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Experimental Research and Numerical Simulations of Metal Additive Manufacturing

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Mechanics of Materials".

Deadline for manuscript submissions: closed (10 October 2023) | Viewed by 13359

Special Issue Editors


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Guest Editor
School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China
Interests: multi-scale modelling of additive manufacturing; composite mechanics; computational methods of modeling material behavior; nanomechanics and suprealloy; numerical simulation of material forming
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Guest Editor
Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
Interests: fluid structure interaction; computational mechanics; solid mechanics; fractional calculus; additive manufacturing; fluid flow solidification

Special Issue Information

Dear Colleagues,

Metal-based additive manufacturing parts make up a significant and growing proportion of 3D printing, with increasingly diverse areas of application in the medical, aerospace, and automotive sectors.

Many factors, including materials and processes, and their expanding use as final or structural parts have contributed to this growth and have led to the need for specialized research in this field, which is of importance in many branches of engineering.

It is well known that several characteristics of printed parts, such as mechanical properties, depend on printing parameters. Therefore, analysis of the influence of manufacturing parameters on printed parts is a key factor in order to optimize the printing process as well as to predict and understand the material properties.

We encourage scientists and engineers to submit papers for inclusion in this Special Issue. There are no restrictions on the type of manufacture, metal, or field of application. Papers on theory, experiments, design, simulation, etc. will be considered for publication, and we expect that many will contain aspects of all of these.

A non-exhaustive list of possible items would be:

  • Process parameters
  • Experimental testing
  • Constitutive models
  • Mesostructure design and effects
  • Numerical simulation
  • Discrete element method
  • Finite element analysis
  • Computational fluid dynamics
  • Phase field simulation
  • Cellular automata simulation
  • Molecular dynamics
  • Machine learning
  • Static and impact strength
  • Fatigue and fracture

Prof. Dr. Wugui Jiang
Prof. Dr. Yanping Lian
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • additive manufacturing
  • numerical simulation
  • experimental testing
  • discrete element method
  • finite element analysis
  • computational fluid dynamics
  • phase-field simulation
  • cellular automata simulation
  • molecular dynamics
  • machine learning

Published Papers (6 papers)

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Research

19 pages, 5141 KiB  
Article
A Fast Prediction Model for Liquid Metal Transfer Modes during the Wire Arc Additive Manufacturing Process
by Jiaqi Ouyang, Mingjian Li, Yanping Lian, Siyi Peng and Changmeng Liu
Materials 2023, 16(7), 2911; https://doi.org/10.3390/ma16072911 - 6 Apr 2023
Cited by 2 | Viewed by 1521
Abstract
The liquid metal transfer mode in wire arc additive manufacturing (WAAM), plays an important role in determining the build quality. In this study, a fast prediction model based on the Young–Laplace equation, momentum equation, and energy conservation, is proposed, to identify the metal [...] Read more.
The liquid metal transfer mode in wire arc additive manufacturing (WAAM), plays an important role in determining the build quality. In this study, a fast prediction model based on the Young–Laplace equation, momentum equation, and energy conservation, is proposed, to identify the metal transfer modes, including droplet, liquid bridge, and wire stubbing, for a given combination of process parameters. To close the proposed model, high-fidelity numerical simulations are applied, to obtain the necessary inputs required by the former. The proposed model’s accuracy and effectiveness are validated by using experimental data and high-fidelity simulation results. It is proved that the model can effectively predict the transition from liquid bridge, to droplet and wire stubbing modes. In addition, its errors in dripping frequency and liquid bridge height range from 6% to 18%. Moreover, the process parameter windows about transitions of liquid transfer modes have been established based on the model, considering wire feed speed, travel speed, heat source power, and material parameters. The proposed model is expected to serve as a powerful tool for the guidance of process parameter optimization, to achieve high-quality builds. Full article
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14 pages, 3044 KiB  
Article
Influence of Latent Heat of Fusion on the Melt Pool Shape and Size in the Direct Laser Deposition Process
by Gleb Turichin, Dmitrii Mukin, Ekaterina Valdaytseva and Maksim Sannikov
Materials 2022, 15(23), 8349; https://doi.org/10.3390/ma15238349 - 24 Nov 2022
Cited by 2 | Viewed by 1295
Abstract
The melt pool calculating method is presented based on the solution of the heat conduction problem in a three-dimensional formulation, taking into account the latent heat of fusion and the change in thermophysical properties with temperature. In this case, the phase transitions of [...] Read more.
The melt pool calculating method is presented based on the solution of the heat conduction problem in a three-dimensional formulation, taking into account the latent heat of fusion and the change in thermophysical properties with temperature. In this case, the phase transitions of melting and crystallization are accounted for using the source method. Considering the latent heat of fusion in the heat transfer process leads to melt pool elongation, as well as to a slight decrease in its width and depth. Depending on the mode, the melt pool elongation can be up to 22%. The penetration depth is reduced by about 5%. The deposition width does not change practically. The presented model was validated by comparing the experimentally determined melt pool shape and its dimensions with the corresponding theoretically calculated results. Experimental data were obtained as a result of coaxial video recording and the melt pool crystallization. The calculated form of the crystallization isotherm changes from a U-shape to a V-shape with an increase in the power and speed of the process, which coincides with the experimental data. Full article
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27 pages, 10406 KiB  
Article
Three-Dimensional Numerical Simulation of Grain Growth during Selective Laser Melting of 316L Stainless Steel
by Feng Xu, Feiyu Xiong, Ming-Jian Li and Yanping Lian
Materials 2022, 15(19), 6800; https://doi.org/10.3390/ma15196800 - 30 Sep 2022
Cited by 8 | Viewed by 2361
Abstract
The grain structure of the selective laser melting additive manufactured parts has been shown to be heterogeneous and spatially non-uniform compared to the traditional manufacturing process. However, the complex formation mechanism of these unique grain structures is hard to reveal using the experimental [...] Read more.
The grain structure of the selective laser melting additive manufactured parts has been shown to be heterogeneous and spatially non-uniform compared to the traditional manufacturing process. However, the complex formation mechanism of these unique grain structures is hard to reveal using the experimental method alone. In this study, we presented a high-fidelity 3D numerical model to address the grain growth mechanisms during the selective laser melting of 316 stainless steel, including two heating modes, i.e., conduction mode and keyhole mode melting. In the numerical model, the powder-scale thermo-fluid dynamics are simulated using the finite volume method with the volume of fluid method. At the same time, the grain structure evolution is sequentially predicted by the cellular automaton method with the predicted temperature field and the as-melted powder bed configuration as input. The simulation results agree well with the experimental data available in the literature. The influence of the process parameters and the keyhole and keyhole-induced void on grain structure formation are addressed in detail. The findings of this study are helpful to the optimization of process parameters for tailoring the microstructure of fabricated parts with expected mechanical properties. Full article
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12 pages, 7066 KiB  
Article
Optimized XGBoost Model with Small Dataset for Predicting Relative Density of Ti-6Al-4V Parts Manufactured by Selective Laser Melting
by Miao Zou, Wu-Gui Jiang, Qing-Hua Qin, Yu-Cheng Liu and Mao-Lin Li
Materials 2022, 15(15), 5298; https://doi.org/10.3390/ma15155298 - 1 Aug 2022
Cited by 28 | Viewed by 4159
Abstract
Determining the quality of Ti-6Al-4V parts fabricated by selective laser melting (SLM) remains a challenge due to the high cost of SLM and the need for expertise in processes and materials. In order to understand the correspondence of the relative density of SLMed [...] Read more.
Determining the quality of Ti-6Al-4V parts fabricated by selective laser melting (SLM) remains a challenge due to the high cost of SLM and the need for expertise in processes and materials. In order to understand the correspondence of the relative density of SLMed Ti-6Al-4V parts with process parameters, an optimized extreme gradient boosting (XGBoost) decision tree model was developed in the present paper using hyperparameter optimization with the GridsearchCV method. In particular, the effect of the size of the dataset for model training and testing on model prediction accuracy was examined. The results show that with the reduction in dataset size, the prediction accuracy of the proposed model decreases, but the overall accuracy can be maintained within a relatively high accuracy range, showing good agreement with the experimental results. Based on a small dataset, the prediction accuracy of the optimized XGBoost model was also compared with that of artificial neural network (ANN) and support vector regression (SVR) models, and it was found that the optimized XGBoost model has better evaluation indicators such as mean absolute error, root mean square error, and the coefficient of determination. In addition, the optimized XGBoost model can be easily extended to the prediction of mechanical properties of more metal materials manufactured by SLM processes. Full article
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16 pages, 8000 KiB  
Article
A Study on the Residual Stress of the Co-Based Alloy Plasma Cladding Layer
by Youbin Lai, Xiang Yue and Wenwen Yue
Materials 2022, 15(15), 5143; https://doi.org/10.3390/ma15155143 - 25 Jul 2022
Cited by 2 | Viewed by 1215
Abstract
The distribution law of residual stress in multi-channel scanned plasma cladding of Co-based alloy under different process parameters was studied by means of simulation and tests, and the optimum process parameters were optimized. The simulation model of the plasma cladding stress field was [...] Read more.
The distribution law of residual stress in multi-channel scanned plasma cladding of Co-based alloy under different process parameters was studied by means of simulation and tests, and the optimum process parameters were optimized. The simulation model of the plasma cladding stress field was established by ABAQUS software, and the influence law of the working current, scanning speed, and scanning mode on the residual stress of the Co-based alloy multi-channel scanning was studied. A set of optimal cladding process parameters were obtained. The residual stress of the cladding layer was measured by the blind hole method and compared with the stress value in the finite element model. The results show that there is residual tensile stress on the surface of the cladding layer. The residual stress along the direction of the scanning path is greater than that along the direction of the scan sequence. The residual stress increases with the increase of the working current. The scanning speed is greater, and the residual stress is smaller. The residual stress of the short-edge scanning is greater than that of the long-edge scanning. The residual stress of the successive scanning is greater than that of the reciprocating scanning. The long-edge reciprocating scanning is the best scanning mode. The best combination of process parameters is the working current of 90 A, the scanning speed of 100 mm/min, and the long-edge reciprocating scanning mode. Full article
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13 pages, 6225 KiB  
Article
Numerical Investigation of the Defects Effect in Additive Manufactured Ti-6Al-4V Struts on Deformation Behavior Based on Microtomographic Images
by Michał Doroszko
Materials 2022, 15(14), 4807; https://doi.org/10.3390/ma15144807 - 9 Jul 2022
Cited by 4 | Viewed by 1485
Abstract
This paper describes the influence of defects occurring in struts under tension, obtained using the additive method of laser powder bed fusion (LPBF), on the stress and strain distributions. The study used struts of different thicknesses separated from Ti-6Al-4V diamond lattice structures. For [...] Read more.
This paper describes the influence of defects occurring in struts under tension, obtained using the additive method of laser powder bed fusion (LPBF), on the stress and strain distributions. The study used struts of different thicknesses separated from Ti-6Al-4V diamond lattice structures. For numerical modeling of stress and strain fields, models that reflect the realistic shape of the tested struts with their imperfections were used. The shape of the diamond structure struts was obtained based on microtomographic measurements. Based on the results obtained, the influence of defects in the material structure on the stress and strain distribution was analyzed. It was observed that the main factor influencing the stress and strain distribution in the struts are micronotches on their external surface. These imperfections have a significantly greater impact on the stress and strain concentration than the micropores inside. Furthermore, the interactions of the imperfections are also important, which in turn affects the stress distributions and the formation of bands of high-stress values inside the material. The relationship between the presence of micropores, the stress–strain curves, and the mechanical properties of the material was also assessed. Full article
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