共查询到19条相似文献,搜索用时 156 毫秒
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为实现隔震结构在静载阶段隔震层位移较小的同时满足动载阶段良好的减震效果,设计了一种由水平隔震单元和高静低动隔震系统(斜置橡胶支座和负刚度装置构成)组成的高静低动三维隔震系统。针对核电厂结构建立了该系统的竖向动力模型,分析了参数对系统传递率的影响,结果表明随着刚度比、阻尼比和力激励幅值比的增大,弹簧压缩比减小,力传递率幅值越小,在共振区体现出更好的隔震效果。通过对高静低动隔震系统进行静力加载试验,结果表明高静低动隔震系统在动载阶段滞回曲线饱满,具有较低刚度特征。通过理论模型与试验结果的对比,表明所提出的高静低动隔震系统理论模型能较好反映该装置系统力学特性。 相似文献
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为了研究三维基底隔震技术在核电站中的应用,基于组合式碟形弹簧支座(CDSB)具有可根据其承载力和刚度需求灵活调整的优点,设计了4种不同组合形式的CDSB,分别与铅芯叠层橡胶支座串联组成4种不同竖向刚度的三维组合式隔震支座(3D-CIB),首次将其应用于反应堆厂房,隔离反应堆厂房筏基底部的水平向和竖向地震动输入,并对比研究不同竖向刚度的3D-CIB对其三维隔震效果的影响。结果表明:与非隔震结构相比,3D-CIB能够有效地减小水平向和竖向的楼层反应谱和加速度响应;3D-CIB的水平向隔震效果受竖向刚度的影响较小,3D-CIB的竖向刚度越小,其竖向隔震效果越好,但同时会相应增大反应堆厂房的水平向和竖向位移响应,其中包括摆动效应;引入摆动率的概念,定量分析了摆动效应,3D-CIB竖向刚度的降低会明显增大摆动效应,在设计中不容忽视,3D-CIB竖向刚度的设计应权衡其隔震效果与位移响应;此外,在地震过程中3D-CIB均处于受压状态,反应堆厂房不存在倾覆的风险。三维隔震效果研究为将来3D-CIB应用于工程实践提供了技术基础。 相似文献
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高温气冷堆是国际核能届公认的第4代反应堆6种堆型之一,也是我国科技重大专项支持研发的新堆型,其石墨堆芯支承结构是散体结构,在地震载荷作用下的结构动力学响应和连续体结构有较大不同,表现出强烈的非线性和离散性。在已经开展的抗震研究基础上,设计并开展了HTR-PM石墨堆芯支承结构1∶4整体模型抗震试验研究,分析了抗震试验过程中测得的动态特性数据,与模型试验结果进行了对比,得到了模型的加速度和位移变化规律:模型的加速度随着模型高度增加而增大;石墨砖的位置越高,其响应振幅越大。由结构的各种动态响应特性及其分布规律可得,高温气冷堆堆芯支承结构设计能够满足抗震设计要求。 相似文献
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HTR石墨砖单柱模型抗震试验与分析 总被引:2,自引:0,他引:2
高温气冷堆的堆芯结构材料主要为石墨砖,在地震载荷下的动力学响应比较复杂。基于山东荣成石岛湾200 MW高温气冷堆示范核电站(HTR-PM)的设计,建立石墨砖单柱模型进行不同工况的振动台试验。通过白噪声、正弦波和人工地震波进行动态特性探查试验和功能验证试验,获得结构的自振频率、阻尼、加速度和位移响应等参数。结果表明,石墨砖单柱的非线性特征明显,自由状态下结构的一阶自振频率在1~5 Hz之间。石墨砖间的相对位移小于5 mm,满足设计准则要求。 相似文献
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核燃料组件运输容器隔振系统的振动分析 总被引:1,自引:0,他引:1
进行了核燃料组件运输容器隔振系统橡胶块的特性试验,测定了橡胶块的静态和动态拉压刚摩和剪切刚度,采用自由振动方法测定了橡胶块的拉压阻尼和剪切阻尼。建立了运输容器隔振系统的数学模型.对隔振系统的幅频特性和隔振传递率进行了分析,确定了系统各运动的共振频率。对运输容器系统受来自运载工具如铁道车辆或公路车辆的纵向冲击情况下的隔振性能进行了研究,导出了运载工具冲击加速度允许值的解析式,并进行了计算和分析。 相似文献
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考虑地基岩土参数不确定性的核电厂结构随机地震反应分析 总被引:1,自引:1,他引:0
在考虑土-结构相互作用(SSI)效应的情况下,引入随机地震反应分析方法,探讨地基岩土参数的不确定性对核电厂地震响应的影响.基于ANSYS程序,采用常数阻抗法,通过设置边界弹簧和阻尼来考虑地基土的作用,并通过设置弹簧和阻尼参数的不确定性,来模拟岩土动态参数的不确定性.针对某1000MW级压水堆核电站反应堆厂房结构,进行随机地震反应的数值仿真分析,并将随机反应结果与确定论分析结果进行了对比.结果表明,随机分析方法是确定论分析方法的有益补充,二者结合能更合理地反映参数的不确定性对结构地震响应的影响. 相似文献
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An analytical model is required when the analysis method or the combined analysis and modal testing method is used as an aid to the seismic qualification (SQ) of equipment cabinets within nuclear power industry. This study proposes a simplified and computationally efficient model to represent the nonlinear dynamic behavior of the cabinet during earthquake. The presented model accounts for the softening behavior of the cabinets by incorporating the Duffing's type of restoring force. The characteristic of nonlinear restoring force for the finite element model (FEM) is based on the relationship of stress-strain of the element. Experiments have also been performed on an actual cabinet of nuclear power plant (NPP) to validate the model. The softening or reduction in dynamic stiffness of cabinets with increase in the excitation levels is observed in the experiments. It is also found that material yielding is not a significant source of the nonlinear behavior of the cabinet. The results obtained from the analysis using the proposed model are found to be in good agreement with the experimental results. The proposed model is expected to be useful for the prediction of seismic behavior of cabinets, particularly during the operation, owing to less computational effort required, accurate prediction of softening and no requirement of tests. 相似文献
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A friction limited base-isolation concept for moderate seismicity areas is presented. The idea of the concept is to combine frictional damping with base-isolation. The aim of the design effort is to develop a system whose stiffness and damping characteristics are selected to optimize the operational properties of the isolator device for the given site conditions, so that most favourable combination of acceleration and displacement responses of the system is achieved. 相似文献
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Seismic response of the liquid storage tanks isolated by lead-rubber bearings is investigated for bi-directional earthquake excitation (i.e. two horizontal components). The biaxial force-deformation behaviour of the bearings is considered as bi-linear modelled by coupled non-linear differential equations. The continuous liquid mass of the tank is modelled as lumped masses known as convective mass, impulsive mass and rigid mass. The corresponding stiffness associated with these lumped masses has been worked out depending upon the properties of the tank wall and liquid mass. Since the force-deformation behaviour of the bearings is non-linear, as a result, the seismic response is obtained by the Newmark's step-by-step method. The seismic responses of two types of the isolated tanks (i.e. slender and broad) are investigated under several recorded earthquake ground to study the effects of bi-directional interaction. Further, a parametric study is also carried out to study the effects of important system parameters on the effectiveness of seismic isolation for liquid storage tanks. The various important parameters considered are: (i) the period of isolation, (ii) the damping of isolation bearings and (iii) the yield strength level of the bearings. It has been observed that the seismic response of isolated tank is found to be insensitive to interaction effect of the bearing forces. Further, there exists an optimum value of isolation damping for which the base shear in the tank attains the minimum value. Therefore, increasing the bearing damping beyond a certain value may decrease the bearing and sloshing displacements but it may increase the base shear. 相似文献
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Milomir Stoykovich 《Nuclear Engineering and Design》1974,27(1):106-120
This paper encompasses criteria used for seismic analysis of nuclear power plant structures such as supporting structures founded on ground, as well as substructures. Nuclear power plant equipment and systems can be treated as substructures. Modeling of structures and substructures is described. Since instructure response spectra play an important role in the design and analysis of nuclear power plant equipment, systems and components, methods for development of instructure response spectra as well as variations of input parameters considered in determining these spectra are described.When the principal contribution to the equipment response is due to flexibility of the supporting substructures, an analytical approach to the problem for obtaining reduced stiffness and associated mass matrices of supporting substructures with finite element representation for use in the dynamic analysis of equipment and supporting structures is presented. When supporting structures and equipment, that have inherently different damping properties, are included as intergral parts of the dynamic models, the approximate evaluation of the modal damping based on the weighted damping according to the modal energy stored in each component is outlined. Use of time history and response spectrum analyses is presented. The effects of relative displacements due to different motion of the support points of substructures in each significant mode of the supporting structures as well as procedures of combining modal responses are detailed. 相似文献
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利用试验和修正后的集中质量有限元模型预测安装在管道中阀门在不同频率成分地震激励下的响应,研究高频地震激励对管道中质量较大核级阀门的危害性。研究结果表明:高频地震激励对核级阀门的危害在于使阀门以其自身固有振型发生共振,此时阀门顶部取代阀门与管道连接位置成为阀门中响应最大的位置,这会导致安装于阀门顶端的驱动机构遭受苛刻的地震工况。增加管道阻尼和阀门刚度能有效降低高频激励对阀门的危害,但增加阀门刚度会导致管道响应增大。利用等效静力法对阀门进行抗震鉴定时,分析结果对阀体水平部位内力估计不足,对阀体垂直部分、阀盖等阀门上部构件的内力估计结果具有较大裕度。 相似文献