• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.3
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• pp.82-91
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• 1996

This is a basic study for the static and dynamic analysis on the elasto-plastic and elasto-viscoplastic of an axi-symmetric shell. The objective of this study was to investigate the mechanical characteristics of a nuclear reinforced concrete containment structure, which was selected as a model, by a numerical analysis using a finite element method. The structure was modeled with discrete ring elements of 8-noded isoparametric element rotating against the symmetrical axis, and the interaction between the foundation and the structure was modeled by Winkler's model. Also, the meridional tendon was modeled with 2-node truss elements, and the hoop tendon was done with point elements in two degrees of freedom. The effect of the tendon was considered without the increasement in total degree of freedom as the stiffness matrix of modeled tendon elements was assembled on the stiffness matrix of ring elements linked with the tendon. The results obtained from the analysis of an example were summarized as follows : 1. The stresses in the hoop direction on the interior and exterior surfaces of the structure were shown in changes of similar trend, and high stresses appeared on the structure wall 2. The stresses in the meridional direction on the interior and exterior surfaces were shown in change of different trend. Especially, the stresses at the junctions between the dome and the wall and between the wall and the bottom plate of the structure were very high, compared with those at other parts of the structure. 3. The stress changes in the direction of thickness on the crown of the dome were much linearly distributed. However, as the amount of tendon increased, the stresses in the upper and lower parts of the wall established with the tendon were shown stress concentration. 4. The stress changes in the direction of thickness on the center of the structure wall was linearly distributed in the all cases, and special stress due to the use of the tendon was not shown.

• Computers and Concrete
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• v.13 no.1
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• pp.1-16
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• 2014

To evaluate the behavior of the advanced unbonded pre-stressed concrete containment vessel (UPCCV) for one typical China nuclear power plant under Japan's March 11 earthquake, five nonlinear time history analysis and a nonlinear static analysis of a 1:10 scale UPCCV structure have been carried out with MSC.MARC finite element program. Comparisons between the analytical and experimental results demonstrated that the developed finite element model can predict the earthquake behavior of the UPCCV with fair accuracy. The responses of the 1:10 scale UPCCV subjected to the 11 March 2011 Japan earthquakes recorded at the MYG003 station with the peak ground acceleration (PGA) of 781 gal and at the MYG013 station with the PGA of 982 gal were predicted by the dynamic analysis. Finally, a static analysis was performed to seek the ultimate load carrying capacity for the 1:10 scale UPCCV.

• Structural Engineering and Mechanics
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• v.58 no.5
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• pp.799-823
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• 2016

A finite element model for the non-linear dynamic analysis of a reinforced concrete (RC) containment shell of a nuclear power plant subjected to extreme loads such as impact and earthquake is presented in this work. The impact is modeled by using an uncoupled approach in which a load function is applied at the impact zone. The earthquake load is modeled by prescribing ground accelerations at the base of the structure. The nuclear containment is discretized spatially by using 20-node brick finite elements. The concrete in compression is modeled by using a modified $Dr{\ddot{u}}cker$-Prager elasto-plastic constitutive law where strain rate effects are considered. Cracking of concrete is modeled by using a smeared cracking approach where the tension-stiffening effect is included via a strain-softening rule. A model based on fracture mechanics, using the concept of constant fracture energy release, is used to relate the strain softening effect to the element size in order to guaranty mesh independency in the numerical prediction. The reinforcing bars are represented by incorporated membrane elements with a von Mises elasto-plastic law. Two benchmarks are used to verify the numerical implementation of the present model. Results are presented graphically in terms of displacement histories and cracking patterns. Finally, the influence of the shear transfer model used for cracked concrete as well as the effect due to a base slab incorporation in the numerical modeling are analyzed.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.1
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• pp.1-11
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• 2015

In order to perform a soil-isolation-structure interaction analysis of seismically isolated nuclear power plant (NPP) structures, the nonlinear behavior of a seismic isolation system may be converted to an equivalent linear model used in frequency domain analysis. Seismic responses for seismically isolated NPP containment structures subjected to a simple artificial acceleration history and different site class earthquakes are evaluated for the equivalent-linear and nonlinear models that have been applied to lead-rubber bearing (LRB) modeling. It can be observed that the maximum displacements of the equivalent linear model are larger than that of the nonlinear model. From the floor response spectrum analysis for the top of NPP containment structures, it can be observed that the spectral acceleration of an equivalent linear model at about 0.5 Hz frequency is about 2~3 times larger than that of a nonlinear model.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.25-36
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• 2009

In this paper, we propose an efficient data management scheme for path queries and containment queries which are occurred frequently. The proposed data management scheme considers a change of the containment of products during a transport and supports a path of changed products by representing a path of various containments. Also, the compression utilizing the structure of supply chain reduces the stored data volumes. As a result, our method outperforms the existing methods in terms of storage efficiency and query processing time.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4179-4188
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• 2021

This study identifies efficient earthquake intensity measures (IMs) for seismic performances and fragility evaluations of the reactor containment building (RCB) in the advanced power reactor 1400 (APR1400) nuclear power plant (NPP). The computational model of RCB is constructed using the beam-truss model (BTM) for nonlinear analyses. A total of 90 ground motion records and 20 different IMs are employed for numerical analyses. A series of nonlinear time-history analyses are performed to monitor maximum floor displacements and accelerations of RCB. Then, probabilistic seismic demand models of RCB are developed for each IM. Statistical parameters including coefficient of determination (R²), dispersion (i.e. standard deviation), practicality, and proficiency are calculated to recognize strongly correlated IMs with the seismic performance of the NPP structure. The numerical results show that the optimal IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, A95, and sustained maximum acceleration. Moreover, weakly related IMs to the seismic performance of RCB are peak ground displacement, root-mean-square of displacement, specific energy density, root-mean-square of velocity, peak ground velocity, Housner intensity, velocity spectrum intensity, and sustained maximum velocity. Finally, a set of fragility curves of RCB are developed for optimal IMs.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.83-92
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• 2007

There are many numerical methods to solve large-scale fluid-structure interaction(FSI) problems. However, these methods require very fine mesh to achieve the reasonable numerical accuracy and stability due to the concentrated and volatile hydrodynamic pressure caused by the liquid sloshing. Consequently, the numerical analysis targeting for the long-period time response with the desired numerical accuracy Is very highly time-consuming. The aim of this paper is to suggest a new method to analyze the hydroelastic behavior of the LNGC containment by using the global-local numerical approach. The reliability of the presented method is firstly examined, and then its efficiency is demonstrated by presenting that the long-period local responses of the LNGC containment are obtained with relatively short CPU time.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.85-90
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• 2007

This paper presents the finite element analysis on the strength safety of a full containment LNG storage tank system with damping safety structures. For the FEM analysis of the inner tank, the combined loads in which are related to a hydrostatic pressure, a cryogenic temperature load, BOG pressure, LNG weight, and a sinking force at the comer of the inner tank have been applied to the inner tank structure. The FEM computed results show that the conventional inner tank is safe for the given combined loads, but the damping safety structure such as compressive springs may be more useful structures to increase the safety of the tank system. The increased stiffness and the appropriate position of the springs are very important design parameters for increasing the damping strength safety of the tank system.

• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.122-129
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.727-728
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• 2005