• Tribology and Lubricants
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• v.39 no.3
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• pp.94-101
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• 2023

Automotive wheel bearings are a critical component of vehicles that support their weight and facilitate rotation. Life and stiffness are significant performance characteristics of wheel bearings. Designing wheel bearings involves finding optimal design variables that satisfy both performances. CO₂ emission reduction and fuel efficiency regulations attribute to the recent increase in design requirements for lightweight and compact automotive parts while maintaining performance. However, achieving a design that maintains performance while reducing weight poses challenges, as performance and weight are generally inversely proportional. In this study, we perform design optimization of automotive wheel bearings considering life and stiffness. We develop a program that calculates the basic rated life and modified rated life based on international standards for evaluating the life of wheel bearings. We develop a regression equation using regression analysis to address the time-consuming stiffness analysis during repetitive analysis. We perform ANOVA and main effect analyses to understand the statistical characteristics of the developed regression equation. Furthermore, we verify its reliability by comparing the predicted and test results. We perform design optimization using the developed life prediction program, stiffness regression equation and weight regression equation. We select bearing specifications and geometry as design variables, weight as the cost function, and life and stiffness as constraints. Through design optimization, we investigate the influence of design variables on the cost function and constraints by comparing the initial and optimal design values.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.3
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• pp.241-248
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• 2016

Plant life cycle consists of design, construction, certification, operation, and maintenance phases, and various and enormous plant life cycle data is involved in each phase. Plant life cycle data should be linked with each other based on its proper relationships, so that plant operators can access necessary plant data during their regular operations and maintenance works. Currently, the relationships of plant life cycle data may not be defined explicitly, or they are scattered over several plant information systems. This paper proposes high level design of a plant life cycle data management system based on pre-defined plant life cycle database design. ISO-15926 standard is adapted for the database design. User-interface designs of the plant life cycle data management system are explained based on analysis of plant owners' requirements. A conceptual design of the database is also described with the entity-relationship diagram.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.151-158
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• 1998

This paper presents an optimal decision model for minimizing the life-cycle cost of steel box girder bridges. The point is that it takes into account service life process as a whole, and the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs and expected failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. The optimal solution identifies those values of the decision variables that result in minimum expected total cost. The performance constraints in the form of flexural failure and shear failure are those specified in the design code. Based on extensive numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on life-cycle cost approach proposed in this study provides a lot more rational and economical design, and thus the proposed approach will propose the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.314-315
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• 2018

The long-life housing certification system must have been applied more than 1,000 households apartments since 2015. The basic design guideline for the popularization of long-life housing has been developed in 2017, which include the concept of long-life housing and basic principle of design long-life housing. The demonstration project of long-life housing is be currently under construction in Sejong-si. The aim of this study is to find items on design checklist considering construction stage. The main goal is the development of design manual of long-life housing.

• Korean Institute of Interior Design Journal
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• v.21 no.1
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• pp.3-10
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• 2012

There is a growing awareness that physical barriers affect the level of independence of people with disabilities. Many researchers insist that barrier free design could influence independence living and quality of life of the disabled. The purpose of this study is to find out the effects of accessible design features of house and public facilities on quality of life of disabled people. A total of 189 questionnaires from the disabled who visited public welfare facilities was analyzed. In order to find out what variables among accessible features in housing and public spaces impact quality of life, multiple regression analysis was carried using SPSS 14. The results showed that accessible designs significantly influence quality of life of the disable. The main reason in which the disabled have difficulties when they move outside is a lack of accessible amenities and facilities. Particularly in house design, accessible main entrance route and accessible main entrance door, and removal of floor level significantly affects quality of life of the disabled. For public spaces, accessible main entrance and installation of ramp or removal of floor levels of main entrance and corridor increase quality of life people with disabilities. This paper suggested that the improvement in housing and public space, in which regulation or bylaws do not specify, should be made to increase accessibility for life quality of the disabled.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4166-4178
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• 2021

The Control Rod Drive Mechanism (CRDM) is an essential part of the reactor, which realizes the start-stop and power adjustment of the reactor by lifting and lowering the control rod assembly. As a moving part in CRDM, the latch directly contacts with the control rod assembly, and the life of latch is closely related to the service life of the reactor. In this paper, the relationship between the life of the latch and the step stress, friction stress, and impact stress in the process of movement is analyzed, and the optimization methodology and process of latch life based on the approximate model are proposed. The design variables that affect the life of the latch are studied through the experimental design, and the optimization objective of design variables based on the latch life is established. Based on this, an approximate model of the life of the latch is built, and the multi-objective optimization of the life of the latch is optimized through the NSGA-II algorithm.

• Korean Institute of Interior Design Journal
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• v.20 no.3
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• pp.110-118
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• 2011

Today aesthetics expression could be a 'Everyday-life Beauty', because today art & design are closely related with a contemporary life. This thesis dealt with a everyday-life and sensitive design which sublimate from everyday-life material to the concept of aesthetics, such a purpose of this thesis establishes a base of everyday-life design through everyday-life aesthetics. This purpose made to pay attention to Japan's aesthetics concept, because Japan has been maintained and developed its own everyday-life aesthetics. Even if Japan doesn't have only everyday-life aesthetics, it is useful that is studies as some kind of a prototype. So this study analyzed about a everyday-life aesthetics and the expression method through the case-study of Japan. According to Yonagi Muneyoshi and Leonard Koren, the Wabi-Sabi has three conceptual characteristics like impermanent, incomplete, and imperfect and six expression characteristics like implication, tranquility, simplicity, coarseness, purity, and association. This study process is as follows. In the first a vocabulary of interior design was derived from three conceptual characteristics and six expression characteristics, and spatial facts was abstracted from it, and then volume, form, and then shape of composition facts of interior space was extracted from it. Finally the expression characteristics of the Wabi-Sabi in interior design was derived from these processes. In conclusion, the expression characteristics of the Wabi-Sabi in interior design is the transitional space through a Shadow, the conversional space through form and material composition, and the copying space through a natural friendship.

• Proceedings of the Korea Society of Design Studies Conference
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• 2003.05a
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• pp.158-159
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• 2003

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.319-328
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• 2000

This paper presents a new design method of the 1 generation wheel bearing unit using a numerical optimization technique in order to increase bearing fatigue life. For calculating the fatigue life, a method of load analysis is studied on the automotive wheel bearing system. The design variables selected are ball size, initial contact angle, number of balls, pitch diameter, pre-load, and distance between ball centers. The method of feasible directions in ADS (Automated Design Synthesis) is utilized to automatically find the optimum design variables. To validate the design method, a computer program is developed and applied to a practical passenger car model. The optimum design results demonstrated the effectiveness of the proposed design method showing that the system life of the optimally designed wheel bearing unit is enhanced in comparison with that of the initial ones within the given available design space.

• Journal of the Korean housing association
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• v.22 no.2
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• pp.73-82
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• 2011

Recently, apartments have had several fundamental problems in planning uniformity caused by fixed space programs and difficulties of maintenance. So decision-makings become more important in design process which were essential to performance realization of long-life housing. Therefore, this study aims to analyze the plans of the Bogeumjari Nae-gok based on the applied designs, and suggests improvements for advanced design process of the long-life housing in the domestic market. This research procedure are as follows: (1) Analyze design guide, district land development plan and local code which have influence on design limitation. (2) Compare partial plans of joined designs and analyze each design characters (3) Implement case studies of design process due to design timetable and design elements of Nae-gok. In result, this study suggests significant fundamental materials for advanced decision-making in design process of long-life housing: details credibility and noise control, etc. This research could be useful in making integrated design process applied for long-life housing.