Analysis on Part Distortion and Residual Stress in Big Area Additive Manufacturing with Carbon Fiber-Reinforced Thermoplastic using Dehomogenization Technique

Conference · Sun Sep 01 04:00:00 EDT 2019

DOI:https://doi.org/10.33599/nasampe/c.19.0694· OSTI ID:1607087

Kim, Pum ^[1]; Baid, Harsh ^[2]; Hassen, Ahmed ^[1]; Kumar, Abhishek ^[3]; Lindahl, John ^[1]; Hoskins, Dylan ^[4]; Ajinjeru, Christine ^[4]; Duty, Chad ^[1]; Yeole, Pritesh ^[4]; Vaidya, Uday ^[1]; Abdi, Frank ^[2]; Love, Lonnie ^[1]; Simunovic, Srdjan ^[1]; Kunc, Vlastimil ^[1]

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1. ORNL
2. AlphaSTAR Corporation
3. Northeastern University, Boston
4. University of Tennessee, Knoxville (UTK)

Part distortion and bottom surface warpage often occur in extrusion-based additive manufacturing. The undesirable deformations during the printing process are due to residual stresses caused by material shrinkage. Analysis on residual stress and deformation requires accurate thermo-mechanical material properties. Polymer composites reinforced with short fibers have intrinsic inhomogeneities with nonuniform fiber orientation. Therefore, homogenized macro properties may not accurately represent the progressive damage behavior or distortion. In this study, fiber orientations in Acrylonitrile Butadiene Styrene (ABS) reinforced with 20%wt carbon fiber are calculated using a de-homogenization technique. Thermal expansion coefficients in multiple directions are obtained from Thermo-Mechanical Analysis (TMA) tests. Temperature dependent stiffness is measured, and temperature dependent strength is estimated. Thermal conductivities in multiple directions and thermal capacity are measured. The calibrated thermo-mechanical properties of the composite with de-homogenized technique are used to analyze the residual stress and distortion of a 4 ft-wide wall printed in the Big Area Additive Manufacturing (BAAM) system. For experimental measurement on the wall printing, Infra-Red (IR) camera captures the temperature field, and Linear Variable Differential Transformer (LVDT) is installed to measure the warpage at the bottom surface. The experimental data are compared to the numerical analysis results. The temperature profile and the distortion profile from experiment are close to the simulation results. Damages due to residual stress and distortion are analyzed.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1607087
• Country of Publication: United States
• Language: English