• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1164-1171
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• 2002

This study analyzed the dependence of part load performance of simple cycle gas turbines on their design performance. Various parametric calculations were carried out to examine effects of design temperature ratio, pressure ratio and component efficiencies using a simplified analysis. In addition, a more practical analysis was done for realistic design conditions with the aid of a comprehensive performance analysis program. The results show that gas turbines with higher design performance exhibit less efficiency degradation during part load operation. The influence of power control method (fuel only centre) and air flow control) on part load performance was examined as well.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.567-571
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• 2011

Air Starter motors are used for the start of medium-speed diesel engine. One of the main part of air starting motors is the axial turbine stage. In this study, design of 1-stage axial type turbine for 14kw class air starter motors has been performed. The turbine blade was designed based on mean-line analysis. 1-D design calculation and numerical analysis with CFD were conducted iteratively. The validation between 1-D design method and numerical analysis for axial clearance has been performed. It revealed that there is optimum axial clearance of turbine design.

• 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.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.2
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• pp.12-17
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• 2006

This study uses a characteristic function to explain correlations between the objective function and design variables. For the use, structural analysis and buckling analysis are carried out. the dimensional change of an original overhead crane is made based on the table of orthogonal array. For two functions or more, the effectiveness of design change can be evaluated in accordance with change in design parameters. Also, the overhead crane's weight is reduced by up to 10.55 percent while its structural stability maintained.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.6
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• pp.1034-1044
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• 2016

This study seeks a method to objectively evaluate sensibility based on Big Data in the field of design. In order to do so, this study examined the sensibility responses on design factors for the public through a network analysis of texts displayed in social media. 'Hanbok', a formal clothing that represents Korea, was selected as the subject for the research methodology. We then collected 47,677 keywords related to Hanbok from 12,000 posts on Naver blogs from January $1^{st}$ to December $31^{st}$ 2015 and that analyzed using social matrix (a Big Data analysis software) rather than using previous survey methods. We also derived 56 key-words related to design elements and sensibility responses of Hanbok. Centrality analysis and CONCOR analysis were conducted using Ucinet6. The visualization of the network text analysis allowed the categorization of the main design factors of Hanbok with evaluation terms that mean positive, negative, and neutral sensibility responses. We also derived key evaluation factors for Hanbok as fitting, rationality, trend, and uniqueness. The evaluation terms extracted based on natural language processing technologies of atypical data have validity as a scale for evaluation and are expected to be suitable for utilization in an index for sensibility evaluation that supplements the limits of previous surveys and statistical analysis methods. The network text analysis method used in this study provides new guidelines for the use of Big Data involving sensibility evaluation methods in the field of design.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.64-67
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• 2017

This work dealt with structural safety analysis about sandwich composite structure of automotive floor board. In this work, structural design and analysis of sandwich composite structure for automobile floor board were performed. Firstly, structural design requirement of automobile floor board was investigated. After structural design, the structural analysis of the automobile floor board were performed by the finite element analysis method. It was performed that the stress and displacement analysis at the applied load condition. After structural test of target structure, structural test results were compared with analysis results. Through the structural analysis, it was confirmed that the designed floor board structure is safety.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.974-982
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• 2009

To improve the effectiveness and economics the bridge design methodology considering the bridge/rail longitudinal analysis and bridge/vehicle dynamic effect suggested in this study. The reliability-based Life-Cycle Costs(LCC) effective optimum design is applied to a 2-main steel girder bridge, 5$\times$(1@50m) for comparison with conventional design, initial cost optimization and equivalent LCC optimization. As a result of the optimum design based on reliability, it may be stated that the design of High-Speed railway bridges considering the bridge/rail longitudinal analysis and bridge/vehicle dynamic effect are more efficient than typical existing bridges and LCC optimization without respect to bridge/rail longitudinal analysis and bridge/vehicle dynamic effect. The result of optimization design considering the interaction, design methodology suggested in this study, is higher than result of initial cost optimization design in initial cost, but that has the advantage than result of initial cost optimization design in expected LCC.

• Earthquakes and Structures
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• v.21 no.5
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• pp.489-503
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• 2021

This research aims to investigate the seismic response of RC shear wall buildings of 5-, 6-, 7-, 8-, 9-, and 10-story designed as conventional and ductile and located in moderate seismic zone in Saudi Arabia in accordance with the seismic provisions of the American code ASCE-7-16. Dynamic analysis is conducted using the developed models in ETABS and the design spectra of the selected zone. The seismic responses of a number of design variations are evaluated in terms of story displacements, drift, shear and moments of both conventional and ductile building models as performance measures and presented comparatively. In addition, pushover analysis is also performed for the lowest and highest building models. Cost estimate of ductile and conventional walls is evaluated and compared to each other in terms of weight of reinforcement bars. In addition, due to the complexity of design and installation of ductile shear walls, sensitivity analysis is performed as well. It is observed that conventional design considerably increases induced seismic responses as well as cost compared to ductile one.

• Journal of KSNVE
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• v.8 no.2
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• pp.267-273
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• 1998

This study aims at performing sensitivity analysis of piezoelectric smart structure for minimizing radiated noise from the structure, The structure consists of a flat plate on which disk shaped piezoelectric actuator is mounted, and finite element modeling is used for the structure. The finite element modeling uses a combination of three dimensional piezoelectric, flat shell and transition elements so thus it can take into account the coupling effects of the piezoelectric device precisely and it can also reduce the degrees of freedom of the finite element model. Electric potential on the piezoelectric actuator is taken as a design variable and total radiated power of the structure is chosen as an objective function. The objective function can be represented as Rayleigh's integral equation and is a function of normal displacements of the structure. For the convenience of computation, all degrees of freedom of the finite element equation is condensed out except the normal displacements of the structure. To perform the design sensitivity analysis, the derivative of the objective function with respect to the normal displacements is found, and the derivative of the norma displacements with respect to the design variable is calculated from the finite element equation by using so called the adjoint variable method. The analysis results are compared with those of the finite difference method, and shows a good agreement. This sensitivity analysis is faster and more accurate than the finite difference method. Once the sensitivity analysis program is used for gradient-based optimizations, one could achieve a better convergence rate than non-derivative methods for optimal design of piezoelectric smart structures.

• International Journal of Reliability and Applications
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• v.2 no.3
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• pp.209-240
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• 2001

Computer-based simulation and analysis is used extensively in engineering for a variety of tasks. Despite the steady and continuing growth of computing power and speed, the computational cost of complex high-fidelity engineering analyses and simulations limit their use in important areas like design optimization and reliability analysis. Statistical approximation techniques such as design of experiments and response surface methodology are becoming widely used in engineering to minimize the computational expense of running such computer analyses and circumvent many of these limitations. In this paper, we compare and contrast five experimental design types and four approximation model types in terms of their capability to generate accurate approximations for two engineering applications with typical engineering behaviors and a wide range of nonlinearity. The first example involves the analysis of a two-member frame that has three input variables and three responses of interest. The second example simulates the roll-over potential of a semi-tractor-trailer for different combinations of input variables and braking and steering levels. Detailed error analysis reveals that uniform designs provide good sampling for generating accurate approximations using different sample sizes while kriging models provide accurate approximations that are robust for use with a variety of experimental designs and sample sizes.