About the Course
This course provides an overview of probabilistic fracture mechanics for low-cycle fatigue applications. These applications feature anomalies under an imposed driving force that exceeds the material threshold, leading to cyclic fatigue crack growth and time-dependent crack growth. Anomalies include, but are not limited to, hard-alpha particles in titanium alloys, surface damage, and anomalies produced by additive manufacturing processes. These anomalies are especially important for higher criticality parts due to their possibility of triggering catastrophic fracture.
Concepts of fatigue approaches in presence of defects will be delivered to students, together with simple description of the ‘short-crack’ effect for describing the fatigue strength of AM materials. These approaches, combined with suitable statistical analyses of defects/inhomogeneities allow simple assessment of the fatigue properties for AM and their transfer to components.
In this course, attendees will be exposed to:
- Theoretical concepts that are foundational to probabilistic fracture mechanics
- Key information needed to perform a risk assessment with probabilistic fracture mechanics
- Tools for the analysis of data coming from qualification tests and CT scans
- Computational tools that are available to support probabilistic fracture mechanics
After completing the course, the attendees will be able to achieve the following:
- Describe the outcomes of an assessment for probabilistic fracture mechanics and how it relates to the overall risk of catastrophic fracture
- Understand the requirements to conduct a probabilistic fracture mechanics assessment and how to satisfy these requirements for additive material
- Discuss limitations of an assessment using probabilistic fracture mechanics
- Understand and describe the size effect in fatigue of AM components
- List tools available for probabilistic fracture mechanics
Who Should Attend
This course is aimed at experienced fatigue life analysts interested in a quick overview of probabilistic fracture mechanics and its applications for additive manufacturing.
Stefano BerettaDr. Stefano Beretta, P.h.D. got his PhD at Kyushu University in 1997 (Supervisor Prof. Y. Murakami) and since then he has been making his career at the Politecnico di Milano, where he became Full Professor in 2002 and is a member of the Editorial Board of Eng. Fract. Mechanics and Metals.He has a long record of services for ESIS (European Structural Integrity Society): member of ESIS Exco from 2002 to 2010 as Newsletter Editor and webmaster, then Vice-President from 2010 to 2014. He is Chairman of TC24 since 2010, where he organized and hosted many international meetings. He was Chairman and organizer of the 3rd Int. Symposium Fatigue Design and Material, held in Lecco, September 2017 and Co-Chair of ASTM Symposium on Structural Integrity of AM Parts (November 2018) in Washington D.C.. in 2019 he was conferred the ASTM Award of Excellence in Additive Manufacturing Research.His main research interests are: fatigue and damage tolerance assessment of railway components together with planning of maintenance and inspections; development of probabilistic methods for defect analysis and assessment under LCF and HCF; the application of DIC to the analysis of fatigue damage and crack closure; ii) the fatigue of AM materials and metamaterials. He founded the METAMAT-Lab at Politecnico di Milano.
James SobotkaDr. James C. Sobotka, Ph.D., PMP employs techniques and insights from computational mechanics to improve methods that support structural integrity decisions. As a Lead Engineer at Southwest Research Institute®(SwRI®), Dr. Sobotka focuses on: method development the deterministic life software NASGRO®; concept development for the probabilistic fracture mechanics software DARWIN®; additive manufacturing process modeling; advanced manufacturing, including subtractive, additive, and metamorphic manufacturing; and exotic metal plasticity and damage models.Dr. Sobotka graduated from the University of Illinois at Urbana-Champaign in 2010 through the Structural Mechanics and Engineering Program in the Department of Civil and Environmental Engineering. Dr. Sobotka spent 16 months as a senior engineer at Bettis Atomic Lab before joining SwRI. Dr. Sobotka is the author of various technical papers on a variety of subjects. He regularly presents at technical conferences, including the TMS annual conference, ICAAM, and ICAF. He has chaired technical sessions at ASME IMECE and will be chairing a session at the International Congress on Fracture 2023. He is a member of ASTM, TMS, and PMI. He has been a panelist at the United States National Congress on Computational Mechanics and at America Makes.