• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.7
• /
• pp.510-514
• /
• 2018

This study discusses and demonstrates the structural stability of highly ordered Pt patterns formed on a transparent and flexible substrate through the process of nanotransfer printing (nTP). Bending tests comprising approximately 1,000 cycles were conducted for observing Pt line patterns with a width of $1{\mu}m$ formed along the direction of the horizontal (x-axis) and vertical (y-axis) axes ($15mm{\times}15mm$); and adhesion tests were performed with an ultrasonicator for a period greater than ten minutes, to analyze the Pt crossbar patterns. The durability of both types of patterns was systematically analyzed by employing various microscopes. The results show that the Pt line and Pt crossbar patterns obtained through nTP are structurally stable and do not exhibit any cracks, breaks, or damages. These results corroborate that nTP is a promising nanotechnology that can be applied to flexible electronic devices. Furthermore, the multiple patterns obtained through nTP can improve the working performance of flexible devices by providing excellent structural stability.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.16 no.3
• /
• pp.281-290
• /
• 2003

Co Evolutionary Structural Design(CESD) Framework is presented, which can deal with the load design and structural topology design simultaneously. The load design here is the exploration algorithm that finds the critical load patterns of the given structure. In general, the load pattern is a crucial factor in determining the structural topology and being selected from the experts어 intuition and experience. However, if any of the critical load patterns would be excluded during the process of problem formation, the solution structure might show inadequate performance under the load pattern. Otherwise if some reinforcement method such as safety factor method would be utilized, the solution structure could result in inefficient conservativeness. On the other hand, the CESD has the ability of automatically finding the most critical load patterns and can help the structural solution evolve into the robust design. The CESD is made up of a load design discipline and a structural topology design discipline both of which have the fully coupled relation each other. This coupling is resolved iteratively until the resultant solution can resist against all the possible load patterns and both disciplines evolve into the solution structure with the mutual help or competition. To verify the usefulness of this approach, the 10 bar truss and the jacket type offshore structure are presented. SORA(Sequential Optimization & Reliability Assessment) is adopted in CESD as a probabilistic optimization methodology, and its usefulness in decreasing the computational cost is verified also.

• Fashion & Textile Research Journal
• /
• v.14 no.1
• /
• pp.109-121
• /
• 2012

This study aims at developing ergonomics patterns for the sleeve of structural firefighting protective clothing through 3D motion analysis in order to ensure efficiency and safety of firefighters who are exposed to harmful environment at work. A new research pattern was developed by applying the total results of 3D motion analysis, changes of body surface length measurements, and 2D data on 3D body shape analysis on the size 3 patterns of the existing coat sleeve. For the sleeves, we used the body surface length of the range of shoulder's flexion and the joint angle of the range of wrist's ulnar deviation. And for the production of structural firefighting protective clothing using the research pattern, we recruited a recognized producer of structural firefighting protective clothing designated by KFI. Unlike everyday clothes, structural firefighting protective clothing should be able to fully protect the wearers from the harmful environment that threatens their lives and should not cause any restrictions on their movement. Therefore, the focus of research and development of such protective clothing should be placed on consistent development of new technologies and production methods that will provide protection and comfort for the wearer rather than production cost reduction or operational efficiency. This study is meaningful as it applied 3D motion analysis instead of the existing methods to develop the patterns. In particular, since 3D motion analysis enables the measurement of the range of motion, there should be continuous research on the development of ergonomics patterns that consider workers' range of motion.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2004.04a
• /
• pp.285-292
• /
• 2004

The objective of this paper is to develop a simplified method to determine yield line patterns of reinforced concrete floor slabs based on the elastic fields. Unlike other methods mainly focused on the plasticity theory, this paper emphasizes the elastic fields, especially principal moments and maximum shears and shows a link between elasticity field and yield line patterns. General criteria on both positive and negative yield lines are suggested in terms of principal moments and maximum shear forces. The proposed method can predict starting point (or regions) of yielding and the further development of yield lines on whole structures. The yield line patterns determined by the proposed method are shown to be coincident with the classical yield line theory. Furthermore, orthotropy in reinforced concrete slab is investigated and yield line patterns for different type of flat slab with non-isotropic strip are studied broadly.

• Journal of the Korean earth science society
• /
• v.34 no.3
• /
• pp.189-194
• /
• 2013

In this study, the patterns of barotropic vortices and their structural rotation were investigated through laboratory experiments. Both stable and unstable barotropic vortices were formed in a rotating water tank with a rotating circular plate depending on the diameter, direction, and speed of rotating circular plate. The patterns of stable vortices turned out to be tripolar, triangular, rectangular, and monopolar vortex. These vortex patterns were affected by the gap between the circular plate and the wall of the water tank. Many unstable vortices were formed by anticyclonically and highly rotating circular plate. These results were caused by the centrifugal instability. The structural angular velocity of the tripolar vortex increased with the tangential velocity of the circular plate. The anticyclonic tripolar vortex had higher structural angular velocity than the cyclonic vortex. The tripolar vortex in the water tank was very similar with the real oceanic tripolar vortex from the view point of the Rossby number and the structural rotation.

• Journal of the Korean Society of Costume
• /
• v.25
• /
• pp.215-231
• /
• 1995

Semiotics is an external expression for show-ing internal meaning, and the signs express the internal meaning. The architects and the designers are very similar each other in using semiotics for expressing their desires. Histori-cally, the design similarity exists between the architecture and the fashion. In this study, the fashion designs are interpreted by using semiotics of architectural design, especially emphasizing external expression methods for representing internal desires. To express the human body's character-istics, the volume, weight support, structural simplicity, controllability and beauty of fashion were used for the fashion designs, and those characters could be found at the architec-tural patterns. Balenciaga's fashion emphasized the volume, the weigh support, the structural simplicity and the controllability, while Roberto Capucci rejected the approach of using women's body curves, but used the volume and simplicity of natures in addition to Balenciaga's heavy weight design patterns. The control and the modern dedication were used to make the simple patterns by Courreges, and then brought the Modernism to the fashion. Courreges used the cutting characters to func-tional design for expressing the structural sim-plicity.

• Structural Engineering and Mechanics
• /
• v.55 no.6
• /
• pp.1157-1176
• /
• 2015

This study presents optimizing structural topology patterns using regularization of Heaviside function. The present method needs not filtering process to typical SIMP method. Using the penalty formulation of the SIMP approach, a topology optimization problem is formulated in co-operation, i.e., couple-signals, with design variable values of discrete elements and a regularized Heaviside step function. The regularization of discontinuous material distributions is a key scheme in order to improve the numerical problems of material topology optimization with 0 (void)-1 (solid) solutions. The weak forms of an equilibrium equation are expressed using a coupled regularized Heaviside function to evaluate sensitivity analysis. Numerical results show that the incorporation of the regularized Heaviside function and the SIMP leads to convergent solutions. This method is tested using several examples of a linear elastostatic structure. It demonstrates that improved optimal solutions can be obtained without the additional use of sensitivity filtering to improve the discontinuous 0-1 solutions, which have generally been used in material topology optimization problems.

• Journal of the Korean Wood Science and Technology
• /
• v.31 no.6
• /
• pp.45-54
• /
• 2003

The density and strength of wood is affected by degradations and defects, such as voids and knots. Old wooden structures such as traditional cultural properties have been deteriorated by these types of defects. They were evaluated by a visual observation that is difficult to evaluate the inner deterioration in structures. In this study, three nondestructive testing techniques were investigated to detect the wooden structural members. Ultrasonic stress wave tests, drilling resistance tests and visual inspections were used to examine the structural wood members. Patterns of Resistograph using by drilling resistance tests could indicate the features of internal wood such as voids, knots, decay, fungi, and so on. The technique just like as ultrasonic stress wave tests, however, difficult to detect exactly area where small amounts of internal deterioration in logs are. In spite of results of ultrasonic stress wave test, the internal deterioration of wooden structural members could be evaluated by the relationship between ultrasonic stress wave tests and drilling resistance tests.

• Advances in aircraft and spacecraft science
• /
• v.10 no.3
• /
• pp.223-243
• /
• 2023

There is a burgeoning demand for minimizing the mass of satellites because of its direct impact on reducing launch-to-orbit cost. This must be done without compromising the structure's efficiency. The present paper introduces a relatively low-cost and easily implementable approach for optimizing structural mass to a maximum natural frequency. The natural frequencies of the satellite are of utmost pertinence to the application requirements, as the sensitive electronic instrumentation and onboard computers should not be affected by the vibrations of the satellite structure. This methodology is applied to a realistic model of Al-Azhar University micro-satellite in partnership with the Egyptian Space Agency. The procedure used in structural design can be summarized in two steps. The first step is to select the most favorable primary structural configuration among several different candidate variants. The nominated variant is selected as the one scoring maximum relative dynamic stiffness. The second step is to use perforation patterns reduce the overall mass of structural elements in the selected variant without changing the weight. The results of the presented procedure demonstrate that the mass reduction percentage was found to be 39% when compared to the unperforated configuration that had the same plate thickness. The findings of this study challenge the commonly accepted notion that isogrid perforations are the most effective means of achieving the goal of reducing mass while maintaining stiffness. Rather, the study highlights the potential benefits of exploring a wider range of perforation unit cells during the design process. The study revealed that rectangular perforation patterns had the lowest efficiency in terms of modal stiffness, while triangular patterns resulted in the highest efficiency. These results suggest that there may be significant gains to be made by considering a broader range of perforation shapes and configurations in the design of lightweight structures.

• Advances in Computational Design
• /
• v.2 no.4
• /
• pp.293-311
• /
• 2017

There are several claimed benefits for the impact of design patterns (DPs) on software quality. However, the association between design patterns and fault-proneness has been a controversial issue. In this work, we evaluate the fault-proneness of design patterns at four levels: the design level, category level, pattern level, and role level. We used five subject systems in our empirical study. As a result, we found that, at the design level, the classes that participate in the design patterns are less fault-prone than the non-participant classes. At the category level, we found that the classes that participate in the behavioral and structural categories are less fault-prone than the non-participant classes. In addition, we found that the classes that participate in the structural design patterns are less fault-prone than the classes that participate in the other categories. At the pattern level, we found that only five patterns show significant associations with fault-proneness: builder, factory method, adapter, composite, and decorator. All of these patterns except for builder show that the classes that participate in each one of them are less fault-prone than the non-participant classes in that pattern. The classes that participate in the builder design pattern were more fault-prone than the non-participant classes and the classes that participate in several patterns: the adapter, the composite, and the decorator design patterns. At the role level, the most significant differences were between the classes that participate in some roles and the non-participant classes. Only three pairs of design pattern roles show significant differences. These roles are concrete-product vs. concrete-creator, adapter vs. adaptee, and adapter vs. client. The results recommend the use of design patterns because they are less fault-prone in general except for the builder design pattern, which should be applied with care and addressed with more test cases.