• Land and Housing Review
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• v.5 no.1
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• pp.35-40
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• 2014

Site coefficient and amplification factor of current domestic Seismic Design Code (KBC-2009) have no consideration for the domestic ground condition in which the base rock is normally placed within 30m form the surface. Accordingly, in this study dynamic centrifugal test and analysis for pile foundation into sand and upper structure were achieved. and the response spectrums of free surface and basement were compared with each other. Within the period 1 sec., the measured spectral acceleration of free surface and basement was bigger than the design spectral acceleration of SC and SD site. However the measured spectral acceleration of free surface and basement for the period over 1.5 sec. was smaller than the design spectral acceleration of SC site. There was no severe difference of spectral acceleration according to the upper structure, embedded depth of foundation and free surface conditions. Consequently, normal domestic apartment housing for the period range over 1.5sec. could be design more economically applying these test result.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.122-129
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• 2016

In modern industries, in whichwhere high productivity is one of the most important concerns, machine tools are facing difficulties to satisfy the high high-speed operation, while and at the same time achieve the precision machining. Generally, the vibrations of the structure increase proportionally to the square of the operating speed so that the precision machining is severely damaged with increased speed. which is a must for the high productivity. Therefore, the suppression of the structural vibrations of the machine tools is the a major concern in the machine tool industry in order to achieve the high productivity and the precision machining simultaneously. In this study, the dynamic properties of a machining center structure were analyzed through the experiment and the computer simulations, and furthermore the results from those were compared to confirm the validity of the simulation model. The design alterations were deduced from the analysis and applied to the simulation model to investigate the effects of those alterations to suppress the vibrations of the machine. The result shows that the relatively simple design alterations, without redesigning the main structure of the machine, can suppress the vibrations effectively.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.66-69
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• 2002

This paper proposes a new dynamic storage structure and methods fur geometric data with detail levels. Using geometric data with detail levels, we can search geometric data quickly. However, the previous structures for detail levels form the bottleneck in the design of database and do not support all types of geometric data with detail levels. Our structure supports all types of geometric data with detail levels. Moreover, our structure does not form bottleneck in the design of database. This paper presents the structure and algorithms for searching and updating of geometric data with detail levels. Experiments are then performed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.163-170
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• 2001

This paper presents results of nonlinear analyses for underground structures including both the soil-structure interaction and nonlinear behavior of concrete material. For this purpose, a hybrid method is employed, in which a dynamic analysis technique for a linear soil-structure interaction system and a general purpose FE program are combined in hybrid and practical manners. A couple of nonlinear analyses are carried out for framed structures in multi-layered half space soil medium. The yielding of concrete structure is considered by a multi-linear stress- strain relationship. The numerical results suggest that ductile design fur the intermediate columns in the underground framed structure is substantially important in aseismic design.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.268-275
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• 2001

Modal analysis does well predict the elastic dynamic response of the torsionally unbalanced structure. But modal analysis overestimates the rotation of the structure in inelastic range, so one side members require ductility too much and the others require ductility too small in comparison with torsionally balanced structure. In this paper, in order to reduce difference of ductility demand between both side members of the torsionally unbalanced structure, design eccentricity of seismic load is evaluated and the method determining the strength center of structure is proposed using modal analysis. For several cases, the ductility demand of stucture is compared to investigate the propriety of the proposed approach.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.257-264
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• 2000

Nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this regard the nonlinear static analysis is a practical alternative for evaluating the earthquake resisting capacity of a structure. In this study the nonlinear static response of a structure was obtained first, and the equivalent viscous modal damping ratio required to satisfy the performance objective was computed in the capacity spectrum format. Then proper amount of viscous dampers were installed to provide the required damping. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the earthquake time history analysis results, the maximum displacement of the model structure with viscous dampers designed in accordance with the proposed method corresponds well with the target displacements that was used in the beginning of the design process.

• Journal of the Korean Geotechnical Society
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• v.40 no.4
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• pp.19-32
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• 2024

Dynamic earth pressure analysis is a key parameter in the seismic design of subterranean structures. However, existing solutions often lack a holistic approach, ignoring crucial elements like soil-structure interaction, the relative flexibility ratio (F) between the soil and a structure, the racking ratio (R) of a structure, and the structure aspect ratio (L/H). In this study, we conducted a thorough suite of dynamic numerical analyses on basements to understand how these factors influence seismic earth pressure. We found that structures with high aspect ratios and low flexibility were more susceptible to seismic pressure than those with lower aspect ratios and greater flexibility. Consequently, we recommend taking the aspect ratio and flexibility into account when estimating the seismic or dynamic earth pressure on basements and exercising caution when using traditional solutions proposed for retaining walls.

• Journal of Korean Association for Spatial Structures
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• v.22 no.1
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• pp.25-32
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• 2022

The seismic behaviors of the arch structure vary according to the rise-span ratio of the arch structure. In this study, the rise-span ratio (H/L) of the example arch structure was set to 1/4, 1/6, and 1/8. And the installation angle of the seismic isolator was set to 15°, 30°, 45°, 60° and 90°. The installation angles of the seismic isolator were set by analyzing the horizontal and vertical reaction forces according to the rise-span ratio of the arch structure. Due to the geometrical and dynamic characteristics of the arch structure, the lower the rise-span ratio, the greater the horizontal reaction force of the static load, but the smaller the horizontal reaction force of the dynamic load. And if the seismic isolator is installed in the direction of the resultant force of the reaction forces caused by the seismic load, the horizontal seismic response becomes small. Also, as the installation angle of the seismic isolator increases, the hysteresis behavior of the seismic isolator shows a plastic behavior, and residual deformation appears even after the seismic load is removed. In the design of seismic isolators for seismic response control of large space structures such as arch structures, horizontal and vertical reaction forces should be considered.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.67-72
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• 2000

A dynamic draft model is necessary to analyze mechanics of tillage and to design optimal tillage tools. In order to deal with draft dynamics, a neural network paradigm was applied to develop dynamic draft models. For the development of the models, three kinds of tillage tools were used to measure drafts in the soil bin and a time lagged recurrent neural network was developed. The neural network had a structure to predict dynamic draft, having a function of one-step-ahead prediction. A procedure for network prediction model identification was established. The results show promising modeling of the dynamic drafts with developed neural network.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.824-829
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• 2002

Since many reciprocating and rotating components are attached to jet loom structure. it is exposed to a more vibration and moise problems than the other textile machinery. Thus the design of the jet loom frame is very important to characterize the dynamic response. In this study, a finite element model of jet loom main frame was developed to investigate the dynamic characteristics of jet loom. Two different finite element models of different main frames were constructed and these models were validated by the experimental results. Dynamic characteristics such natural frequencies and mode shapes were in good agreement between the finite element analysis and experimental results within 10% error range. It is expected that the result from this study can be used as the basic information of jet loom dynamic analysis and be extended for further analysis of forced response case.