• Steel and Composite Structures
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• v.33 no.1
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• pp.143-162
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• 2019

A number of desirable characteristics concerning excellent durability, aesthetics, recyclability, high ductility and fire resistance have made stainless steel a preferred option in engineering practice. However, the relatively high initial cost has greatly restricted the application of stainless steel as a major structural material in general construction. This drawback can be partially overcome by introducing composite stainless steel-concrete structures, which provides a cost-efficient and sustainable solution for future stainless steel construction. This paper presents a preliminary numerical study on stainless steel-concrete composite beam-to-column joints with bolted flush endplates. In order to ensure a consistent corrosion resistance within the whole structural system, all structural steel components were designed with austenitic stainless steel, including beams, columns, endplates, bolts, reinforcing bars and shear connectors. A finite element model was developed using ABAQUS software for composite beam-to-column joints under monotonic and symmetric hogging moments, while validation was performed based on independent test results. A parametric study was subsequently conducted to investigate the effects of several critical factors on the behaviour of composite stainless steel joints. Finally, comparisons were made between the numerical results and the predictions by current design codes regarding the plastic moment capacity and the rotational stiffness of the joints. It was concluded that the present codes of practice generally overestimate the rotational stiffness and underestimate the plastic moment resistance of stainless steel-concrete composite joints.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2672-2678
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• 2011

Carbody of rolling stock has been gradually changed as whole wood, steel frame with wood car body, whole steel car body with rivet and whole monocoque carbody with welding. And also mild steel has been used widely to material of structure, but usage of stainless and aluminium which have lightweight and high corrosion resistance is being increased lately. Structure is being commercialized to AED(All Extrusion Design),whole double skin with hollow excluded shape such as aluminium structure from SSD(Sheet Stringer Design), single skin consists of traditional frame and outside plat. Traditional aluminium carbody had many problems from reduced strength in welding combination section because car body is consist of small extruded material affected heat by welding. On this study, we proposed the plan to improve the body strength and quality with large-scale aluminium extruded material by minimizing welding concentration in combination section.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.3
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• pp.259-263
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• 2004

In the manufacture progress of LCD or semiconductor, there are used many kinds of gas like erosion gas, dilution gas, toxic gas as a progress which used these gas there are required high puritize to increase accumulation rate of semiconductor or LCD materials work progress of semiconductor or LCD it demand many things like the material which could minimize metallic dust that could be occured by reaction between gas and transfer pipe laying material, illumination of the surface, emition of the gas, metal liquation, welding etc also demand quality geting stricted. Material-Low-sulfur-contend (0.007-0010), vacuum-arc-remelt(VAR), seamless, high-purity tubing material is recommend for enhance welding lower surface defect density All wetted stainless steel surface must be 316LSS elecrto polishinged with ${\leq}0.254{\mu}m$($10.0{\mu}in$) Ra average surface finish, $Cr/Fe{\geq}1.1$ and $Cr_2O_3$ thickness ${\geq}25{\AA}$ From the AES analytical the oxide layer thickness (23.5~36 angstroms silicon dioxide equivalent) and chromum to iron ratios is similar to those generally found on electropolished stainless steel., molybdenum and silicon contaminants ; elements characteristic of stainless steel (iron, nickel and chromium); and oxygen were found on the surface Phosphorus and nitrogen are common contaminants from the electropolish and passivation steps.

• Journal of Korean Society of Steel Construction
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• v.11 no.4 s.41
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• pp.417-424
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• 1999

In this paper a nonlinear analysis of three-dimensional steel frames is developed. This analysis accounts for material and geometric nonlinearities. The material nonlinearity includes gradual yielding associated with flexural behaviors. The geometric nonlinearity includes the second-order effects associated with $P-{\delta}\;and\;P-{\Delta}$ effects. The material nonlinearity at the node is considered using the concept of P-M hinge consisting of many fibers. The geometric nonlinearity is considered by the use of stability function. The nonlinearity caused by shear and torsional interaction effects is neglected. The modified incremental displacement method is used as the solution technique. The load-displacements predicted by the proposed analysis compare well with those given by other approaches.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.3
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• pp.191-198
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• 2013

In this paper, the effects of uncertain material constant on the nonlinear behavior of steel frames with semi-rigid joints are examined. As to the probabilistic model, a normal distribution is assumed to simulate the uncertain elastic modulus of steel material. A nonlinear structural analysis program, which can consider both semi-rigidity in joints of the steel frames and uncertainty in the material constant, is developed. Including the geometric, material and connection nonlinearites which are the parameters of nonlinear behavior of steel frames, probabilistic analysis is conducted based on the Monte-Carlo simulation. In the probabilistic analyses, we consider the three different cases for random variables. The deterministic analysis results are shown to be in good agreement with those of the previous research results in the literature. As to the probabilistic analyses, it is observed that the coefficient of variation(COV) of displacements increases as the loading increases, and that the values of COV are dependent on the structural features of the frames.

• The korean journal of orthodontics
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• v.48 no.2
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• pp.107-112
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• 2018

Objective: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. Methods: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. Results: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. Conclusions: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

• Journal of the Korean Wood Science and Technology
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• v.47 no.5
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• pp.655-662
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• 2019

This study evaluated the multi-bonding performances of timbers as well as those of reinforcement and timber to obtain data for preparing guidelines regarding the use of timbers as large structural members. For the multi-bonding performances of timbers, four types of bonding surfaces were prepared according to the pith position. For the bonding performances of FRP (fiber-reinforced plastic)/steel plate and timber, a total of 11 types of specimens were produced for the selection of the appropriate adhesive. The bonding performances of the produced specimens were evaluated through a water soaking delamination test, a water boiling delamination test, and a block shear strength test. The test results showed that the bonding strength of the bonding surface according to the pith position was highest in the specimen for which the two sections with the pith at the center of the cross-section on timber and between the bonding surfaces (the tangential and radial sections were mixed) were bonded. Furthermore, the specimens for which the section (radial section) with the pith on the bonding surface of the timber was bonded showed a high delamination percentage. The results of the block shear strength test showed that the bonding section did not have a significant effect on the shear strength, and that the measured wood failure percentage was higher than the KS standard value. The PVAc adhesive showed the highest bonding strength between larix timber and GFRP (glass FRP). Furthermore, the epoxy and polyurethane adhesives showed good bonding strength for CFRP (carbon FRP) and structure steel, respectively.

• Korean Journal of Metals and Materials
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• v.46 no.3
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• pp.118-124
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• 2008

Abstract: A minimum commitment method(MCM) was applied to predict the long-term creep rupture life for type 316LN stainless steel(SS). Lots of the creep-rupture data for the type 316LN SS were collected through world-wide literature surveys and the experimental data of KAERI. Using these data, the long-term creep rupture life above ${10}^5$ hour was predicted by means of the MCM. In order to obtain the most appropriate value for the constant A being used in the MCM equation, trial and error method was used for the wide ranges from -0.12 to 0.12, and the best value was determined by using the coefficient of determination, $R^2$ which is a statistical parameter. A suitable value for the A in type 316LN stainless steel was found to be at -0.02 ~ -0.05 ranges. It is considered that the MCM will be superior in creep-life prediction to commonly-used timetemperature parametric method, because the P(T) and G($\sigma$) functions are determined from the regression method based on experimental data.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.222-229
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• 2017

High manganese steel exhibits excellent mechanical properties with respect to strength and durability at low temperatures. Recently, high manganese steel has been considered as an alternative to existing materials, such as nickel steel and SUS304L for application as tank material for Liquefied Natural Gas (LNG) cargo containment systems. In the present study, tensile tests were performed at room and cryogenic temperatures in order to investigate the mechanical properties and non-linear tensile behavior of high manganese steel. In addition, elasto-plastic damage model was applied using the finite element analysis software ABAQUS via a user defined material subroutine (UMAT) to describe the material behavior. Finally, the results of the finite element simulations using the UMAT were compared to those of the tensile tests in order to validate the proposed UMAT. It has been demonstrated that the UMAT can effectively describe the non-linear tensile behavior of high manganese steel.

• Structural Engineering and Mechanics
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• v.9 no.4
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• pp.323-338
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• 2000

An analytical approach for the prediction of the behaviour of steel-fiber reinforced concrete beams subjected to torsion is described. The analysis method employs a special stress-strain model with a non-linear post cracking branch for the material behaviour in tension. Predictions of this model for the behaviour of steel-fiber concrete in direct tension are also presented and compared with results from tests conducted for this reason. Further in this work, the validation of the proposed torsional analysis by providing comparisons between experimental curves and analytical predictions, is attempted. For this purpose a series of 10 steel-fiber concrete beams with various cross-sections and steel-fiber volume fractions tested in pure torsion, are reported here. Furthermore, experimental information compiled from works around the world are also used in an attempt to establish the validity of the described approach based on test results of a broad range of studies. From these comparisons it is demonstrated that the proposed analysis describes well the behaviour of steel-fiber concrete in pure torsion even in the case of elements with non-rectangular cross-sections.