• Title/Summary/Keyword: structural materials

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A Study on Material Substitution Design and Evaluation Method for Structural Components of Rolling Stocks (철도차량 구조부품의 소재대체 설계 및 평가기법 연구)

  • 구정서;정현승
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.4
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    • pp.74-84
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    • 2004
  • In this paper, a theoretical method was derived to redesign carbody members by substituting light-weight materials, and to estimate their structural characteristics. Some performance indices to estimate structural behaviors were derived in order to obtain equivalent designs in case of material substitutions under important design constraints of rolling stock, such as bending stiffness, natural frequency, bending and buckling strength. Validity of the theoretical method was evaluated by comparing its results with finite element results in some examples where the aluminium alloy was substituted for the structural steel. The numerical results of the examples show that the proposed method gives reasonable initial guesses for the material substitution designs.

A Whole LCA of the Sustainable Aspects of Structural Systems in Tall Buildings

  • Trabucco, Dario;Wood, Antony;Vassart, Olivier;Popa, Nicoletta
    • International Journal of High-Rise Buildings
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    • v.5 no.2
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    • pp.71-86
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    • 2016
  • This paper summarizes the results of a two-year-long research project conducted by the CTBUH on the life cycle assessment (LCA) of tall building structural systems. The research project was made possible thanks to a $300,000 contribution from ArcelorMittal and the support of some of the most important structural engineering firms and players in the tall building industry. The research analyzed all life phases of a tall building's structural system: the extraction and production of its materials, transportation to the site, construction operations, final demolition of the building, and the end-of-life of the materials. The impact of the building structure during the operational phase (i.e., impact on daily energy consumption, maintenance, and suitability to changes) was also investigated, but no significant impacts were identified during this phase.

The Application of Piezoelectric Materials in Smart Structures in China

  • Qiu, Jinhao;Ji, Hongli
    • International Journal of Aeronautical and Space Sciences
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    • v.11 no.4
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    • pp.266-284
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    • 2010
  • Piezoelectric materials have become the most attractive functional materials for sensors and actuators in smart structures because they can directly convert mechanical energy to electrical energy and vise versa. They have excellent electromechanical coupling characteristics and excellent frequency response. In this article, the research activities and achievements on the applications of piezoelectric materials in smart structures in China, including vibration control, noise control, energy harvesting, structural health monitoring, and hysteresis control, are introduced. Special attention is given to the introduction of semi-active vibration suppression based on a synchronized switching technique and piezoelectric fibers with metal cores for health monitoring. Such mechanisms are relatively new and possess great potential for future applications in aerospace engineering.

Development of 50m Class Airship Structures (복합재를 이용한 50m급 비행선 구조개발)

  • 양남선;강왕구;김동민;이진우;염찬홍
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.127-131
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    • 2003
  • KARI developed 50m class unmanned airship. The airship employ the pressure envelope design principle. The envelope must be considered as a main structural element of the airship. The envelope & three ballonets are fabricated by polyfiber composite laminates. Other structural components (gondola, tailwing, nosecone & engine mounts) are manufactured by carbon fiber & glass fiber laminates. In order to develop a big unmanned airship, a large amount of structural design, analysis and tests had to be made. The paper describes the structural configuration of the 50m class uumanned airship which are basic starting point of the structural development of an airship. The paper includes the various designing processes, components development tests and analysis results. Envelope & ballonets development processes which are very different to conventional airplane design are given in details with actual analysis & test results. The paper also describes the structural design and analysis results for other composite made structures. Each components were tested by static design limit loads and structural safety were confirmed. The paper shows the manufactured structural components and assembled airship.

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Load Transfer Mechanism of a Hybrid Beam-Column Connection System with Structural Tees

  • Kim, Sang-Sik;Choi, Kwang-Ho
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.199-205
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    • 2006
  • The composite frame system with reinforced concrete column and steel beam can be improved in its structural efficiency by complementing the shortcomings of the two systems. The system, however, has many inherent problems in practical design and construction process due to the dissimilarities of the materials. Considering these circumstance, this research aims for the development of a composite structural system which connects the steel beams to the R/C columns with higher structural safety and economy. Basically, the proposed connection system is composed of four split tees, structural angles reinforced by a stiffener, high strength steel rods, connecting plates and shear plates. Structural tests have been carried out to investigate the moment transfer mechanism 1Tom the beam flange to steel rods or connecting plates through the structural angle reinforced by a stiffener. The four prototype specimens have been tested until the flange of the beam reached a plastic state. The test results indicated that no distinct material dissimilarities between concrete and steel have been detected for the proposed hybrid beam-column connection system and that the stress transfer through the structural angle between the beam flange and steel rods or connecting plates was very encouraging.

Evaluation of Structural Safety for Hydrogen Tube Trailer Considering Dynamic Property (동적 특성을 고려한 수소 튜브 트레일러의 구조 안전성 평가)

  • Y. B. Kim;M. G. Kim;D. C. Ko
    • Transactions of Materials Processing
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    • v.33 no.3
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    • pp.169-177
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    • 2024
  • Recently, hydrogen energy has been widely used because of strict regulations on greenhouse gas emissions. For using the hydrogen energy, it is required to supply hydrogen through a tube trailer. However hydrogen tube trailer can have excessive load problems during transportation due to reasons such as road shape and driving method, which may lead a risk of hydrogen leakage. So it is necessary to secure a high level of safety. The purpose of this study is to evaluate structural safety for the conservative design of hydrogen tube trailer. First, finite element(FE) modeling of the designed hydrogen tube trailer was performed. After that, safety evaluation method was established through static structural simulation based on the standard GC207 conditions. In addition, effectiveness of the designed model was confirmed through the results of the structural safety evaluation. Finally, driving simulation was used to derive acceleration graph according to time, which was considered as a dynamic property for the evaluation of conservative tube trailer safety evaluation. And dynamic structural simulation was conducted as a condition for actual transportation of tube trailer by applying dynamic properties. As a results, conservative safety was evaluated through dynamic structural simulation and the safety of hydrogen tube trailer was confirmed through satisfaction of the safety rate.

Oxidation Behavior of Ti Added Alumina Dispersion Strengthening Copper Alloy (티타늄이 첨가된 알루미나 분산강화 동합금의 산화물 형성 거동)

  • Joh, Hongrae;Han, Seung Zeon;Ahn, Jee Hyuk;Lee, Jehyun;Son, Young Guk;Kim, Kwang Ho
    • Korean Journal of Materials Research
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    • v.25 no.4
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    • pp.202-208
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    • 2015
  • Alumina dispersion strengthening copper(ADSC) alloy has great potential for use in many industrial applications such as contact supports, frictional break parts, electrode materials for lead wires, and spot welding with relatively high strength and good conductivity. In this study, we investigated the oxidation behavior of ADSC alloys. These alloys were fabricated in forms of plate and round type samples by surface oxidation reaction using Cu-0.8Al, Cu-0.4Al-0.4Ti, and Cu-0.6Al-0.4Ti(wt%) alloys. The alloys were oxidized at $980^{\circ}C$ for 1 h, 2 h, and 4 h in ambient atmosphere. The microstructure was observed with an optical microscope(OM) and a scanning electron microscope(SEM) equipped with energy-dispersive X-ray spectroscopy(EDS). Characterization of alumina was carried out using a 200 kV field-emission transmission electron microscope(TEM). As a result, various oxides including Ti were formed in the oxidation layer, in addition to ${\gamma}$-alumina. The thickness of the oxidation layer increased with Ti addition to the Cu-Al alloy and with the oxidation time. The corrected diffusion equation for the plate and round type samples showed different oxidation layer thickness under the same conditions. Diffusion length of the round type specimen had a value higher than that of its plate counterpart because the oxygen concentration per unit area of the round type specimen was higher than that of the plate type specimen at the same diffusion depth.