• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.5
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• pp.483-490
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• 2016

In plant industry, sulfur storage tank is made of steel and annular plate is connected with concrete foundation of ring wall type by anchor bolt. Due to keep sulfur at high temperature in tank by coil, sulfur storage tank is expanded larger than another tank stores fluid at room temperature. Generally, structural design of tank foundation is performed analysis with loading of temperature gradient between inner and outer surface, this method can't consider the phenomenon that load is intensively transferred to concrete foundation at anchor bolt. This means that temperature load is underestimated and causes crack of concrete near anchor bolt. In this study, evaluation formula considering temperature load transfer mechanism through anchor bolt is proposed and load acting on concrete foundation is rationally decided. For this purpose, it is analyzed variation of thermal load per various anchor bolt number using finite element model including tank annular plate and anchor bolt. Solution is proposed as specified term combining result of analysis and theoretical solution for evaluating load transferred by anchor bolt. For confirmation of validation of proposed formula, it is applied in design of sulfur storage tank at plant site, it shows that the formula can be practically applied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2297-2304
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• 2002

Two-dimensional and three-dimensional finite element methods have been used to analyze the deformation behavior of a shadow mask due to thermal and tension load. The shadow mask inside the Braun tube of a TV set has numerous slits through which the electron beams are guided to land on the designed phosphor of red, green or blue. Its thermal deformation therefore causes landing shift of the electron beam and results in decolorization of a screen. For the realistic finite element analysis, the effective thermal conductivity and the effective elastic modulus arc calculated, and then the shadow mask is modeled as shell without slits. Next a transient thermal analysis of the shadow mask is performed, wherein thermal radiation is a major heat transfer mechanism. Analysis of the resulting thermal deformation is followed, from which the landing shift of the electron beam is obtained. The present finite element scheme may be efficiently used to reduce thermal deformation of a shadow mask and in developing prototypes of a large screen flat TV.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1480-1491
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• 2015

In new deregulated electricity market, short-term price forecasting is key information for all market players. A better forecast of market-clearing price (MCP) helps market participants to strategically set up their bidding strategies for energy markets in the short-term. This paper presents a new prediction strategy to improve the need for more accurate short-term price forecasting tool at spot market using an artificial neural networks (ANNs). To build the forecasting ANN model, a three-layered feedforward neural network trained by the improved Levenberg-marquardt (LM) algorithm is used to forecast the locational marginal prices (LMPs). To accurately predict LMPs, actual power generation and load are considered as the input sets, and then the difference is used to predict price differences in the spot market. The proposed ANN model generalizes the relationship between the LMP in each area and the unconstrained MCP during the same period of time. The LMP calculation is iterated so that the capacity between the areas is maximized and the mechanism itself helps to relieve grid congestion. The addition of flow between the areas gives the LMPs a new equilibrium point, which is balanced when taking the transfer capacity into account, LMP forecasting is then possible. The proposed forecasting strategy is tested on the spot market of the Nord Pool. The validity, the efficiency, and effectiveness of the proposed approach are shown by comparing with time-series models

• Earthquakes and Structures
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• v.11 no.4
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• pp.723-740
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• 2016

Reinforced concrete corbels are generally used to transfer loads within a structural system, such as buildings, bridges, and facilities in general. They commonly present low aspect ratio, requiring an accurate model for shear strength prediction in order to promote flexural behavior. The model described here, originally developed for walls, was adapted for corbels. The model is based on a reinforced concrete panel, described by constitutive laws for concrete and steel and applied in a fixed direction. Equilibrium in the orthogonal direction to the shearing force allows for the estimation of the shear stress versus strain response. The original model yielded conservative results with important scatter, thus various modifications were implemented in order to improve strength predictions: 1) recalibration of the strut (crack) direction, capturing the absence of transverse reinforcement and axial load in most corbels, 2) inclusion of main (boundary) reinforcement in the equilibrium equation, capturing its participation in the mechanism, and 3) decrease in aspect ratio by considering the width of the loading plate in the formulation. To analyze the behavior of the theoretical model, a database of 109 specimens available in the literature was collected. The model yielded an average model-to-test shear strength ratio of 0.98 and a coefficient of variation of 0.16, showing also that most test variables are well captured with the model, and providing better results than the original model. The model strength prediction is compared with other models in the literature, resulting in one of the most accurate estimates.

• Structural Engineering and Mechanics
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• v.61 no.5
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• pp.593-603
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• 2017

A high-efficiency simplified modelling approach is proposed for investigating the nonlinear responses of reinforced concrete linings of shield tunnels. Material and geometric nonlinearities are considered in the analysis of the lining structures undergoing large deformation before ultimately losing the load-carrying capacity. A beam-spring element model is developed to capture the force-transfer mechanism between lining segments and radial joints. The developed model is validated by comparing analyzed results to experimental results of a single-ring lining structure under two loading conditions: the ground overloading and the lateral unloading respectively. The results show that the lining structure under the lateral unloading due to excavation on the both sides of the tunnel is more vulnerable compared to the case of ground overloading on the top of the tunnel. A parameter study is conducted and results indicate that the lateral pressure coefficient has the greatest influence on the behaviour of the lining structure.

• Steel and Composite Structures
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• v.34 no.6
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• pp.803-818
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• 2020

Semi-rigid connections with blind bolts could solve the difficulty that traditional high strength bolts were unavailable to splice a steel/composite beam to a closed section column. However, insufficient investigations have focused on the performance of semi-rigid connection to square concrete filled double-skin steel tubular (CFDST) columns. In this paper, a component model was developed to evaluate the mechanical behavior of semi-rigid composite connections to CFDST columns considering the stiffness and strength of column face in compression and column web in shear which were determined by the load transfer mechanism and superstition method. Then, experimental investigations on blind bolted composite joints to square CFDST columns were conducted to validate the accuracy of the component model. Dominant failure modes of the connections were analyzed and this type of joint behaved semi-rigid manner. More importantly, strain responses of CFDST column web and tubes verified that stiffness and strength of column face in compression and column web in shear significantly affected the connection mechanical behavior owing to the hollow part of the cross-section for CFDST column. The experimental and analytical results showed that the CFDST column to steel-concrete composite beam semi-rigid joints could be employed for the assembled structures in high intensity seismic regions.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.4
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• pp.27-37
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• 2012

The construction of a moment connection for a rectangular hollow section (RHS) column and a H-shaped beam is difficult because the RHS is a closed section. When a inner diaphragm is used for such a connection, in general, it is installed after cutting the HSS columns, which results in increased construction work. This paper suggests a new fabrication method to overcome such problems: An inner diaphragm is welded to inside a C-shaped section first, and then a column is fabricated by welding two C-shaped sections. This fabrication method is superior to a classic method in terms of constructibility. An experimental and a numerical study using Ansys 9.0 were performed in order to compare the strength of connections with respect to the presence of concrete, the corner shape of diaphragm, and the axis of loading. The experimental results including initial stiffness and ultimate loads are reported and the analytical results including load transfer mechanism, degree of stress concentration, and strain distribution are also reported.

• Steel and Composite Structures
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• v.4 no.2
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• pp.149-167
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• 2004

Offshore platforms have to serve in harsh environments and hence are likely to be damaged due to wave induced fatigue and environmental corrosion. Welded tubular joints in offshore platforms are most vulnerable to fatigue damage. Such damages endanger the integrity of the structure. Therefore it is all the more essential to assess the capacity of damaged structure from the point of view of its safety. Eight internally ring stiffened fatigue damaged tubular joints with nominal chord and brace diameter of 324 mm and 219 mm respectively and thickness 12 mm and 8 mm respectively were tested under axial brace compression loading to evaluate the reserve capacity of the joints. These joints had earlier been tested under fatigue loading under corrosive environments of synthetic sea water and hence they have been cracked. The extent of the damage varied from 35 to 50 per cent. One stiffened joint was also tested under axial brace tension loading. The residual strength of fatigue damaged stiffened joint tested under tension loading was observed to be less than one fourth of that tested under compression loading. It was observed in this experimental investigation that in the damaged condition, the joints possessed an in-built load-transfer mechanism. A bi-linear stress-strain model was developed in this investigation to predict the reserve capacity of the joint. This model considered the strain hardening effect. Close agreement was observed between the experimental and predicted results. The paper presents in detail the experimental investigation and the development of the analytical model to predict the reserve capacity of internally ring stiffened joints.

• Structural Engineering and Mechanics
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• v.72 no.4
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• pp.409-420
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• 2019

The paper presents the results of an experimental and numerical programme to characterize the behaviour of steel beams reinforcement by composite plates. Important failure mode of such plated beams is the debonding of the composite plates from the steel beam due to high level of stress concentration in the adhesive at the ends of the composite plate. In this new research, an experimental and numerical finite element study is presented to calculate the stresses in the sika carbodur and sika wrap reinforced steel beam under mechanical loading. The main objective of the experimental program was the evaluation of the force transfer mechanism, the increase of the load capacity of the steel beam and the flexural stiffness. It also validated different analytical and numerical models for the analysis of sika carbodur and sika wrap reinforced steel beams. In particular, a finite element model validated with respect to the experimental data and in relation to the analytical approach is presented. Experimental and numerical results from the present analysis are presented in order to show the advantages of the present solution over existing ones and to reconcile debonding stresses with strengthening quality.

• Ceramist
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• v.21 no.4
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• pp.312-330
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• 2018

Energy storage/conversion has become crucial not only to meet the present energy demand but also more importantly to sustain the modern society. Particularly, electrical energy storage is critical not only to support electronic, vehicular and load-levelling applications but also to efficiently commercialize renewable energy resources such as solar and wind. While Li-ion batteries are being intensely researched for electric vehicle applications, there is a pressing need to seek for new battery chemistries aimed at stationary storage systems. In this aspect, Zn-ion batteries offer a viable option to be utilized for high energy and power density applications since every intercalated Zn-ion yields a concurrent charge transfer of two electrons and thereby high theoretical capacities can be realized. Furthermore, the simplicity of fabrication under open-air conditions combined with the abundant and less toxic zinc element makes aqueous Zn-ion batteries one of the most economical, safe and green energy storage technologies with prospective use for stationary grid storage applications. Also, Zn-ion batteries are very safe for next-generation technologies based on flexible, roll-up, wearable implantable devices the portable electronics market. Following this advantages, a wide range of approaches and materials, namely, cathodes, anodes and electrolytes have been investigated for Zn-ion batteries applications to date. Herein, we review the progresses and major advancements related to aqueous. Zn-ion batteries, facilitating energy storage/conversion via $Zn^{2+}$ (de)intercalation mechanism.