scholarly journals Elasto-plastic response analysis of nuclear containment vessel structures under strong earthquakes

Author(s):  
Zhicheng Xue ◽  
Yao Zhang ◽  
Qiang Pei ◽  
Kongchen Zhu ◽  
Ziran Yan
2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Yutao Pang ◽  
Aijun Ye

AbstractCoastal highway bridges are usually supported by pile foundations that are submerged in water and embedded into saturated soils. Such sites have been reported susceptible to scour hazard and probably liquefied under strong earthquakes. Existing studies on seismic response analyses of such bridges often ignore the influence of water-induced hydrodynamic effect. This study assesses quantitative impacts of the hydrodynamic effect on seismic responses of coastal highway bridges under scour and liquefaction potential in a probabilistic manner. A coupled soil-bridge finite element model that represents typical coastal highway bridges is excited by two sets of ground motion records that represent two seismic design levels (i.e., low versus high in terms of 10%-50 years versus 2%-50 years). Modeled by the added mass method, the hydrodynamic effect on responses of bridge key components including the bearing deformation, column curvature, and pile curvature is systematically quantified for scenarios with and without liquefaction across different scour depths. It is found that the influence of hydrodynamic effect becomes more noticeable with the increase of scour depths. Nevertheless, it has minor influence on the bearing deformation and column curvature (i.e., percentage changes of the responses are within 5%), regardless of the liquefiable or nonliquefiable scenario under the low or high seismic design level. As for the pile curvature, the hydrodynamic effect under the low seismic design level may remarkably increase the response by as large as 15%–20%, whereas under the high seismic design level, it has ignorable influence on the pile curvature.


Author(s):  
Akihito Otani ◽  
Syozaburo Toyoda ◽  
Izumi Nakamura ◽  
Hajime Takada

When piping systems are subjected to extreme seismic excitation, they undergo a plastic deformation that produces a large damping effect via energy dissipation. Based on our studies of the damping effect of the elasto-plastic response of piping, we have presented a simplified method for predicting the elasto-plastic response of piping in PVP conferences over the last several years. The method has taken the plastic deformation of in-plane bending elbows into consideration. The elasto-plastic response predicted by the method resulted in good agreement with piping model excitation tests. In this paper, we report an additional method to consider out-of-plane bending elbow and the mixed bending of in-plane and out-of-plane bending. The simulation results by this method and the comparisons with 3D piping model excitation tests are also reported.


2014 ◽  
Vol 490-491 ◽  
pp. 625-628
Author(s):  
Chun Lai Tian ◽  
Lin Yang ◽  
Rui Chang Zhao

In order to obtain frequencies and modal shapes of a nuclear containment vessel, the computational analyses have been carried out through free structure finite element analysis software. The finite element model of the vessel is built with shell element and solved by the type of the dynamics frequency solver. Results show that mainly deformation area is on the vessels cylindrical shell and the maximum displacements occur at its center. Compared with the design validation values, the frequencies obtained are a little lower. It may be because that the model built here is a completely vessel shell without any hatches or attachments. It is provided that a reliable method of computational structural analyses for the nuclear containment without commercial software cost.


2010 ◽  
Vol 163-167 ◽  
pp. 4022-4026
Author(s):  
Bo Wen ◽  
Di Tao Niu

The nonlinear dynamic response analysis of substation with structure-equipments interaction is studied in this paper. The results comparing with that of no interaction are shown that it’s necessary to considering structure-equipments interaction in substations. In frequent earthquakes, the structure-equipments interaction in substation is inconspicuous and the traditional equivalent load method is feasible. However, in strong earthquakes, the electric equipments really participate in the dynamic response and operate the reaction on main structure and the action goes against the main structure seismic design and couldn’t be ignored. In this condition, the traditional equivalent load method will be insecure any more. Because of the visible torsional response effect, the seismic ability of the corner columns in structure should be increased. The research results can be referenced by similar lifeline system.


Author(s):  
Akihito Otani ◽  
Izumi Nakamura ◽  
Hajime Takada

When piping systems are subjected to extreme seismic excitation, they undergo a plastic deformation that produces a large damping effect via energy dissipation. Based on our studies of the damping effect of the elasto-plastic response of piping, we have presented a simplified method for predicting the elasto-plastic response of piping in PVP conferences over the last several years. Yet the elasto-plastic response of piping calculated by this method resulted in conservative predictions compared with the results of piping model excitation tests. In the proposed method, we calculate the vibration energy of piping and the dissipation energy with plastic deformation by FEM analysis and obtain the equivalent damping ratio as a ratio between the two. The equivalent damping ratio and response are interdependent and can be calculated as a pair of converged values. In this paper we report simulation results from 3D piping model excitation tests as well as the results from 2D piping model tests. The simulation method is a modified and improved version of the method reported earlier. The results obtained by the revised method more closely matched the results of the excitation tests.


2019 ◽  
Vol 795 ◽  
pp. 66-73
Author(s):  
Ya Lin Zhang ◽  
Hu Hui

The low temperature tensile properties, Charpy-V notch impact performance and fracture toughness of SA738Gr.B steel plate for domestic CAP1400 containment vessel were tested. On this basis, the reference temperature T0 of the master curve method was obtained. The fracture toughness distribution of the steel in the whole ductile-brittle transition zone is predicted and its applicability is verified by the theoretical basis of the master curve method. The results show that the reference temperature of SA738Gr.B steel master curve method is-123.6 °C. The master curve method is appropriate for SA738Gr.B steel with domestic nuclear containment vessel.


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