• Steel and Composite Structures
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• v.47 no.2
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• pp.203-216
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• 2023

The composite beam connections often encountered fracture failure in the welded bottom flange joint, and a bottom flange bolted connection has been proposed to increase the deformation ability of the bottom flange joint. The seismic performance of the bottom flange bolted composite beam connection was suffered from both the composite action of concrete slab and the asymmetric load transfer mechanisms between top and bottom beam flange joints. Thus, this paper presents a comprehensive numerical study on the working mechanism of the bottom flange bolted composite beam connections. Three available modelling methods and a new modelling method on the flange-stud-slab interactions were compared. The efficient numerical modeling method was selected and then applied to the parametric study. The influence of the composite slab, the bottom flange bolts, the shear composite ratio and the web hole shape on the seismic performance of the bottom flange bolted composite beam connections were investigated. A hogging strength calculation method was then proposed based on numerical results.

• Journal of the Korean Geosynthetics Society
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• v.12 no.1
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• pp.11-19
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• 2013

Coarse-grained soils are typical engineering materials commonly used in many civil engineering applications such as structural fills, subgrade and drainage fills for dam, railway and bridge. Various researches have been performed with related to constitutive laws for numerical analysis of such structures. This paper presents a parametric study for a constitutive model for coarse grained materials. The model is a kind of the bounding surface models based on critical state theory. A distinct feature of the model is to capture the response of coarse-grained materials with different void ratios and confining pressures using a single set of model parameters. The model behavior is defined with a set of elastic parameters, critical state parameters, and model-specific parameters. The parametric study was performed for the model-specific parameters. The result of parametric study shows that the model is capable to capture stress-dilatancy behavior and kinematic-hardening under non-associative plastic flow.

• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.381-394
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• 2020

The structural performance of cold-formed steel (CFS) built-up battened columns were numerically investigated in this paper. The built-up column sections were formed by connecting two-lipped channels back-to-back, with a regular spacing of battens plates, and have been investigated in the current study. Finite element models were validated with the test results reported by the authors in the companion paper. Using the validated models, the parametric study was extended, covering a wider range of overall slenderness to assess the accuracy of the current design rules in predicting the design strengths of the CFS built-up battened columns. The parameters viz., overall slenderness, different geometries, plate slenderness (b/t ratio) and yield stress were considered for this study. In total, a total of 228 finite element models were analyzed and the results obtained were compared with current design strength predicted by Effective Width Method of AISI Specifications (AISI S100:2016) and European specifications (EN1993-1-3:2006). The parametric study results indicated that the current design rules are limited in predicting the accuracy of the design strengths of CFS built-up battened columns. Therefore, a design equation was proposed for the AISI and EC3 specifications to predict the reliable design strength of the CFS Built-up battened columns and was also verified by the reliability analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.424-429
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• 1998

Numerical studies are performed to investigate the behavior of flat plates under combined in-plane and out-of-plane loads. The numerical model is verified by comparison with experiments for plates simply supported on four edges. Through study on different load combination and loading sequence, the critical load condition that governs the strength of the flat plate is determined. Parametric studies are performed to investigate the buckling coefficient and the effective flexural rigidity so that the moment magnification method is applicable to the flat plates.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.281-282
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• 2003

Numerical investigations are carried out to study the mass flux and temperature distribution in a calandria using a 3-D RANS code. The computations made for simulations of flow and convective heat transfer with near-to working conditions. The work provides an estimate of the safe working limits of the heat dissipation by virtue of prediction of the 'hot spots' in the calandria. The work assumes significance for preliminary designs of the reactors and for detailed critical parametric analysis that would be otherwise more expensive.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.127-134
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• 2009

In this paper, an numerical approach is performed to investigate the effects of smear zone, occurred by penetrating vertical drains, on consolidation behavior of soft clay deposits. Such a numerical analysis is applied to the field condition to confirm its applicability. Parametric numerical analyses is carried out to study influencing factors such as permeability in smear zone, boundary of smear zone and discharge capacity of vertical drains on the consolidation of soil. As results of analyses, for the given conditions of soil, degree of consolidation is getting faster with increase of permeability of vertical drain. Degree of consolidation is delayed with decrease of permeability of smear zone. As the ratio of drain width to smear zone increases, the degree of consolidation decreases. Proposed values of influencing factors by previous researchers is found to be reliable from results of numerical analyses with Cam-clay model.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.6
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• pp.258-262
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• 2016

Foam reaction injection molding (FRIM) is a widely used process for manufacturing polyurethane foam with complex shapes. The modified theoretical model for polyurethane foam forming reaction during FRIM process was established in our previous work. In this study, using the modified model, parametric study for FRIM process was performed in order to optimize experimental conditions of FRIM process such as initial temperature of mold, thickness of mold, and injection amount of polymerizing mixture. In addition, we applied the modified model to real application of refrigerator cabinet to determine optimal manufacturing conditions for polyurethane FRIM process.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.2
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• pp.178-186
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• 2018

The scale effects on the permanent deformations and fractures of structures subjected to impact loadings have been aware by structural engineers for a long time. Experimental investigations have been performed with various structures to demonstrate the effects, but very few are directly related with marine structural elements. Furthermore, the causes of the scale effects have not clearly been answered yet. In this study, to quantify the scale effects on the permanent deflections, lateral collision tests were performed on steel unstiffened plates and the numerical analyses of the tested models were also conducted using a commercial package, Abaqus. After the substantiation of the numerical tool using the test results, a parametric study was carried out considering and neglecting the strain-rate hardening. Based upon the parametric study results, it may be concluded that the main cause of the scale effects on the permanent deflections of steel unstiffened plates subjected to lateral collision loads is the strain-rate effects.

• Journal of Ocean Engineering and Technology
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• v.32 no.5
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• pp.333-340
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• 2018

This paper addresses the concept of the representative mean position, which was devised to improve the numerical efficiency of a time domain fatigue analysis of a mooring chain. To investigate the influence of an artificial offset of the floater on the fatigue of the mooring chain, a parametric study was performed on the moored FPSO under various combinations of offsets and environmental conditions. Tension time histories were calculated using the de-coupled analysis method, and fatigue damages were calculated to determine the influence of the offset. The parametric study was extended to a more realistic case to determine the actual effect of the representative mean position, where a comparison was made between the two different analysis results, one using the representative mean position and the other one using the actual mean position. It was confirmed that the application of the representative mean position guaranteed the conservatism of the fatigue damage with the enhanced numerical efficiency in the time domain fatigue analysis.

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.305-314
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• 2021

In order to reduce enormous cost of real-scale underwater explosion experiments on ships, the mechanical response of the ships have been analyzed by combining scaled-down experiments and Hopkinson's scaling law. However, the Hopkinson's scaling law is applicable only if all variables vary in an identical ratio; for example, thickness of ship, size of explosive, and distance between the explosive and the ship should vary with same ratio. Unfortunately, it is infeasible to meet such uniform scaling requirement because of environmental conditions and limitations in manufacturing scaled model systems. For the facile application of the scaling analysis, we propose a generalized scaling law that is applicable for non-uniform scaling cases in which different parts of the experiments are scaled in different ratios compared to the real-scale experiments. In order to establish such a generalized scaling law, we conducted a parametric study based on numerical simulations, and validated it with experiments and simulations. This study confirms that the initial peak value of response variables in a real-scale experiment can be predicted even when we perform a scaled experiment composed of different scaling ratios for each experimental variable.