• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.17-28
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• 2009

PEB system is more economical when compared with structures commonly used Hot rolled and welded light H-beam was introduced in the Standard Livestock Housing. This study suggested more economical technology for structural design by the reduction of live load, relief of deflection limit and reduction of importance factor. And, when applying wind Load as a result of examination with Low Rise Building Systems Manual considering open model, we can know that when the wind load is big, enclosed model is more stable than open model. In short, Suggesting more economical model and providing the method to reduce natural disaster, by the application of PEB system and the development of technology for structural design, are considered to strengthen the competitive power of farmhouse.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1747-1755
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• 2008

Design of the reinforced roadbed thickness is concerned with safe operation of trains at specified levels of speed, axle load and tonnage. There are two methods for evaluating it. One is using an experimental equation and the other is using elastic theory with considering axle load, material properties of subsoils and allowable elastic settlement. Multi-layered theory is used to determine reinforced roadbed thickness by RTRI. Although their reinforced roadbed thickness is designed with an objective of achieving a minimum standard 2.5mm of settlement on the subgrade surface, it is hardly applied to real design. Li(1994) has suggested the experimental model which design approach is to limit plastic strain and deformations for the design period. It is worth due to adopting soil equivalent number of repeated load application. Moreover, it has been a more advanced method than existing design methods because including resilient modulus of subsoil beneath track, soil deviator stress caused by train axle loads and MGT. In this paper, it is analyzed under domestic track conditions to estimate the reinforced roadbed thickness with different soil types.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.179-185
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• 2002

In this study, the structural design method for the modified long-endurance UAV is presented. Composite materials using room temperature curing method and wet lay up procedure is applied to all wing structures. The modified wing is composed of 3-piece component for improvement of ground handling. As the sandwich structure is efficient for light weight and high stiffness, all skin is used the sandwich consisting of glass/ epoxy fabric and balsa wood. The proof test is performed up to limit load corresponding to 4g load condition for the modified wing structure.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.407-413
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• 2011

Reliability analysis of pile type quaywalls were done by using response surface method. Pier structures have implicit form of limit state function since they are flexible in motion, which is different from gravity type quaywalls. To solve a reliability analysis problem with implicit limit state function, response surface method was applied. Reliability indices of structure under seismic load were found for pier structures Then, they were compared with those found by simulation method. In numerical analysis, both the inclined type and vertical type were analyzed.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.269-275
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• 1999

A variable blank holding force method is proposed to improve deep drawing characteristics of sheet materials. In this method, the blank holding force (BHF) is controlled throughout a drawing process so that the punch load does not exceed a critical value, which is slightly less than the conventional process with the conforming process with the variable BHF is more flexible than the conventional process with the constant BHF and it could be used for improving the product's quality and drawability. In this paper we suggest a method controlling the BHF as a function of punch travel during the forming process. The optimization BHF curves are determined theoretically and experimentally. It is concluded that for the case of optimum BHF control methods the drawn cup height and the drawing formability achieved by this method are increased than those for constant BHF method. Also, as comparing the wall thickness distribution of the cup drawn by the constant BHF and the optimum BHF control, the BHF control reduce the wall thickness variation of the drawn cup at the cup wall and make the cup thickness distribution more uniformly than the constant BHF.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.890-897
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• 2003

This paper compares engineering estimation schemes of C＊ and creep COD for circumferential and axial through-wall cracked pipes at elevated temperatures with detailed 3-D elastic-creep finite element results. Engineering estimation schemes included the GE/EPRI method, the reference stress method where reference stress is defined based on the plastic limit load and the enhanced reference stress method where the reference stress is defined based on the optimized reference load. Systematic investigations are made not only on the effect of creep-deformation behaviour on C＊ and creep COD, but also on effects of the crack location, the pipe geometry, the crack length and the loading mode. Comparison of the FE results with engineering estimations provides that for idealized power law creep, estimated C＊ and COD rate results from the GE/EPRI method agree best with FE results. For general creep-deformation laws where either primary or tertiary creep is important and thus the GE/EPRI method is hard to apply, on the other hand, the enhanced reference stress method provides more accurate and robust estimations for C* and COD rate than the reference stress method.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.242-246
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• 1999

For the fabrication of fault current limiting device using HTSC thick film, YBa$_2Cu_3O_x$ superconducting thick film was formed by surface diffusion process of the Y$_2BaCUO_5$ and the mixed compound of (3BaCuO$_2$+2CuO) expected to be liquid phase above the peritectic temperature of YBa$_2Cu_3O_x$. For the surface diffusion, the compounds of 3BaCuO$_2$+2CuO mixed with binder material was patterned on Y$_2BaCUO_5$ substrate by the screen printing method. After proper sintering, the characteristics of current limit on thick film fabricated was measured. The thick film was able to limit the current from 2.8213 mA$_{rms}$nu to 4.2034 mA$_{rms}$ with 500${\omega}$ load resistance, and from 4.1831 mA$_{rms}$ to 4.2150 mA$_{rms}$ with 10${\omega}$ load resistance.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.17 no.1
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• pp.28-35
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• 2021

The flow accelerated corrosion (FAC) is one of significant aging and degradation mechanism and can affect structural integrity of CANDU feeder pipes. Pipe burst can occur under normal operation pressure (min. 10 MPa) if wall-thinning of the feeder pipe due to FAC is accumulated. Previous studies considered simple shapes of feeder pipe with local wall-thinning in order to conservatively assess structural integrity of wall-thinned feeder pipe. In this paper, a new FE model is developed, having an actual shape of the feeder pipe (double bent) as well as the actual wall-thinning shape and location based on the in-service inspection result. Then, the burst pressure assessment of the wall-thinned feeder pipe is performed using lower bound limit load analysis considering elastic-perfectly plastic material. In addition, an improved formulation to predict the burst pressure of the wall-thinned feeder pipe is presented and the safety margin is compared with an existing assessment method.

• Steel and Composite Structures
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• v.20 no.2
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• pp.379-397
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• 2016

Due to creep and shrinkage of the concrete core, concrete-filled steel tubular (CFST) arches continue to deform in the long-term under sustained loads. This paper presents analytical investigations of the effects of geometric nonlinearity on the long-term in-plane structural performance and stability of three-pinned CFST circular arches under a sustained uniform radial load. Non-linear long-term analysis is conducted and compared with its linear counterpart. It is found that the linear analysis predicts long-term increases of deformations of the CFST arches, but does not predict any long-term changes of the internal actions. However, non-linear analysis predicts not only more significant long-term increases of deformations, but also significant long-term increases of internal actions under the same sustained load. As a result, a three-pinned CFST arch satisfying the serviceability limit state predicted by the linear analysis may violate the serviceability requirement when its geometric nonlinearity is considered. It is also shown that the geometric nonlinearity greatly reduces the long-term in-plane stability of three-pinned CFST arches under the sustained load. A three-pinned CFST arch satisfying the stability limit state predicted by linear analysis in the long-term may lose its stability because of its geometric nonlinearity. Hence, non-linear analysis is needed for correctly predicting the long-term structural behaviour and stability of three-pinned CFST arches under the sustained load. The non-linear long-term behaviour and stability of three-pinned CFST arches are compared with those of two-pinned counterparts. The linear and non-linear analyses for the long-term behaviour and stability are validated by the finite element method.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.33-40
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• 2008

The load distribution and deformation of rock-socketed drilled shafts subjected to axial loads are evaluated by a load-transfer method. The emphasis is on quantifying the effect of coupled soil resistance in rock-socketed drilled shafts using the 2D elasto-plastic finite element analysis. Slippage and shear load transfer behavior at the pile-soil interface are investigated by using a user-subroutine interface model (FRlC). It is shown that the coupled soil resistance provides the influence of pile toe settlement as the shaft resistance is increased to an ultimate limit state. The results show that the coupling effect is closely related to the value of pile diameter over rock mass modulus (D/$E_{mass}$) and the ratio of total shaft resistance against total applied load ($R_s$/Q). Through comparisons with field case studies, the 2D numerical analysis reseanably presented load transfer of pile and coupling effect due to the transfer of shaft shear loading, and thus represents a significant improvement in the prediction of load deflections of drilled shafts.