March 28, 2018
11:00 am - 12:00 pm
For all its promise, metal based additive manufacturing is still limited by costly trial and error production to optimize process parameters. Due to variability in AM machines and processes, quantifying and certifying mechanical properties of AM-fabricated parts can also present a challenge. In this regard, Additive Manufacturing (AM) process simulation may be used to predict as-built material characteristic and final part residual stress & deformation for certification and qualification purposes. GENOA 3DP simulates the manufacturing process by generating a structural mesh from STL file or printer G-CODE and utilizing commercial FE thermal/stress analysis with a detailed multi-scale material model to predict build outcomes as related to the specified process parameters. In order to obtain accurate results, the methodology must take advantage of a detailed and exact material model that explains material behavior at critical load states (i.e. thermal, structural, etc.).
To achieve the desired accuracy in the analysis of metal AM, a grain and grain boundary finite element representative volume element (FE RVE) was proposed and implemented. The computational method was validated against residual stress measurements to establish its thermal-structural credentials. The method was extended to predict oxidation and damage of as built parts. To validate the approach, GENOA 3DP was utilized in diverse industrial applications for different classes of materials (17-4 PH steel, Ti-6Al-4V, and Inconel 718) and classes of components, (e.g. internal structure of a wing). Integrated Computational Materials Engineering (ICME) and GENOA 3DP software were used to simulate specimen fabrication and, along with commercial design optimization tools, create an optimized beam topology for simple loading conditions. The developed methodology, based on the Building-block Verification, Validation and Accreditation (VVA) strategy, demonstrates a viable process for AM simulation leading to AM part certification.