Adaptive Finite Element Methods and Machine-learning-based Surrogates for the Phase Field Fracture Model

A Warren Distinguished Lecture with
Ravindra Duddu

Civil and Environmental Engineering
Mechanical Engineering
Earth and Environmental Sciences
Vanderbilt University, Nashville, Tennessee

ABSTRACT
Modeling and understanding fracture propagation is necessary to improve the safety and reliability of civil and aerospace structures and to design better materials and structures with enhanced fracture resistance. Over the last decade, the phase field models of fracture emerged as robust computational approaches, owing to their ability to simulate complex crack morphologies, including splitting and merging. However, the main challenge with applying the phase field fracture model to real case scenarios is the computational cost associated with resolving the diffuse crack interface. Adaptive finite element methods and machine-learning-based model surrogates offer the potential to enable accurate and efficient simulations. In this talk, Duddu gives an overview of his research work conducted in the past few years. First, he presents our work on adaptive continuous/discontinuous finite element methods for phase field fracture simulations using strain-energy and stress-based crack driving force functions. Second, he discusses the calibration and validation of these models with experimental data performed as a part of the damage mechanics challenge. Third, he presents a CNN-based surrogate for the phase field fracture model that can predict damage/stress field given the microstructure. He discusses the accuracy of the surrogate model for predicting the uniaxial tensile strength of fiber-reinforced composite microstructures and its potential use in inverse design aimed at maximizing strength. 

Acknowledgements: This work has been funded by the NSF, NASA, 3M Company, and The Royal Society. It is done in collaboration with researchers in the US (Vanderbilt University and University of South Carolina), the UK (University of Oxford, Imperial College London and Durham University), and India (IIT Madras and IIT Jodhpur). 

SPEAKER
Ravindra Duddu got his B. Tech in Civil Engineering from the IIT Madras. He obtained his MS and Ph.D. in Civil and Environmental Engineering from Northwestern University. He worked as postdoctoral researcher at the UT Austin and Columbia University, New York. He is an Associate Professor of Civil and Environmental Engineering at Vanderbilt University, with secondary appointments in Mechanical Engineering and Earth and Environmental Sciences.

Duddu’s research interests are in computational solid mechanics with a focus on multi-physics modeling of material damage evolution. Specific applications involve the fracture of Antarctic glaciers and ice shelves, fracture and fatigue of composite materials, and corrosion of metal alloys. He is a recipient of the US National Science Foundation CAREER award, Fulbright Kalam-Climate Fellowship, UK The Royal Society International Exchanges award, and ONR Summer Faculty Fellowship. He is the Chair of technical committees on Computational Mechanics and Fracture and Failure Mechanics associated with ASCE and ASME.