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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Computational Structural Engineering Institute of Korea
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Journal DOI :
The Computational Structural Engineering Institute
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Volume & Issues
Volume 29, Issue 4 - Aug 2016
Volume 29, Issue 3 - Jun 2016
Volume 29, Issue 2 - Apr 2016
Volume 29, Issue 1 - Feb 2016
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Seismic Analysis for Multi-pile Concrete Foundation in 5MW Class Offshore Wind Turbine
Kim, Woo Seok ; Jeong, Yuseok ; Kim, Kidu ; Kim, Kyeong Jin ; Lee, Jae Ha ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 209~218
DOI : 10.7734/COSEIK.2016.29.3.209
Recently, Wind-turbine electronic generator become popular. Wind-Turbine is free to cost for purchase and noise problem. For this reason, trend is shifting from Wind-turbine on land to offshore. Research and Development for offshore Wind-turbine has been conducted by various research institution. However, There is no solid design code for offshore Wind-turbine even in domestic as well as foreign. In this paper, conduct seismic analysis and compare results using design codes Korea Bridge Design Codes, Korea Harbor and Marina Design Codes, and DNV OS. Time-History analysis conducted for checking time dependent effect. The Added-Mass Method applied to consider water-structure effects and compared for w/ water and w/o water condition.
Construction Monitoring Methods of FCM Bridge Using Temperature Data
Kim, Hyun-Joong ; Moon, Dae Joong ; Nam, Soon Sung ; Jeong, Ju Yong ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 219~227
DOI : 10.7734/COSEIK.2016.29.3.219
In this study, we have proposed a method of monitoring of bridges under construction in view of the long-term behavior of the prestress concrete bridge of which the Free Cantilever Method is applied. As a method to confirm the ability of the long-term behavior of the concrete box girder, temperature sensors and strain gauges were installed, and the measured data was used to calculate creep coefficient. Moreover, we have measured the stress of the concrete box girder during construction which was applied with creep coefficient and compared with the changes in temperature to analyze the vertical displacement along the segment. In conclusion, monitoring of the FCM bridge during construction in consideration of the long-term behavior can be analyzed efficiently by suing temperature and displacement data without the use of laser displacement meter or laser delfectometer.
A Thermal Stress Analysis of Beams with Out-of-Plane Warping
Jeong, Yong-Min ; Kim, Jun-Sik ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 229~235
DOI : 10.7734/COSEIK.2016.29.3.229
In this paper, a methodology, which is able to predict the thermal stresses accurately yet efficiently, is presented for beam structures via Saint-Venant`s principle. In general, higher-order beam theories have been known to be effective for the prediction of thermal stresses. In contrast to this, we propose the method to predict the thermal stresses of beam structures by post-processing the classical beam theory via Saint-Venant`s principle. The approach includes an out-of-plane warping displacement to account for the through-the-thickness thermal deformation. With this, one can accurately recover the thermal stresses as compared to the elasticity solutions. In fact, they are identical for the beams made of isotropic materials. The effect of out-of-plane warping is also investigated, it turns out that the effect is negligible in mechanical stress analysis but not in thermal stress analysis.
Development of MLS Difference Method for Material Nonlinear Problem
Yoon, Young-Cheol ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 237~244
DOI : 10.7734/COSEIK.2016.29.3.237
This paper presents a nonlinear Moving Least Squares(MLS) difference method for material nonlinearity problem. The MLS difference method, which employs strong formulation involving the fast derivative approximation, discretizes governing partial differential equation based on a node model. However, the conventional MLS difference method cannot explicitly handle constitutive equation since it solves solid mechanics problems by using the Navier`s equation that unifies unknowns into one variable, displacement. In this study, a double derivative approximation is devised to treat the constitutive equation of inelastic material in the framework of strong formulation; in fact, it manipulates the first order derivative approximation two times. The equilibrium equation described by the divergence of stress tensor is directly discretized and is linearized by the Newton method; as a result, an iterative procedure is developed to find convergent solution. Stresses and internal variables are calculated and updated by the return mapping algorithm. Effectiveness and stability of the iterative procedure is improved by using algorithmic tangent modulus. The consistency of the double derivative approximation was shown by the reproducing property test. Also, accuracy and stability of the procedure were verified by analyzing inelastic beam under incremental tensile loading.
Environmental Fatigue Evaluation of Top-Mounted In-Core Instrumentation Nozzle
Yoon, Hyo-Sub ; Kim, Jong-Min ; Maeng, Cheol-Soo ; Kim, Gee-Seok ; Kim, Hyun-Min ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 245~252
DOI : 10.7734/COSEIK.2016.29.3.245
The development of Top-Mounted In-Core Instrumentation(TM-ICI) is an ongoing project to reduce the risk due to severe accidents by inserting the instrumentation into a reactor closure head instead of a reactor bottom head. As part of this project, environmental fatigue analyses for TM-ICI nozzle have been performed using two methods of NUREG/CR-6909 and Code Case N-761. TM-ICI nozzle is subjected to transient loads for level A, level B and test conditions that should be evaluated for a fatigue analysis. It is found that a cumulative usage factor considering reactor coolant environment for TM-ICI nozzle is evaluated as less than 1, which is ASME Code allowable criteria of a fatigue analysis.
Genetic Algorithm Based Optimal Seismic Design Method for Inducing the Beam-Hinge Mechanism of Steel Moment Frames
Park, Hyo-Seon ; Choi, Se-Woon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 253~260
DOI : 10.7734/COSEIK.2016.29.3.253
In this paper, the optimal seismic design method for inducing the beam-hinge collapse mechanism of steel moment frames is presented. This uses the non-dominated sorting genetic algorithm II(NSGA-II) as an optimal algorithm. The constraint condition for preventing the occurrence of plastic hinges at columns is used to induce the beam-hinge collapse mechanism. This method uses two objective functions to minimize the structural weight and maximize the dissipated energy. The proposed method is verified by the application to nine story steel moment frame example. The minimum column-to-beam strength ratio to induce the beam-hinge collapse mechanism are investigated based on the simulation results. To identify the influence of panel zone on the minimum column-to-beam strength ratio, three analytic modeling methods(nonlinear centerline model without rigid end offsets, nonlinear centerline model with rigid end offsets, nonlinear model with panel zones) are used.
Seismic Performance of SDF Systems with Tuned Liquid Damper Subjected to Ground Motions
Han, Sang-Whan ; Oh, Seung-Bo ; Ha, Sung-Jin ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 261~268
DOI : 10.7734/COSEIK.2016.29.3.261
Tuned Liquid Dampers(TLD) are energy dissipation devices that have been proposed to control the dynamics response of structure. The TLD has been shown to effectively control the wind response of structures. However, controlling responses of structures with TLD under seismic loads are not fully investigated. The objective of this study is to evaluate the seismic performance of single degree of freedom(SDF) with TLDs having various tuning and mass raitos. For this purpose, analytical studies are conducted. Different soil conditions are considered in this study. As a result, performance of TLD, appeared diffrently depending on the natural period, damping ratio of the structure. Also TLD tuning ratio appeared differently.
Evaluation of Shear Capacity of Wide Beams Reinforced with GFRP and Steel Plates with Openings by Various Supporting Areas
Kim, Heecheul ; Ko, Myung Joon ; Kim, Min Sook ; Lee, Young Hak ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 269~275
DOI : 10.7734/COSEIK.2016.29.3.269
In this paper, shear performance of concrete wide beams was evaluated through shear failure tests. The specimens were designed to have two continuous spans with a column at the center of the wide beam. Also the specimens were reinforced with plates with openings as shear reinforcements. For the test, total eight specimens, including five specimens were reinforced with steel plates and the other three specimens were reinforced with GFRP plates were manufactured. And the shear strengths obtained from the tests were compared with ones from the equation provided by ACI 318. Support width of wide beam, support section of wide beam and shear reinforcement material were considered as variables. The results showed that the support width was proportional to the increase of shear strength. Also, regardless of material type of shear reinforcement, the shear reinforcing effect was similar when the amount of shear reinforcement was the same.
Application of High-precision Accelerometer Made in Korea to Health Monitoring of Civil Infrastructures
Kwon, Nam-Yeol ; Kang, Doo-Young ; Sohn, Hoon ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 277~283
DOI : 10.7734/COSEIK.2016.29.3.277
A high-precision force-feedback 3-axes accelerometer developed in Korea has been investigated and studied for the verification of feasibility in the computational analysis and health monitoring of civil infrastructures. Through a series of experiment, the nonlinearity, bandwidth, low-frequency signal measurement accuracy and bias characteristics of the accelerometer has been thoroughly compared to those of two accelerometers produced by two market leaders in domestic and global accelerometer market. The experiment results shows that the overall measurement performance of the accelerometer has superiority over the performance of the two accelerometers from global market leader companies. Especially, the accelerometer shows a better low-frequency signal measurement accuracy and constant bias characteristic, which are mostly required in the computational analysis and the long-term health monitoring of large-scale civil infrastructures.
Hydroelastic Responses of Floating Structure by Modeling Dimensions
Hong, Sanghyun ; Hwang, Woongik ; Lee, Jong Seh ;
Journal of the Computational Structural Engineering Institute of Korea, volume 29, issue 3, 2016, Pages 285~292
DOI : 10.7734/COSEIK.2016.29.3.285
In this study, FE-BE direct coupling methods of 1D and 2D problems are considered for the pontoon-type floating structure and the difference of the modeling dimensions is investigated for the hydroelastic response. The modeling dimensions are defined as the 1D problem consisting 1D beam-2D fluid coupling and the 2D problem consisting 2D plate-3D fluid coupling with zero-draft assumption. For case studies, hydroelastic responses of the 1D Problem are compared to those of the 2D Problem for a wide range of aspect ratio and regular waves. It is shown that the effects of the elastic behavior are increased by decreasing the incident wavelength, whereas the effects of the rigid behavior are increased by increasing the incident wavelength. In 2D problem, the incident wave angle can be considered, and slightly more accurate results can be obtained, but the computational efficiency is lower. On the other hand, in 1D problem with plate-strip condition, the incident wave angle cannot be considered, but when the aspect ratio is large, the overall responses can be analyzed through a simplified model, and the computational efficiency can be improved.