• 제목/요약/키워드: Angular Distortion

검색결과 119건 처리시간 0.02초

용접 각 변형량 해석해를 이용한 용접 공정변수 최적화에 관한 연구 (A Study on an Optimization of Welding Process Parameters by using an Analytic Solution for the Welding Angular Distortion)

  • 이세환
    • Journal of Welding and Joining
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    • 제21권7호
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    • pp.42-48
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    • 2003
  • Welding distortion is a current issue in many industrial parts, especially for heavy industry such as shipbuilding, plant industry. The welding process has many processing parameters influencing welding angular distortion such as heat input power, welding speed, gas flow rate, plate thickness and the welded material properties, etc. In this work, the conventional local minimization concept was applied to find a set of optimum welding process parameters, consisted of welding speed, plate thickness and heat input, for a minimum angular distortion. An analytic solution for welding angular distortion, which is based on laminated plate theory, was also applied to investigate and optimize the welding process parameters. The optimized process parameters and the angular distortion for various parametric conditions could be easily found by using the local minimum concept.

열간가공의 변형에 미치는 곡률의 영향에 관한 연구 (Effect of Curvature on Deformation caused by Thermal Plate Forming)

  • 이주성
    • 한국해양공학회지
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    • 제25권2호
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    • pp.67-72
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    • 2011
  • This study had the goal of investigating the effect of the curvature along the heating line on the transverse angular distortion of plates having an initial curvature from line heating. A thermo-elasto-plastic analysis was carried out using 54 models with various radii of curvature, plate thicknesses, and heating speeds. The results show the effect of the curvature along the heating line on the angular distortion in relation to changes in the magnitudes of the curvature, heating speed, and plate thickness. The present numerical results show that the time history of the angular distortion after cooling and reaching the final deformed shape for a plate having an initial curvature is quite different from that of a flat plate. This emphasized the importance of considering the curvature effect on the transverse angular distortion. From the viewpoint of the curvature effect on the deformation, it has been seen that the curvature does not affect the transverse shrinkage. In this study the predicting formula for the transverse angular distortion was derived through a regression analysis. It showed that as the curvature increased, the angular distortion was reduced because of the higher bending rigidity at the same heat input parameter, and the peak points moved toward the origin as the curvature increased.

맞대기 용접시의 각변형 거동에 관한 연구 (Behavior of angular distortion in butt joint welding of thin plate structure)

  • 배강열;김희진
    • Journal of Welding and Joining
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    • 제6권3호
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    • pp.21-26
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    • 1988
  • The behavior of angular distortion in butt joint wleding of thin plate structure is investigated with an experimental model and partially with a computational model. The experimental model studying the effects of specimene size and degree of restraint on the angular distorion offers a good method for analyzing the behavior of the distrotion. In addition, the distrotion during welding was demonstrated by both experimental measurement and numericla prediciton. The facts evealed in this study are as follows : 1) distrotion angles were changed with variations of specimene wldth. 2) With the restraint, angular distrotion was reduced to 20% to that of free joint. 3) After the restraint being removed, the effect of restraint was also remained. 4) Same heat input per unit thickness caused same amount of distortion. 5) The mode of angular distortion was expected to be changed with expected to be changed with time, i.e. convex movement during heating and concave one during cooling.

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Distortion Control of the Curved Panel Using Elastic Bending Method

  • Kim H. G.;Shin S. B.;Youn J. G.
    • International Journal of Korean Welding Society
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    • 제5권1호
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    • pp.29-34
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    • 2005
  • Finite element analysis (FEA) and experimental studies on an elastic bending method have been performed in order to control the angular distortion at the fillet weldment for curved panel. Process parameters for the elastic bending method such as clamping span and release time were analyzed with reference to welding condition and geometric effect of the curved panel, which can minimize or prevent the angular distortion by producing a proper skin stress to the fillet weldment. The amounts of the angular distortion decrease almost in a linear manner with an increase in the skin stress. The skin stress required for non-angular distortion at the fillet weldment is strongly dependent on the plate thickness, not the heat intensity applied. The clamping span for obtaining uniform skin stress was defined as functions of the plate thickness and length of the free edge. Clamp should be removed after the fillet weldment is cooled down to room temperature for non-angular distortion. Effectiveness of the elastic bending method established was verified by its application to an actual curved panel.

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Fillet 용접시 크기에 따른 각변형량의 고찰 (A Study of Angular Distortion at the Fillet Welding)

  • 임동용;이정수
    • 대한조선학회 특별논문집
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    • 대한조선학회 2007년도 특별논문집
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    • pp.22-25
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    • 2007
  • Angular distortion in welding process is decided by the various variables. We can make the prediction of welding distortion in similar reality by the analysis of data through many specimen tests. However it is difficult that prediction of welding distortion applies to the ship building. We can establish that angular distortion varies directly as the specimen size. And, it makes clear distortion's difference between constraint and unconstraint, according to the change of a plate thickness.

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다층 양면 개선 맞대기 용접부의 각 변형 예측에 관한 연구 (A Study on the Angular Distortion Prediction of Double Sided Multi-pass Butt Weldment)

  • 신상범;윤중근
    • Journal of Welding and Joining
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    • 제25권1호
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    • pp.37-41
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    • 2007
  • The purpose of this study is to establish the predictive method of angular distortion of the double-sided multi-pass butt weldment achieve it, the behavior of angular distortion in the butt weldment were investigated using comprehensive finite element analyses and experiments. The angular distortion in the multi-pass butt weldment strongly depends on the welding heat input(Q) and the effective bending rigidity of the weld throat. The effective bending rigidity of the first welding pass on the backing side was defined as the function of dimensionless parameter(k) and a bending rigidity of bead-on-plate weldment. Based on the results, the predictive equation for angular distortion of multi-pass butt weldment was proposed and verified by experiments.

고주파 유도가열을 이용한 선상가열 시 각 변형 예측에 관한 연구 (A study on the prediction of the angular distortion in line heating with high frequency induction heating)

  • 박동환;진형국;박성식;신상범
    • Journal of Welding and Joining
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    • 제33권1호
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    • pp.80-86
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    • 2015
  • The purpose of this study is to establish the predictive method of the angular distortion caused by the line heating process with high frequency induction heating. In order to do it, the heat input model for the high frequency induction heating system was established through comparing the temperature evaluation results obtained by both FEA and experiment. The critical heating conditions to prevent the degradation of the work piece with various thicknesses were identified by FEA and microstructure test results. Under the critical heating conditions, the extensive line heating tests were performed. According to the test results, it was found that the angular distortion behavior of the heated plates could be defined as the function of heat intensity and the rigidity of heated plate. In addition, it was clarified that the angular distortion strongly depended on the size of test specimen such as the length and the width of the heated plate. Based on these results, the predictive equation for the angular distortion was established with the function of heat intensity, bending rigidity and size of heated plate.

PREDICTION AND CONTROL OF ANGULAR DISTORTION IN THICK WELDMENTS

  • Kim, Sang-Il;Kang, Joong-Kyoo;Han, Yong-Sub
    • 대한용접접합학회:학술대회논문집
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    • 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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    • pp.700-705
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    • 2002
  • The welding distortion of a hull structure in the shipbuilding industry is inevitable at each assembly stage. The geometric inaccuracy caused by the distortion tends to preclude the introduction of automation and mechanization and needs the additional man-hours for the adjusting work at the following assembly stage. To overcome this problem, a distortion control method should be applied. For this purpose, it is necessary to develop an accurate prediction method which can explicitly account for the influence of various factors on the welding distortion. In order to minimize the weld-induced angular distortion in thick weldments, this paper proposes the optimum groove design for various plate thicknesses as the distortion control method. The validity of this method has been substantiated by a number of numerical simulations and experiments.

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적층판 이론을 이용한 용접부 각 변형량 해석에 관한 연구 (A Study on the Angular Distortion in Weldment6s using the Laminated Plate Theory)

  • 손광재;양영수;최병익
    • Journal of Welding and Joining
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    • 제17권2호
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    • pp.91-96
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    • 1999
  • The problems of welding distortion in a welded structures are major concern in heavy industry. Weld-induced angular distortion's formula, composed weld parameter such as heat input and plate thickness, is developed analytically by the use of an elliptic cylindrical inclusion with an eigenstrain in an infinite laminated plate theory. The source of angular distortion in weldments is the plastic strains, which are caused by non-uniform temperature gradient. The distributions of the plastic strain corresponding eigenstrain are assumed by the use of Rosenthal's solution expressing thermal history. Comparison of calculated results with experimental data shows the accuracy and validity of the proposed method.

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후판 구조의 각변형 예측 및 제어에 관한 연구 (A Study on the Prediction and Control of Angular Distortion in Thick Weldments)

  • 허주호;김상일
    • Journal of Welding and Joining
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    • 제21권5호
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    • pp.518-524
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    • 2003
  • The block assembly of ship consists of a series of heat processes such as cutting, bending, welding, residual stress relaxation and fairing. With the fast development of computers, the thermal elasto-plastic analysis method has become a versatile tool for practical applications in the ship production. If numerical analysis is proved to be an advantageous tool to predict the residual deformation due to various heat processes, the optimum methods which can remove the welding distortion can be presented at each assembly stage, which will result in great progress in improving the accuracy of block assembly. In order to minimize the weld-induced angular distortion in thick weldments, this paper proposes the optimum groove design for various plate thickness as the distortion control method. The validity of this method has been substantiated by a number of numerical simulations and experiments.