Additive Manufacturing Benchmarks 2022 (AM-Bench 2022): Mechanical Behavior V
Program Organizers: Brandon Lane, National Institute of Standards and Technology; Lyle Levine, National Institute of Standards and Technology
Thursday 10:30 AM
August 18, 2022
Room: Regency Ballroom I & II
Location: Hyatt Regency Bethesda
Session Chair: Nikolas Hrabe, National Institute of Standards and Technology - Boulder
10:30 AM Invited
AM Bench 2022 Macroscale Tensile Challenge at Different Orientations , Part 1: Measurement Description: Jake Benzing1; Nicholas Derimow1; Newell Moser1; Orion Kafka1; Jordan Weaver1; Ross Rentz1; Nik Hrabe1; 1National Institute of Standards and Technology
This additive manufacturing benchmarking challenge (CHAL-AMB2022-04-MaTTO) asks the modelling community to predict the average stress-strain response of tension specimens that were excised from pieces of IN625 manufactured by laser powder bed fusion (L-PBF). The uniaxial tension tests are gripped in clevises, conducted at quasi-static strain rates under displacement control, and strain is measured with an extensometer. With respect to the build direction, multiple tensile orientations (parallel, perpendicular, and intervals between the extremes) were selected to measure the anisotropy and compare between L-PBF scan strategies, which are an X-only raster and an X-Y raster (90-degree scan rotation between X and Y scan paths). The challenge provides information on chemical composition, grain structure (electron backscatter diffraction measured on three orthogonal directions) and pore structure (volume-based measurements via X-Ray computed tomography) from unused blocks of material manufactured on the same build plate.
11:00 AM Invited
AM Bench 2022 Macroscale Tensile Challenge at Different Orientations, Part 2: Predictions and Trends: Newell Moser1; Jake Benzing1; Nicholas Derimow1; Orion Kafka1; Nik Hrabe1; Jordan Weaver1; 1National Institute of Standards and Technology
This presentation is part two to the related presentation by Benzing et al., which describes the experimental process of measuring the stress-strain response, as well as microstructural properties and crystallography, of tension specimens that were excised from laser powder bed fusion (PBF-L) samples and manufactured with different scan strategies (CHAL-AMB2022-04-MaTTO). In this talk, we provide an overview of the types of submitted models that were used to predict the stress-strain response of these PBF-L IN625 tensile specimens. We discuss how the models were compared with the experimental results and then summarize the performance of the model predictions. This talk will also provide a forum for discussion amongst the assembled researchers, in which any difficulties or marked successes can be mentioned, and any feedback for the challenge itself be brought to the AM Bench organizers.
11:30 AM
NAFEMS Benchmarks for Metal Additive Manufacturing Simulation: a Complementary Set of Cases: Sjoerd Van Der Veen1; Jacob Rome2; 1Airbus Operations SAS; 2Aerospace Corporation
Many new software tools dedicated to the simulation of additive manufacturing (AM) processes have been commercialised recently. Most employ the finite element (FE) method to solve the governing equations that modellers use to describe the AM processes. NAFEMS, the International Agency for Finite Element Methods and -Standards, is known for its benchmarks of finite element problems. NAFEMS's Metal Additive Manufacturing Focus Group are preparing a set of benchmark cases, complementary to other initiatives, such as AMbench. Two examples: one case is designed to test the capability of an FE implementation to predict buckling, which often occurs during the building of thin-walled AM parts. Another to test the capability to capture problems of large displacement during build. All combined, they provide a comprehensive set for modellers, to test their simulations against real-life AM aspects.
11:50 AM
Analysis of Existing Hot Tearing Tests and Their Transferability to Additive Manufacturing: Andrew Wall1; Michael Benoit1; 1UBC Okanagan
Hot tearing is a well known casting and welding defect that negatively affects the mechanical properties of many alloys. Many tests exist for both casting and welding to assess hot tearing susceptibility of materials and processes. Hot tearing is also an issue observed in additive manufacturing (AM), yet no susceptibility tests currently exist. Consequently, assessment of hot tearing in AM is currently subjective; the extent of cracking is assessed qualitatively, or in cases where cracks are quantified, there is no consistency among the research parameters. In this presentation, we will review existing crack tests for casting and welding and discuss their potential relevance to AM. This literature review revealed factors that are common among existing tests, as well as unique concepts among individual tests. These concepts will be related to AM to assess their applicability to the development of a standardized benchmark specimen to evaluate hot tearing in AM.