• Proceedings of the KSR Conference
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• 2005.11a
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• pp.1159-1164
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• 2005

Seismic analysis methods in use on ground structure are equivalentstatic analysis, response-displacement method and dynamic analysis etc. Equivalentstatic analysis does not considerdynamic effect, and dynamic analysis process is very complex. then 'Urbanrail transit earthquake-resistance design standard (2005.06)' is persuading that analyze by response displacement method that consider enough dynamic effect of ground structure statically. But, It is very complex and difficult to apply response-displacement method in the field. So, modified equivalentstatic analysis or pseudo static analysis that is easy to apply in the field and have rationality of design is practically used. In this study, I try to prescribe the applicable scale of structure and static analysis that have calculative effectiveness about response-displacement method by comparing and analyzing the result of each analysis method according to the scale of urban rail transit' box type concrete structure and by performing seismic analysis that apply modified equivalentstatic analysis, pseudo static analysis and response-displacement method changing the kind of ground, depth of bedrock, size of structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.194-201
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• 2000

In this study the modified seismic coefficient method for seismic analysis of buried box structures is developed for practical purpose. The loading coefficient in the modified seismic coefficient method is determined from the results of the response displacement analysis. In the developed method adequate velocity response spectrum in accordance with soil condition is also needed to seismic design of buried box structures, In order to investigate applicability of the modified seismic coefficient method various analyses are performed with different parameters such as depth of base rock height and width of box buried depth and value of standard penetration test. Results from the modified seismic coefficient method are compared with those of the response displacement method in terms of the maximum bending moment and the location of it. From the comparison it is shown that the feasibility of the modified seismic coefficient method for seismic analysis of buried box structures.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.119-126
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• 2006

Capacity spectrum method(CSM) of ATC-40(1996) and displacement coefficient method(DCM)of FEMA-273(1997) are applied to evaluate the seismic performance of bridges. In this study, equivalent response is obtained from nonlinear static analysis for the 3spans continues bridge and nonlinear maximum displacement response is calculated using CSM and DCM. Nonlinear maximum displacement response of DCM is larger than this of CSM. It is method that DCM can evaluate target displacement and ductility of structural to be easy and simple, but tend to overestimate the maximum displacement response. Therefore, this method is mainly used at preparation design level to evaluate the structural response. It is not desirable to evaluate the seismic performance using DCM.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.83-93
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• 2004

In this study. the Modified Response Displacement Method(MRDM) for seismic design of underground box-type structures is proposed. Firstly, to investigate the applicability of the conventional RDM, various parametric studies are performed according to buried depth and soil conditions. Results from the conventional RDM are compared with those of time history analysis in terms of the maximum bending moment and relative displacement. The comparison shows that the velocity response spectrum and the determination method of foundation modulus which significantly influence the accuracy of RDM should be modified. Thus, the modified velocity response spectrum and the new determination method of foundation modulus are proposed under consideration of domestic conditions. In order to demonstrate the accuracy and validity of the proposed MRDM numerical analyses are performed according to different parameters such as depth of base rock, height and width of box, buried depth and soil condition. the comparison with the results of the time history analysis verifies the feasibility of the proposed MRDM for the seismic analysis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.317-324
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• 2022

In this paper, an analysis method that considers the initial static displacement of structural members using an equivalent single-degree-of-freedom system is presented. Newmark's dynamic analysis algorithm was improved to consider the effect of the initial static displacements of structural members. The effect of the initial static displacement on the maximum response according to the assumed duration of the blast load and natural period of the member was investigated. The effects of positive and negative static displacements on the maximum dynamic responses of structural members subjected to a positively applied blast load were also studied. Modified response charts for the shock-type and pressure-type waves are presented so that static displacements can easily be considered. Using a design example, we demonstrate the significance of the modified response chart that considers the static displacement. Based on the results of this study, the maximum response of a the structural member can be easily obtained whilst considering its initial static displacement. The modified response chart presented in this study can be used for the structural design of plants and military facilities.

• Earthquakes and Structures
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• v.4 no.4
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• pp.341-363
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• 2013

Earthquake response calculation, parametric analysis and seismic parameter optimization of base-isolated structures are some critical issues for seismic design of base-isolated structures. To calculate the earthquake responses for such non-symmetric and non-classical damping linear systems and to implement the earthquake resistant design codes, a modified complex mode superposition design response spectrum method is put forward. Furthermore, to do parameter optimization for base-isolation structures, a graphical approach is proposed by analyzing the relationship between the base shear ratio of a seismic base-isolation floor to non-seismic base-isolation one and frequency ratio-damping ratio, as well as the relationship between the seismic base-isolation floor displacement and frequency ratio-damping ratio. In addition, the influences of mode number and site classification on the seismic base-isolation structure and corresponding optimum parameters are investigated. It is demonstrated that the modified complex mode superposition design response spectrum method is more precise and more convenient to engineering applications for utilizing the damping reduction factors and the design response spectrum, and the proposed graphical approach for parameter optimization of seismic base-isolation structures is compendious and feasible.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.337-342
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• 1997

This paper describes the design and evaluation of new type piezoelectric bimorph actuator that shows much large mechanical response than those conventional types. The bimorph actuator has modified structure combined with the multilayer actuator(MLA) and the composite multilayer actuator called "Moonie". The design and performancean alysis of bimorph actuator are carried out with Finite Element Method (FEM). Theoretical calculation results show that the generating force and displacement of Moonie-modified bimorph actuator can be improved by about 130% and 150%, respectively. The overshooting and ringing phenomena of the bimorph can be effectively restrained by the pseudo step electric field having a rising time coincied with a period of the fundamental vibration mode of the bimorph.e bimorph.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.732-737
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• 2005

This paper performed pseudo static analysis and dynamic analysis for CFRD and evaluated reliability with the results of Shaking Table Test. The Seismic coefficient method, modified seismic coefficient method, Newmark method of Pseudo static analysis and frequency domain response analysis, time domain history analysis of dynamic analysis were used. The analysis results were differ between analysis method, but the trends of acceleration and displacement were good agreement with the results of shaking table test.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.2982-2994
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• 1993

Low-velocity impact responses of composite laminates are investigated using the finite element method based on various theories. In two-dimensional nonlinear analysis, a displacement field considering higher order shear deformation and large deflection of the laminate is assumed and a finite element formulation is developed using a C$^{o}$-continuous 9-node plate element. Also, three-dimensional linear analysis based on the infinitesimal strain-displacement assumptions is performed using 8-node brick elements with incompatible modes. A modified Hertzian contact law is incorporated into the finite element program to evaluate the impact force. In the time integration, the Newmark constant acceleration algorithm is used in conjuction with successive iterations within each time step. Numerical results from static analysis as well as the impact response analysis are presented including impact force histories, deflections, strains in the laminate. Impact responses according to two typical low-velocity impact conditions are compared each other.

• Coupled systems mechanics
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• v.11 no.6
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• pp.485-504
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• 2022

This paper presents nonlinear oscillations of a carbon nanotube reinforced composite beam subjected to lateral harmonic load with damping effect based on the modified couple stress theory. As reinforcing phase, three different types of single walled carbon nanotubes distribution are considered through the thickness in polymeric matrix. The non-linear strain-displacement relationship is considered in the von Kármán nonlinearity. The governing nonlinear dynamic equation is derived with using of Hamilton's principle.The Galerkin's decomposition technique is utilized to discretize the governing nonlinear partial differential equation to nonlinear ordinary differential equation and then is solved by using of multiple time scale method. The frequency response equation and the forced vibration response of the system are obtained. Effects of patterns of reinforcement, volume fraction, excitation force and the length scale parameter on the nonlinear responses of the carbon nanotube reinforced composite beam are investigated.