Additive Manufacturing Modeling and Simulation: Microstructure, Mechanics, and Process: AM Modeling - Mechanical Properties
Sponsored by: TMS Computational Materials Science and Engineering Committee
Program Organizers: Jing Zhang, Purdue University in Indianapolis; Brandon McWilliams, US Army Research Laboratory; Li Ma, Johns Hopkins University Applied Physics Laboratory; Yeon-Gil Jung, Korea Institute of Ceramic Engineering & Technology
Monday 2:00 PM
October 18, 2021
Room: A113
Location: Greater Columbus Convention Center
Session Chair: Jing Zhang, Indiana University - Purdue University Indianapolis; Brandon McWilliams, CCDC Army Research Laboratory; Li Ma, Johns Hopkins University Applied Physics Laboratory; Yeon-Gil Jung, Changwon National University
2:00 PM
Grain-scale Residual Stress Modeling in Wire Arc Additive Manufacturing of Haynes 282 Super Alloy: Santanu Paul1; Wei Xiong1; Albert To1; 1University of Pittsburgh
The most important topic hindering the build success of industrial components using Wire Arc Additive Manufacturing (WAAM) is the understanding of the residual stresses in the component. This study will present a multi-scale thermomechanical finite element (FE) model for predicting the intragranular or Type III residual stresses developed in the component during the layer-by-layer deposition of the WAAM process. The multi-scale model will incorporate the residual distortions computed using the modified inherent strain model and the grain texture predicted by the Discrete Dendrite Dynamics (DDD) method along with the periodic boundary conditions for a static equilibrium analysis for prediction of Type III residual stresses. First, a global thermomechanical analysis of the component will be conducted lasting several thermal cycles. Finally, based on interpolation of the solution from the global analysis onto the outer zone of the sub-model, the local mechanical analysis will be done separately and processed by the sub-model.
2:20 PM
Now On-Demand Only - Influence of Microstructure on Fatigue Crack Growth: An Combined Experiment and Model Investigation in EBM Nickel-Based Supper Alloy Haynes 282: Jiahao Cheng1; Patxi Fernandez-Zelaia1; Sebastien Dryepondt1; Xiaohua Hu1; Michael Kirka1; 1Oak Ridge National Laboratory
With ORNL’s recent advancement in powder-bed fusion-based additive manufacturing technique, printing of Nickel-based superalloy with accurate site-specific control of grain orientation and morphology at microscale is enabled. This creates the possibility of microstructure-design for improved material properties and service life. This research focuses on Haynes 282, an γ' precipitation-strengthened nickel-based superalloy known for its exceptional high-temperature creep resistance and fabricability and used for advanced ultrasupercritical (A-USC) steam turbines. Fatigue cracking is the dominating failure in such components, thus understanding and improving fatigue crack resistance through microstructure optimization is imperative. In this study, a Hayne 282 specimen with ‘composite’ microstructure (i.e. different regions of the specimen have distinct microstructures) was fabricated and controlled experiment of fatigue crack growth in the ‘composite’ microstructure was conducted. The results showed higher crack growth rate in coarse columnar grain region than in fine equiaxed grain region, which is analyzed with crystal plasticity finite element modeling.
2:40 PM Cancelled
Part-level Fast Predictions of Residual Stresses during LPBF of Al-Mg-Zr Alloys Using Microstructure Informed Inherent Strain Method: Abhishek Ramakrishnan1; Dan Satko1; Ayman Salem1; Jan Kasprzak2; Nam Phan2; 1MRL Materials Resources LLC; 2Naval Air Systems Command
Residual stress contributes to part distortion and warping during additive manufacturing due to accumulation of thermal strains during cyclic heating and cooling. Mechanical simulations based on an inherent strain approach have been widely used for fast predictions of residual stresses at the part level. However, experimental calibration of the inherent strain tensors for each material and set of processing parameters reduces simulation efficiency. MRL has demonstrated a fast, physics-based prediction of residual stress and distortion at the part level which considers processing parameters and feedstock within an Integrated Computational Adaptive Additive Manufacturing (iCAAM) framework. Taking into account the effect of microstructure evolution as a function of processing temperature on thermodynamic and thermomechanical properties of multicomponent alloy systems, results in a microstructure-informed inherent strain tensor. Model validation at the coupon and part level are presented on Al-Mg-Zr alloy with performance that meets the performance metrics of the Al6xxx series.
3:00 PM
Distortion Modeling during Sintering of Binder Jet Printed Parts: Basil Paudel1; Albert To1; 1University of Pittsburgh
During sintering of binder jet (BJ) printed parts, non-linear and often anisotropic distortion is seen with shrinkage values in the range of ~5-20%. The geometry and complexity of the part combined with the sintering stress and high temperature creep makes prediction of the final part geometry after sintering more difficult, thus hindering its wide adoption in the industry. In the present study, a viscoplastic constitutive model is adopted to predict the distortion during sintering of the stainless steel 316L BJP parts. The effects of friction and gravity are considered. The model is implemented through the usermat subroutine in Ansys and is used to simulate the distortion of a sintered part. The shrinkage results from the numerical analysis using the identified parameters are validated against experimental measurements. It is shown that the calibrated model predicts the shrinkage and shape distortion reasonably well during the sintering process.
3:20 PM Break
3:40 PM
Modeling and Experimental Validation of Stresses in 3D Printed, Polymeric Biliary Stents: Victoria Cordista1; Rebecca Lawson1; Bailey Stanley1; Sagar Patel1; Joanna Thomas1; 1Mercer University
Stents are inserted in the extrahepatic bile ducts (EHBD) to alleviate cholestasis. Current plastic biliary stents do not allow multidirectional flow at a duct bifurcation. Metal stents allow multidirectional flow but not subsequent diagnostic imaging. Our efforts are focused on predicting the behavior of new, 3D printed polymeric biliary stent designs that can be deployed at a duct junction without inhibiting bile flow. To ensure our design simulations were accurate, we obtained the mechanical characteristics of the stent material through tensile testing. We performed bend testing on the stent designs to determine maximum deformation. Our experimental values were used to validate our ANSYS simulation data. ANSYS input parameters were adjusted until simulated reaction force values on the stents were within 10% of experimental data. At that point the Von Mises stresses predicted by ANSYS were assumed to accurately represent stresses experienced by our biliary stents.
4:00 PM
Residual Stress Induced Cracking Modeling: Kevin Glunt1; Wen Dong1; Santanu Paul1; Albert To1; 1University of Pittsburgh
Figuring out how to additively manufacture parts using a wider range of materials is essential for the growth of the AM industry, yet these materials can be brittle and subject to cracking under large residual stresses. These stresses are produced from the heating and cooling cycle during the Laser Powder Bed Fusion (L-PBF) process. Modeling is critical for identifying which printing features will cause a significant change in the chances of cracking within the part. The simulation will save time from the costly test prints generally used. A multi-physics model was developed in ANSYS to properly show if cracking will occur under specific printing conditions. The simulation results are compared to experiments for L-PBF processed Stellite 6, a widely used cobalt base alloy that is notoriously difficult to process using L-PBF due to its susceptibility to cracking.
4:20 PM
Improving the Mechanical Performance of AlSi10Mg Lattice Structures Manufactured by Laser Powder Bed Fusion (L-PBF): Hend Alqaydi1; Sultan Alneyadi2; Jide Oyebanji1; Dong Lee1; Nesma Aboulkhair1; 1Technology Innovation Institute; 2Pennsylvania state university
In metal Additive Manufacturing (AM), AlSi10Mg is a widely used light-weight material, owing to its excellent properties, e.g. specific strength. AM of lattice structures has showcased them as very attractive routes for promoting design-for-performance over design-for-manufacture, specifically when light-weighting is sought. Lattice structures have exhibited outstanding potential for fabricating components with tunable characteristics. Due to their high surface-to-volume ratio, triply periodic minimal surface lattice structures (TPMS) are promising candidates for a wide range of applications. Investigations on the volume fraction and strut thicknesses that are critical to improve the mechanical properties are increasing. This study focusses on the TPMS lattices manufactured in AlSi10Mg using Laser Powder Bed Fusion, investigating the influence of the relative density and strut thicknesses to engineer a desired mechanical performance by combining experimental methods and simulation modelling. Furthermore, the change in behaviour arising when two distinctive lattice structure types are hybridized is evaluated for functional grading.