• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1053-1058
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• 2003

Piezoelectric under water acoustic transducer is a kind of device for under water detection working as not only an actuator but also a sensor. The technique that can predict acoustical characteristics of transducer is important for robust design of transducer in harsh underwater environment. This paper represents the development of software for analyzing dynamic characteristics of piezoelectric acoustic transducers based on finite element method. Modal and transient analysis modulo for acoustic transducers are developed TWO dimensional model for Tonpilz transducer is used for the test of the developed nodal and transient analysis modules. and comparison is made with a commercial code, ANSYS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.964-968
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• 1996

The demands of size and quality of large steel shaft forgings for ship building, power plant, steel plant, etc. are rapidly increasing, and some of these productions are manufactured from ingot weighing more than 300 tons. For use as rotating components. shafts require toughness, strength and homogeneity, and therefore are produced through a variety of heat treatments. According to the increase of ingot size, micro- and macrosegregation and also mass effect of the product increase. Thus, special care should be paid to the heat treatment of such large shaft forgings. In this paper, the heat treatment of large shaft forgings such as rotor and back-up roll is calculated using the commercial finite element code SYSWELD. Calculated distributions of temperature and phase are compared with experimental data. The continuous cooling transformation diagram, thermal and mechanical properites of each phase are used. The phase proportion, hardness and residual stress during water quenching are discussed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.59-64
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• 2008

Spindle units of machine tool are very important part in the manufacturing area. Recently high speed machining has become the main issue of metal cutting. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Due to increase of the rotational speed of the spindle, there has been renewal of interest in tooling system of high speed spindle. This paper concerns the static stiffness in the main spindle interface according to variation of clamping force, rotational speed and tool holder shank. Finite element analysis is performed by using a commercial code ANSYS workbench. From the results, it has been shown that the geometry of tool holder shank is mostly influence on the variation of the static stiffness in the main spindle interface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.922-924
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• 2014

This paper is concerned with the analysis of natural vibration characteristics of an accelerometer used in power plant. The malfunction of the accelerometer in high-temperature environment may produce erroneous sensor signal and the erroneous signal may cause unpredicted accidents in power plants. Hence, the accelerometer which endures high temperature needs to be developed. In this study, the natural vibration characteristics of the accelerometer were investigated prior to the development of the high-temperature accelerometer. The main mechanical part of the accelerometer is a spiral spring. In this study, the dynamic characteristics of the spiral spring were investigated first by using a commercial finite element code. Numerical results show that the thickness of the spiral spring affects the dynamic characteristics. Numerical investigation on the effect of temperature on the performance of the accelerometer will follow.

• Journal of KSNVE
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• v.7 no.2
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• pp.331-345
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• 1997

A theoretical formulation for the analysis of free vibration of clamped-free cylindrical shells with plates attached at arbitrary axial position(s) was completed and it was programed to get the numerical results which yield natural frequencies and mode shape of the combined system of the plate and the shells. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis. The results shows good agreement with those of ANSYS and test results in frequencies and mode shapes. The method developed herein is likely to be used for the analysis of the free vibration of the clamped-free circular cylindrical shells with any kinds of lids such as hollow circular plates, conical shells, spherical shells, or semi-spherical shells.

• Design & Manufacturing
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• v.2 no.2
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• pp.43-47
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• 2008

This paper is concerned with the analysis of material flow characteristics of stepped rod forming. The analysis in this paper concentrated on the evaluation of the design parameters for deformation patterns of tube forming, load characteristics, extruded length, and die pressure. The design factors such as punch nose radius, die corner radius, friction factor, and punch face angle are involved in the simulation. The stepped rod forming is analyzed by using a commercial finite element code. This simulation makes use of stepped rod material and punch geometry on the basis of punch geometry recommended by International Cold Forging Group. As radius ratio is large, forming load was reduced but extruded length ratio was increased.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.235-240
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• 2005

In this paper, vibration suppression of a CD-ROM main base with piezoelectric shunt circuit is studied. Admittance is introduced to predict the performance of piezoelectric shunt damping. Numerical admittance obtained by commercial finite element code, ANSYS, correlates well with experimentally measured one. Multi-mode piezoelectric shunt damping is realized based on the target mode and frequencies obtained by the admittance analysis. Experimental results prove that admittance of the piezoelectric structure is capable of predicting the performance of piezoelectric shunt damping and the vibration of the main base with the piezoelectric patches is reduced effectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.70-73
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• 2009

The aim of this research is to obtain a numerical material model for an amorphous glassy polymer, polycarbonate (PC), which can be used in finite element analysis (FEA) of the micro thermal imprint process near the glass transition temperature. An understanding of the deformation behavior of the PC specimens was acquired by performing tensile stress relaxation tests. The viscoelastic material model based on generalized Maxwell model was introduced for the material near Tg to establish the FE model based on the commercial FEA code ABAQUS/Standard with a suitable set of parameters obtained for this material model from the test data. Further validation of the model and parameters was performed by comparing the analysis of FE model results to the experimental data.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.98-101
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• 2000

Recently, composite material which has much excellent mechanical characteristics has been applied in many industries. However, it has a brittle characteristic under impact condition and its invisible characteristics of the damaged area has been the motivation of many engineers investigation. The modified failure criterion is implemented to predict the failure behavior of the composite plate subjected to low velocity impact using commercial finite element analysis code, ABAQUS-Ver. 5.8. The new criterion is in good agreement with experimental results and can predict the failure behavior of the composite plate subjected to low velocity impact more accurately.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.174-181
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• 2002

The paper presents an effective analytical method for SSI systems which can have separation or sliding at the soil-structure interface. The method is based on a hybrid approach which combines a linear SSI code KIESSI-2D in frequency domain with a commercial finite element package ANSYS to obtain nonlinear dynamic responses in time domain. The method is applied to a 2-D underground box structure which experiences separation and sliding at the soil-structure interface. Material nonlinearity of the concrete structure is also included in the analysis. Effects of the interface conditions are examined and some critical factors affecting the seismic performance of underground structures are identified.