• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.335-342
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• 2002

A continuum-based design sensitivity analysis (DSA) method fur non-shape problems is developed for geometrically nonlinear elastic structures. The non-shape problem is characterized by the design variables that are not associated with the domain of system like sizing, material property, loading, and so on. Total Lagrangian formulation with the Green-Lagrange strain and the second Piola-Kirchhoff stress is employed to describe the geometrically nonlinear structures. The spatial domain is discretized using the 4-node isoparametric plane stress/strain elements. The resulting nonlinear system is solved using the Newton-Raphson iterative method. To take advantage of the derived analytical sensitivity In topology optimization, a fast and efficient design sensitivity analysis method, adjoint variable method, is employed and the material property of each element is selected as non-shape design variable. Combining the design sensitivity analysis method and a gradient-based design optimization algorithm, an automated design optimization method is developed. The comparison of the analytical sensitivity with the finite difference results shows excellent agreement. Also application to the topology design optimization problem suggests a very good insight for the layout design.

• Journal of the Ergonomics Society of Korea
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• v.36 no.2
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• pp.69-86
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• 2017

Objective: The present study is intended to develop an improved bus seat armrest design by evaluating various bus armrest designs from ergonomic aspects. Background: An ergonomic armrest design which considers the sitting postures and body shapes of passengers can improve the convenience and comfort of a bus seat. Method: Subjective satisfaction of each of five design dimensions (length, width, height from seatpan, shape, and angle) was evaluated for seven bus seat armrest designs in various sizes and shapes by 58 participants (28 males and 33 females) using a 7-point scale (1: very dissatisfied, 4: neutral, and 7: very satisfied). Improved bus seat armrest designs adjustable in length and rotatable to the left or right (sliding and rotating armrest, SRA) with a concave, flat, or convex shape of the upper part were developed by considering the preferred design features and the body size and shape in sitting posture and needs of passengers and then compared with a conventional armrest. Results: A bus seat armrest with a wide width (40~50mm), a long length (360mm), a lower height (213mm), and a curved shape was found significantly preferred in terms of comfort. The proposed armrest designs (SRA-convex, SRA-flat, and SRA-concave) improved satisfaction by 46~62% for length suitability, 184~216% for width suitability, 205~214% for angle suitability, 138~181% for contact area suitability, and 49~64% for height suitability, 138~174% for comfort, and 93~111% for overall satisfaction. Conclusion: The preferred design features and passengers' needs of bus seat armrest were identified and the SRA designs were recommended for better usability. Application: The ergonomic design process of bus seat armrest employed in the present study can be applied to designing armrests in various vehicles for better convenience and comfort.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.74-84
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• 2015

The core activities of a bicycle manufacturer are design, engineering analysis, and manufacturing. Therefore, it is important to develop a configuration design system for bicycles in order to automate the design process and facilitate the use of design data in engineering analysis and manufacturing. In this paper, we present a method to develop a bicycle configuration design system based on the part-shape information model. The proposed method enables the construction of a CAD library using modeling functions with equations and parameters that are common to most 3D mechanical CAD systems. Furthermore, the part-shape information model ensures the independence between the configuration design system and the library, making it possible to extend the CAD library flexibly without changing the system architecture.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.355-362
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• 2004

An efficient boundary-based technique is developed for addressing shape design sensitivity analysis in various problems. An analytical sensitivity formula in the form of a boundary integral is derived based on the continuum formulation for a general functional defined in problems. The formula, which is expressed in terms of the boundary solutions and shape variation vectors, can be conveniently used for gradient computation in a variety of shape design problems. While the sensitivity can be calculated independent of the analysis means, such as the finite element method (FEM) or the boundary element method (BEM), the FEM is used for the analysis in this study because of its popularity and easy-to-use features. The advantage of using a boundary-based method is that the shape variation vectors are needed only on the boundary, not over the whole domain. The boundary shape variation vectors are conveniently computed by using finite perturbations of the shape geometry instead of complex analytical differentiation of the geometry functions. The supercavitating flow problem and fillet problem are chosen to illustrate the efficiency of the proposed methodology. Implementation issues for the sensitivity analysis and optimization procedure are also addressed in these problems.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.2
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• pp.170-177
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• 2013

This study is focused on the shape design and flow analysis on a 200 W-class Gyromill type vertical axis wind turbine rotor blade. Single tube theory is adopted for the shape design of the turbine blade. 2-dimensional CFD analysis is conducted to examine the turbine performance with basic shape, and then 3-dimensional shape is determined from the examination of the performance. By the CFD analysis on the 3-dimensional shape of the wind turbine, performance of the turbine is examined and also, shape of the wind turbine rotor blade is determined accordingly. From the results of this study, a 200 W-class Gyromill type vertical axis wind turbine rotor blade is designed and the reliability of the design method is confirmed by CFD analysis.

• Journal of the Korea Fashion and Costume Design Association
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• v.25 no.1
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• pp.33-47
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• 2023

In this study, the difference in human body dimensions between the age groups of Generation M (27 to 39 years old) and Generation Z (20 to 26 years old) was analyzed. This study also analyzed if there was a change in the body shape of the MZ generation, who have different sensibilities from the "young people" of the past. In addition, major changes in human body dimensions were carefully analyzed and presented as basic data for clothing design. Therefore, a t-test was performed to verify the significant differences in the measurements of each age group. To examine the change in human body measurements according to the measurement year, the 7th and 8th size Korea data statistics were analyzed. The main required dimensions of clothing design were analyzed graphically for visual changes according to measurement year and age group. As a result of the analysis, Generation Z was found to have a difference in body shape from Generation M, and is generally smaller and slimmer with broader shoulders. In addition, the body shape change between the 7th and 8th measurement periods was significantly higher than the 8th measurement overall. Height has increased and back length has become shorter, resulting in a larger ratio of lower body length. In addition, the proportion of obesity abnormalities has increased. Therefore, since the dimensional system set from the past data can cause problems for the fitting of clothing for the MZ generation, it is necessary to design the clothing and reset the dimensional system making it suitable for the changed the body shape of the MZ generation.

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.10a
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• pp.6-7
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• 2004

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.146-148
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• 1998

For the shape design of electromagnetic devices using the FEM, the choice of design parameters influence to the success of the optimization process. If the design parameter distribution has a one to one corespondence with finite element model, we can encounter not only serious accuracy problem but also obtain a zigzag shape along the interface. The nodes between those design parameters can be parameterized by interpolating using one among many interpolation methods. The conventional parameterization of design parameters has a limit of application for shape, because design parameters and movable nodes are linearly intepolated. In this paper, using the B-spline curve that use to present any interfaces in computer graphics, the curvilinear parameterization between design parameters and node points is compared with the linear parameterization.

• Korean Institute of Interior Design Journal
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• v.15 no.3 s.56
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• pp.111-117
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• 2006

In the recent years, domestic construction companies have tried to differentiate their apartments using brand positioning. Respective construction companies are attracting public attention with discriminative brands. This study investigated residents' preferences focusing on apartments facade design used in marketing strategy of brand apartments. Four concepts in surveyed brand apartments are deluxe, modern, eco-friendly and comfortable. According to the related study on design factor of apartment facade, the design factors are chosen such as the overall building shape, balcony form, main color, exterior wall shape, material, main access shape, pent house design and window size. As a result of analysis, there was a difference between brand concepts and consumers' views. Therefore, apartment facade design to differentiate their own companies' brand images should consider the perception of customers.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.306-314
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• 2004

This paper explains the qualitative shape representation scheme and general shape analysis procedure based on shape feature categories. It takes two different groups of architectural drawings as examples and comparer them so as to confirm that the procedure is capable of comparing one group with another. In order to verify the validity of qualitative shape representation scheme, we used statistical methods as well as symbolic representation and analysis techniques. This paper concludes that two different groups of architectural drawings of similar kind are analyzed to be distinguished and specifically characterized. 11 drawings of Kahn and 13 drawings of Aalto are taken into considerations. Linear regressions are used in characterizing the shape featural relationships.