• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1718-1723
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• 2003

This paper presents a computational method for deformation modes of a flexible body in multibody system from the experimental modal analysis and an efficient method for flexible multibody dynamic analysis by use of the modes. It is difficult to directly use experimental modal parameters in flexible multibody dynamic analysis. The major reasons are that there are many inconsistencies between experimental and analytical modal data and experimental noises are inherent in the experimental data. So two methods, such as, a method for ortho-normalization of experimental modes and the other one for mode expansion, are suggested to gain deformation modes of a flexible body from the experimental modal parameters. Using the virtual work principle, the equation of motion of a flexible body is derived. The effectiveness of the proposed method will be verified in the numerical example of cab vibration of a truck by comparing analysis and test results.

• The Journal of Korean Academic Society of Nursing Education
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• v.15 no.1
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• pp.120-127
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• 2009

Purpose: In the literature power analysis in experimental studies is often executed and reported falsely. This descriptive study was done to promote the correct application of the Cohen(1988)'s power analysis method. Method: Articles of experimental studies from a nursing journal were selected and reviewed to examine the uses of and the reports on the power analysis process. Also, the appropriate power analysis process was discussed with an example of the most common experimental design, an independent two-group design with t test analysis plan. Result: Around half the experimental studies examined reported that they carried out power analysis. Cohen's method was the most frequently utilized but with accuracy in question. Conclusion: Power analysis to estimate sample size is the interplay between alpha, power, and effect size, and other factors in the case of t test analysis. Researchers should have a clear understanding of how to apply the Cohen's power analysis method so they do not produce poorly estimated sample sizes.

• Structural Monitoring and Maintenance
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• v.5 no.3
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• pp.345-361
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• 2018

The set of processes performed to determine the dynamic characteristics of the constructed structures is named experimental modal analysis. Using experimental modal analysis and interpreting its results, structural failure can be assessed and then it would be possible to plan for their repair and maintenance. The purpose of the experimental modal analysis is to determine the resonance frequencies, mode shapes and Mode damping for the structure. Diverse methods for determining the shape of the mode by various researchers have been presented. There are pros and cons for each of these methods. This paper presents a method for determining the mode shape of the structures using the response spectrum in the experimental modal analysis. In the first part, the principles of the proposed method are described. Then, to check the accuracy of the results obtained from the proposed method, single and multiple degrees of freedom models were numerically and experimentally investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.328-334
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• 2001

Up to now. vibration analysis and vibration engineering have been developed, encompassing the aspects of both experimental and analytical techniques. Using experimental modal analysis or modal testing, the mode shapes and frequencies of practical structure can be measured accurately. Curve-Fitting Method is realized through experimental modal identification. In the experimental modal parameter estimation, the estimation of modal damping factor is difficult for complicated and large structure. Also numbers of Selected mode are determined before the procedure. This paper describes the vibration shape of the super-structure model of ship through experimental modal analysis.

• 한국기계연구소 소보
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• s.10
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• pp.11-20
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• 1983

Photoelasticity is an experimental technique for stress and strain analysis that is particularly useful for members having complicated geometry, complicated loading conditions, or both. The principle and engineering applications of photoelastic stress analysis are briefly reviewed. Experimental stress analysis with Reflection Polariscope at KIMM Structural Mechanics Laboratory was applied to the following practices: Stress analysis of the crosshead of the structural fatigue testing machine; Experimental safety verification of domestic excavator.

• Journal of the Korea Society for Simulation
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• v.11 no.3
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• pp.1-12
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• 2002

Experimental design in simulation provides an efficient way of economizing simulation runs since a considerable number of simulation runs that originally were planned can be reduced by this approach. This experimental design method is an active area of research together with the output analysis and so no single panacea seems to exist so far. Thus, selection of techniques of experimental design and output analysis more likely depends upon the objective of simulation analysis, budget constraint and sometimes the analyst's subjective judgment. This paper attempts to describe an experimental design methodology for port investment analysis using a case study in a bulk terminal in Korea. Detailed display will be focused on simulation period, warm-up period, the number of replications needed in production runs after brief explanation on the system configuration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.233-237
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• 1998

In this work, to identify the dynamic characteristics of disk-spindle system in hard disk drive, experimental modal analysis was performed. And an experimental analysis system including testing apparatus, precision sensors, and analysis software was established in order to perform the testing effectively. From the experimental results, coupled and uncoupled modal characteristics of 3-disk spindle system are clearly identified.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.72-76
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• 2001

Experimental design in simulation provides an efficient way of economizing simulation runs since a considerable number of simulation runs that originally were planned can be reduced by this approach. This experimental design method is an active area of research together with the output analysis and so no single panacea seems to exist so far. Thus, selection of techniques of experimental design and output analysis more lithely depends upon the objective of simulation analysis, budget constraint and sometimes the analysts subjective judgment. This paper attempts to describe an experimental design methodology for port investment analysis using a case study in a bulk terminal in Korea. Detailed display will be focused on simulation period, warm-up period, the number of replications needed in production runs after brief explanation on the system configuration.

• The KSFM Journal of Fluid Machinery
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• v.13 no.3
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• pp.59-64
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• 2010

To analyze the three-dimensional flow in tunnel caused by operation of jet fan, both experimental and computational studies have been conducted. The experimental analysis of tunnel flow induced by jet fan is conducted on a real-scale apparatus with jet fan and tunnel, and air velocity at the monitoring points is measured for variation of fan's RPM. The three-dimensional numerical analysis including tunnel and jet fan is carried out for the same geometric configuration as the experimental analysis. The experimental and computational results are compared to examine the applicability of the numerical method.

• Journal of KSNVE
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• v.10 no.6
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• pp.1009-1016
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• 2000

This paper describes the procedure of increasing the efficiency of experimental modal analysis and updating the quality of FE model using the scaled commercial vehicle frame. In this study, it was found that the experimental modal analysis could be more efficient when the measurements were made on the areas with high kinetic energies. Such areas could be located with the aid of FE modal analysis. Also, the number of measurement points could be decided by considering the dynamic characteristics of full FE model. The correlation of FE model and experimental modal analysis was assessed by the differences between the natural frequencies and MAC matrix, which is based on normal modes. These differences of modal parameters were reduced through the sensitivity and optimization analysis of which objective function consisted of the errors of natural frequencies and the diagonal terms of MAC matrix.