Effect of stress relaxation on distortion in additive manufacturing process modeling

Denlinger, Erik R.; Michaleris, P.

doi:10.1016/j.addma.2016.06.011

Cited by 124 publications

(108 citation statements)

References 26 publications

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“…The residual stress at the mid cross section of the substrate for the simulation was 508 MPa, a value that can be compared with the measured value of 740 MPa. Denlinger et al [3] performed a similar simulation and obtained a residual stress of just above 500 MPa. They explain the difference between the simulation and measurements with the temperature-dependent precipitation hardening that the simulation model does not take into account.…”

Section: Discussionmentioning

confidence: 93%

“…This model has been used extensively for modeling the heat input of both arc and beam heat sources. In the simulation of the current case by Denlinger et al [3] they also used this heat input model.…”

Section: Heat Source Modelmentioning

confidence: 99%

“…This leads to additional knowledge about the process and may also reduce the number of trial and error experiments necessary to find the process parameters. There are a number of publications about simulation of additive manufacturing; e.g., [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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History Reduction by Lumping for Time-Efficient Simulation of Additive Manufacturing

Malmelöv

Lundbäck

Lindgren

2019

Metals

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Additive manufacturing is the process by which material is added layer by layer. In most cases, many layers are added, and the passes are lengthy relative to their thicknesses and widths. This makes finite element simulations of the process computationally demanding owing to the short time steps and large number of elements. The classical lumping approach in computational welding mechanics, popular in the 80s, is therefore, of renewed interest and is evaluated in this work. The method of lumping means that welds are merged. This allows fewer time steps and a coarser mesh. It was found that the computation time can be reduced considerably, with retained accuracy for the resulting temperatures and deformations. The residual stresses become, to a certain degree, smaller. The simulations were validated against a directed energy deposition (DED) experiment with alloy 625.a thermo-mechanical model where whole layers were added simultaneously when a part with 50 layers was built. This model was validated against an experiment. Keller et al. [17,18] described a model where several layers were added simultaneously. With their model they were able to predict deformation and residual stresses at the macroscopic level. In the current work the temperature and deformation evolution is studied when the passes are added transiently, and only lumped in the build direction. To the authors' knowledge there is no publication where the approach has been used in this way. The inherent strain method is another approach for fast prediction of the resulting deformation and residual stress in AM processes [19,20]. The method was first proposed for welding by Ueda and coworkers [21][22][23]. Li et al. [24,25] used the inherent strain approach, but instead of using strain, a residual stress tensor is added to each layer in the mechanical macro-scale model. The simulation was performed with a multi-scale model in three different scales. A micro-scale model was used to predict an equivalent heat source, which was the input to the meso-scale model. Because the AM process is very fast, it was assumed that the heat could be added to the whole layer simultaneously. In the thermo-mechanical meso-scale model, a residual stress tensor from one added layer was calculated.Finally, the mechanical model on the macro-scale was computed, wherein the material was added layer by layer and the pre-determined residual stress tensor was applied on each added layer. The drawback with the inherent strain method is that it often requires calibration. The inherent strains are in general sensitive to changes in the boundary conditions.The main aim of this work was to study the method lumping of welds, described above, and evaluate the error introduced in the modeling and the achieved reduction in computation time for the simulations. A detailed thermo-mechanical FE model was validated with in situ temperature and displacement measurements for directed energy deposition (DED) with alloy 625. All experimental data and results that are used for comparison with the sim...

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Section: Discussionmentioning

confidence: 93%

Section: Heat Source Modelmentioning

confidence: 99%

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History Reduction by Lumping for Time-Efficient Simulation of Additive Manufacturing

Malmelöv

Lundbäck

Lindgren

2019

Metals

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“…For the AM with a relatively small number of weld passes, it is permissible to have detailed modeling of each pass when constructing a part (Denlinger and Michaleris 2016). With this method of modeling, the heat input from the beam energy is usually applied as a volumetric heat flow, the center of which moves along the deposition path, thus representing a moving heat source.…”

Section: Introductionmentioning

confidence: 99%

Numerical 3D simulation of wire deposition process to predict distortion of parts

Smetannikov

Maksimov

Трушников

et al. 2019

Mech Adv Mater Mod Process

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In the work, on the basis of the analysis of publications, existing approaches to the numerical modeling of additive processes of product formation are shown. The work itself is devoted to the study of the influence of parameters of the process of surfacing wire materials on the formation of residual deformations in parts. A mathematical formulation of the non-stationary thermomechanical problem is presented, and algorithms for solving the problem using the technology of birth and death of finite elements in the ANSYS package are described. Verification of the model created by the finite element was carried out on the basis of data from the experiment on surfacing a multilayer sample. The effect on the level of residual warping of the following process parameters was studied: the exposure time before the next layer was deposited; the motion path of the burner; ambient temperature. It is shown that the change in ambient temperature is the most effective way to reduce the residual distortions of the form.

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“…In case of additive technologies with a rather small number of deposition passes, it is acceptable to thoroughly model each pass in the course of production of components [35,36]. With this modeling method, the supply of heat brought by a thermal source is generally used as a volume thermal flow whose center moves along a deposition trajectory, thereby representing a moving source of heat.…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Plasma 3D Deposition of Wire Materials

Трушников¹,

Smetannikov²,

Perminov³

et al. 2018

Additive Manufacturing of High-Performance Metals and Alloys - Modeling and Optimization

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The numerical modeling of the physical process of manufacturing parts using additive technologies is complex and needs to consider a variety of thermomechanical behavior. This is connected with the extensive use of the finite element computer simulation by means of specialized software packages that implement mathematical models of the processes. The algorithm of calculation of nonstationary temperature fields and stressstrain state of the structure during the process of 3D deposition of wire materials developed and implemented in ANSYS is considered in the paper. The verification of the developed numerical algorithm for solving three-dimensional problem of the production of metal products using arc 3D deposition of wire materials with the results of the experiment is carried out. The data obtained from calculations on the developed numerical model are in good agreement with the experiment.

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Effect of stress relaxation on distortion in additive manufacturing process modeling

Cited by 124 publications

References 26 publications

History Reduction by Lumping for Time-Efficient Simulation of Additive Manufacturing

History Reduction by Lumping for Time-Efficient Simulation of Additive Manufacturing

Numerical 3D simulation of wire deposition process to predict distortion of parts

Modeling of the Plasma 3D Deposition of Wire Materials

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