Sample files for use with the examples are available from the Downloads page.
Expand the downloaded ZIP archive into a convenient directory from which to run Local Simulation inside the numbered directories.
Problem description
For this example, you will run commands inside directory 02.
A generic geometry of Inconel 625 is built in a powder bed system and simulated. The layer height is 0.04 mm. The part geometry is imported in the analysis through an STL file, and it is automatically meshed within Local Simulation. The substrate is assumed to be 24 mm thick. The actual build plate is planned to have 5 similar geometries on it. Here, a simplified analysis is performed on just 1 of the geometries. The *PBDL card is used to add the deposition multiplier for the geometries that are not included in the analysis. The *PBIS card insulates the side of the small substrate in the analysis, simulating the effect of having other builds on the build plate nearby.
The *PBSS card constrains the sides of the small substrate in the analysis, mimicking the effect of being attached to the larger build plate. The build plate has an initial temperature of 100o C, which is modeled using *INIT. The resulting mesh is illustrated in Figure 1.
Figure 1: Auto-generated finite element mesh
A time incremental thermal analysis is performed first to compute the temperature history of the part. Layers are activated in groups, and additional time increments are used to model heat conduction into the part. The thermal analysis includes only the part and substrate. Heat loss into the powder is modeled as convection with a value of 25.d-6 W/((mm2)°C) using the *CONV option.
A time incremental mechanical analysis is performed after the thermal analysis is completed. Similarly to the thermal analysis, layers are activated in groups using *PBPA and the computed temperature distribution from the mechanical analysis is used to compute deformation due to the thermal expansion. The input process parameter file (pp.prm) was generated in Example 1 of this manual.
After the thermo-mechanical simulation has been completed, the distort_stl post-processing program will be used to produced both a warped STL, which shows the predicted displacements, and a compensated STL, which, if printed, should mitigate much of the distortion of the original geometry, getting the part closer to the desired shape.