Actual application of FEM to analysis of large scale mechanical problems in welding

Nishikawa, Hiroyasu; Serizawa, Hisashi; Murakawa, Hidekazu

doi:10.1179/174329307x164274

Cited by 63 publications

(28 citation statements)

References 6 publications

(7 reference statements)

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“…The high efficient ISM is apt for the strong non-linear welding problem and the computation time can be reduced notably. [31][32][33] Finite element model Figure 1 shows the FE mesh of fillet welded joint used in this study, with a flange, 100061000628 mm, and a web erected on the flange plate, 1000640622 mm. Quadratic brick elements were used.…”

Section: Interactive Substructure Methodsmentioning

confidence: 99%

Welding distortion investigation in fillet welded joint and structure based on iterative substructure method

Wang

Zhang

Liu

et al. 2009

Science and Technology of Welding and Joining

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In this paper, prediction and controlling angular distortion in fillet welded joint and structure were investigated. First, two methods to reduce angular distortion in fillet welded joint were investigated by experimental and numerical analysis. One was to apply a constant external force in-process and the other was rigid clamping. In numerical analysis, a new in-house finite element code has been developed based on the idea of iterative substructure method (ISM) to calculate welding distortion in rational time. During experimental analysis, the constant external force was designed and applied in-process to reduce angular distortion of fillet welded joint. The results showed that the distortion can be efficiently predicted by ISM, which were in good agreement with the experimental ones. Applying constant external force in process was a more effective method to reduce distortion than using rigid clamping. In addition, with a constant load distance from weld bead, the locations of the applied constant external force and rigid clamping along the longitudinal direction (welding direction) have little influence on the magnitude of welding angular distortion. Finally, the angular distortion of a large fillet welded structure was predicted with ISM and also controlled with applying a constant external force based on the simulation results of the fillet welded joint.

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Section: Interactive Substructure Methodsmentioning

confidence: 99%

Welding distortion investigation in fillet welded joint and structure based on iterative substructure method

Wang

Zhang

Liu

et al. 2009

Science and Technology of Welding and Joining

Self Cite

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show abstract

“…In this linear equation system solution procedure, the global and local analyses are performed independently and iteratively. Iterative substructure method (Murakawa et al, 2005;Nishikawa et al, 2007) employs superposed global and local meshes. The two meshes are analyzed alternately under assumed enforced displacement and external force boundary condition on the global-local interface.…”

Section: Introductionmentioning

confidence: 99%

An s-version finite element method without generation of coupling stiffness matrix by using iterative technique

Yumoto

Yusa

Okada

2016

Mechanical Engineering Journal

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In s-version finite element method (s-FEM) proposed by Fish (1992), a local mesh that represents the local feature such as a hole or a crack is superposed on a global mesh that represents the shape of the whole analysis model. The interaction between global and local meshes is represented by coupling stiffness matrices. Since the global and local meshes can be generated independently, mesh generation efforts are reduced remarkably. However, s-FEM has a common issue. The generation of coupling stiffness matrices takes a considerable amount of program development efforts, which include constructing accurate cross-element integration methodology and programming it for various element types. For such an issue, we propose an iterative s-FEM that does not require the generation of coupling stiffness matrices at all. The coupling term is now evaluated by global and local stresses that are computed on the respective mesh and then transferred to the other by interpolation techniques. The global and local stresses are treated as initial stress in the finite element computations. The global and local analyses are performed alternately under assumed initial stress, and converged solution is achieved by iteration with a monitored residual being sufficiently small. In proposed iterative s-FEM, an issue about linear independence of global and local elements, which is known to occur in the original s-FEM, does not occur. In numerical experiments, converged solution was successfully obtained within several hundred iteration counts. Accurate stress distribution for a stress concentration problem and an accurate stress intensity factor for a linear elastic fracture mechanics problem were computed by proposed iterative s-FEM. In addition, several stress interpolation techniques were compared in the numerical experiments. Nearest neighbor interpolation for the global stress and local least squares interpolation for the local stress showed good convergence and accurate solution.

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“…As for the thermal elastic-plastic finite element analyses, an in-house code was employed based on ISM (Iterative Substructure Method) [15,16] in this research, and the accuracy of our code is already revealed through the comparison with not only experiments but also other commercial codes, where the element type was set as linear [4,17,18]. In order to demonstrate the multi-pass welding numerically, the elements representing the filler metal in the groove were deactivated before the welding, and when the weld bead was deposited, the corresponding elements were activated [12].…”

Section: Methods For Analysismentioning

confidence: 99%

Finite element analysis of deformation in early stage of multi-pass circumferential dissimilar welding of thick-walled pipes with narrow gap

2016

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Three-dimensional thermal elastic-plastic finite element analyses were conducted in order to reveal the mechanism of gap shrinkage in early stage of multi-pass narrow gap welding of thick-walled dissimilar pipes and thick plates. The gap shrinkage up to the 8th pass indicates that the shrinkage of plates becomes to be much larger than that of pipes with increasing the weld passes. In addition, through the decomposition of gap shrinkage to transverse shrinkage and angular distortion, it is found that the gap shrinkage of pipes is mainly governed by the transverse shrinkage, while the shrinkage of plates is influenced by both the transverse shrinkage and angular distortion. Moreover, the serial computational results with various groove shapes suggest that the transverse shrinkage of pipes almost linearly increases with increasing the weld pass, and its increment can be predicted by a linear approximation function obtained by the transverse shrinkage of plates regardless of the groove shape.

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Actual application of FEM to analysis of large scale mechanical problems in welding

Cited by 63 publications

References 6 publications

Welding distortion investigation in fillet welded joint and structure based on iterative substructure method

Welding distortion investigation in fillet welded joint and structure based on iterative substructure method

An s-version finite element method without generation of coupling stiffness matrix by using iterative technique

Finite element analysis of deformation in early stage of multi-pass circumferential dissimilar welding of thick-walled pipes with narrow gap

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