• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.847-847
• /
• 2004

Automobile cooling fans are operated with a radiator module. To design low noise, high performance cooling fan, radiator resistance should be considered in the design process. The system (radiator) resistance reduces axial velocity and increases effective angle of attack. This increasing effective angle of attack mechanism causes blade stall, performance decrease and noise increase. In this paper, To analyze fan performance, freewake and 3D CFD calculations are used To design high performance fan with consideration of system resistance, optimal twist concept is applied through momentum and blade element theory. To predict fan noise, empirical formula and acoustic analogy methods are used.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.04a
• /
• pp.363-368
• /
• 2000

The Korean Bridge Design Standard Specifications adopted the seismic design requirements in 1992. However, The current seismic design requirements for bridges are based on the USA seismic codes for sever earthquake. This provides the basic factors that affects the performance of spiral reinforced concrete piers for seismic loading, and The specimen tests are performed based on load-displacement, effective stiffness and displacement ductility, etc. The quasi-static test was adopted in order to investigate seismic performance of the spiral reinforced concrete pier specimens which had different transverse steel amount, spacing and longitudinal steel ratio under different axial load levels. This study is concluded that seismic design for transverse reinforcement content of spiral reinforced concrete column has influenced on axial load and effective stiffness etc.

• International Journal of Advanced Culture Technology
• /
• v.6 no.3
• /
• pp.105-116
• /
• 2018

As an international company in the automotive industry for years, Sichuan Hyundai has encountered serious difficulties since its entering into China. With huge investment and great ambition to conquer the China commercial vehicle market, successive setbacks have put the company in jeopardy. Design thinking, emphasizing "user-driven innovation" can help to look for effective and possible solutions from a very strong and effective perspective. This thesis first provides a comprehensive look of the economic background of China in order to get a overall understanding of the market. Then the paper did an analysis of Sichuan Hyundai from the perspective of design thinking. By identifying the reliability bias of Sichuan Hyundai, key problems such as the product, advertisement and cultural communication were discussed. With a emphasis on the intuitive thinking, the paper provides some feasible solutions and also implications for the future development.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.103-107
• /
• 2003

The objective of this thesis is to develop the optimal design of composite links containing complicated cross-section. To accomplish this objective, a composite links structural analysis program was developed. The method of calculating effective modulus of composite beam containing complicated cross-section is proposed. Genetic algorithm was implemented for the optimization method to manipulate the discrete ply angles as the design variables and to utilize its high reliability to find the global optimum. The design variables were the number of plies, the fiber orientations and the stacking sequence. The optimal design of composite links was performed by genetic algorithm to minimize the weight of the structure and to constrain ply failure

• The KSFM Journal of Fluid Machinery
• /
• v.13 no.6
• /
• pp.25-29
• /
• 2010

In this paper, a numerical study has been carried out to investigate the influence of silencer design variables on the performance of a jet fan. In order to achieve an optimum jet fan design and to explain the interactions between the different geometric configurations in the jet fan, three-dimensional computational fluid dynamics and the Design of Experiments method have been applied. Two geometric variables, i.e., cap size and silencer length, were employed to improve the performance of the jet fan. The objective functions of the jet fan are defined as the effective velocity and total efficiency at the operating condition. Based on the results of computational analyses, the flow characteristics were discussed. The effect of silencer with a specific roughness on the performance was also discussed.

• Transactions of Materials Processing
• /
• v.15 no.3 s.84
• /
• pp.226-231
• /
• 2006

The fuel injector is a pa.1 that controls the fuel supply of automotive engine. The housing of the fuel injector supports the rod, the needle valve and the solenoid. In this study, the rigid-plastic FE-analysis by using the design of experiments (DOE) and the response surface methodology (RSM) has been performed to produce the product reducing the under-fill and the maximum effective strain. From the results of DOE, the stem of counter punch and the face angle of punch at the $1^{st}$ process, and the stem of punch at the $2^{nd}$ process were determined as the significant design variables far each response such as the upper under-fill, lower under-fill and the maximum effective strain. From the results of RSM, the optimal values of the design variables have been also determined by simultaneously considering the responses.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1997.04a
• /
• pp.481-487
• /
• 1997

The development of transportation and construction equipment has required higher engine power and lower operation cost. The sound which the engine emits often degrade the performance of the whole system which adopts that engine. Specially the marine engine requires high restriction on the noise level for the customer's comfort and safety. The noise and vibration of Diesel engine must be carefully considered in the early design step. The double antivibration system is effective to increase the efficiency of antivibration, and the acoustic enclosure for reducing the noise level. 2 DOF model was effective to estimate the antivibration performance, which allows to determine the mass of the engine bed and the specification of the engine mount. The mass distribution of the enclosure system can be considered effectively by using the FEM model. The design contains structurally rigid engine bed by FEM, which is for reducing the influence of the flexible vibration, rubber mount selection as well as the acoustic enclosure design.

• Journal of electromagnetic engineering and science
• /
• v.16 no.2
• /
• pp.67-73
• /
• 2016

This paper presents simple expressions for the effective permeability of bulk metamaterial consisting of ring resonators (RRs) or split ring resonators (SRRs) based on the convenient geometrical factors of the structure compared with wavelength. The resonant frequency dependence of the medium permeability, including loss effects, is analyzed in detail. Inverting the analysis equations, useful design (or synthesis) equations are derived for a systematic design process with some examples. This paper may particularly be useful for the design of a bulk metamaterial with a specific negative relative permeability at a desired frequency. The loss of metamaterials consisting of RRs (or SRRs) is also analyzed over a wide frequency band from 10 MHz to 10 THz.

• Korean Journal of Remote Sensing
• /
• v.16 no.2
• /
• pp.157-175
• /
• 2000

A synthetic aperture radar (SAR) system is able to provide all-weather, day-and- night superior imaging capability of the earth surface, and thus is extremely useful in surveillance for both civil and military applications. In this paper, the X-band high resolution spaceborne SAR system design is demonstrated with the key design performance for a given mission and system requirements characterized by the small satellite system. The SAR multi-mode imaging technique is presented with a critical parameter assessment, and the standard mode results are analyzed in terms of the image quality performances. In line with the system requirement X-band SAR payload and ground reception/processing subsystems are designed and the major design results are presented with the key performance characteristics. This small satellite SAR system shows the wide range of imaging capability with high resolution, and proves to be an effective surveillance systems in the light weight, high performance and cost-effective points of view.

• Journal of Ship and Ocean Technology
• /
• v.5 no.1
• /
• pp.30-37
• /
• 2001

Ship optimal design is a multi-objective decision-making process and its optimal solution does not exit in general. It is a problem in which the decision-maker is very interested that an effective solution is how to be found which has good characteristic and is substituted for optimal solution in a sense. In the previous methods of multi-objective decision-making, the weighting coefficients are decided from the point of view of individuals which have a bit sub-jective an unilateral behavior. in order to fairly and objectively decide the weighting coeffi-cients, which are considered to be optimal in all system of multi-objective decision-making and satisfactory solution to the decision-maker, the pater presents a method of applying the Technology of the Biggest Entropy. It is proved that the method described in the paper is very feasible and effective be means of a practical example of ship optimal design.