Seminar:

Computational Algorithms for Regularized Models of Dynamic Fracture and Fragmentation
Tuesday, February 18, 2020
3:30PM – 5PM
POB 6.304

John Dolbow

Over the past decade, there has been considerable progress made towards the development of gradient-based damage and phase-field models of fracture. In these methods, sharp fracture surfaces are regularized with a scalar damage field that varies continuously throughout the domain. The evolution of the damage field is governed by a secondary equation that incorporates a length scale. These models have significantly advanced the field of fracture mechanics, to the point where simulations of complex fracture processes are beginning to be truly predictive in some relatively simple cases. While these models have seen considerable success, they have also suffered from a number of shortcomings. These include, for example, the transmission of tractions across fully damaged surfaces, difficulties in recovering the sharp fracture geometry, and the sheer computational expense of resolving the length scale. In this talk, we describe recent efforts to address these issues. We present a new derivation for a phase-field model of cohesive fracture that allows for fully-damaged surfaces to properly transmit tractions under frictionless contact conditions. We will also describe efforts to enable continuous to discontinuous transitions as fracture surfaces propagate, as well as a global-local approach to improve computational efficiency. Finally, we will present applications of these methods to a range of problems in dynamic fracture and fragmentation of quasi-brittle systems, including fluid-driven fracture and other types of coupled problems.

Bio
John Dolbow is a Professor of Mechanical Engineering and Materials Science at Duke University, where he directs the Duke Computational Mechanics Laboratory. Professor Dolbow received his BS in Mechanical Engineering from the University of New Hampshire in 1995, and his Ph.D. in Theoretical and Applied Mechanics from Northwestern University in 1999. He has been a faculty member at Duke University since 1999, and his research concerns the development of numerical methods for evolving interface problems. He has received various awards for his research, including Young Investigator awards from both the USACM and the IACM. He has held visiting appointments at Harvard University, the Okinawa Institute of Science and Technology, and Sandia National Laboratories. He is the Editor-In-Chief of the journal Finite Elements in Analysis and Design. He currently serves as the President of the US Association for Computational Mechanics, as well as the Secretary-General of the International Association for Computational Mechanics. Finally, he is a member of the US Department of Energy Advanced Scientific Computing Advisory Committee.

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