• 한국기계가공학회지
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• 제17권2호
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• pp.37-46
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• 2018

Present research is to evaluate and improve the sealing performance of the duct cap assembly for the ice dispensers through structural analysis. The nonlinear contact problems to check the sealing performance were analyzed using ANSYS software. The results of the analyses related to the sealing performance: the displacement distribution, the contact condition between the cap-silicon and the case, and the pressure distribution on the contact surface, were examined and discussed. Based on the results of the existing design of the duct cap assembly, two cases of the design modifications to improve the sealing performance were introduced. By examining the results of the two cases, a final design improvement plan was proposed and analyzed. It is shown that the sealing performance of the proposed final design is much more favorable than the existing design. The method of structural analysis and design improvement of the duct cap assembly presented in this paper will help improve the sealing performance of the ice dispenser duct caps.

• 국제초고층학회논문집
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• 제1권3호
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• pp.195-201
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• 2012

Today, a great effort to develop PBSD procedure to be utilized in Korea is given by domestic structural engineers, academics, and governmental organizations. After Great East Japan Earthquake (2011) took place, lots of clients in Korea became to concern of their buildings so that requests of seismic performance evaluation and seismic rehabilitation for existing buildings have been gradually increased. Such interests in seismic events initiated a rapid development of a series of guidelines for seismic performance evaluation and seismic performance enhancement. For new buildings, however, design guidelines for PBSD are yet well prepared in Korea and prescriptive design methods are dominant design procedure still. Herein, seismicity demands used in seismic performance evaluation and some important design parameters in NLRH are introduced. Some project examples for seismic performance evaluation and rehabilitation applying passive energy dissipation devices are also described in the latter part of paper.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.922-929
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• 2019

This paper presents the drop performance test of the control rod assembly which is one of the main components strongly related to the safety of the prototype generation IV sodium-cooled fast reactor. To investigate the drop performance, a real-sized control rod assembly that was recently modified based on the drop analysis results was newly fabricated, and several free drop tests under different flow rate conditions were carried out. Then the results were compared with those obtained from the previous tests conducted on the conceptually designed control rod assembly to demonstrate the improvement in performance. Moreover, the drop performance tests under several types and magnitudes of seismic loadings were also conducted to investigate the effect of the seismic loading on the drop performance of the modified control rod assembly. The results showed that the effects of the type and magnitude of the seismic loading on the drop performance of the modified control rod assembly were not significant. Also, the drop time requirement was successfully satisfied, even under the seismic loading conditions.

• 대한기계학회논문집
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• 제18권12호
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• pp.3357-3368
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• 1994

Total pressure losses required to calculate the total-to-total efficiency are estimated by integrating empirical loss coefficients of four loss mechanisms along the mean-line of blades as follows; blade profile loss, secondary flow loss, end wall loss and tip clearance loss. The off-design points are obtained on the basis of Howell's off-design performance of a compressor cascade. Also, inlet-outlet air angles and camber angle are obtained from semi-empirical relations of transonic airfoils' minimum loss incidence and deviation angles. And nominal point is replaced by the design point. It is concluded that relatively simple loss models and Howell's off-design data permit us to calculate the off-design performance with satisfactory accuracy. And this method can be easily extended for off-design performance prediction of multi-stage compressors.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.670-675
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• 2001

This paper describes aerodynamic preliminary design performance prediction and flow analysis for turbine of the marine middle engine turbocharger. The performance characteristics of turbocharger turbine are investigated at various operating conditions using mass flow rate and computational flow analysis for rotor and nozzle at design point are performed. Preliminary design results are performed by applying mean line and radial equilibrium theory. Performance prediction and flow analysis results show good agreement with experiments. From 3 dimensional flow analysis result, efficiency is 0.6% greater than design point. Therefore, this design approach is useful for preliminary design, and helps to increase the design capability for optimized rotor blade.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.138-147
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• 2000

Vehicle suspension systems are parts which effect performances of a vehicle such as ride quality, handing characteristics, straight performance and steering effort etc. Kinematic design is a decision of joints` position for straight performance and steering effort. But, when vehicle is rebounding and bumping, chang of joints` displacement is nonlinear and a surmise of straight performance and steering effort at that joints` position is difficult. So design of suspension systems is done through a inefficient method of tried-and-error depending on designer`s experience. In this paper, kinematic design of suspension systems was done through the optimal design using a genetic algorithm. For this optimal design, the function for quantification of straight performance and steering effort was made, and the kinematic design method of suspension systems having this function as the objective function was suggested.

• 국제초고층학회논문집
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• 제11권3호
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• pp.197-205
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• 2022

One of important design challenges in Chongqing Raffles City Plaza project is Sky Bridge structural design and its connection scheme in high level. This article systematically describes the structural system and its design and analysis methodology, with discussing the impacts on structural performance due to different connection approaches. The seismic isolation scheme in high level is innovatively adopted to the final design. Under the conditions of various load cases, the different models and assumptions are implemented. A full assessment on Sky Bridge's structural performance, seismic isolation, and its connection is conducted in terms of seismic performance based design. By co-operating with architecture, MEP and other disciplines, the structural economy index is fulfilled.

• 한국공간구조학회논문집
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• 제13권1호
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• pp.69-77
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• 2013

This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete moment frame and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. It also shows the result of the seismic performance improvement which is the ratio of seismic performance appreciation result yield displacement 19%, yield strength ratio 24%, displace ductility ratio the maximum 27% comparing Multi degree of freedom, column member of Reinforced Concrete with the performance improvement column member considering the thickness of the determined Steel Jacket. The developed Algorithm and program are easy to apply seismic design and application to the original Reinforced Concrete building, at the same time, it applicate to display well the design result of Target displacement performance level about nonlinear behavior.

• International Journal of Aeronautical and Space Sciences
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• 제18권1호
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• pp.154-164
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• 2017

This work conducts a validation study for the XH-59A helicopter using a rigid coaxial rotor system in order to establish the techniques of the conceptual design and performance analysis for the lift-offset compound rotorcraft. As a tool for conceptual design and performance analysis, NDARC (NASA Design and Analysis of Rotorcraft) is used for the present study. An assumed mission profile is considered for the conceptual design of the XH-59A. As a validation result of the design, the dimensions and weight of the XH-59A are appropriately designed when compared to the target values since the relative error is less than 0.5%. Then, performance analyses are conducted for the designed XH-59A model with and without auxiliary propulsion in hover and forward flight conditions. The present analyses show good validity since the prediction results compare well with both the flight test and previous analyses. Therefore, the techniques for the conceptual design and performance analysis of the lift-offset compound helicopter are overall considered to be appropriately established. In addition, this study investigates the influence of the lift-offset on the rotor effective lift-to-drag ratio of the XH-59A helicopter with auxiliary propulsion. As a result, the improvement of the rotor effective lift-to-drag ratio can be obtained by appropriately increasing the lift-offset in high-speed flight.

• 한국BIM학회 논문집
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• 제11권3호
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• pp.1-11
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• 2021

BIM is one of the means of reducing the economic loss caused by design errors. These features of BIM have led to increased use of BIM. With the increasing use of BIM, several studies have been conducted to analyze the performance of BIM. As the importance of BIM staff is emphasized in the performance analysis of BIM, the human resource allocation of BIM staff can become an important research issue. However, there are few studies to measure the workforce effectiveness of BIM staff. Ham et al (2020) measured BIM workforce efficiency using FCFS queue model rules. Since design errors can have different effects on the project depending on the type, there are design errors that must be dealt with first. Therefore, in this study, a priority queue was used to solve design errors with high priority first. The performance of BIM-based design verification was analyzed by quantitatively analyzing the performance of BIM staff when the priority rule was applied to the design error processing sequence.