• Title/Summary/Keyword: Transverse Shrinkage

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A study on the transverse shrinkage for the butt joint welding of plate (평판의 맞대기 이음 용접시의 가로수축에 관한 연구)

  • 이우수;왕지석
    • Journal of Welding and Joining
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    • v.5 no.3
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    • pp.46-52
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    • 1987
  • The mechanism of transverse shrinkage for the butt joint weldig of plates is investigated in this paper. It was certified that the compressive plastic strain due to thermal expansion of materials during heating play an important role on the transverse shrinkage. It was also pointed out that the transverse shrinkage has to be treated with the samples of which the shapes are as close to real shapes of welded materials as possible, because the distribution of temperature and relative rigidity of materials during welding have great influence on the transverse shrinkage. The formulas for the calculation of transverse shrinkage were presented and the experiments were carried out in order to verify the formulas. the main results are as follows; 1. For the bead-on-plate welding, the transverse shrinkage in the begining parts of welding is the smallest, the end parts is next and the transverse shrinkage of mid section is the largest. 2. In bead-on-plate welding, the equations presented in this paper concerning transverse shrinkage coincide fairly well with the experimental values generally. 3. Transverse shrinkage increases generally as specific heat input per unit thickness increaes.

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Prediction of a transverse shrinkage of butt welded joints in shipyard conditions using the design of experimental approach

  • Urbanski, Tomasz;Taczala, Maciej
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.784-798
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    • 2020
  • This paper presents the results of research on transverse shrinkage of welded butt joints conducted according to the principles of experimental design and under production conditions for two main welding techniques used in shipbuilding (FCAW and SAW). Analysis took into account the technological and structural parameters influencing the assembly suitability of a large steel structure. The presented method of evaluation makes it possible to apply approximation formulae to predict transverse shrinkage in real sections of a ship hull. The determined predictive formulae were verified to actual transverse shrinkage measurements during prefabrication of hull sections at a shipyard as well as the equations referring to the analyzed form of deformation available in the literature.

A Study on the Prediction of Shrinkage and Residual Stress for the HY-100 Weldment Considering the Phase Transformation (상 변태를 고려한 HY-100강 용접부의 수축 및 잔류응력 예측에 관한 연구)

  • Lee, Hee-Tae;Shin, Sang-Beom
    • Journal of Welding and Joining
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    • v.25 no.1
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    • pp.42-48
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    • 2007
  • For high performance and structural stability, application of high strength steel has continuously increased. However, the change of the base metal gives rise to problems with the accuracy management of the welded structure. It is attributed to the martensite phase transformation of the high strength low alloy steel weldment. The purpose of this study is to establish the predictive equation of transverse shrinkage and residual stress for the HY-100 weldment. In order to do it, high speed quenching dilatometer tests were performed to define a coefficient of thermal expansion(CTE) at the heating and cooling stage of HY-100 with various cooling rates. Uncoupled thermal-mechanical finite element(FE) models with CTE were proposed to evaluate the effect of the martensite phase transformation on transverse shrinkage and residual stresses at the weldment. FEA results were verified by comparing with experimental results. Based on the results of extensive FEA and experiments, the predictive equation of transverse shrinkage and longitudinal shrinkage force at the HY-100 weldment were formulated as the function of welding heat input/in-plane rigidity and welding heat input respectively.

Analysis of concrete shrinkage along truss bridge with steel-concrete composite deck

  • Siekierski, Wojciech
    • Steel and Composite Structures
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    • v.20 no.6
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    • pp.1237-1257
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    • 2016
  • The paper concerns analysis of effects of shrinkage of slab concrete in a steel-concrete composite deck of a through truss bridge span. Attention is paid to the shrinkage alongside the span, i.e., transverse to steel-concrete composite cross-beams. So far this aspect has not been given much attention in spite of the fact that it affects not only steel-concrete decks of bridges but also steel-concrete floors of steel frame building structures. For the problem analysis a two-dimensional model is created. An analytical method is presented in detail. A set of linear equations is built to compute axial forces in members of truss girder flange and transverse shear forces in steel-concrete composite beams. Finally a case study is shown: test loading of twin railway truss bridge spans is described, verified FEM model of the spans is presented and computational results of FEM and the analytical method are compared. Conclusions concerning applicability of the presented analytical method to practical design are drawn. The presented analytical method provides satisfactory accuracy of results in comparison with the verified FEM model.

Investigation of Likelihood of Cracking in Reinforced Concrete Bridge Decks

  • ElSafty, Adel;Abdel-Mohti, Ahmed
    • International Journal of Concrete Structures and Materials
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    • v.7 no.1
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    • pp.79-93
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    • 2013
  • One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits liveload deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

Long-term Behavior of Steel-Concrete Composite Girders due to Concrete Shrinkage (콘크리트 건조수축에 의한 합성거더의 장기거동)

  • Bae, Doo Byong;Youn, Seok Goo;Ham, Sang Hee
    • Journal of Korean Society of Steel Construction
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    • v.16 no.6 s.73
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    • pp.807-818
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    • 2004
  • Experimental tests and theoretical methods of the analysis of the concrete shrinkage behaviors of steel-concrete composite girders are described herein. Steel-concrete composite test specimens were fabricated in the laboratory, and long-term behaviors such as deflections, curvatures, and strains were measured for one year. Test results were compared to the analytical results obtained by using the age-adjusted effective modulus method (AEMM). In addition, composite girders have been analyzed to investigate the effects of several parameters on the concrete shrinkage behaviors. From the long-term test results, it could be used to validate AEMM for the evaluation of the shrinkage behavior of composite girders. Because the shrinkage of the reinforced concrete slab in composite girders may lead to large tensile stresses in the concrete section, the transverse cracking of the slab could occur both in the positive and negative regions. Therefore, if the cracking of concrete would be ignored,it might lead to an overestimation of the stresses of the steel section of composite girders. Based on this research, it is proposed that the effect of transverse concrete cracking on the shrinkage behavior of steel-concrete composite bridges be considered.

Crack Control of Early-Age High Strength Concrete Deck in Composite Bridge (합성거더교 초기재령 고강도 콘크리트 바닥판의 균열 제어)

  • Bae, Sung-Geun;Kim, Se-Hun;Jeong, Sang-Kyoon;Cha, Soo-Won
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.493-496
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    • 2008
  • The risk of transverse cracking in concrete decks of composite bridges is affected by many factors related to the bridge design, materials, and construction. Among others, the thermal and shrinkage stresses are the most important factors that affect the transverse cracking in early-age concrete decks. The thermal stress at the concrete deck is mainly affected by both ambient temperature and solar radiation. The shrinkage stress at the general strength concrete deck is mainly affected by drying shrinkage and the high strength concrete deck is mainly affected by autogeneous shrinkage. Three-dimensional finite element models of composite bridges were made to investigate the stress due to thermal and shrinkage stress.

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Behavior of Global Bending Distortion of Hatch-cover in Container Carrier during Fabrication Process (컨테이너 운반선 해치-커버 제작시 전 굽힘 변형 거동에 관한 연구)

  • Lee, Dong-Ju;Kim, Gyung-Gyu;Shin, Sang-Beom
    • Journal of Welding and Joining
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    • v.28 no.4
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    • pp.41-48
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    • 2010
  • The purpose of this study is to establish the control method of the global bending distortion caused by fabrication process of hatch-cover in a container ship. In order to do it, the transitional behavior of global bending distortion in the deck of hatch-cover during fabrication process was measured by 3-dimensional measuring instrument. From the results, the principal factor controlling the global bending distortion was identified as the bending moment associated with the longitudinal shrinkage force and transverse shrinkage caused by welding and flame heating and the change of the centroid axis of hatch-cover in each fabrication process. Therefore, in this study, with the predictive equations of the longitudinal shrinkage force and transverse shrinkage caused by welding and flame heating and the simplified thermo elastic method, the predictive method for the global bending distortion was established and verified by comparing with the measured result. Based on the results, the amount of reverse bending distortion of main stiffeners was determined to prevent the global bending distortion of hatch-cover.

A Study on the Deformation Control of Thin Plate Block by Applying the Tensioning Method (장력법을 적용한 박판블록의 변형제어에 관한 연구)

  • Kim, Cheol-Ho;Yang, Jong-Soo;Kim, Ho-Kyung
    • Journal of Welding and Joining
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    • v.25 no.6
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    • pp.59-63
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    • 2007
  • The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates and in addition internal and external constraints have much more influence upon weld-induced deformation of thin plates. This paper deals with the application of the mechanical tensioning method to butt weld of thin plates to reduce the transverse and longitudinal deformation. In order to investigate the quantitative effect of tensioning method upon the reduction of angular deformation and shrinkage in longitudinal and transverse direction of weld line, butt welding test has been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present experimental study, it has been found that the tensioning method is very effective in reducing the weld-induced residual stress as well as the weld-induced deformation.

The effect of the injection molding conditions on the shrinkage of HIPS (사출성형조건이 HIPS 수축율에 미치는 영향)

  • Cha B. S.;Rhee B. O.;Choi K. I.;Koo B. H.;Park H. P.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.259-264
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    • 2005
  • The shrinkage of the product in injection molded part occurs due to the volume change with variation of temperature and pressure and is influenced by the processing conditions of injection molding. Mold designers greatly concerns the shrinkage of parts for a high dimensional accuracy. In this study, bar type HIPS specimen with 15x19 grid on the surface was tested. The amount of shrinkage of flow and transverse directions was examined with respect to the injection molding conditions such as melt temperature, injection speed, holding pressure, mold temperature and cooling time. As the packing pressure increased, the difference of shrinkage of both directions is decreased and the absolute shrinkage value also decreased.

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