• Title/Summary/Keyword: 블라스트

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Effect of Blast Cleaning on Fatigue Behavior of Non-load-carrying Fillet Welded Cruciform Joints (블라스트 표면처리가 하중비전달형 십자필렛 용접이음의 피로거동에 미치는 영향)

  • Kim, In Tae;Jung, Young Soo;Kim, Kwang Jin;Lee, Dong Uk
    • Journal of Korean Society of Steel Construction
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    • v.21 no.1
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    • pp.55-62
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    • 2009
  • Blast cleaning has been applied in steel bridges for cleaning forged surface and increasing adhesive property of applied coating systems. Blasting is the operation of cleaning or preparing a surface by forcible propelling a stream of abrasive metals against it. Blast cleaning may improve surface geometry and induce compressive residual stress, and eventually may increase fatigue life of weld joints. In this paper, fatigue tests were carried out on three types of non-load-carrying fillet welded cruciform joints, as-welded joints, blast-treated joints, and stress-relieved joints after blasting, in order to investigate effect of blast cleaning on fatigue behavior of the weld joints. By Blast cleaning, the weld toe radius was increased by 29% and compressive residual stress was induced near weld toes. Blast cleaning increased fatigue life and fatigue endurance limit of the weld joints. When the applied stress ranges decreased, the increment in fatigue life became larger. About a 150% increase in fatigue limit could be realized by using blast cleaning.

Improving Fatigue Strength of Weld Joints by Blast Cleaning used in Painting Steel Bridge (강교 도장용 블라스트 표면처리에 의한 용접이음의 피로강도 향상)

  • Kim, In-Tae;Jung, Young-Soo;Lee, Dong-Uk
    • Journal of Korean Society of Steel Construction
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    • v.23 no.2
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    • pp.137-146
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    • 2011
  • In the fabrication of steel bridges, blast cleaning prior to painting is carried out on the steel members to clean the forged surface and to increase the adhesive property of the applied painting systems. The effect of blast cleaning on the fatigue strength improvement of the weld joints, however, is not clear. In this study, Almen strips and steel specimens were blast-treated, conforming to ten types of blast-cleaning conditions deducted from the blast-cleaning conditions of seven steel structure fabrication companies. The arc height, roughness, hardness, and compressive residual stress were measured before and after the implementation of the ten blast-cleaning methods, and the relationship between the blast conditions and the measured values was studied. The geometry of the weld toe and the compressive residual stress near the weld toe were also measured before and after the blast cleaning of the butt-welded joints, and fatigue tests were carried out on the butt weld joints. The test results showed that blast cleaning significantly increases the fatigue strength and limit.

The Effect of Blast Cleaning for Steel Bridge Painting on Fatigue Behavior of Out-of-Plane Gusset Welded Joints (강교 도장용 블라스트 처리가 면외거셋 용접이음의 피로거동에 미치는 영향)

  • Kim, In Tae;Le, Van Phuoc Nhan;Kim, Kwang Jin;Lee, Dong Uk
    • Journal of Korean Society of Steel Construction
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    • v.20 no.5
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    • pp.583-590
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    • 2008
  • Blasting has been applied in newly-built steel structures for cleaning forged surfaces and increasing the adhesive property of applied painting systems. However, the effect of the blast cleaning on fatigue behavior of welded joints is not clear. In this paper, fatigue tests were carried out on out-of-plane gusset welded joints and the effect of the blast cleaning on the fatigue behavior was studied. The curvature radius at the weld toe of the surface-treated specimens by using the blast method is larger than that of as-welded specimens. By the blast cleaning compressive residual stresses were induced into weld toes. The experimental results showed that the fatigue life of surface-treated specimens is longer than that of as-welded specimens, even though the fatigue life of surface-treated specimens and that of as-welded specimens are not clearly different in the high stress range. About a 160% increase in fatigue limit could be realized by using blast cleaning.

Improvement of Blast Efficiency by Correlation Analysis of Impella Blast and Steel Balls for Surface Treatment of Steel Bridges (강교 보수도장의 표면처리를 위한 임펠라 블라스트와 스틸볼의 상관관계 분석을 통한 블라스트 효율 향상)

  • Chang, Byoung Ha;Jang, Dong Wook;Seo, Myoung Kook;Lee, Ho Yeon;Park, Jae Hyun
    • Journal of Drive and Control
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    • v.19 no.1
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    • pp.8-15
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    • 2022
  • The demand for the re-painting of steel bridges is increasing, but surface treatment is still centered on human resources for on-site re-painting processes. Worker safety accidents continue to occur because the work is performed in a narrow space. Recently, PS balls with excellent surface treatment have been used for blasting, but the working environment is poor due to the large amount of dust generated. In this study, an effective surface treatment method using impeller blasting equipment was developed. The correlation between steel ball size, impeller rotation speed, and exposure time was studied to optimize the efficiency of the surface treatment.

Design and Implementation of Personalized Sequence BLAST System (전용 서열블라스트 시스템 설계 및 구현)

  • Young-Sang Choi;Han-Suk Choi
    • Proceedings of the Korea Information Processing Society Conference
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    • 2008.11a
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    • pp.364-366
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    • 2008
  • 본 논문에서는 지놈 연구에서 반드시 필요한 유전체 서열정보의 상동성 검색을 위해 해외 데이터베이스에만 의존하고 있는 국내 지놈 연구자들에게 더욱 빠르고 쉽게 접근할 수 있는 서열블라스트를 만들 수 있는 방법을 제공함으로써 국내 지놈연구에 도움이되고자 특정 종류의 유전자정보 만을 모아놓은 지놈 서열블라스트 시스템을 설계하고 구현하는 방법을 제시하였다. 이 시스템을 활용하면 많은 생물 지놈 연구자들의 연구시간을 획기적으로 단축할 수 있을 것이다.

Study on the Sandblast Machine in Painting of Steel Structures for Environmental Pollution Prevention (공해방지를 위한 강구조물의 도장용 샌드블라스트 장치에 관한 연구)

  • 임우조;황태호;이진열
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1996.05a
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    • pp.47-52
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    • 1996
  • 본 연구에서는 각종 강구조물의 도장전 샌드블리스트 작업에 다른 공해를 방지하기 위해, 모래-물의 2상류를 분사할 수 있는 샌드블라스트 장치를 제작하여, 2상류 분사에 따른 마멸-부식(wear-corrosion)특성과 slurry erosion에 의한 anchor pattern 및 침식-마멸거동을 고찰하고, 물에 의한 강구조물의 부식방지를 위한 부식억제제가 강구조물의 도막에 미치는 방식특성을 구명함으로써 공해방지, 부식손상 및 산업의 국제경쟁력 향상에 기여하고자 한다.

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Increase heat dissipation efficiency of Al plate according to surface roughness treatment by sandpaper or sandblast (사포, 샌드블라스트로 표면 거칠기 처리에 따른 알루미늄 판의 방열 효율 증대)

  • Lee, Dong-Hee;Lee, Jong-Hyeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.1
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    • pp.170-178
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    • 2019
  • Recently, as the interest in energy savings has increased, there has been increasing use of LED lighting, which is an eco-friendly device that replaces high energy consuming fluorescent lamps and incandescent lamps. In the case of a high output LED, however, the life time is shortened due to deterioration caused by heat generation. As a solution to this problem, this paper evaluated the LED life extension effect by increasing the convective heat transfer coefficient of the heat sink surface for LED packaging. A roughing process was carried out using sandpaper and sand blasting. The changes in surface roughness and surface area after each surface treatment process were evaluated quantitatively and the convective heat transfer coefficient was measured. When sandblasting and sandpaper were used to roughen the aluminum surface, a higher convection heat transfer coefficient was obtained compared to the untreated case, and a high heat dissipation efficiency of 82.76% was obtained in the sandblast treatment. Therefore, it is expected that the application of heat dissipation to the heat sink will extend the lifetime of the LED significantly and economically by increasing the heat efficiency.

Performance Improvement of BLAST using Grid Computing and Implementation of Genome Sequence Analysis System (그리드 컴퓨팅을 이용한 BLAST 성능개선 및 유전체 서열분석 시스템 구현)

  • Kim, Dong-Wook;Choi, Han-Suk
    • The Journal of the Korea Contents Association
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    • v.10 no.7
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    • pp.81-87
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    • 2010
  • This paper proposes a G-BLAST(BLAST using Grid Computing) system, an integrated software package for BLAST searches operated in heterogeneous distributed environment. G-BLAST employed 'database splicing' method to improve the performance of BLAST searches using exists computing resources. G-BLAST is a basic local alignment search tool of DNA Sequence using grid computing in heterogeneous distributed environment. The G-BLAST improved the existing BLAST search performance in gene sequence analysis. Also G-BLAST implemented the pipeline and data management method for users to easily manage and analyze the BLAST search results. The proposed G-BLAST system has been confirmed the speed and efficiency of BLAST search performance in heterogeneous distributed computing.

연 잎 구조를 응용한 금속 표면의 발수 특성 개발

  • Byeon, Eun-Yeon;Lee, Seung-Hun;Kim, Jong-Guk;Kim, Yang-Do;Kim, Do-Geun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.167-167
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    • 2013
  • 최근 발수 특성은 자동차 표면, 건축 구조물, 가전제품 및 모바일 기기 등 여러 분야에서 사용되고 점차 그 필요성이 대두되고 있다. 이러한 발수성의 표면은 연 잎이나 곤충의 날개, 도마뱀의 발바닥 등 자연계의 여러 곳에서 관찰 할 수 있다. 특히 연 잎의 표면에서 나타나는 초발수 특성이 마이크로와 나노 크기의 돌기 구조와 표피 왁스 성분에 기인한다는 것이 밝혀지면서 이를 응용한 다양한 연구가 진행되고 있다. 본 연구에서는 물리적인 표면처리로 마이크로와 나노 구조물을 형성하고 그 위에 표면에너지를 낮출 수 있는 물질을 증착하여, 발수 특성을 가지는 표면을 개발하였다. 알루미늄 표면에 마이크로 크기의 알루미나(Al2O3) 분말을 이용한 블라스트(blast) 공정으로 마이크로 구조를 형성하고, 선형 이온 소스(LIS)를 이용한 Ar 이온 빔 에칭으로 나노 구조를 형성하였다. FE-SEM 분석을 통해 수~수십 마이크로 구조 위에 나노 크기의 구조가 형성 된 것을 관찰하였다. 마이크로와 나노 구조가 형성된 알루미늄의 표면에너지를 낮추기 위해 trimethylsilane (TMS) 및 Ar을 이용한 플라즈마처리로 표면에 기능성 코팅막을 형성하였다. 그 결과 TMS처리 전에 비해 표면에너지가 99.75 mJ/m2에서 9.05 mJ/m2으로 급격히 낮아지고 접촉각이 $54^{\circ}$에서 $123^{\circ}$로 향상되었다.

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