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SUMMARY:On the Feasibility of a Digital Twin of Additive Manufacturing and
  Fatigue - Professor Anthony Rollett\, Carnegie Mellon University 
DTSTART:20260313T140000Z
DTEND:20260313T150000Z
UID:TALK241741@talks.cam.ac.uk
CONTACT:46601
DESCRIPTION:A recent project entitled “Development of an Ecosystem for Q
 ualification of Additive Manufacturing Processes and Materials in Aviation
 ” demonstrated the inverse dependence of fatigue on pore number density 
 in AM Ti-6Al-4V. The fatigue-based process window was much narrower than t
 ypically reported but explainable in terms of observed variations based on
  spatter rates and intermittent lack of melt pool overlap. A current “In
 stitute for Model-Based Qualification & Certification of Additive Manufact
 uring (IMQCAM)” focuses on creating a numerical digital twin (DT) for pr
 edicting fatigue as a function of process parameters. We report on recent 
 developments in modeling microstructure\, texture and pores along with var
 iations in heat treatment. We conclude that establishing a qualified mater
 ials process is feasible via an efficient survey of a limited domain of pr
 ocess space. In terms of predictability of fatigue\, the limited data sugg
 ests that the scatter in life is smallest in the long crack (Paris Law) re
 gime\, intermediate for short cracks and largest for crack nucleation. Thi
 s provides an important background for Uncertainty Quantification (UQ)\, w
 hich is a major focus for the IMQCAM team and which has already revealed a
  significant sensitivity to compositional variations\, for example. Ultima
 tely\, we aim to create a probabilistic model of fatigue that connects the
  initiation\, short-crack and long-crack phases. Support for this approach
  to fatigue is justified by analysis of experimental measurements of the s
 eparate stages and its stress scaling.\n\n\nSupport from multiple agencies
  is gratefully acknowledged\, including NASA\, DOE/BES\, DOE/NNSA\, ONR\, 
 NSF\, OEA\, Commonwealth of Pennsylvania\, and Ametek. I am indebted to my
  many collaborators.\n\n\nBrief bio: Rollett earned an MA in Metallurgy & 
 Materials Science in 1980 from Cambridge and a PhD in Materials Engineerin
 g from Drexel in 1987. He has been a member of the Dept. of Materials Scie
 nce & Engineering at Carnegie Mellon University since 1995 which included 
 five years as Department Head at CMU. He is a University Professor and the
  Co-Director of the Next Manufacturing Center on additive manufacturing. P
 reviously\, he worked at the Los Alamos National Laboratory with five year
 s as a Group Leader then Deputy Division Director. He has been a Fellow of
  ASM since 1996\, Fellow of the Institute of Physics (UK) since 2004 and F
 ellow of TMS since 2011. He received the Cyril Stanley Smith Award from TM
 S in 2014\, was elected as Member of Honor by the French Metallurgical Soc
 iety in 2015 and then became the US Steel Professor of Metallurgical Engin
 eering and Materials Science in 2017. He received the Cyril Stanley Smith 
 Award from the International Conference on Recrystallization and Grain Gro
 wth in 2019 and the Hans Bunge Award from the Intl. Conf. on Textures of M
 aterials (ICOTOM) in 2024. He was an\n\nInternational Francqui Professor (
 Belgium) in 2022 and received the ASM Gold Medal in 2024. His research foc
 uses on processing-microstructure-properties relationships with interests 
 in additive manufacturing\, the measurement and prediction of microstructu
 ral evolution\, the relationship between microstructure and properties\, e
 specially three-dimensional effects\, texture & anisotropy and the use of 
 synchrotron x-rays.
LOCATION:Department of Engineering - LR4
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