Computational Method for Transient Welding Deformation and Stress for Large Scale Structure Based on Dynamic Explicit FEM

Shibahara, Masakazu; Ikushima, Kazuki; Itoh, Shinsuke; Masaoka, Koji

doi:10.2207/qjjws.29.1

Cited by 23 publications

(15 citation statements)

References 1 publication

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“…Thus, the computing time is reduced by omitting the forward elimination of the stiffness matrix for the whole region (A+B). [2] To simulate the welding deformation, thermal elastic plastic analysis or inherent strain analysis is used. Thermal elastic plastic analysis can simulate transient welding mechanical phenomena.…”

Section: Analysis Methods Of This Studymentioning

confidence: 99%

“…However, the tendency for the computing time and memory to increase is the same as that for thermal elastic plastic analysis if the computation method is implicit static FEM. In this research, Idealized Explicit FEM is used [2]. In this method, a step is divided into hundreds of time steps and the displacements are computed for each.…”

Section: Analysis Methods Of This Studymentioning

confidence: 99%

See 1 more Smart Citation

Investigation of factors influencing welding deformation of ship block by inherent strain analysis using idealized explicit FEM

Hata

Itoh

Sugihiro

et al. 2012

J. Phys.: Conf. Ser.

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Investigation of factors influencing welding deformation of ship block by inherent strain analysis using idealized explicit FEM Abstract. It is impossible to avoid welding deformations when steel structures such as ships are assembled. Therefore, quantitative prediction and effective control of residual welding deformation are necessary. However, the current finite element analysis requires very long computational time and memory. To solve this problem, we have developed an inherent strain analysis method using idealized explicit FEM and have applied this proposed method to a ship block model. The simulated results agree well with the measured deformation. Furthermore, the influence of various factors on the welding deformation of targeted ship block is also investigated.

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Section: Analysis Methods Of This Studymentioning

confidence: 99%

Section: Analysis Methods Of This Studymentioning

confidence: 99%

Investigation of factors influencing welding deformation of ship block by inherent strain analysis using idealized explicit FEM

Hata

Itoh

Sugihiro

et al. 2012

J. Phys.: Conf. Ser.

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“…Once an element is determined as fractured, its stiffness is set to 0. In the elastic-plastic analysis, the Idealized Explicit FEM 3) proposed by one of authors is applied for the efficient computation. propagates along the outer periphery of the weld nugget.…”

Section: ® Tmentioning

confidence: 99%

Study on fracture mode of spot weld joint using continuum damage mechanics model

Ikushima

Takahiro

Ryohei

et al. 2017

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY

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Recently, weight saving of car bodies have been required due to the enhancement of regulations for emissions of CO2, and to improve collision safety, high tensile steel is widely used on car bodies. However, joint strength may decrease on high tensile steel. In addition, joint strength depends on fracture mode. Therefore, it is necessary to predict crack propagation direction and investigate the factors which influence the crack propagation direction. In this research, the author has proposed ductile crack analysis method based on continuum damage mechanics. In ductile crack propagation analysis, various potential models have been proposed as damage term. However, in such models, it is difficult to obtain convergence on the calculation of nonlinear constitutive relation. Therefore, in this study, a simplified ductile fracture evaluation method, which is based on the elastic-plastic analysis considering large deformation and strain, was proposed. The proposed method was applied to the analysis of cross tension test on spot weld joints. As a result, it was found that crack propagates along the outer periphery of the weld nugget on larger nugget diameter. These fracture modes are called plug fracture and higher cross tensile strength can be obtained in plug fracture. However, in smaller nugget diameter, crack propagates across the internal nugget. It is called interface fracture and joint strength decreases in this fracture mode. These tendencies agree with the results obtained by experiments. Therefore, in this study, it can be said that crack propagation direction can be predicted on cross tension test on spot weld joints by using the proposed method.

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“…To carry out a large-scale analysis of welding residual stress in practical problem, the authors developed the idealized explicit finite element method (IEFEM) [8]. IEFEM is based on dynamic explicit FEM [9].…”

Section: Introductionmentioning

confidence: 99%

Development of idealized explicit FEM using GPU parallelization and its application to large-scale analysis of residual stress of multi-pass welded pipe joint

2015

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In this research, the authors developed the idealized explicit finite element method (IEFEM) to achieve shorter computing time and lower memory consumption in analyses of welding deformation and residual stress. IEFEM was parallelized by a graphics processing unit (GPU) to achieve even faster computation. To show its applicability to largescale problems, the proposed method was applied to the analysis of the multi-pass welding of V-groove pipe joint that has 1 million elements, 13 layers, and 33 passes. In the analysis, isotropic hardening, kinematic hardening, and combined hardening were considered to investigate the influence of hardening rule on residual stress distribution. As a result, it is found that residual stress distributions were larger in the order of isotropic hardening, combined hardening, and kinematic hardening. In addition, the analyzed residual stress and experimental measurements showed good agreement. The computing time was approximately 70 h. From these results, it was shown that IEFEM can analyze a large-scale welding residual stress problem in realistic time with high accuracy.

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Computational Method for Transient Welding Deformation and Stress for Large Scale Structure Based on Dynamic Explicit FEM

Cited by 23 publications

References 1 publication

Investigation of factors influencing welding deformation of ship block by inherent strain analysis using idealized explicit FEM

Investigation of factors influencing welding deformation of ship block by inherent strain analysis using idealized explicit FEM

Study on fracture mode of spot weld joint using continuum damage mechanics model

Development of idealized explicit FEM using GPU parallelization and its application to large-scale analysis of residual stress of multi-pass welded pipe joint

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