• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.131-138
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• 1993

To analysis machanical behavior for RC frame under monotonic & Cyclic load, it is needed to investigate elasto-plastic behavior for steel & concrete. Therefore, in this study, we idealized material model(steel and concrete) to take into account elasto-plastic, limit state, and developed structural analysis program that consider complex non-linearity. We investigated simple beam and portal frame under cyclic & monotonic loading, so we confirmed the propriety.

• KCID journal
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• v.7 no.2
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• pp.49-56
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• 2000

A hydraulic model study have been carried out on roughness coefficient of corrugated helical steel pipe. The study was performed in the 0.6m wide flume of Hydraulic Laboratory for the pipe diameter of 0.6m and 1.6m. Additional study was performed in 2m wi

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.133-138
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• 2004

Domestic freight car holding amount is possessing much amount than other vehicle model about 14,000. Problem is happening in bogie device of cast steel structure because is structure that there are many wear departments. Therefore, the KNR is restricting running speed of empty car by 70km/h low. In this research, presented speed elevation way as dynamic characteristic analysis result that use ADAMS and confirm running safety by main line test.

• Journal of Industrial Technology
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• v.18
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• pp.217-223
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• 1998

The springback characteristics of some sheet metals such as commercially pure aluminium, mild steel and stainless steel in a forming process are investigated experimentally. Three geometrical parameters for evaluating springback in the plane-strain draw-bending, which was a benchmark model of NUMISHEET '93 conference, are defined. The measurement of the springback parameters is carried out accurately and easily by using an image analysis system developed in this study. The effects of the blank holding pressure and tensile strength of the material on the springback are also examined.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.2
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• pp.115-119
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• 2016

Winding is one of the major processes in roll-to-roll systems. Taper tension profile in a winding determines the distribution of stress in the radial direction, i.e., the radial stress in the wound rolls. Maximum radial stress is major cause of material defect, and this study has been actively proceeded. Traditional models of radial stress model were focused on flexible and light substrate. In this study, we developed an advanced radial stress model including effects of both these parameters(weight and stiffness) on the radial stress. The accuracy of the developed model was verified through FEM(Finite Element Method) analysis. FEM result of maximum radial stress value corresponds to 99 % in comparison to result with the model. From this study, the material defects does not occur when the steel winding. And steel industry can be applied to improve the winding process.

• Journal of Korean Society of Steel Construction
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• v.15 no.4 s.65
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• pp.413-422
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• 2003

Most engineers tend to rely on their intuition or existing data in formulating structural design or preliminary estimate of various conditions. Because of these variations, the artificial neural network is used as an alternative design model of the warren truss since it can handle uncertainty through the probability method. This research validated the approximate structural design model of the warren truss, with its proper parameter values of the neural network and design process falling within 10 percent torrence of the different designs that resulted between this model and the MIDAS program. The suggested model for the process was adapted for the truss design using the member section table, while time saving and efficiency are based on the allowed range of torrence.

• Journal of Welding and Joining
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• v.33 no.3
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• pp.68-74
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• 2015

Superduplex stainless steels are important materials to the oil and gas industry, especially for off-shore production. TIG welding of super duplex stainless steels to obtain the optimal phase balance between austenite and ferrite is mainly achieved by controlling the cooling rate and the weld chemistry. The latter depends on the filler wire chosen and the shielding gas used. If TIG welding of superduplex stainless steels is performed with argon shielding gas only, then nitrogen gets lost from the weld pool, which can result in a ferrite-rich weld metal, with an inferior corrosion resistance than parent metal. In the present study, nitrogen permeation model from the shield gas which gets into the weld metal in DCEN-TIG welding has suggested. This plasma stream model shows characteristics of permeation of nitrogen ions into the molten metal due to the strong physical effect of plasma stream which formed by the arc pressure rather than the permeation of nitrogen ions caused by electric effect.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.442-445
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• 2006

This paper presents an analytical prediction of nonlinear characteristics and behavior characteristics PSC structures with un-bonded tendon system. In this paper, a numerical model for un-bonded tendon is proposed based on the finite element method, which can represent straight or curved un-bonded tendon behavior. this model and time-dependent material model used to investigate the time-dependent behavior of un-bonded prestressed concrete structures. The accuracy and objectivity of the assessment process may be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of concrete structures and steel plate was used. The material nonlinearities are taken into account by comprising the tension, compression, and shear models of cracked concrete and models for reinforcements and tendons in the concrete. The smeared crack approach is incorporated. It accounts for the aging, creep and shrinkage of concrete and the stress relaxation of prestressed steel. The proposed un-bonded tendon model and numerical method of un-bonded prestressed concrete structures is verified by comparison with reliable experimental results.

• Journal of Information Technology Applications and Management
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• v.22 no.2
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• pp.201-217
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• 2015

In this paper, we report computational testing result to examine the validity of firm's bankruptcy risk estimation through quantification of supply chain risk. Supply chain risk in this study refers to upstream supply risk and downstream demand risk, To assess the firm's risk affected by supply chain risk, we adopt unit of analysis as industry level. since supply and demand relationships of the firm could be generalized by the industry input-output table and the availability of various valid economic indicators which are chronologically calculated. The research model to estimate firm's risk level is the linear regression model to assess the industry bankruptcy risk estimation of the focal firm's industry with the independent variables which could quantitatively reflect demand and supply risk of the industry. The publicly announced macro economic indicators are selected as the candidate independent variables and validated through empirical testing. To validate our approach, in this paper, we confined our research scope to steel industry sector and its related industry sectors, and implemented the research model. The empirical testing results provide useful insights to further refine the research model as the valid forecasting mechanism to capture firm's future risk estimation more accurately by adopting supply chain industry risk aspect, in conjunction with firm's financial and other managerial factors.

• Steel and Composite Structures
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• v.33 no.6
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• pp.767-776
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• 2019

In this article, a simple and robust multi-objective assessment method to control design angles and node positions connected among steel outrigger truss members is proposed to approve both structural safety and economical cost. For given outrigger member layouts, the present method utilizes general-purpose prototypes of outrigger members, having resistance to withstand lateral load effects directly applied to tall buildings, which conform to variable connecting node and design space deposition. Outrigger layouts are set into several initial design conditions of height to width of an arbitrary given design space, i.e., variable design space. And then they are assessed in terms of a proposed multi-objective function optimizing both minimal total displacement and material quantity subjected to design impact factor indicating the importance of objectives. To evaluate the proposed multi-objective function, an analysis model uses a modified Maxwell-Mohr method, and an optimization model is defined by a ground structure assuming arbitrary discrete straight members. It provides a new robust assessment model from a local design point of view, as it may produce specific optimal prototypes of outrigger layouts corresponding to arbitrary height and width ratio of design space. Numerical examples verify the validity and robustness of the present assessment method for controlling prototypes of outrigger truss members considering a multi-objective optimization achieving structural safety and material cost.