预应力对核安全壳结构模态特性及抗震性能的影响

Analysis of Influence of Prestressing on Modal Characteristics and Seismic Performance of Nuclear Containment Structure

目的研究预应力对核安全壳结构的模态频率、振型周期以及内力、位移分布情况的影响,确定最不利内力、位移分布模式,验证核安全壳结构的抗震稳定性.方法基于有限元分析软件ANSYS进行了核安全壳在自重、自重与预应力共同作用两种工况下的模态特性和抗震性能分析.结果预应力对核安全壳结构的第一、二阶模态频率和振型周期的影响较大,频率影响值为3.35 Hz时,振型周期减小0.1 s.基底输入南京地震波激励时,自重与预应力共同作用下结构最大主应力为343.529 k Pa,发生在筒壁与底板交接处,预应力承担结构最大主应力值的31.21%.基底最大剪力为21786 k N,预应力承担最大剪力的31.63%;结构顶点最大侧移减少1.43 mm.结论研究结果与核安全壳的预应力系统设计理念一致,能为核安全壳的极限承载力分析、概念设计和安全评估等提供参考.

The purpose of this study is to explore the influence of prestressing on distribution of modal frequency,internal force and displacement of nuclear containment structure,in order to obtain the most dangerous internal force and displacement distribution patterns,and verify seismic stability of nuclear containment. Modal characteristics and seismic performance of nuclear contain-ment are analyzed using the finite element softw are ANSYS in two different working conditions of nuclear containment under self weight and under the combination of self weight and prestressing.The research result show s that prestressing has a great contribution to the first two mode frequencies and vibration mode,while the frequency value is 346 Hz,the reduced value of corresponding vibration mode cycle is 0. 1 s under two different working conditions. Nanjing earthquake wave is inputted at the base of nuclear containment,the maximum principal stress value is 343. 529 k Pa at the junction of the cylinder and the bottom plate,and the prestressing takes 31. 21%. The maximum shear force value of the base is 21 786 k N,and the prestressing takes 31. 63%. The decreasing maximum lateral value is 1. 433 mm. The study results have value for the analysis of the ultimate compressive bearing capacity,conceptual design and safety assessment.