scholarly journals Element activation method and non-conformal dynamic remeshing strategy to model additive manufacturing

2021 ◽  
Author(s):  
Cédric Laruelle ◽  
Romain Boman ◽  
Luc Papeleux ◽  
Jean-Philippe Ponthot

Modeling of Additive Manufacturing (AM) at the part scale involves non-linear thermo-mechanical simulations. Such a process also imposes a very fine discretization and requires altering the geometry of the models during the simulations to model the addition of matter, which is a computational challenge by itself. The first focus of this work is the addition of an additive manufacturing module in the fully implicit in-house Finite Element code Metafor [1] which is developed at the University of Liège. The implemented method to activate elements and to activate and deactivate boundary conditions during a simulation is adapted from the element deletion algorithm implemented in Metafor in the scope of crack propagation [2]. This algorithm is modified to allow the activation of elements based on a user-specified criterion (e.g. geometrical criterion, thermal criterion, etc.). The second objective of this work is to improve the efficiency of the AM simulations, in particular by using a dynamic remeshing strategy to reduce the computational cost of the simulations. This remeshing is done using non-conformal meshes, where hanging nodes are handled via the use of Lagrange multiplier constraints. The mesh data transfer used after remeshing is based on projection methods involving finite volumes [3]. The presented model is then compared against a 2D numerical simulation of Direct Energy Deposition of a High-Speed Steel thick deposit from the literature [4].

Author(s):  
Karolien Kempen ◽  
Bey Vrancken ◽  
Sam Buls ◽  
Lore Thijs ◽  
Jan Van Humbeeck ◽  
...  

Cracks and delamination, resulting from residual stresses, are a barrier in the world of additive manufacturing and selective laser melting (SLM) that prohibits the use of many metals in this field. By preheating the baseplate, thermal gradients are lowered and stresses can be reduced. In this work, some initial tests were performed with M2 high speed steel (HSS). The influence of preheating on density and mechanical and physical properties is investigated. The paper shows many promising results for the production of SLM parts in materials that are very sensitive to crack formation and delamination. When using a preheating of 200 °C, crack-free M2 HSS parts were produced with a relative density of 99.8%.


2021 ◽  
Vol 111 (06) ◽  
pp. 368-371
Author(s):  
Sebastian Greco ◽  
Marc Schmidt ◽  
Benjamin Kirsch ◽  
Jan C. Aurich

Additive Fertigungsverfahren zeichnen sich durch die Möglichkeit der endkonturnahen Fertigung komplexer Geometrien aus. Die geringe Produktivität etablierter Verfahren wie etwa dem Pulverbettverfahren hemmen aktuell den wirtschaftlichen Einsatz additiver Fertigung. Das Hochgeschwindigkeits-Laserauftragschweißen (HLA) soll durch deutlich erhöhte Auftragsraten und somit bisher unerreicht hoher Produktivität bei der additiven Fertigung dazu beitragen, deren Wirtschaftlichkeit zu steigern.   Additive manufacturing enables the near-net-shape production of complex geometries. The low productivity of established processes such as powder bed processes is currently limiting the economic use of additive manufacturing. High-speed laser direct energy deposition (HS LDED) is expected to improve the economic efficiency of additive manufacturing by significantly increasing deposition rates and thus previously unattained high productivity.


2021 ◽  
Author(s):  
Quy Duc Thinh Pham ◽  
Truong Vinh Hoang ◽  
Quoc Tuan Pham ◽  
Than Phuc Huynh ◽  
Van Xuan Tran ◽  
...  

In this study, a data-driven deep learning model for fast and accurate prediction of temperature evolution and melting pool size of metallic additive manufacturing processes are developed. The study focuses on bulk experiments of the M4 high-speed steel material powder manufactured by Direct Energy Deposition. Under non-optimized process parameters, many deposited layers (above 30) generate large changes of microstructure through the sample depth caused by the high sensitivity of the cladding material on the thermal history. A 2D finite element analysis (FEA) of the bulk sample, validated in a previous study by experimental measurements, is able to achieve numerical data defining the temperature field evolution under different process settings. A Feed-forward neural networks (FFNN) approach is trained to reproduce the temperature fields generated from FEA. Hence, the trained FFNN is used to predict the history of the temperature fields for new process parameter sets not included in the initial dataset. Besides the input energy, nodal coordinates, and time, five additional features relating layer number, laser location, and distance from the laser to sampling point are considered to enhance prediction accuracy. The results indicate that the temperature evolution is predicted well by the FFNN with an accuracy of 99% within 12 seconds.


2017 ◽  
Vol 34 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Min Zhang ◽  
Changjun Chen ◽  
Lanlan Qin ◽  
Kai Yan ◽  
Guangping Cheng ◽  
...  

2019 ◽  
Vol 236 ◽  
pp. 42-45 ◽  
Author(s):  
R.T. Jardin ◽  
J. Tchoufang Tchuindjang ◽  
L. Duchêne ◽  
H.-S. Tran ◽  
N. Hashemi ◽  
...  

2015 ◽  
Vol 12 (1) ◽  
pp. 21-23
Author(s):  
Jozef Struharňanský ◽  
Dana Stančeková ◽  
Anton Martikáň ◽  
Daniel Varga ◽  
Viktor Kuždál ◽  
...  

Abstract In this article, unconventional kinematics of turning is examined with the aim on influence of cutting parameters on surface layers residual stress. The auto-rotary cutting tool prototype for turning was developed, designed and constructed at the University of Zilina. The tool is made of high speed steel. Residual stress examination of material 100Cr6 was performed by non-destructive measuring method of X-ray diffraction. This method is able to determine normal and shear stress conditions without damaging the examined sample.


2020 ◽  
Vol 38 (8A) ◽  
pp. 1226-1235
Author(s):  
Safa R. Fadhil ◽  
Shukry. H. Aghdeab

Electrical Discharge Machining (EDM) is extensively used to manufacture different conductive materials, including difficult to machine materials with intricate profiles. Powder Mixed Electro-Discharge Machining (PMEDM) is a modern innovation in promoting the capabilities of conventional EDM. In this process, suitable materials in fine powder form are mixed in the dielectric fluid. An equal percentage of graphite and silicon carbide powders have been mixed together with the transformer oil and used as the dielectric media in this work. The aim of this study is to investigate the effect of some process parameters such as peak current, pulse-on time, and powder concentration of machining High-speed steel (HSS)/(M2) on the material removal rate (MRR), tool wear rate (TWR) and the surface roughness (Ra). Experiments have been designed and analyzed using Response Surface Methodology (RSM) approach by adopting a face-centered central composite design (FCCD). It is found that added graphite-silicon carbide mixing powder to the dielectric fluid enhanced the MRR and Ra as well as reduced the TWR at various conditions. Maximum MRR was (0.492 g/min) obtained at a peak current of (24 A), pulse on (100 µs), and powder concentration (10 g/l), minimum TWR was (0.00126 g/min) at (10 A, 100 µs, and 10 g/l), and better Ra was (3.51 µm) at (10 A, 50 µs, and 10 g/l).


2020 ◽  
Vol 38 (9A) ◽  
pp. 1352-1358
Author(s):  
Saad K. Shather ◽  
Abbas A. Ibrahim ◽  
Zainab H. Mohsein ◽  
Omar H. Hassoon

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.


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