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Cracking Under Stress Developing a petascale simulation framework for stress corrosion cracking Priya Vashishta Univerity of Southern California

Corrosion is an enormously complex technological and economic problem with an annual cost of about 3% of the U.S. gross domestic product. The performance and lifetime of materials used in nuclear technology and in advanced power generation technologies such as turbines, combustors, and fuel cells is often severely limited in corrosive environments or extreme conditions of high pressure and temperature in an environment containing oxygen. Most critical here is premature and catastrophic failure of materials resulting from chemically influenced corrosion.

The basic requirements for the operation of structural systems exposed to corroding conditions under stress loads are safety and reliability. Such safe and reliable operation is endangered by the uncertainties in stress corrosion cracking. To prevent stress corrosion cracking and to predict the lifetime beyond which stress corrosion cracking may cause failure requires that we understand the atomistic mechanisms underlying stress corrosion cracking, that is, the conditions influencing initiation, dynamics, and growth rates of stress corrosion cracking.

This multidisciplinary team consists of computational material scientists, applied mathematicians, and computer scientists from four universities and two Department of Energy labs to develop a stress corrosion cracking computational framework consisting of modeling techniques, algorithms, analytical underpinnings, and release-quality software for:

• petascale simulations with quantum-level accuracy;
• trillion-atom molecular dynamics simulations based on density functional theory and temperature-dependent model generalized pseudopotential theory;
• quasicontinuum method embedded with, and accelerated molecular dynamics coupled with quasicontinuum to reach macroscopic time scales relevant to stress corrosion cracking

The integrated stress corrosion cracking framework, as well as each simulation methodology individually packaged, will be made available to the public domain under a GNU General Public License ( http://www.gnu.org/ ), and released through a web portal linked to the National Energy Research Scientific Computing Center (NERSC) and other Department supercomputing centers.

Advances in materials and chemistry are often critical to progress in all three mission areas. The performance and lifetime of materials widely used in energy and nuclear technologies are often severely limited by corrosion under stress loads. Safe and reliable operation is endangered by this stress corrosion cracking, and improved modeling is necessary for more accurate risk assessments. This project will bring quantum-level accuracy to multi-million-atom, nanosecond simulations of stress corrosion cracking.

Science Application: Materials Science and Chemistry

Project Title: Hierarchical Petascale Simulation Framework for Stress Corrosion Cracking

Principal Investigator: Priya Vashishta
Affiliation: University of Southern California

Participating Institutions and Co-Investigators:
California State University-Northridge, Gang Lu
Harvard University, Efthimios Kaxiras
Los Alamos National Laboratory, Stephan Eidenbenz, Arthur F. Voter
Lawrence Livermore National Laboratory, Randy Q. Hood, John A. Moriarty, Lin H. Yang
Purdue University, Ananth Grama
University of Southern California, Rajiv K. Kalia, Aiichiro Nakano

Funding Partners: U.S. Department of Energy - Office of Science, Advanced Scientific Computing Research, and the National Nuclear Security Agency.

Budget and Duration: Approximately $1.1 million per year for five years ¹

Other SciDAC Materials Science & Chemistry efforts

¹Subject to acceptable progress review and the availability of appropriated funds