• Computers and Concrete
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• v.7 no.2
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• pp.145-158
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• 2010

In this work the implementation of a production-level port of the Microplane constitutive model for concrete into the EPIC code is described. The port follows guidelines outlined in the Material Model Module (MMM) standard used in EPIC to insure a seamless interface with the existing code. Certain features of the model were not implemented using the MMM interface due to compatibility reasons; for example, a separate module was developed to initialize, store and update internal state variables. Objective strain and deformation measures for use in the material model were also implemented into the code. Example calculations were performed and illustrate the veracity of this new implementation.

• Nuclear Engineering and Technology
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• v.42 no.6
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• pp.636-655
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• 2010

A thermal-hydraulic code, named CUPID, has been being developed for the realistic analysis of transient two-phase flows in nuclear reactor components. The CUPID code development was motivated from very practical needs, including the analyses of a downcomer boiling, a two-phase flow mixing in a pool, and a two-phase flow in a direct vessel injection system. The CUPID code adopts a two-fluid, three-field model for two-phase flows, and the governing equations are solved over unstructured grids with a semi-implicit two-step method. This paper presents an overview of the CUPID code development and assessment strategy. It also presents the code couplings with a system code, MARS, and, a three-dimensional reactor kinetics code, MASTER.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.279-296
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• 2010

For the analysis of transient two-phase flows in nuclear reactor components, a three-dimensional thermal hydraulics code, named CUPID, has been developed. The CUPID code adopts a two-fluid, three-field model for two-phase flows, and the governing equations were solved over unstructured grids, which are very useful for the analysis of flows in complicated geometries. To obtain numerical solutions, the semi-implicit numerical method for the REALP5 code was modified for an application to unstructured grids, and it has been further improved for enhanced accuracy and fast running. For the verification of the CUPID code, a set of conceptual problems and experiments were simulated. This paper presents the flow model, the numerical solution method, and the results of the preliminary assessment.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.918-921
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• 2010

본 연구에서는 Simulink Model(이하 Model)을 C Code 로 변환시켜주는 자동 코드 생성기, SimAutoCodeGenerator 를 제안하였다. Model 의 테스트케이스를 생성하기 위한 작업에서 반복적인 프로그램의 실행을 통한 테스터와의 다양한 피드백이 필요하다. 이때, Simulink는 이런 작업을 하는 데 있어서 적절한 정보를 제공하기 어려울 뿐만 아니라 테스트 케이스를 생성하는데 필요한, 실행 시 특정 시점으로 돌아가는 기능을 수행하기 위해서는 프로그램을 정지한 후 다시 실행해야하는 문제점을 가지고 있다. 본 연구에서는 이와같은 단점을 보완하기 위하여 Model 을 C 코드로 변환하였다. 생성된 C 코드는 Model 과의 일치성을 증명한 후 자동 테스트케이스 생성을 위한 프로그램에 쓰이게 될 것이다. 먼저 C 코드의 생성 메커니즘을 알아보고 생성된 C 코드와 Model 의 일치성을 증명하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.3
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• pp.175-186
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• 2013

Based on Model Code 2010, flexural and residual strength, flexural toughness of SFRC with design strength of 60 MPa are evaluated. For comparisons, SFRC with design strength 40 MPa was tested. Distribution of steel fibers in crack surface of specimens was evaluated by visual inspection. The used steel fibers were hooked fibers with aspect ratio of 64, 67 and 80. In all specimens, mix ratio of steel fibers was 0.5% Vol. In results, only SFRC with the highest aspect ratio satisfied requirements specified in Model Code 2010. The results demonstrated that the use of high aspect ratio will provide enough flexural toughness for high strength concrete. Also, it is found that low slump of high strength concrete can help to enhance isotropic fiber distribution.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.581-592
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• 2016

Tensile constitutive stress-strain model of steel fiber reinforced concrete (SFRC) in fib MC2010 was investigated. In order to model tensile behavior of SFRC, three point loading flexural tests were conducted on notched small beams according to BE-EN-14651. Design parameters for the constitutive model were determined from the flexural tests. Flexural test and finite element analysis were conducted on large SFRC beam without steel reinforcements and compared with each other. In addition, parametric study on the effect of compressive and tensile model, and characteristic length on flexural behavior of the SFRC beam was conducted also. In results, pre-peak load-displacement curves from the FE analysis was close to experimental curves but significant difference was shown in post-peak behavior. The reason of the difference is originated from the fact that the fiber distribution and orientation were not being properly considered in the MC2010 model. This study shows that modification and detail explanations on the orientation factor K in MC2010 might require to better reproduce the behaviour of large scale SFRC beams.

• Structural Engineering and Mechanics
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• v.81 no.2
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• pp.163-178
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• 2022

This paper aimed to study the local bond-slip behavior between ultra-high-performance concrete (UHPC) and a reinforcing bar after exposure to high temperatures. A series of pull-out tests were carried out on cubic specimens of size 150×150×150 mm with deformed steel bar embedded for a fixed length of three times the diameter of the tested deformed bar. The experimental results of the bond stress-slip relationship were compared with the Euro-International Concrete Committee (CEB-Comite Euro-International du Beton)-International Federation for Prestressing (FIP-Federation Internationale de la Precontrainte) Model Code and with prediction models found in the literature. In addition, based on the test results, an empirical model of the bond stress-slip relationship was proposed. The evaluation and comparison results showed that the modified CEB-FIP Model code 2010 proposed by Aslani and Samali for the local bond stress-slip relationship for UHPC after exposure to high temperatures was more conservative. In contrast, for both room temperature and after exposure to high temperatures, the modified CEB-FIP Model Code 2010 local bond stress-slip model for UHPC proposed in this study was able to predict the test results with reasonable accuracy.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.71-74
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• 2010

In this study the optical properties, such as relative transmittance and reflectance of PDP were analyzed with 3D optical code. Because of the electrode structure, the reference model shows 21.3 % higher transmittance than the test model and the reference model shows 16.6 % higher reflectance than the test model. The calculated reflectance of reference and test models is compared to the measured reflectance and the difference between calculation and measurement is 4.9 %.

• Earthquakes and Structures
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• v.4 no.3
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• pp.265-283
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• 2013

This research was prompted by the paucity of specific code provisions regarding the design of short columns for shear. The purpose of this paper was to investigate whether the use of the normal shear design procedure of various codes may or may not be applied to reliably calculate the shear strength of short columns. Provisions of the codes American ACI 318M-08, Canadian CSA A23.3-04, Japanese AIJ Guidelines, New Zealand NZS 3101, European EN 1998 (EC8) parts 1 and 3, combined with EN 1992-1-1 (EC2), and draft fib Model Code 2010, as well as a strut-and-tie model are applied on short columns tested under cyclic loading that failed in shear. Actual shear resistances are compared to predictions, and the resulting shortcomings of the codes are identified. EN1998-3 appears to be the only code among those considered that may be reliably applied to estimate the shear resistance of short columns. Further, the proposed strut-and tie model can be a useful tool for the detailed design and assessment of short columns.

• Earthquakes and Structures
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• v.13 no.4
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• pp.397-407
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• 2017

With the growing demand for metallic dampers in engineering practice, it is urgent to establish a reasonable approach to evaluating the mechanical performance of metallic dampers under seismic excitations. This paper introduces an effective method for parameter identification of the modified Bouc-Wen model and its application to evaluating the fatigue performance of metallic dampers (MDs). The modified Bouc-Wen model which eliminates the redundant parameter is used to describe the hysteresis behavior of MDs. Relations between the parameters of the modified Bouc-Wen model and the mechanical performance parameters of MDs are studied first. A modified Genetic Algorithm using real-integer hybrid coding with relative fitness as well as adaptive crossover and mutation rates (called RFAGA) is then proposed to identify the parameters of the modified Bouc-Wen model. A reliable approach to evaluating the fatigue performance of the MDs with respect to the Chinese Code for Seismic Design of Buildings (GB 50011-2010) is finally proposed based on the research results. Experimental data are employed to demonstrate the process and verify the effectiveness of the proposed approach. It is shown that the RFAGA is able to converge quickly in the identification process, and the simulation curves based on the identification results fit well with the experimental hysteresis curves. Furthermore, the proposed approach is shown to be a useful tool for evaluating the fatigue performance of MDs with respect to the Chinese Code for Seismic Design of Buildings (GB 50011-2010).