Announcing Zay Jeffries Night 2025!
ASM International Cleveland Chapter invites you to attend our Monday, April 14th meeting.
Our special guest is Professor Tony Rollett, who will be speaking on "Towards a Digital Twin for Fatigue".
Please follow the link to register and we look forward to seeing you there!
Title: Towards a Digital Twin for Fatigue
We provide an overview of a NASA University Leadership Initiative project entitled “Development of an Ecosystem for Qualification of Additive Manufacturing Processes and Materials in Aviation”. This work provided the base for a newly started NASA Science & Technology Research Institute “Institute for Model-Based Qualification & Certification of Additive Manufacturing (IMQCAM)” that will create a numerical digital twin (DT) for fatigue. The ULI project included multiple universities and other institutions working together to build a quantitative connection between AM processing, microstructure and properties in laser powder bed fusion of Ti-6Al-4V. Microstructure focused on defect structure as a function of process conditions and the key property measured was 4-point bend fatigue life. The key result of a systematic variation across power-velocity space was that the defect number density was anti-correlated with fatigue life. The resulting process window was much narrower compared to typical presentations. Printing the same bend bars in different machines at different sites produced similar results. Hypotheses are offered for the observed variations based on spatter rates and melt pool variability. We conclude that establishing a qualified materials process is feasible via an efficient survey of a limited domain of process space. Uncertainty Quantification is a major focus for the IMQCAM team which has already revealed a significant sensitivity to feedstock variations, for example. Several component models exist such as microstructure prediction in Ti64 and 718 as well as microstructure-sensitive fatigue but linking models together in the DT requires substantial effort in terms of data exchange.
Support from multiple agencies is gratefully acknowledged, including NASA, DOE/BES, DOE/NNSA, ONR, NSF, OEA, Commonwealth of Pennsylvania, and Ametek.
Brief bio: I have been a member of the faculty at Carnegie Mellon University since 1995. I am also the Co-Director of the NextManufacturing Center on additive manufacturing. Previously, I worked for the University of California at the Los Alamos National Laboratory. I spent nine years in management with four years as a Group Leader (and then Deputy Division Director) at Los Alamos, followed by five years as Department Head at CMU (up to 2000). I have been a Fellow of ASM since 1996, Fellow of the Institute of Physics (UK) since 2004 and Fellow of TMS since 2011. I received the Cyril Stanley Smith Award from TMS in 2014, was elected as Member of Honor by the French Metallurgical Society in 2015 and then became the US Steel Professor of Metallurgical Engineering and Materials Science in 2017. I received Cyril Stanley Smith Award from the International Conference on Recrystallization and Grain Growth in 2019 and the Hans Bunge Award from the Intl. Conf. on Textures of Materials (ICOTOM) in 2024. I was an International Francqui Professor (Belgium) in 2022 and I received the ASM Gold Medal and was promoted to University Professor in 2024. My research focuses on processing-microstructure-properties relationships with interests in additive manufacturing, the measurement and prediction of microstructural evolution, the relationship between microstructure and properties, especially three-dimensional effects, texture & anisotropy and the use of synchrotron x-rays.