• 한국소음진동공학회논문집
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• 제11권4호
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• pp.43-51
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• 2001

An experimental modal analysis is the process to identify structure's dynamic characteristics such as resonant frequencies, damping values and mode shapes. An experimental model was made of stainless steel in the shape of a circular cylindrical shell and installed on the test bed with jigs. For investigating vibrational characteristics of the continuous circular cylindrical shell with intermediate supports, modal testing is performed by using impact hammer, accelerometer and 8-channel FFT analyzer. The frequency response function(FRF) measurements are also made on the experimental model within the frequency range from 0 to 4kHz. Modal parameters are identified from resonant peaks in the FRF's and animated deformation patterns associated with each of the resonances are shown on a computer screen. The experimental results are compared with analytical and FEA results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1149-1153
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• 2000

All critical equipment installed aboard naval ships and submarines is required to be shock-qualified by tests on the MIL-S-901 shock test machines where testing is practical. The intent of the shock requirements is to produce combat vessels which are resistant to the underwater explosion weapon attack. To efficiently design equipment for passing a series of shock tests, the shock environment of the shock test machine should be clearly identified. In this paper, the shock characteristics of the MIL-S-901 Medium Weight Shock Machine(MWSM) are reviewed, based on the existing test data. An analytical model for the MWSM is also discussed.

• 한국정밀공학회지
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• 제13권5호
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• pp.30-37
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• 1996

The objective of this research is to explore the analysis and test method for the reliable design and fabrication of a high precision dynamically tuned gyroscope. The tuning frequency is decided by the calculation of mass moment of inertia of rotor and gimbal and the stiffness of flexures. Due to the complex geometry of the flexure, calculation of the stiffness of the suspension flexure is difficult. In this paper, three analytical methods for obtaining the stiffness of the flexure are porposed and a special testing method is used for checking the accuracy of the computed results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.470-475
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• 2000

This research covers the resting of precast/prestressed concrete I-Girder bridge. The research was designed to examine processes for improving the condition evaluation and rating of prestressed concrete bridge. To establish procedures that allow for the full utilization of prestressed concrete bridge capacity, a 28-year old sample was loaded to failure in site. The bridge was constructed with 12 spans, and girders of each span were simply supported. At each loading stage, the deflections, reinforcement strains, prestressing wire strains and concrete strains were examined. Failure behavior was analyzed, and failure load was also evaluated. The test results wee compared to the analytical results from the non-linear finite element analysis.

• 복식
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• 제58권5호
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• pp.211-231
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• 2008

To conserve historic textiles, analyses of textile materials, pollutants and deterioration are prerequisite steps. Based upon analytical results, guides for conservation of historic textiles are established. In analyses of textile materials, pollutants and deterioration, there are chemical methods(burning, solubility and staining), physical methods(microscopy and density) and instrumental analysis(Fourier Transform Infrared Spectroscopy (FT-IR), Fourier Transform Raman Spectroscopy(FT-Raman), Gas Chromatography(GC), Mass Spectroscopy(MS), X-Ray Fluorescence (EDXRF, WDXRF), Energy Dispersive Spectroscopy(EDS), and X-Ray Diffraction(XRD), Tensile Testing Machine etc.). Combination of qualitative and quantitative analyses makes accurate diagnosis of textile condition possible. As examples of analyses and conservation of historic textiles, Chuninsan(19 century) similar to sunshade with handing down historic textile and golden decorative skirt(17 century) with excavated costume are taken.

• 한국군사과학기술학회지
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• 제21권3호
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• pp.342-348
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• 2018

The important issue of equipment installed in maritime weapon system is shock survivability against underwater explosion(UNDEX). If the shock survivability of equipment should not be guaranteed, the successful mission also could not be achieved. For that reason, the shock-resistance of each equipment under UNDEX environment should be demonstrated before deployment at combat field. However, the actual UNDEX test on the ocean is too expensive to conduct. Also, it has diverse dangerous factors. The main characteristic of UNDEX is a dual-pulse shock. The vertical shock test machine able to simulate dual pulse shock signal on the ground will be introduced in this paper. The dual-pulse shock signal presented in certain shock standard was achieved with this shock-test machine on the ground. The analytical procedure to set a test condition was verified by comparing simulation result with experiment result.

• Environmental Analysis Health and Toxicology
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• 제19권1호
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• pp.25-32
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• 2004

Aim of the present study was the development of a bioassay which enables the detection of toxic effects of heavy metal ions to a bacterium, Escherichia coli. Inhibition effects of the metals on growth rates of the bacterium were studied in the absence or presence of fulvic acid. This method does not clearly differentiate among metals, but does detect overall AGB inhibition rate (toxicity) for 5 different heavy metals. The toxicity of the metals in the absence of fulvic acid in the same testing conditions was significantly increased in following order: Hg < Pb, Zn < Cd < Cu, whereas the inhibition rate (toxicity) in the presence of FA was shown to be increased In following order: Cd < Pb, Hg < Cu < Zn. The results of the present study indicate that this simple and fast biomonitoring assay with direct exposure of E coli. might be a valuable supplement to analytical methods of contaminated media.

• 대한전자공학회논문지
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• 제24권3호
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• pp.527-534
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• 1987

This paper proposes a new syndrome-testable design method for large MOSPLA's. In the conventional syndrome test method, the testing array circuit for testability is added but it has the defect that the circuit gives effect on the normal operation of the basic PLA circuit. Therefore, by adding the shift registers to the product lines of the basic MOSPLA's this defect is eliminated and the number of test patterns is decreased. In order to reduce the number of fault free syndromes to be predetermined, also, one output line, which is connected to all product lines is added. Therefore the number of output lines be observed is decreased. And the analytical method to compute fault free syndromes is presented. By unsing this method, the time and the effort to compute the syndromes are decreased.

• Structural Engineering and Mechanics
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• 제10권5호
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• pp.505-516
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• 2000

This paper is a presentation of an experimental study about the elastic-partly plastic behavior of rectangular hollow steel pinned struts subjected to static cyclic axial loading and the evaluation of the compressive strength of retrofitted crooked struts. Retrofitting is achieved by welding stiffening plates along the webs of damaged struts. The material follows a quasi-kinematic hardening hysteresis path as observed from coupon tests. Test results are compared to those of an analytical model showing a good agreement for both standard and retrofitted struts. The comparison of different stiffener plate dimensions shows that more efficient strengthening is achieved by using long thin stiffeners rather than short thick ones.

• Structural Engineering and Mechanics
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• 제41권4호
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• pp.441-458
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• 2012

The shear strength is an important factor in the design of prestressed concrete beams. Therefore, researchers have utilized various methods to determine the shear strength of these elements for the design purposes. To evaluate some of the proposed theoretical methods, numerous models of post-tensioned beams with or without vertical prestressing are selected and analyzed using the finite element method and assuming nonlinear behavior for the materials. In this regard the validity of modeling is evaluated based on some tests results. In the second part of the study two beam specimens are built and tested and their load-deformation curve and cracking pattern are studied. The analytical results consist of compressive strut slope and mid span load deflection are compared with some experimental results, and the results of some codes' formulas. Finally comparing the results of nonlinear analysis with the experimental values, a new formula is proposed for determining strut slopes in prestressed concrete beams.