厂家要求。在7度多遇烈度、基本烈度地震作用下,顶板的位移较小,钢筋应变远小于屈服应变,层间位移角小于《建筑抗震设计规范》规定的钢筋混凝土框架结构弹性层间位移角限值,结构基本处于弹性变形的范围内。对于7度罕遇工况,结构表现出一定的弹塑性,钢筋峰值应变仍未达到屈服应变,层间位移角仍未达到弹塑性层间位移角限值。罕遇烈度地震作用下,柱网疏密变化处的3个柱子,变形远小于其他柱子,对结构是有利的。该柱网加密的基础设计符合《建筑抗震设计规范》标准,柱网横向加密,充分利用了连续梁受力特点以减少结构中的弯矩,避免了两个粗大角柱的柱网布置形式,结构受力更均匀,并且为工艺上创造了灵活的空间。
[Abstract]:As the installed capacity of turbogenerator increases, the basic structure supporting steam turbine becomes complex. In the past, the columns of the turbine foundation of large power plants were mostly two columns, but because of the further increase of the installed capacity, the equipment and disturbance force of the steam turbine were greatly increased, so the design scheme of changing the columns into four columns appeared. Because of the change of structure form, the traditional design method can not guarantee the safe operation of the unit when the earthquake occurs, so special research is needed. In this paper, based on the spring isolation foundation of 2 脳 1100MW turbogenerator, the 1:8 scale model of the four-column turbine spring isolation foundation is designed and constructed. The following research work is carried out: first, through the multi-point exciting vibration test, The dynamic characteristics of the spring isolation foundation are obtained, including the natural vibration frequency, mode shape and damping ratio. In particular, the low order typical vibration modes of the condenser are obtained, which creates conditions for more accurate analysis of the dynamic response of the condenser. By establishing the numerical model of the spring vibration isolation foundation and the non-vibration isolation model under the same conditions in ABAQUS software, the dynamic characteristics of the two structures are compared, and the important role of the spring vibration isolator in improving the dynamic characteristics of the structure is fully illustrated. Secondly, the dynamic stiffness curves of the bearing blocks in the 5% frequency range of 25Hz soil are obtained by measuring the dynamic stiffness of the structural beams by hammering method. Thirdly, the seismic response of the structure is obtained by quasi dynamic test of 7 degree frequently-encountered intensity, basic intensity and rare intensity. These include: velocity time history, acceleration time history, recovery force time history, displacement time history of roof, displacement time history of cylinder, condenser and other key positions, strain history of steel bar, distribution and development of cracks, etc. The results show that the dynamic stiffness of each bearing seat is more than 4 脳 10 6 KN / m, which meets the requirements of the manufacturer. The displacement of roof is smaller, the strain of reinforcing bar is much less than yield strain, and the displacement angle of story is less than the limit of elastic displacement angle of reinforced concrete frame structure stipulated in the Code for Seismic Design of buildings under the earthquake intensity of 7 degrees and basic intensity. The structure is basically in the range of elastic deformation. For 7 degree rare cases, the structure shows a certain elastoplasticity, the peak strain of steel bar is still not up to yield strain, and the interstory displacement angle is still not up to the limit value of elastic-plastic interlayer displacement angle. Under the action of rare earthquake intensity, the deformation of the three columns in the dense change of the column network is much smaller than that of the other columns, which is beneficial to the structure. The foundation design of the column net is in accordance with the Standard of Building aseismic Design Code, and the column network is transversely encrypted, which makes full use of the stress characteristics of continuous beam to reduce the bending moment in the structure, and avoids the layout of the column net of two coarse corner columns. The structure forces more evenly, and creates the flexible space for the craft.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM62;TM311

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