共查询到19条相似文献,搜索用时 171 毫秒
1.
人工地震加速度时程及其可接受性判据 总被引:1,自引:1,他引:0
在结构与设备地震动力响应分析中,时程分析法的应用越来越普遍,三维地震动力响应时程分析要求以三维地震加速度时程数据或三维地震位移时程数据作为输入数据,由于缺乏设备与结构所在地的实际地震加速度时程数据,一般是从设计地震响应频谱导出人工地震加速度时程作为地震时程分析输入数据。 相似文献
2.
根据18-5临界装置某机柜抗震试验分析的要求,利用ANSYS大型通用有限元程序,建立临界装置厂房结构的有限元模型。在其地基处输入给定的位移时程,对结构进行动力分析,计算得到厂房结构中机柜位置处的位移时程、加速度时程等力学量。用该关键位置处的加速度时程计算其相应的加速度响应谱,分别给出了运行基准地震(OBE)和安全停堆地震(SSE)作用下该厂房标高3.50 m主控制室位置处阻尼比为2%、4%、5%和7%的楼层响应谱。 相似文献
3.
4.
压水堆一回路系统包含压力容器、蒸汽发生器、主泵、稳压器、主管道和波动管等重要部件,各部件在地震激励下的动态响应与整个系统的结构形式密切相关。本文从系统的角度,以非能动先进压水堆一回路为研究对象,运用ANSYS建立了其三维有限元模型,在模态分析的基础上,进行了三正交方向输入下的反应谱分析,得到了系统在地震载荷下的响应。并对反应谱输入角度和支撑刚度进行了敏感性研究,给出了这些特性参数对结构设计和分析的指导性意见。此外,通过直接积分法得到系统的地震时程响应,并与谱分析的模拟结果进行了对比,同时也为主泵等单个部件的详细地震分析提供位移、加速度输入。最后通过三维实体模型与集中质量模型抗震计算结果的比较,说明建立三维实体模型的必要性。本文为核电站一回路重要设备的结构分析提供了技术支持。 相似文献
5.
为研究地震作用下的控制棒落棒历程,基于惯性阻力计算方法、粘性阻力计算方法及碰撞接触算法,以第三代核电先进型研发项目某堆型控制棒驱动线为背景,进行了地震载荷下的落棒历程计算。在多点激励试验装置上对该堆型驱动线1∶1样机进行地震试验,采用多频波法,在驱动线与反应堆的多处关联点施加地震载荷,包括运行基准地震(OBE)试验和安全停堆地震(SSE)试验。研究结果表明,各工况下落棒时间、落棒位移、速度和加速度时程的计算曲线与试验曲线符合较好。因此,本研究建立的研究方法能够为核电厂安全分析提供必要的分析方法。 相似文献
6.
本文针对LGM冷冻水机组(DEL)抗震分析的实际问题,应用相关的程序,对由机组所处标高处加速度楼层反应谱(RRS)计算得到的人工地震加速度时程进行了相关性分析校核,并对此人工加速度时程进行了频谱及功率谱密度计算,表明此处采用的人工加速度时程的频谱及功率谱密度包括目标谱(RRS)及其功率谱密度的80%,满足有关规范的要求,可以作为DEL时程分析的输入,同时也说明本文采用的分析方法是可行的,为并今后进行类似工作提供了有益的参考。 相似文献
7.
8.
9.
拟合峰值位移与目标反应谱的人造地震动 总被引:4,自引:1,他引:3
提出了一种以绝对加速度反应谱和峰值位移为目标合成人造地震动时程的方法.该方法首先利用传统的频域内调整傅立叶幅值谱的方法生成以给定峰值加速度APG反应谱ST(ω,ζ)和强度包线为目标的初始加速度时程a(t);然后利用在时域内叠加窄带时程的方法来进一步调整a(t)以使其峰值位移DpG逼近目标峰值位移DTPG,并且提高对目标反应谱的拟合精度.算例分析结果表明,该算法所得结果具有非常高的拟合精度. 相似文献
10.
11.
An automated solution algorithm is presented for the treatment of multiple-support excitation piping problems. The method is an extension of the well-known response spectrum analysis method which is routinely used for seismic analysis of structural systems. The new algorithm was incorporated in Kraftwerk Union's proprietary computer code KWUROHR for static and dynamic analysis of piping systems.In this paper the numerical results from the use of envelope and multiple-support acceleration input spectra are presented for two typical piping systems in nuclear power plants. From the comparison of these results it becomes obvious that the multiple-support excitation method should be recommended as standard analysis procedure for systems attached to support points which are subjected to different acceleration spectra. The additional computer cost is negligible. 相似文献
12.
为准确模拟快堆堆本体中液体晃动对主容器的作用,本文建立了一种考虑流固耦合效应的快堆堆本体抗震试验模化方法,不仅保证加速度相似比严格为1,还保证了流体与结构的质量比与原堆的相同。依照上述试验模化方法,分别设计了与快堆原型比尺为1∶25(大)和1∶50(小)两个缩比试验模型。为验证上述理论方法的有效性,对这两个模型进行了地震动力学数值模拟,并比较了大模型和小模型的模拟结果。比较结果表明,大、小模型的地震动响应参数比值满足推导得到的理论准则,从而通过数值试验方法验证了上述模化方法的有效性。该模化方法可为快堆堆本体抗震试验提供理论依据。 相似文献
13.
V. N. Shah 《Nuclear Engineering and Design》1981,64(2):195-202
A modal superposition method which can perform the seismic analysis of a structure subjected to translational and rotational base excitation is presented. Discussed are two different approaches to derive the equations of motion. In the first approach, the reference axes are fixed in space. While in the second approach, they are rigidly fixed at the base of the structure. For rotational base excitation, it is shown that the application of second approach results in equation of motion with asymmetric, time-dependent coefficient matrix due to presence of the Coriolis acceleration term.Analytic integration is used to integrate the modal equations of motion derived by the first approach. Most of the mode shapes have to be included in the time history analysis.The modal superposition method is applied to the seismic analysis of a building subjected to translational and rotational excitation. The displacement results and the computer cost of this analysis are compared with those of using the direct integration method. The computer cost associated with the modal superposition method is lower than that associated with the direct integration method. 相似文献
14.
Mode truncation is often used in seismic structural analyses of the classically as well as the nonclassically damped structures. In some cases, however, it can introduce significant error in calculated response due to the, so-called, missing mass effect. This error can be minimized by employing the mode acceleration technique, originally proposed by William in 1949. Herein, this technique is applied to develop a response spectrum approach for generation of interaction-free floor response spectra for nonclassically damped structures. This approach requires that the seismic input be defined in terms of the relative acceleration and relative velocity ground response spectra. Because of the special characteristics of these inputs, this approach can calculate floor response spectra as accurately with only a first few modes as those calculated with the complete set of modes. The applicability of the approach for generation of floor spectra directly from the ground response spectra is established by a numerical simulation study. 相似文献
15.
Based on a precise probabilistic formulation, a spectrum superposition method has been proposed to obtain very accurate estimate of the seismic response of structures with significant contribution from high-frequency rigid modes. The proposed approach computes the exact statistics of the ordered-peaks of response, which is defined in terms of the first few moments of the power spectral density function (PSDF) of the response. Like many other studies, the PSDFs for various response quantities have been defined in terms of the PSDF of input ground acceleration, the modal properties of a few lowest frequency modes and the pseudostatic response of the structure to an acceleration of unit magnitude. However, the other methods express the final results directly in terms of the response spectrum amplitudes under several simplifying assumptions, which results in unacceptable error in many cases. Due to its exactness, the proposed method has been found to give consistently good agreement with the exact solution for a wide variety of input excitations and structural systems. Furthermore, the present method also has the response spectrum as its basis by defining the PSDF of input excitation which is compatible with a given design spectrum. 相似文献
16.
为实现反应堆大厂房屏蔽问题的快速计算,需要建立一种能够尽可能减少数值负注量率、保证迭代格式的线性特性、同时能够在较大的网格内取得良好精度、计算量较小的离散纵标方法(SN)空间离散格式。本研究基于单群SN固定源输运方程的空间解析解,采用解析基函数展开方法实现SN空间离散;为了提高计算效率,采用权重系数方法,避免单个网格内大量的指数运算;研究高阶源项的计算方法,提高数值计算精度;最后基于Krylov子空间方法实现自散射源项的快速迭代计算。数值结果表明该方法可在材料区域较为均匀的光厚介质中取得较大的优势,可用于反应堆大厂房屏蔽问题的快速计算。 相似文献
17.
18.
19.
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