• Title, Summary, Keyword: Structural Sizing

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Sizing System Development of Korean Structural Firefighting Protective Clothing (한국 소방용 방화복의 치수체계 개발)

  • Han, Sul-Ah;Nam, Yun-Ja;Choi, Young-Lim
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.5
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    • pp.827-839
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    • 2009
  • Sizing system of Korean structural firefighting protective clothing that is national approved should be met for specification of structural firefighting protective clothing that is identified by Ministry of Public Administration and Security(MOPAS). However if you look over the specification of sizing system, the standard is based on only 'height' and the others are indicated as the size of completed product. KS K ISO 13688 and EN 340 which is met on ISO 13688 which indicates sizing system about protective clothing has the standards of height, chest and waist circumference. Also NFPA 1971 that has standards of sizing system is based on chest circumference, cervical to wrist length, waist circumference and inseam. That is different from Korean standards. Therefore, fire fighting protective clothing standards which is based on only height should be compensated and not be relied on foreign standards like ISO. It is indispensable for developing our own sizing system of structural fire fighting protective clothing. In this studying, Korean new sizing system of structural fire fighting protective clothing was developed for providing basic information of ergonomic structural fire fighting protective clothing. The analyzed target age was between 20 and 59 years old fire fighter who extinguish the fire. And it was analyzed by 3D measurement among data of the $5^{th}$ Size Korea. On conclusion, in case of structural fire fighting protective clothing coat, physical dimension was to be chest circumference, cervical to wrist length. Three dimensions as 5cm space of circumference and four dimensions as 2.5cm space of cervical to wrist length were derived, which means that totally 12 dimensions were defined. Dimension standards of pants was based on the analysis of waist circumference and crotch height. Six dimensions as 5cm space of waist circumference and three dimensions as 5cm space of crotch height were derived, which means that totally 14 dimensions were defined.

Structural Sizing for Optionally Piloted PAV Preliminary Design (유무인 겸용 개인항공기(OPPAV) 개념설계를 위한 구조물 사이징)

  • Kim, Sung Joon;Lee, Seung-gyu
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.28 no.1
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    • pp.83-89
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    • 2020
  • Personal air vehicle (PAV) is considered by aviation engineers as a solution to provide fast urban mobility. The purpose of designing a optionally piloted PAV (OPPAV) is to provide an individual air vehicle. The airframe structure is designed with high strength carbon fiber composite to reduce the aircraft weight. This paper presents an overview of sizing process for OPPAV at the conceptual design level. It consists of load analysis, structural sizing and development of efficient design allowable values for composite material. The weight is estimated based on sizing process, including strength and stiffness requirements. The objective of this study is to present a overview of structural sizing procedure and fast tool for preliminary design phases.

Observer-Teacher-Learner-Based Optimization: An enhanced meta-heuristic for structural sizing design

  • Shahrouzi, Mohsen;Aghabaglou, Mahdi;Rafiee, Fataneh
    • Structural Engineering and Mechanics
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    • v.62 no.5
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    • pp.537-550
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    • 2017
  • Structural sizing is a rewarding task due to its non-convex constrained nature in the design space. In order to provide both global exploration and proper search refinement, a hybrid method is developed here based on outstanding features of Evolutionary Computing and Teaching-Learning-Based Optimization. The new method introduces an observer phase for memory exploitation in addition to vector-sum movements in the original teacher and learner phases. Proper integer coding is suited and applied for structural size optimization together with a fly-to-boundary technique and an elitism strategy. Performance of the proposed method is further evaluated treating a number of truss examples compared with teaching-learning-based optimization. The results show enhanced capability of the method in efficient and stable convergence toward the optimum and effective capturing of high quality solutions in discrete structural sizing problems.

Suggestion of Structural Sizing Methodology on a Coaxial Double-tube Type Hot Gas Duct for the VHTR (초고온가스로의 동심축 이중관형 고온가스덕트에 대한 구조정산 방법론 제안)

  • Song, Kee-Nam;Kim, Y.W.
    • Proceedings of the KSME Conference
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    • pp.717-724
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    • 2008
  • Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the VHTR. In this study, structural sizing methodology for the primary HGD with a coaxial double-tube of the VHTR that produces heat at temperatures in the order of $950^{\circ}C$ was suggested and a structural pre-sizing of it was carried out as an example.

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Improvement of Coated Paper Properties by Surface Sizing with Cationic Polymers (양성고분자를 이용한 표면사이징을 통한 도공지의 물성 개선)

  • 전대구;이학래
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.35 no.3
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    • pp.21-28
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    • 2003
  • It is essential to use base papers having proper surface characteristics in coating operation for improving coated paper quality and coater runnability. To fulfill these purposes surface sizing of coating base stock with anionic oxidized starch is commonly practiced. It is suggested that use of cationic starch for surface sizing rather than conventional oxidized starch will improve coated paper quality since cationic starch penetrates less into paper structure because of its strong electrostatic interaction with anionically charged paper surface. Strong interaction of cationic surface sizing starch with anionic coating color is expected to promote rapid immobilization of the coating color and improve coating holdout and optical property. The immediate objective of this study was to examine the influence of surface sizing starches on the properties of coated papers. Structural characteristics of the coatings formed on the substrate surface sized with cationic and anionic starches were examined. To enhance the efficiency of cationic surface sizing starch on coated paper properties, strongly charged cationic polymers were added to the surface sizing starch and its effect on coated paper properties was evaluated. Results showed that opacity and light scattering coefficient of coated paper were higher when base paper surface sized with cationic starch was used. Addition of less than 1% of cationic poly-DADMAC to the cationic surface sizing starch improved the opacity of coated paper significantly.

New Approaches to Flaw Classification and Sizing for Quantitative Ultrasonic Testing (정량적 초음파 시험을 위한 결함분류와 크기산정의 새로운 기법)

  • 송성진
    • Journal of the Korean Society of Safety
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    • v.12 no.2
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    • pp.3-16
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    • 1997
  • In modern high performance engineering applications, the structural integrity of materials and structures are quite often evaluated using fracture mechanics. This evaluation in turn requires information on the flaw geometry (location, type, shape, size, and orientation). The ultrasonic nondestructive evaluation (NDE) method is one technique that is commonly used to provide such information. Flaw classification (determination of the flaw type ) and flaw sizing (prediction of the flaw shape, orientation and sizing parameters) are very important issues for quantitative ultrasonic NDE. In this paper new approaches to both classification and sizing of flaws are described together with extensive review of previous works on both topics. In the area of flaw classification, a methodology is developed which can solve classification problems using probabilistic neural networks, and in the area of flaw sizing, a time-of-flight equivalent (TOFE) sizing method is presented. The techniques proposed here are in a form that can be used directly in many practical applications to quantitative estimates of the flaw's significance.

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Discrete optimal sizing of truss using adaptive directional differential evolution

  • Pham, Anh H.
    • Advances in Computational Design
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    • v.1 no.3
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    • pp.275-296
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    • 2016
  • This article presents an adaptive directional differential evolution (ADDE) algorithm and its application in solving discrete sizing truss optimization problems. The algorithm is featured by a new self-adaptation approach and a simple directional strategy. In the adaptation approach, the mutation operator is adjusted in accordance with the change of population diversity, which can well balance between global exploration and local exploitation as well as locate the promising solutions. The directional strategy is based on the order relation between two difference solutions chosen for mutation and can bias the search direction for increasing the possibility of finding improved solutions. In addition, a new scaling factor is introduced as a vector of uniform random variables to maintain the diversity without crossover operation. Numerical results show that the optimal solutions of ADDE are as good as or better than those from some modern metaheuristics in the literature, while ADDE often uses fewer structural analyses.

Investigation of FIV Characteristics on a Coaxial Double-tube Structure (동심축 이중관 구조에서 유동기인진동 특성 고찰)

  • Song, Kee-Nam;Kim, Yong-Wan;Park, Sang-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1108-1118
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    • 2009
  • A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

Structural optimization and proposition of pre-sizing parameters for beams in reinforced concrete buildings

  • de Medeiros, Guilherme Fleith;Kripka, Moacir
    • Computers and Concrete
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    • v.11 no.3
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    • pp.253-270
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    • 2013
  • The aim of the present paper is to show the application of optimization strategies for the cost of beams in reinforced concrete buildings and to propose pre-sizing parameters. In order for these goals to be met, an optimization software program was developed. The program combines the analysis of structures by the grid model, reinforced concrete sizing, and the simulated annealing optimization heuristic. Sizing is compliant with the NBR 6118 (2007) Brazilian standard, according to which flexural, shearing, torsion, and web reinforcements and serviceability limit states (deflection and crack width limitation) are checked. Besides the dimensions of the situations mentioned above, the influence the cost of each material (steel, concrete and formwork) has on the overall cost of structures was also determined.

Advances in the design of high-rise structures by the wind tunnel procedure: Conceptual framework

  • Simiu, Emil;Yeo, DongHun
    • Wind and Structures
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    • v.21 no.5
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    • pp.489-503
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    • 2015
  • This paper surveys and complements contributions by the National Institute of Standards and Technology to techniques ensuring that the wind tunnel procedure for the design of high-rise structures is based on sound methods and allows unambiguous inter-laboratory comparisons. Developments that enabled substantial advances in these techniques include: Instrumentation for simultaneously measuring pressures at multiple taps; time-domain analysis methods for estimating directional dynamic effects; creation of large simulated extreme directional wind speed data sets; non-parametric methods for estimating mean recurrence intervals (MRIs) of Demand-to-Capacity Indexes (DCIs); and member sizing based on peak DCIs with specified MRIs. To implement these advances changes are needed in the traditional division of tasks between wind and structural engineers. Wind engineers should provide large sets of directional wind speeds, pressure coefficient time series, and estimates of uncertainties in wind speeds and pressure coefficients. Structural engineers should perform the dynamic analyses, estimates of MRIs of wind effects, sensitivity studies, and iterative sizing of structural members. The procedure is transparent, eliminates guesswork inherent in frequency domain methods and due to the lack of pressure measurements, and enables structural engineers to be in full control of the structural design for wind.