Towards an Open-Source, Preprocessing Framework for Simulating Material Deposition for a Directed Energy Deposition Process

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Towards an Open-Source, Preprocessing Framework for Simulating Material Deposition for a Directed Energy Deposition Process

Authors: Matthew J. Dantin*†, William M. Furr*†, Matthew W. Priddy*†

*Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS 39762, USA
†Center for Advanced Vehicular Systems (CAVS), 200 Research Blvd. Starkville, MS 39759


This work focuses on the development of an open-source framework to simulate material deposition for arbitrary geometries with respect to desired process parameters during a directed energy deposition (DED) process. This framework allows the flexibility to define the element activation criteria used in conjunction with Abaqus. A Python script was developed to extract toolpath coordinates from G-code and implement an element activation sequence that is unique to a specific CAD drawing. This is important for simulating the additive manufacturing construction of complex geometries because the thermal history of the component is dependent on laser path, which has a significant effect on residual stresses and distortion. The results of varying the element activation criteria are compared with simulated temperature profiles.

Introduction and Methodology

The paper being summarized here details the development and application of a pre-processing framework to easily simulate material deposition in a complex geometry part. This framework will be especially useful for simulating the directed energy deposition additive manufacturing process, but can be applied to the powder bed fusion process as well. The framework is based primarily on the UEPACTIVATIONVOL user subroutine in Abaqus versions 2017 and newer. A general overview of the framework is presented in Fig. 1.
Framework Image.PNG
Figure 1: Framework overview
The framework begins with a g-code generation software that the user preferes. The required CAD file of the part is used to generate a g-code file to define the tool path. An Abaqus input file containing mesh information will also need to be created. Using a python script, the g-code is used to generate a file of tool-path x,y,z positions with respect to time. Using this, the python code relates element centroid locations obtained from the mesh information in the Abaqus input file to define a list of element activation times for each element number based on a user-defined activation criteria. The criteria utilized in this paper are shown below in Figure 2. The elements were activated within a user-defined radius in the x-y plane.
Activation Criteria.PNG
Figure 2: Element activation schematic

Results and Discussion=

The results of the proposed framework were applied to an oxygen sensor socket that shows a number of interesting features found in complex geometries. The results of a heat transfer simulation using a Gaussian distributed heat flux and element activation defined through the proposed framework, can be shown below in Figure 3. The temperature values shown do not exhibit realistic temperature values, as the applied heat flux was much less than would normally be present in the interest of computation times. The results do show the heterogeneous thermal history that occurs during additive manufacturing.
Figure 3: Oxygen sensor temperature profile at various time steps.

Link Original Paper


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