• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.126-135
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• 1989

In this study, in order to perform dynamic design of machine tools reasonably and effectively, a method was formulated to be applicable to the structures connected by joints having elasticity and damping by using substructure synthesis method. And to analyze chatter-free performance, a 3 dimensional cutting dynamics theory was used. Computer program package for the dynamic design of machine tools was developed by combining those and spplied to improvement of performance of NC lathe. Also, the optimization in the structural modifications of machine tool substructure was studied by evaluating the effects of the substructural modifications on total system performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.455-456
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• 2006

Multi-tasking machines are widely used in machine tool industries nowadays. This study focuses on the effect of load on the structure stabilities of laser multi-tasking machine which is comprehensively combined turning center and laser machine. For design of the machine, simulation of structural analysis is carried out varying number of elements. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. This method showed a proper number of elements can be selected to obtain good result by reduced computation time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.103-110
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• 2014

In this study, spur and helical box models of an existing machine tool are investigated using structural and fatigue analyses. As the helical box model is shown to have less stress and deformation than those characteristics of the spur box model, the helical box has more strength and more transmission efficiency on the structure. In terms of fatigue analysis, the helical box model has more repeated fatigue strength than that of the spur box model. These study results can be effectively utilized in the design of real gear boxes of machine tools by anticipating and investigating prevention and durability against damage.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.291-296
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• 2001

Recently, many methods are studied to analyze the noise of HDD and to reduce it. In this study, the simulation tool(SPATH) was developed to analyze a noise of HDD. The prediction technique of sound pressure level(SPL) of a given structural shape enables us to design a cover and a base with much less vibration and noise. In this paper, we measured the force of disk-spindle motor and predicted SPL from HDD by computational simulation. To get a SPL of HDD by computational simulation, modal analysis and forced vibration analysis were performed with ANSYS, and sound radiation was computed using SYSNOISE. The calculated results were compared with experimental results and a good agreement was obtained.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.278-281
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• 2005

Today, manufacturing capability at the micro or nano scale production field is requested strongly in view of parts and product miniaturization. Miniaturized parts and products will introduce lots of benefits in terms of high precision functionality and low energy consumption. This paper presents the results of micro milling machine tool development for micro machining process. Finite element analysis has been performed to know the relationship between design dimensional variables and structural stiffness in terms of static, dynamic, thermal aspects. Performance evaluation through machining has been tested and discussed for achievable machining characteristics.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.451-458
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• 2014

This study is a practical research for setting a process of making references of design decision and guidlines of limitation in the movement from the design development to the construction design by StrAuto. StrAuto, as a parametric modeling and optimization tool for building structure, enables a quantity of design cases to be analyzed automatically by changing parameters of sturctural properties. So the designer using StrAuto can check a lot of analysis data crossing thousands of cases, see which case is out of acceptable range, and make a decision for design and optimization. In this thesis, the application of StrAuto optimization process to the residence tower UIC project shows the practical applicability in the construction design and value engineering. StrAuto optimized ideally volume of core walls by 31.3% and lead the final revised model applied to the construction design to reduce volume by 18.1%. The significance of this research is the implementation of process that the designer can quickly review a number of cases and get a direction for construction design and optimization after design development.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.637-647
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• 1997

As stated in Part(I), the use of the isolator is meant to protect a structure from seismic risk, by concentrating the inelastic deformations to relatively cheap and replaceable devices while the rest of the structures remains elastic. This research has been carried out to investigate the effects of various structural parameters and isolator characteristics on the seismic response of Base Isolated Bridges. Simplified analysis method for practical design is developed by using the results. The Proposed Code-Type approach method can be used to estimate the inertial forces accurately, not only at the isolator but throughout the height of the Base-Isolated Bridges. The proposed method is recommended to use in preliminary design tool or even a final design tool for Base Isolated Bridges. For the validation of simplified design method, examples with artificial earthquake time history and design response spectrum for P.C Box Bridge with bilinear hysteretic steel damper are evaluated.

• Structural Engineering and Mechanics
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• v.42 no.2
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• pp.191-210
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• 2012

The Force Density Method (FDM) is a well known and extremely versatile tool in form finding of cable nets. In its linear formulation such method makes it possible to find all the possible equilibrium configurations of a net of cables having a certain given connectivity and given boundary conditions on the nodes. Each singular configuration corresponds to an assumed force density distribution. Its improvement as Non-Linear Force Density Method (NLFDM) introduces the possibility of imposing assigned relative distances among the nodes, the tensile level in the elements and/or their initial undeformed length. In this paper an Extended Force Density Method (EFDM) is proposed, which makes it possible to set conditions in terms of given fixed nodal reactions or, in other words, to fix the positions of a certain number of nodes and, at the same time, to impose the intensity of the reaction force. Through such extension, the (EFDM) enables us to deal with form findings problems of cable nets subjected to given constraints and, in particular, with mixed structures, made of cables and struts. The efficiency and the robustness of method are assessed through comparisons with other form finding techniques in dealing with characteristic applications to the prestress design of cable systems. As a further extension, the EFDM is applied to structures having some parts not yet geometrically defined, as can happen in designing new creative forms.

• Structural Engineering and Mechanics
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• v.56 no.4
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• pp.625-648
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• 2015

Modern super-tall buildings are more sensitive to strong winds. The evaluation of wind loads for the design of these buildings is of primary importance. A direct monitoring of wind forces acting on super-tall structures is quite difficult to be realized. Indirect measurements interpreted by inverse techniques are therefore favourable since dynamic response measurements are easier to be carried out. To this end, a Kalman filtering based inverse approach is developed in this study so as to estimate the wind loads on super-tall buildings based on limited structural responses. The optimum solution of Kalman filter gain by solving the Riccati equation is used to update the identification accuracy of external loads. The feasibility of the developed estimation method is investigated through the wind tunnel test of a typical super-tall building by using a Synchronous Multi-Pressure Scanning System. The effects of crucial factors such as the type of wind-induced response, the covariance matrix of noise, errors of structural modal parameters and levels of noise involved in the measurements on the wind load estimations are examined through detailed parametric study. The effects of the number of vibration modes on the identification quality are studied and discussed in detail. The made observations indicate that the proposed inverse approach is an effective tool for predicting the wind loads on super-tall buildings.

• Structural Engineering and Mechanics
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• v.8 no.1
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• pp.85-102
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• 1999

With the advent of computer, the finite element method has become a most powerful numerical method for structural analysis. However, bridge designers are reluctant to use it in their designs because of its complex nature and its being time consuming in the preparation of the input data and analyzing the results. This paper describes the development of a computer based finite element model using the idea of eccentric beam elements for the analysis of slab-on-girder bridges. The proposed method is supported by a laboratory test using a reinforced concrete bridge model. Other bridge analytical schemes are also introduced and compared with the proposed method. The main aim of the comparison is to prove the effectiveness of the shell and eccentric beam modelling in the studies of lateral load distribution of slab-on-girder bridges. It is concluded that the proposed finite element method gives a closer to real idealization and its developed computer program, SHECAN, is also very simple to use. It is highly recommended to use it as an analytical tool for the design of slab-on-girder bridges.