Blending Glowworm Swarm Optimization Algorithm with Thermal-Mechanical Coupling Finite Element Model for Optimization Method of Box Structure Welding Technology

Du Xiao-xin,Zhang Jian-fei,GuoYuan 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4

Welding sequence is the important influence factor of the temperature field and residual stress and deformation in welding structure, At present, determining the welding sequence is usually based on experience and test method. For complex structure it is very difficult to get the optimum welding sequence. This study is aiming to settle the problem of solving the optimum welding sequence of complex box welding structure. In our study, we take the welding deformation as objective function, and then, associate glowworm swarm optimization algorithm with thermal-mechanical coupling and nonlinear thermal elastoplastic finite element model to optimize numerical simulation, eventually the optimum welding sequence is determined. Optimization results demonstrate that the optimum welding sequence obtained by our method has small welding deformation and little change rate. At the same time, our method is faster, more accurate, more effective than the traditional experience or test method.

Welding sequence optimization using the strain direct boundary method based on the welding induced change in structural stiffness

노홍준,윤희찬,임헌봉,HyunIk Yang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

The method proposed in this study is to determine the welding sequence to suppress welding de-formation using the strain directed as boundary (SDB) method. Welded joints are modeled by constructing tack welds and gaps as kinematic constraints in shell models. In addition, the SDB method considering the elastoplastic properties is used to evaluate the effect on the previous welding procedure. The results of the constructed analysis model are compared with the experimental results. The residual strain of each weld is calculated using the verified model, and joint stiffness is determined and compared by considering this together with the relationship between tensile stress and shrinkage strain of the weld. The optimal welding sequence is determined by comparing the stiffness of each welding joint, and this is compared and verified with the experimental results. In addition, it is confirmed that the determined welding sequence reduced the out-of-plane deformation by 2.01 % compared to the original welding sequence. The proposed method thus provides an analytical approach for welding sequence design.

Numerical Optimization of the Welding Sequence for Mitigating Welding Deformation in Aluminum Pipe Structures by Using a Genetic Algorithm

Minwook Choi,Chunbiao Wu,Jae-Woong Kim 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.12

Aluminum is widely used in fields that require lightweight technology, such as in the aerospace and automobile industries. The welding of aluminum alloys, however, tends to generate large deformations in the welded structures due to its large heat conductivity and thermal expansion. Therefore, this study aims to reduce welding deformations that occur in the welding process by obtaining an optimal welding sequence. The welding sequence optimization process consists of two main stages. The first involves the prediction of the welding deformation behavior by using thermo-elastic-plastic finite element analysis. The second stage optimizes the welding sequence by using a genetic algorithm (GA), which can efficiently optimize very large solution spaces considering not only the welding sequence, but also the welding direction. In addition, this study proposed an appropriate and efficient GA for the present optimization problem. The optimization results showed that the developed finite element analysis model were in good agreement with the experimental results, and the proposed optimization tool can reduce the welding deformation considerably.

연료탱크 제작시 시뮬레이션을 통한 용접변형 해석

양영수(Young-Soo Yang),김덕윤(Duck-Youn Kim),배강열(Kang-Yul Bae) 한국기계가공학회 2016 한국기계가공학회지 Vol.15 No.6

To attach a fuel tank to an excavator, two sets of mounting plates on which three bosses are attached are welded onto the tank. In this study, the welding process of a fuel tank for an excavator was modeled using a finite element numerical method. The tank was modeled as a simple plate to which the mounting plate or bosses were attached by fillet welding. Thermal and thermo-elasto-plastic analyses of the welding process were carried out to predict the temperature distribution and material distortion during welding, respectively. Three different welding sequences for the tank were also modelled to compare the deformation that occurred due to each welding sequence. The results of the analysis predicted that changing the welding sequence around the mounting plate could not position the boss within the allowable dimensional range. The results also revealed the sequence in which the maximum distortion of the bosses welded onto the tank was 30% less than the maximum distortion due to the other sequences.

Numerical Analysis of Welding Direction and Sequence for Controlling Distortion and Residual Stress in Aluminum Plate-Sleeve Structures

Shusen Zhao,Yanmin Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.6

When manufacturing aluminum alloy space-frame radomes, the vertical welding distortion is the main factor that affects assembly accuracy, and the residual stress affects the service performance. This paper aims to decrease welding distortion while ensuring that the residual stress is within the appropriate range by adjusting welding direction and sequence. The thermal-elastic–plastic finite element method is used to predict the welding distortion and residual stress in mid-thick aluminum plate-sleeve structures. The numerical model was verified by experimental results of temperature, vertical distortion, and residual stresses. The effect of welding direction and sequence on the distortion and residual stress was examined by the numerical model. Results indicate that the welding direction significantly affects the distribution and magnitude of X-direction distortion (longitudinal shrinkage) but has little effect on vertical distortion and residual stress. The welding sequence significantly affects the magnitude of vertical distortion and the distribution of residual stress. Then, considering the vertical distortion and residual stress, a scheme (Case 3) is recommended for welding mid-thick aluminum plate-sleeve structures. The maximum vertical distortion of the current production scheme (Case 1) and final determined scheme (Case 3) are 5.43 mm and 2.73 mm, and the corresponding maximum tensile residual stress is 186.5 MPa and 193.8 MPa, respectively. Comparing Case 1 with Case 3, Case 3 can reduce the vertical distortion by 49.7%, while the maximum tensile residual stress of the two is close, and the difference is less than 10 MPa.

박판 필릿용접구조물의 좌굴변형에 관한 연구

추환수,조상명,Chu, Hwan-Su,Cho, Sang-Myung 대한용접접합학회 2009 대한용접·접합학회지 Vol.27 No.3

The structures distorted by welding have to be corrected. Since the correcting work needs a lot of costs and time, it is very important to minimize the buckling distortion due to welding of thin plate structure. Therefore the aim of this study is to investigate the effect of single bead on plate welding and fillet welding on the buckling distortion. In the single bead on plate welding, it was found that the welding speed and welding sequence were the most dominant factors on distortion. In the fillet welding, there were four typical buckling modes observed, and the welding sequence was the most influential factor on the buckling distortion. However typical distortion measuring method is not considered for the distortion correcting process costs of each buckling modes, therefore, in this study, the measuring method is developed to classify the buckling modes for torsion of specimen and buckling distortion depend on nodal point for the bead on plate welding specimen and fillet welds.

Review on Mitigation of Welding-Induced Distortion Based on FEM Analysis

Chunbiao Wu,Jae-Woong Kim 대한용접·접합학회 2020 대한용접·접합학회지 Vol.38 No.1

Welding distortion is an unavoidable issue due to localized expansion and contraction during the heating and cooling cycles, and has a negative effect on the fabrication process. However, mitigating weld distortion to meet product requirements is a challenging task, because welding shrinkage can’t be prevented, only controlled. This paper provides a comprehensive literature review of various techniques to reduce and optimize the deformation induced by welding in the design stage and manufacturing process. Finite element numerical analysis methods are usually employed to predict welding distortion, and can cost less than actual experiments. The review of these approaches is useful to fully understand the main mechanisms used to mitigate weldinginduced distortion, and for choosing the most suitable method to minimize deformation based on realistic fabrication requirements.

Ship block assembly sequence planning considering productivity and welding deformation

Minseok Kang,Jeongyeon Seo,Hyun Chung 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

Ship block assembly sequence planning considering productivity and welding deformation

Kang, Minseok,Seo, Jeongyeon,Chung, Hyun The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.4

The determination of assembly sequence in general mechanical assemblies plays an important role in terms of manufacturing cost, duration and quality. In the production of ships and offshore plants, the consideration of productivity factors and welding deformation is crucial in determining the optimal assembly sequence. In shipbuilding and offshore industries, most assembly sequence planning has been done according to engineers' decisions based on extensive experience. This may result in error-prone planning and sub-optimal sequence, especially when dealing with unfamiliar block assemblies composed of dozens of parts. This paper presents an assembly sequence planning method for block assemblies. The proposed method basically considers geometric characteristics of blocks to determine feasible assembly sequences, as well as assembly process and productivity factors. Then the assembly sequence with minimal welding deformation is selected based on simplified welding distortion analysis. The method is validated using an asymmetric assembly model and the results indicate that it is capable of generating an optimal assembly sequence.

Effect of Welding Sequence on the Residual Stresses of Plate with Longitudinal Stiffeners

Kim, N.I.,Lee, J.S.,Choe, W.H. The Korean Welding and Joining Society 2004 International journal of Korean welding society Vol.4 No.1

In this paper, a study on the residual stress of plate with longitudinal stiffeners is explained in terms of the welding sequences. In order to verify the results of numerical analysis, the hole drilling method (HDM) is performed, to measuring the residual stresses of the test plates in $CO_2$ Flux Cored Arc Welding (FCAW) under various welding conditions. The non-linear transient analysis technique for the numerical analysis in a large and complicate structure is considered. The residual stress of plate in consideration of the welding sequences and directions is evaluated by some numerical simulations and also by experiments. Comparison of numerical analysis results with experimental data shows the accuracy and validity of the proposed method.