TY - JOUR
T1 - Implementation of a viscoplastic substrate creep model in the thermomechanical simulation of the WAAM process
AU - Springer, S.
AU - Röcklinger, A.
AU - Leitner, M.
AU - Grün, F.
AU - Gruber, T.
AU - Lasnik, M.
AU - Oberwinkler, B.
N1 - Funding Information:
Open access funding provided by Montanuniversität Leoben. Special thanks are given to the Austrian Research Promotion Agency (FFG; project number 32765288), who funded the research project with funds of the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology (bmk) and the Federal Ministry for Digital and Economic Affairs (bmdw).
Publisher Copyright:
© 2021, The Author(s).
PY - 2022/3
Y1 - 2022/3
N2 - This research work focusses on the implementation of a viscoplastic creep model in the thermomechanical simulation of the wire arc additive manufacturing (WAAM) process for Ti-6Al-4 V structures. Due to the characteristic layer by layer manufacturing within the WAAM process, viscoplastic material effects occur, which can be covered by implementing a creep model in the thermomechanical simulation. Experimental creep tests with a wide temperature, load and time range were carried out to examine short-term creep behaviour in particular. A Norton-Bailey creep law is used to accurately fit the experimental data and describe the base material’s creep behaviour. Subsequently, the fitted Norton-Bailey creep law was implemented in the thermomechanical simulation of the WAAM process. Finally, to determine the effect of creep on global distortion and local residual stress state in the substrate, simulations of a simplified linear, three-layer WAAM structure, with and without applying the implemented creep law, were carried out and compared to experimental data. The thermomechanical simulation with implemented creep model reveals a significant improvement in the numerical estimation of distortion and residual stress state in the substrate. The maximum distortion is reduced by about 13% and respectively the mean absolute percentage error between simulation and experiment decreases by about 34%. Additionally, the estimation accuracy with respect to the local residual stress state in the substrate improved by about 10%.
AB - This research work focusses on the implementation of a viscoplastic creep model in the thermomechanical simulation of the wire arc additive manufacturing (WAAM) process for Ti-6Al-4 V structures. Due to the characteristic layer by layer manufacturing within the WAAM process, viscoplastic material effects occur, which can be covered by implementing a creep model in the thermomechanical simulation. Experimental creep tests with a wide temperature, load and time range were carried out to examine short-term creep behaviour in particular. A Norton-Bailey creep law is used to accurately fit the experimental data and describe the base material’s creep behaviour. Subsequently, the fitted Norton-Bailey creep law was implemented in the thermomechanical simulation of the WAAM process. Finally, to determine the effect of creep on global distortion and local residual stress state in the substrate, simulations of a simplified linear, three-layer WAAM structure, with and without applying the implemented creep law, were carried out and compared to experimental data. The thermomechanical simulation with implemented creep model reveals a significant improvement in the numerical estimation of distortion and residual stress state in the substrate. The maximum distortion is reduced by about 13% and respectively the mean absolute percentage error between simulation and experiment decreases by about 34%. Additionally, the estimation accuracy with respect to the local residual stress state in the substrate improved by about 10%.
KW - Additive manufacturing
KW - Thermomechanical simulation
KW - Ti-6Al-4 V
KW - Viscoplastic model
KW - WAAM
UR - http://www.scopus.com/inward/record.url?scp=85120847573&partnerID=8YFLogxK
U2 - 10.1007/s40194-021-01232-x
DO - 10.1007/s40194-021-01232-x
M3 - Article
AN - SCOPUS:85120847573
SN - 0043-2288
VL - 66
SP - 441
EP - 453
JO - Welding in the World
JF - Welding in the World
IS - 3
ER -