Challenges and Descriptions

List of 2018 AM-Bench Test Challenge Problems

Modelers are invited to submit simulation results for any number of challenges they like before the deadline of 11:59 (ET) on May 18, 2018.  Tabulated results along with figures are recommended whenever possible.  Modeling results may be submitted AMBench [at] nist.gov (subject: AM-Bench%20Modeling%20Results) (here).

All evaluations of submitted modeling results will be conducted by the AM-Bench 2018 organizing committee.  Award plaques will be awarded at the discretion of the organizing committee.

AMB2018-01: Laser powder bed fusion 3D builds of nickel-based superalloy IN625 and 15-5 stainless steel test objects

• Part deflection (CHAL-AMB2018-01-PD): Predict the deflection of as-built bridge structure after part of it is separated from the build plate.  See section 3.1 for details.

• Residual elastic strains (CHAL-AMB2018-01-RS): Predict the residual elastic strains within as-built bridge structure.  See section 3.2 for details.
• Microstructure (CHAL-AMB2018-01-MS): predict any/all of the following – primary phases, grain size, aspect ratio, dendritic vs cellular microstructure, primary arm spacing, and elemental segregation within the thick and thin legs, as observed on transverse and longitudinal views.  Regarding phase predictions, part of this aspect of the challenge includes being able to make assumptions about what phases might be present. See section 3.3.2 for details.
• Phase fractions (CHAL-AMB2018-01-PF): Predict the phases and phase fractions, including major precipitates, within the transverse samples from the thick and thin legs of the as-built 15-5 specimens. See section 3.3.3 for details.
• Phase evolution (CHAL-AMB2018-01-PFRS): Predict the phases and phase fractions, including major precipitates, as a function of time for residual stress anneals of IN625 and 15-5, from transverse specimens cut from thick and thin legs. See section 3.3.4 for details.

AMB2018-02: Individual laser traces on bare metal plates of IN625, using the three cases: A) 150 W, 400 mm/s, B) 195 W, 800 mm/s, C) 195 W, 1200 mm/s.  Some example data are available for case B) for model calibration. 

Note 1: After experiments were performed on the AMMT, it was determined that the laser power calibration was erroneous, and the actual power was lower than commanded.  The true laser power levels for AMMT were A) 137.9 W, 400 mm/s, B) 179.2 W, 800 mm/s, C) 179.2 W, 1200 mm/s.  Laser power levels for the CBM experiments are as expected. 

Note 2: Upon further investigation into why the AMMT and CBM melt pool geometries differed in CHAL-AMB2018-02-MP, it was determined that the true laser spot sizes for both AMMT and CBM systems were different than intended and originally reported.  The AMMT laser spot D4σ diameter was 170 μm (FWHM) of 100 μm) and the CBM laser spot D4σ diameter was 100 μm (FWHM of 59 μm).  See the updated Table 2 in the AMB2018-02 Test Description for details.  This does not affect the accuracy of the CHAL-AMB2018-02 measurements, such as melt pool geometry, cooling rate, or microstructure.

• Melt pool geometry (CHAL-AMB2018-02-MP): 1) Predict the equilibrium length of the laser melt pool as defined by the solidus temperature, from the front of the melt pool to the back. 2) Predict the equilibrium size and shape of the transverse cross sections of the solidified laser traces.  See sections 3.1.1 and 3.2.3 for details.
• Cooling rate (CHAL-AMB2018-02-CR): Predict the surface cooling rate at the center of the melt track, defined as the time to cool from the solidus temperature to 290 °C below the solidus temperature.  See section 3.1.2 for details.
• Topography (CHAL-AMB2018-02-TP): Predict the 3D surface features of the solidified laser tracks, including the height distribution perpendicular to the laser track and the geometry and spacings of the chevron features.  See section 3.2.1 for details.
• Grain shapes (CHAL-AMB2018-02-GS): Predict the morphology, growth direction, and other general grain characteristics observed in the transverse cross sections of the melt tracks.  The provided example EBSD data may be useful.  See section 3.2.3 for details.
• Dendritic microstructure (CHAL-AMB2018-02-DM): Predict the general character, length scale, and/or elemental segregation of the dendritic/cellular microstructure. See section 3.2.3 for details.
• Three-dimensional structure (CHAL-AMB2018-02-3D): - Predict the morphology, growth direction, and crystal orientation of grains as a function of position in the laser track.  It is recognized that these simulations will be specific to the assumed grain structure of the baseplate since this information is not being provided at this time.  See section 3.2.4 for details.

AMB2018-03: Materials extrusion polymer 3D builds of test objects.  Test object will be a rectangular coupon of polycarbonate.  

• Part Thickness (CHAL-AMB2018-03-Th): Predict the thickness of the thinnest dimension of the rectangular coupon after it is separated from the build plate.  See section 3.1 for details.
• Part Mass (CHAL-AMB2018-03-Ma): Predict the mass of the coupon after it is separated from the build plate and cut.  See section 3.2 for details.
• Part Tensile Properties (CHAL-AMB2018-03-TP):  Predict the tensile properties of the part after it is separated from the build plate and cut.  Predict the location of the failure point.  Predict the mode of failure.  See section 3.3 for details.
• Part Void Distribution (CHAL-AMB2018-03-VD):  Predict the shape and size distribution of voids part after it is separated from the build plate and cut.  See section 3.4 for details.
• Part Cross Section (CHAL-AMB2018-03-CS):  Predict the shape and size distribution of voids within the part after it is separated from the build plate and cut.  See section 3.5 for details.

AMB2018-04: Polymers Powder Bed Fusion: Test object will be a dogbone shape part from Nylon 12. 

• Part Thickness (CHAL-AMB2018-04-Th): Predict the thickness of the thinnest dimension of the dogbone.  See section 3.1 for details.
• Part Mass (CHAL-AMB2018-04-Ma): Predict the mass of the part after it is separated from the build plate and cut.  See section 3.2 for details.
• Part Tensile Properties (CHAL-AMB2018-04-TP):  Predict the tensile properties of the part after it is separated from the build plate and cut.  Predict the location of the failure point.  Predict the mode of failure.  See section 3.3 for details.
• Part Void Distribution (CHAL-AMB2018-04-VD):  Predict the shape and size distribution of voids within the part after it is separated from the build plate.  See section 3.4 for details.
• Part Cross Section (CHAL-AMB2018-04-CS):  Predict the internal shape of a cross-section of the coupon after it is separated from the build plate and cut.  See section 3.5 for details.
• Part Crystallinity and Melting (CHAL-AMB2018-04-CM): Predict the melt onset temperature, the melt peak temperature, the enthalpy and the crystallinity of a piece of the coupon.  See section 3.6 for details.