• Journal of Advanced Marine Engineering and Technology
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• v.16 no.3
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• pp.51-57
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• 1992

Authors had analyzed the Press machine's vibrational characteristics by Substructure Synthesis Method. This paper discribes the structural Dynamic Optimization for the machine using Sensitive Analysis Method. The substructure synthesis method and sensitive analysis methods are used for the vibration analysis and structural modification. The results obtained are as follows ; 1. The tooling precision of the press machine is ruled by the bending vibration of the slide. 2. The structural Modification Method for minimizing impact responses is proposed, and modal analysis and sensitive analysis method are introduced to solve it. 3. The impact responses of running machine were reduced to 40% of the unmodified machine by using the proposed method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.155-158
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• 2005

Sub-frame is a key component to damp the vibration of engine-born and isolate the input force from a ground. To enhance the performance of the sub-frame of vehicle, its structure should be designed to be a high performing mechanical filter that exclude the low frequency vibration elements. In this paper, a contribution analysis based on the frequency response function(FRF) is introduced to detect a high sensitive position of the target sub-frame and its results are validated with a SDM(structural dynamic modification) analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.852-855
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• 2005

Structural Dynamic Modification(SDM) is a technique to improve structure's dynamic characteristics by adding and removing substructures or changing material properties and shape of structures. This paper describes SDM techniques applied to a large structure with too many DOFs. The goal of this SDM technique is to modify a targe structure efficiently for its natural frequencies to avoid excitation frequencies. In this case, models reduced by Component Mode Synthesis(CMS) method that is a coupling technique are used to analyze a large structure efficiently. This paper considers a helicopter deck model with 55,000 DOFs as an application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.219-222
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• 2004

This research is about SDM (Structural Dynamics Modification) technique using embosses. SDM using embosses do not need to add additional mass element ana model of embosses and resulting huge calculation for getting analytical solution of an embossed structure. The object of this research is to suggest a method to guide placing embossment in a structure to raise its natural frequencies. Two methods to optimize model with embossing are suggested, indepuldently. The former is response surface analysis by neural network. And the latter is an indirect method using modal dynamic strain energy.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.444-447
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• 2004

A new approach to compute the control moves in Extended Dynamic Matrix Control (EDMC) is presented. In this approach, the number of variables, determined in the inner loop of the control algorithm using iterative methods, is reduced from P , the prediction horizon to M , the control horizon. Since M is usually much smaller than P , this modifies the control algorithm from computational point of view. To justify the modification, the computational requirements are compared to those of the existing EDMC algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.567-572
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• 1991

This paper proposes an algorithm of fuzzy model modification which improves fuzzy relation matrix for multi-input/single output dynamic systems. Zadeh's possibility distribution plays an important role in the proposed algorithm and in the use of fuzzy models which are constructed by the proposed algorithm. The required computer capacity and time for implementing the proposed algorithm and resulting models are significantly reduced by introducing the concept of the referential fuzzy sets. A nonlinear system is given to show that the proposed algorithm can provide the fuzzy model with satisfactory accuracy.

• Journal of Mechanical Science and Technology
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• v.14 no.5
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• pp.490-498
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• 2000

The authors have proposed methods (lead crowning and profile modification) for modifying the geometry of spur gears and investigated the contact pattern as well as the transmission errors to recommend the appropriate amount of modification. Based on the investigation, dynamic load of the modified spur gear drive has been calculated, which is helpful to predict the life of the designed gear drive. Computer programs for simulation of meshing, contact and dynamics of the modified spur gears have been developed. The developed theory is illustrated with numerical examples.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.224-230
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• 1996

In the mechanical systems with large damping, the conventional SDM method developed for no damping systems will lead to an error solution. Here, we introduce a SDM method based on the experimental modal model for large damping systems. The sensitivities of natural frequencies and mode shapes with respect to mass, damping, and stiffness coefficients of structures are used to calculate the position and quantity of modification, and predict the new dynamic characteristics. Through numerical simulation and experiment, the effectiveness of the proposed method is tested.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.179-186
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• 2024

In this paper, a modification coefficient for equivalent single degree of freedom (SDOF), considering the plasticity range of the member subjected to shock wave type of blast load, was developed. The modification coefficient for the equivalent SDOF was determined through comparison with the analysis of a multi-degree of freedom (MDOF) system. The parameters influencing the equivalent SDOF system analysis were chosen as the boundary conditions of the member and the ratio of the duration of blast load to the natural period of the member. The modification coefficient was calculated based on the elastic load-mass transformation factor. The modification coefficient curve was derived using an elliptical equation to ensure it exists between the upper and lower parameter bounds. Using the modification coefficient on examples with varying cross sections and boundary conditions reduced the SDOF analysis error rate from 15% to 3%. This study shows that using the modification coefficient significantly improves the accuracy of SDOF analysis. The modification coefficient proposed in this study can be used for blast analysis.

• 한국당과학회:학술대회논문집
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• 2006.11a
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• pp.45-45
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• 2006