Session: 12-08-01: Peridynamic Modeling of Materials’ Behavior

Paper Number: 100085

100085 - Simulating Corrosion Damage in Crevices and From Galvanic Couples: Peridynamic Models, Part I 

Some particularly dangerous types of localized corrosion that can lead to fracture and catastrophic failure, crevice and galvanic corrosion have been especially difficult to predict using computational models. Computational modeling of crevice corrosion, for example, is complicated because of the extreme aspect ratio of crevices, which are long and narrow spaces, sometimes only a few micrometers tall, but covering lengths of even centimeters. Crevice corrosion attack mostly happens at the mouth of the crevice, where deep trenches can be observed in experiments. Outside of that particular region, corrosion damage is relatively minor, but it cannot be ignored, since it influences what happens near the crevice mouth. A recent peridynamic model for crevice corrosion is able to predict its evolution, in great detail [1], and offer an explanation for the stabilization of the major corrosion attack near the mouth of the crevice. Deep trenches are obtained with the computational model near the crevice mouth in an autonomous way, by only using far-field boundary conditions. We explain the reasons behind this seemingly peculiar behavior of corrosion damage. In galvanic corrosion, high corrosion rates are induced near the metal-metal interface and accurate representation of the electric potential is critical in obtaining predictive results. We have recently showed that classical models require an artificial step be created in the geometry of the bi-material in order to obtain results similar to those seen in experiments [2]. Without this artifice, results from classical models of galvanic corrosion produce misleading smooth damage profiles, hiding potentially dangerous sharp corrosion attack that could easily trigger crack growth and catastrophic failure. The peridynamic (PD) model for galvanic corrosion is able to predict the correct damage profiles caused by galvanic corrosion without the need to artificially change the sample’s geometry. This is because the PD model uses a mathematical formulation that eliminates various singularities present in classical models defined on particular geometrical configurations.

In the second part of this talk I will discuss recent computational methods (the Fast Convolution-Based Method, FCBM) aimed at efficient and memory-light computations of corrosion damage problems. We show how the FCBM for diffusion problems [3] can be modified to treat corrosion damage problems, and how to introduce material heterogeneities in the FCBM calculations. The introduction of stochastic fields in the formulation leads to results that resemble experimental observations of cross-section of corrosion pits and their lacy covers.  

Acknowledgements: This work has been supported in part by the US National Science Foundation Grant No. 1953346. This work was completed utilizing the Holland Computing Center of the University of Nebraska, which receives support from the Nebraska Research Initiative.

References:

[1] S. Jafarzadeh, J. Zhao, M. Shakouri, F. Bobaru, "A peridynamic model for crevice corrosion damage", Electrochimica Acta, 401, 139512 (2022). https://doi.org/10.1016/j.electacta.2021.139512

[2] J. Zhao, S. Jafarzadeh, M. Rahmani, Z. Chen, Y.-R. Kim, F. Bobaru, "A peridynamic model for galvanic corrosion and fracture", Electrochimica Acta, 391, 138968 (2021). https://doi.org/10.1016/j.electacta.2021.138968 

[3] S. Jafarzadeh, L. Wang, A. Larios, F. Bobaru, "A fast convolution-based method for peridynamic transient diffusion in arbitrary domains", Computer Methods in Applied Mechanics and Engineering, 375, 113633, (2021). https://doi.org/10.1016/j.cma.2020.113633

Presenting Author: Florin Bobaru University of Nebraska-Lincoln

Presenting Author Biography: Florin Bobaru is a Professor and Hergenrader Distinguished Scholar of Mechanical Engineering in the Department of Mechanical and Materials Engineering at University of Nebraska-Lincoln. He received his B.S and M.S. degrees in Mathematics and Mechanics from University of Bucharest, Romania, in 1995 and 1997, respectively, and his Ph.D. degree from Cornell University in Theoretical and Applied Mechanics in 2001. He introduced peridynamic modeling for corrosion damage and SCC. He is an Associate Editor for “Journal of Peridynamics and Nonlocal Modeling”, a Regional Editor for the “International Journal of Fracture”, and the main editor for the “Handbook of Peridynamic Modeling” (2016). His paper on “Peridynamic modeling of repassivation in pitting corrosion of stainless steel” (with S. Jafarzadeh and Z. Chen) published in Corrosion journal, was awarded the 2020 CORROSION Best Paper Award by NACE. A new book on “Corrosion Damage and Corrosion-Assisted Fracture: Peridynamic Modeling and Computations” is to appear in 2022 at Elsevier.

Authors:

Florin Bobaru University of Nebraska-Lincoln
Longzhen Wang University of Nebraska-Lincoln