• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.629-634
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• 2004

Modal parameters of the total missile structure including a hinge mechanism are estimated by the experimental modal analysis. The free-free boundary condition is simulated by hanging the missile structure with a wire rope, and the missile structure is excited by the random vibration technique. Test results are used to verify the FE analysis, the 1-D FE model is modified by 3-D model at the hinge part. Consequently, the modal parameters of the missile structure are estimated preciously.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.77-84
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• 2003

In this paper, the refined plastic-hinge analysis accounting for the effect of strain reversal caused by non-proportional loading is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem, conventional refined plastic-hinge analyses have underestimated the strength of structures subjected to non-proportional loading, is overcome. The modified stiffness degradation model approximating the effect of strain reversal is discussed in detail. The proposed analysis is verified by the comparison of the finite element analysis. A case study shows that the effect of strain reversal is a very crucial element to be considered in second-order plastic-hinge analysis. The proposed analysis is shown to be an efficient, reliable tool ready to be implemented into design practice.

• Journal of Korean Society of Steel Construction
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• v.21 no.2
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• pp.155-164
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• 2009

In this study, a computationally efficient parallel axial-flexural plastic hinge model is proposed for nonlinear dynamic progressive collapse analysis of welded steel moment frames. To this end, post-yield flexural behavior and the interaction of bending moment and axial force of the double-span beams in the column's missing event was first investigated by using material and geometric nonlinear parametric finite element analysis. A piece-wise linear parallel point hinge model that captures the moment-axial tension interaction was then proposed and applied to nonlinear dynamic progressive collapse analysis of welded steel moment frames with the use of the OpenSees Program. The accuracy as well as the efficiency of the proposed model was verified based on the inelastic dynamic finite element analysis results. The importance of including the catenary action effects for proper progressive collapse resistant analysis and design was also emphasized.

• Earthquakes and Structures
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• v.11 no.5
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• pp.823-840
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• 2016

The plastic hinge lengths of beams and columns are a critical demand parameter in the nonlinear analysis of structures using the finite element method. The numerical model of a plastic hinge plays an important role in evaluating the response and damage of a structure to earthquakes or other loads causing the formation of plastic hinges. Previous research demonstrates that the plastic hinge length of reinforced concrete (RC) columns is closely related to section size, reinforcement ratio, reinforcement strength, concrete strength, axial compression ratio, and so on. However, because of the limitations of testing facilities, there is a lack of experimental data on columns with large section sizes and high axial compression ratios. In this work, we conducted a series of quasi-static tests for columns with large section sizes (up to 700 mm) and high axial compression ratios (up to 0.6) to explore the propagation of plastic hinge length during the whole loading process. The experimental results show that besides these parameters mentioned in previous work, the plastic hinge of RC columns is also affected by loading amplitude and size effect. Therefore, an approach toward considering the effect of these two parameters is discussed in this work.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.29-36
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• 2005

The purpose of this study is to investigate the inelastic behavior of reinforced concrete bridge columns with unbonding of main reinforcements at plastic hinge region. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. The effect of unbonding of main reinforcements at plastic hinge region has been also taken into account to model the concrete and reinforcing steel. The proposed numerical method for the inelastic behavior of reinforced concrete bridge columns with unbonding of main reinforcements at plastic hinge region is verified by comparison with reliable experimental results.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.285-292
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• 2012

Fixed connection is generally used for beam and column connections of concrete structures, but significant damages at the connection due to severe earthquakes have been reported. In order to reduce damages of the connection and improve seismic performance of the connection, several innovative connections have been suggested. One newly proposed connection type allows a rotation of the connection for applications in rotating or rocking beams, columns, and shear walls. Such structural elements would provide a nonlinear lateral force-displacement response since their contact depth developed during rotation is gradually reduced and the stress across the sections of the elements is non-linearly distributed around a contact area, which is called an elastic hinge region in the present study. The purpose of the present study is to define the elastic hinge region or length for the rocking columns, through investigating the cross-sectional stress distribution during their lateral behavior. Performing a finite element analysis (FEA), several parameters are considered including axial load levels (5% and 10% of nominal strength), different boundary conditions (confined-ends and cantilever types), and slenderness ratios (length/depth = 5, 7, 10). The FEA results showed that the elastic hinge length does not directly depend on the parameters considered, but it is governed by a contact depth only. The elastic hinge length started to develop after an opening state and increased non-linearly until a rocking point(pre-rocking). However, the length did not increase any more after the rocking point (post-rocking) and remained as a constant value. Half space model predicting the elastic hinge length is adapted and the results are compared with the numerical results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.1
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• pp.15-22
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• 2022

This paper introduces research on the hinge joint of modular structure joints using finite element analysis. The modular structure has a characteristic in that it is difficult to expect the integrity of columns and beams between unit modules because the construction is carried out such that the modules are stacked. However, the current modular design ignores these structural characteristics, considers the moment transmission for the lateral force, and analyzes it in the same manner as the existing steel structure. Moreover, to fasten the moment bonding, bolts are fastened outside and inside the module, resulting in an unreasonable situation in which the finish is added after assembly. To consider the characteristics that are difficult to expect, such as unity, a modular structure system using hinge joints was proposed. This paper proposed and reviewed the basic theory of joints by devising a modified scissors model that is modified from the scissors model used in other research to verify the transmission of load when changing from the existing moment junction to a hinge junction. Based on the basics, the results were verified by comparing them with Midas Gen, a structural analysis program. Additionally, the member strength and usability were reviewed by changing the modular structure designed as a moment joint to a hinge joint.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1366-1371
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• 2006

A structural coupling method is developed for the dynamic analysis of a nonlinear structure with concentrated nonlinear hinge joints or sliding lines. Component mode synthesis method is extended to couple substructures and the nonlinear models. In order to verify the improved coupling method, a numerical plate model consisting of two substructures and torsional springs, is synthesized by using the proposed method and its model parameters are compared with analysis data. Then the coupling method is applied to a three-substructure-model with the nonlinearity of sliding lines between the substructures. The coupled structural model is verified from its dynamic analysis. The analysis results show that the improved coupling method is adequate for the structural nonlinear analyses with the nonlinear hinge and sliding mode condition.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.349-356
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• 2010

In this study, a new design method of pile bent structure considering plastic hinge was proposed on the basis of the beam-column model. Based on the analysis results, it is found that the positioning of plastic hinge on the pile bent structure was influenced by nonlinear behavior of material and p-$\Delta$ effect. Moreover, concrete cracking began to occur at the joint section between the pile and column in case of pile bent structure with different cross-sections. The plastic hinge can be developed on the pile bent structure when large displacement was occurred, and pile bent structures can be maintained well only if it is developed on the column part. Therefore, in this study, the optimized cross-section ratio between column and pile was analyzed to induce the plastic hinge at the joint section between the pile and column. Based on this, the optimized diameter ratio of pile and column can be obtained below the inflection point of the bi-linear curve depending on the relations between column-pile diameter ratio($D_c/D_p$) and normalized lateral cracking load ratio($F/F_{Dc=Dp}$). And through this study, it is founded that in-depth limit($L_{As}$=0.4%) normalized by the pile length($L_P$) are proportionally decreased as the pile length($L_P/D_P$) increases up to $L_P/D_P$=17.5, and beyond that in-depth limit converges to a constant value. Finally, it is found that the proposed limit depth by taking into account the minimum concrete-steel ratio would be more economical design of the pile bent structure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.955-956
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• 2009