• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.171-177
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• 2000

It is essential to understand the creep behavior, which shows how long the characteristics of material maintains because press joined molding GMT-Sheet for recycle is usually used in the severe environment. In this study, we predict joining strength of GMT-Sheet for recycle, when lap length was changed. and we will investigate how compression ratio have an effect on creep behavior in press joined molding. The result of experiment of forming condition concerned with joining problem of GMT-Sheet is as followings joining efficiency. of GMT-Sheet, increases as lap joint length I, increases. Increase of compression ratio causes decrease o f joining efficiency after of GMT-Sheet joining. As the result of creep test, GMT-Sheet is easily damaged in high temperature range, because it is sensitive to the temperature

• Composites Research
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• v.31 no.1
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• pp.8-11
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• 2018

Sheet molding compound (SMC) is one of the most economical fiber reinforced composite fabrication processing for automotive applications. In this study, we studied the optimum formulation for the production of SMC which shows low specific gravity without lowering the mechanical properties by using glass bubble (GB) which is a low specific gravity filler and glass fiber (GF) as a reinforcing material. The tensile strength increased with the increase of the GF in the SMC, and the specific gravity decreased with the increase of the GB. The synergistic effect of improving the mechanical properties as the specific gravity is lowered is found in the optimum formulation. The synergy effect was confirmed by the internal structure analysis that the dispersion effect of the crack propagation of the GB and the improvement of the binding force between the fiber and the matrix due to the incorporation of the GB.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.413-416
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• 2006

Two clad composites of five ply sheets comprising STS430/AA3003/AA3003/AA3003/STS430 and STS430/AA3003/STS430/AA3003/STS430 were produced by roll cladding at $350^{\circ}C$. In order to clarify the deformation behavior and strain states in the composites during roll cladding, the variation of individual sheet thickness and the evolution of through thickness textures and microstructures of the composites were investigated. The thickness reduction of each sheet depended on the location of the sheet and on the strength of each sheet in the composites. In order to elucidate the evolution of textures and microstructures in AA3003 sheets, the strain states in AA3003 sheets during roll cladding were calculated by FEM. The formation of shear textures and fine grains in AA3003 sheet was discussed in terms of the strain states in each sheet layer. Finally, the strain states extracted from the FEM were verified by texture simulations

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.83-90
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• 2016

Increasing the amount of filler in paper is of high interest for paper industry while maintaining its key sheet quality properties. In this study, a MFC-GCC composite, made through a co-grinding NBSK (Northern bleached softwood kraft) pulp with a ground calcium carbonate (Intracarb 60), was used as a strength aid in paper in order to evaluate a potential cost reduction through filler increase without sacrificing paper quality. Hand-sheets were made of NBSK and/or eucalyptus pulp by using white water recirculation in a Tappi sheet former and was compared its properties without or with MFC additions at different filler levels. It was found that the MFC-GCC composite has a large surface area compared to the fiber, allowing the formation of more hydrogen bonds in the web, thus giving natural strength to the paper. Overall results are encouraging that the MFC-GCC composite allows papermaker to reduce basis weight and maintain critical sheet properties.

• Computers and Concrete
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• v.33 no.6
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• pp.739-754
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• 2024

This study presents an innovative AI-driven approach to assess the ultimate axial load in Double-Skinned Profiled Steel sheet Composite Walls (DPSCWs). Utilizing a dataset of 80 entries, seven input parameters were employed, and various AI techniques, including Linear Regression, Polynomial Regression, Support Vector Regression, Decision Tree Regression, Decision Tree with AdaBoost Regression, Random Forest Regression, Gradient Boost Regression Tree, Elastic Net Regression, Ridge Regression, and LASSO Regression, were evaluated. Decision Tree Regression and Random Forest Regression emerged as the most accurate models. The top three performing models were integrated into a hybrid approach, excelling in accurately estimating DPSCWs' ultimate axial load. This adaptable hybrid model outperforms traditional methods, reducing errors in complex scenarios. The validated Artificial Neural Network (ANN) model showcases less than 1% error, enhancing reliability. Correlation analysis highlights robust predictions, emphasizing the importance of steel sheet thickness. The study contributes insights for predicting DPSCW strength in civil engineering, suggesting optimization and database expansion. The research advances precise load capacity estimation, empowering engineers to enhance construction safety and explore further machine learning applications in structural engineering.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.59-66
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• 2014

Insulation of rooftop is one of the major performance to energy-saving construction. Further, waterproofing performance is also important. For such a reason, it is need to develop waterproofing method containing thermal insulation property. This study was wanted to evaluate thermal insulation performance about the composite waterproofing method of thermal supplement type that is developed recently. As a result of waterproofing performance test, every test item was showed over the performance standards of KS (Korean (Industrial) Standards). And the result of thermal insulation performance test, the highest temperature in the styrofoam box was $25.91^{\circ}C$, the bubble sheet box was $17.28^{\circ}C$, the insulation sheet box was $15.47^{\circ}C$ and the waterproofing sheet box of thermal supplement type was $24.11^{\circ}C$. In observations of thermal bridges of sheet's joint, thermal bridges was not identified at the sheet's joint. As a result, composite waterproofing method of thermal supplement type is interpreted to have thermal insulation performance.

• Structural Engineering and Mechanics
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• v.87 no.6
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• pp.517-527
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• 2023

The severe deterioration of structures has led to extensive research on the development of structural repair techniques using composite materials. Consequently, previous researchers have devised various analytical methods to predict the interface performance of bonded repairs. However, these analytical solutions are highly complex mathematically and necessitate numerous calculations with a large number of iterations to obtain the output parameters. In this paper, an artificial neural network prediction models is used to calculate the interfacial stress distribution in RC beams strengthened with FRP sheet. The R2value for the training data is evaluated as 0.99, and for the testing data, it is 0.92. Closed-form solutions are derived for RC beams strengthened with composite sheets simply supported at both ends and verified through direct comparisons with existing results. A comparative study of peak interfacial shear and normal stresses with the literature gives the usefulness and effectiveness of ANN proposed. A parametrical study is carried out to show the effects of some design variables, e.g., thickness of adhesive layer and FRP sheet.

• Steel and Composite Structures
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• v.13 no.6
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• pp.571-586
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• 2012

The paper addresses some key issues related to the design of composite slabs with cold-formed profiled steel sheets. An experimental programme is first presented, involving six composite slab specimens tested with a view to evaluating Eurocode 4 (EC4) provisions on testing of composite slabs. In four specimens, the EC4-prescribed 5000 load cycles were applied using different load ranges resulting from alternative interpretations of the reference load $W_t$. Although the rationale of the application of cyclic loading is to induce loss of chemical bond between the concrete plate and the steel sheet, no such loss was noted in the tests for either interpretation of the range of load cycles. Using the recorded response of the specimens the values of factors m and k (related to interface shear transfer in the composite slab) were determined for the specific steel sheet used in the tests, on the basis of three alternative interpretations of the related EC4 provisions. The test results confirmed the need for a more unambiguous description of the m-k test and its interpretation in a future edition of the Code, as well as for an increase in the load amplitude range to be used in the cyclic loading tests, to make sure that the intended loss of bond between the concrete slab and the steel sheet is actually reached. The study also included the development of a special-purpose software that facilitates design of composite slabs; a parametric investigation of the importance of m-k values in slab design is presented in the last part of the paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.499-504
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• 2003

Future bridge decks must have high load-resistance capacity as well as fatigue strength to withstand the increase in traffic loading and the increase in span length between girders due to the decrease in the number of main girders. Steel-concrete composite bridge decks may be proper deck types to satisfy such requirements. To promote the application of composite bridge decks, a rational process to predict and evaluate the fatigue behavior of steel concrete composite bridge deck is required. Various types of steel-concrete composite bridge decks have been developed in many countries. In this study, combining advantages of the existing composite deck types, a new type of composite bridge deck is proposed. An experimental study is performed to examine the fatigue behavior of the proposed composite bridge deck. This composite bridge deck consists of corrugated steel sheet, welded T-beams, stud-type shear connectors and reinforced concrete filler. The fatigue tests are conducted under four-point bending test with three different stress ranges in constant amplitude. The fatigue category of the fillet welding between corrugated steel sheet and the T-beam is evaluated based on the S-N data obtained from the experiment.

• Steel and Composite Structures
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• v.35 no.4
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• pp.509-525
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• 2020

Steel-concrete composite slabs with profiled steel sheeting are widely used in the execution of floors in steel and composite buildings. The rapid construction process, the elimination of conventional replaceable shuttering and the reduction of temporary support are, in general, considered the main advantages of this structural system. In slabs with the spans currently used, the longitudinal shear resistance commonly provided by the embossments along the steel sheet tends to be the governing design mode. This paper presents an innovative reinforcing system that increases the longitudinal shear capacity of composite slabs. The system is constituted by a set of transversal reinforcing bars crossing longitudinal stiffeners executed along the upper flanges of the steel sheet profiles. This type of reinforcement takes advantage of the high bending resistance of the composite slabs and increases the slab's ductility. Two experimental programmes were carried out: a small-scale test programme - to study the resistance provided by the reinforcing system in detail - and a full-scale test programme to test simply supported and continuous composite slabs - to assess the efficacy of the proposed reinforcing system on the global behaviour of the slabs. Based on the results of the small-scale tests, an equation to predict the resistance provided by the proposed reinforcing system was established. The present study concludes that the resistance and the ductility of composite slabs using the reinforcing system proposed here are significantly increased.