Petros Sofronis

For More Information

• I2CNER website

Education

• Ph.D. Theoretical & Applied Mechanics University of Illinois at Urbana-Champaign 1987
• M.S. Theoretical & Applied Mechanics University of Illinois at Urbana-Champaign 1983
• B.S. Mechanical Engineering Aristoteleion University, Greece 1980

Academic Positions

• James W. Bayne Professor, Department of Mechanical Science and Engineering, UIUC, 2013-date
• Director of the International Institute for Carbon-Neutral Energy Research, Dec. 2010-date
• Associate Head for Mechanics Programs, Department of Mechanical Science and Engineering, 2007-2012
• Professor, Department of Mechanical Science and Engineering, UIUC, Apr. 14, 2005-date
• Department Affiliate, Materials Research Laboratory, UIUC, 2008-date
• Department Affiliate, Department of Theoretical and Applied Mechanics, UIUC, Aug. 2005-06
• Department Affiliate, Department of Materials Science and Engineering, UIUC, 2001-date
• Department Affiliate, Department of Mechanical and Industrial Engineering, UIUC, 2001-Apr. 13, 2005
• Professor, Department of Theoretical and Applied Mechanics, UIUC, 2004-Apr. 13, 2005
• Associate Professor, Department of Theoretical and Applied Mechanics, UIUC, 1997-04
• Visiting Associate Professor, University of Pennsylvania, Philadelphia, Jan.-Jun. 1999
• Assistant Professor, Department of Theoretical and Applied Mechanics, UIUC, 1991-97
• Visiting Lecturer, University of California, Santa Barbara, 1991
• Assistant Research Engineer, University of California, Santa Barbara, 1990-91
• Military, Greek Armed Service, 1988-90
• Post-doctoral Research Associate, Department of Theoretical and Applied Mechanics, UIUC, 1987-88
• Post-doctoral Research Associate, University of California-Santa Barbara, 1986-87
• Research Assistant, Department of Theoretical and Applied Mechanics, UIUC, 1981-85

Major Consulting Activities

• BP America Production Company, 2012

Professional Registrations

• Technical Chamber of Greece, 1980

Research Statement

Professor Sofronis studies solid mechanics, micromechanics and fracture mechanics. He is currently developing a mechanistic understanding of hydrogen embrittlement in pipeline steels to determine whether hydrogen fuel can be safely transported at enormous pressures through existing pipelines. These pipelines are formed from low-strength steel that deforms easily but also has high resistance to rupturing. He is particularly concerned with hydrogen embrittlement, in which materials fail catastrophically at much lower load levels than they can sustain in the absence of hydrogen. The steel in pipelines can have many impurities and inclusions, where hydrogen degradation can be initiated.

He and Professor Ian Robertson of the Department of Materials Science and Engineering have used models and experiments to show that hydrogen embrittlement may result from a synergistic action between brittle and ductile failure. Their study of degradation in nickel alloy 690 is widely used in the nuclear energy industry and was the first systematic simulation of the synergistic action of hydrogen-enhanced localized plasticity and hydrogen-induced decohesion.

Professor Sofronis and his research group are also working with Sandia National Laboratories to develop a model of material response in the presence of hydrogen by accounting for and including all of its effects on microstructure that have been observed by Professor Robertson in the Transmission Electron Microscope. The result will be a much-needed and long-awaited tool for predicting hydrogen-induced failures through computer simulation. The researchers are also exploring ways to mitigate hydrogen fractures by hindering hydrogen ingress into materials, and they are investigating new material microstructures that are compatible with hydrogen.

Selected Articles in Journals

• Sanders, J. W., M. Dadfarnia, J. F. Stubbins, P. Sofronis, "On the Fracture of High Temperature Alloys by Creep Cavitation under Uniaxial or Biaxial Stress States," Journal of the Mechanics and Physics of Solids, 98, 49-62, 2017.
• Wang, S., M. L. Martin, I. M. Robertson, P. Sofronis, "Effect of Hydrogen Environment on the Separation of Fe Grain Boundaries," Acta Materialia, 107, 279-88, 2016.
• Dadfarnia, M., M. L. Martin, A. Nagao, P. Sofronis, and I. M. Robertson, "Modeling Hydrogen Transport by Dislocations," J. Mech. Phys. Solids, 78, 511-25, 2015.
• Kirchheim, R., B. P. Somerday, P. Sofronis, "Chemomechanical Effects on the Separation of Interfaces Occurring during Fracture with Emphasis on the Hydrogen-iron and Hydrogen-nickel System, Acta Materialia, 99, 87-98, 2015.
• Nagao, A., S. Wang, M. L. Martin, B.P. Somerday, P. Sofronis, "Recent Advances on Hydrogen Embrittlement of Structural Materials," International Journal of Fracture, 196, 223-43, 2015.
• Robertson, I. M.,P. Sofronis, A. Nagao, M. L. Martin, S. Wang, D.W. Gross, and K. E. Nygren,"Hydrogen Embrittlement Understood," Metallurgical and Materials Transaction, 46A, 2323-2341, 2015.
• Dadfarnia, M., B.P. Somerday, P. E. Schembri, P. Sofronis, J. W. Faulk III, K. A. Nibur, and D. K. Balch, "On Modeling Hydrogen-Induced Crack Propagation Under Sustained Load," JOM, The Minerals, Metals & Materials Society, 66, 1390-1398, 2014.
• Nagao, A., M. L. Martin, M. Dadfarnia, P. Sofronis, and I. M. Robertson, "The Effect of Nano-sized (Ti,Mo)C Precipitates on Hydrogen Embrittlement of Tempered Lath Martensitic Steel," Acta Materialia, 74, 244-254, 2014.
• Wang, S., M. L. Martin, P. Sofronis, S. Ohnuki, N. Hashimoto, and I. M. Robertson, "Hydrogen-induced Intergranular Failure of Iron," Acta Materialia, 69, 275-282, 2014.
• Somerday, B. P., P. Sofronis, K. A. Nibur, C. San Marchi, and R. Kirchheim, "Elucidating the Variables, Affecting Accelerated Fatigue Crack Growth of Steels in Hydrogen Gas with Low Oxygen Concentrations," Acta Materialia, 61, 6153-6170, 2013.
• Martin, M. L., P. Sofronis, I. M. Robertson, T. Awane, and Y. Murakami, "A Microstructural Based Understanding of Hydrogen-Enhanced Fatigue of Stainless Steels," International Journal of Fatigue, 57, 28-36,2013.
• Nibur, K. A., B. Somerday, P. Sofronis, C. San Marchi, J. W. Faulk, M. Dadfarnia, P. Sofronis, "The Relationship Between Crack-Tip Strain and Subcritical Cracking Thresholds For Steels in High-Pressure Hydrogen Gas," Metallurgical and Material Transactions, 44 (1), 248-169, 2013.
• Nagao, A., C. D. Smith, M. Dadfarnia, P. Sofronis, and I. M. Robertson, "The Role of Hydrogen in Hydrogen Embrittlement Fracture of Lath Martensitic Steel," Acta Materialia, 60, n 13-14,5182-5189, 2012.
• Pataky, G. J., M. D. Sangid, H. Sehitoglu, R. F. Hamilton, H. J. Maier, and P. Sofronis, "Full Field Measurements of Anisotropic Stress Intensity Factor Ranges in Fatigue," Engineering Fracture Mechanics, 94,13-28, 2012.
• Murakami, Y., T. Kanezaki, P. Sofronis, "Hydrogen embrittlement of high strength steels: Determination of the threshold stress intensity for small cracks nucleating at nonmetallic inclusions," Engineering Fracture Mechanics, v 97, n 1, 227-243, 2012.
• Onoue, K., Y. Murakami, and P. Sofronis, “Japan’s Energy Supply: Mid-to-long-term Scenario – A Proposal for a New Energy Supply System in the Aftermath of the March 11 Earthquake," International Journal of Hydrogen Energy, 37 (10), 8123-8132, 2012.
• Martin, M. L., B. P. Somerday, R. O. Ritchie, P. Sofronis, and I. M. Robertson, “Hydrogen-Induced Intergranular Failure in Nickel Revisited.” Acta Materialia, v 60, 2739-2745, 2012.
• Dadfarnia, M., P. Sofronis, and T. Neeraj, "Hydrogen Interaction with Multiple Traps: Can it be Used to Mitigate Embrittlement?," International Journal of Hydrogen Energy, 36:16, 10141-10148, August 2011.
• Dadfarnia, M., P. Sofronis, B. P. Somerday, D. K. Balch, P. Schembri, and R. J. Melcher, "On The Environmental Similitude for Fracture in the SENT Specimen and a Cracked Hydrogen Gas Pipeline," Engineering Fracture Mechanics, 78(12), 2429-2438, 2011.
• Briceno, M., J. Fenske, M. Dadfarnia, P. Sofronis, and I. M. Robertson, "Effect of Ion Irradiation-produced Defects on the Mobility of Dislocations in 304 Stainless Steels," Journal of Nuclear Materials, 409 (1), 18-26, 2011.
• Martin, M., I. M. Robertson, and P. Sofronis, "Interpreting Hydrogen-Induced Fracture Surfaces in Terms of Deformation Processes, ”A New Approach, Acta Materialia, 59 (9), 3680-3687, 2011.
• Martin, M., J. Fenske, P. Sofronis, and I. M. Robertson, "On the Formation and Nature of Quasi-Cleavage Fracture Surfaces in Hydrogen Embrittled Steels," Acta Materialia, 59 (4), 1601-1606, 2011.
• Novak, P., R. Yuan, B. P. Somerday, P. Sofronis, and R. O. Ritchie, “A Statistical, Physical-based, Micro-mechanical Model of Hydrogen-induced Intergranular Fracture in Steel,” Journal Mech. Phys. Solids, 58, 206-226, 2010.
• Dadfarnia, M., P. Novak, D. C. Ahn, J. B. Liu, P. Sofronis, D. D. Johnson, and I. M. Robertson, “Recent Advances in the Study of Structural Materials Compatibility with Hydrogen,” Advanced Materials, 22, 1128-1135, 2010.
• Sobotka, J. C., R. H. Dodds Jr., and P. Sofronis, “Effects of Hydrogen on Steady, Ductile Crack Growth: Computational Studies,” International Journal of Solids and Structures, 46, 4095-4106, 2009.
• Somerday, B. P., D. K. Balch, M. Dadfarnia, K. A. Nibur, C. H. Cadden, and P. Sofronis, “Hydrogen Assisted Crack Propagation in Austenitic Stainless Steel Fusion Welds,” Metallurgical and Materials Transactions A, 40, 2350-2362, 2009.
• Dadfarnia, M., B. P. Somerday, P. Sofronis, I. M. Robertson, and D. Stalheim, “Interaction of Hydrogen Transport and Material Elastoplasticity in Pipeline Steels,” Journal of Pressure Vessel and Technology, 041404-1 through 041404-13,131,2009.
• Dadfarnia, M., P. Sofronis, B. Somerday, and I. Robertson, “On the Small Scale Character of the Stress and Hydrogen Concentration Fields at the Tip of an Axial Crack in Steel Pipeline: Effect of Hydrogen-induced Softening on Void Growth,” International Journal of Materials Research, 99, 557-570, 2008.
• Xu, F., N. Aravas, and P. Sofronis, “Constitutive Modeling of Solid Propellant Materials with Evolving Microstructural Damage,” Journal of the Mechanics and Physics of Solids, 56, 2050-2073, 2008.
• Liang, Y., P. Sofronis, D. C. Ahn, R. Dodds, and D. Bammann, “Effect of Hydrogen Trapping on Void Growth and Coalescence in Metals and Alloys,” Mechanics of Materials, 40, 115-132, 2008.
• Ahn, D. C., P. Sofronis, and R. Dodds, Jr., “Modeling of Hydrogen-Assisted Ductile Crack Propagation in Metals and Alloys,” International Journal of Fracture, 145, 135-157, 2007.
• Xu, F., P. Sofronis, N. Aravas, and S. Meyer, “Constitutive Modeling of Porous Viscoelastic Materials,” European Journal of Mechanics A/Solids, 26, 936-955, 2007.
• Ahn, D. C., P. Sofronis, and R. Dodds, “On Hydrogen-Induced Plastic Flow Localization During Void Growth and Coalescence,” International Journal of Hydrogen Energy, 32, 3734-3742, 2007.
• Ahn, D. C., J. Belak, M. Kumar, P. Sofronis, and R. Minich, “On Void Growth by Dislocation Emission: Experiment and Simulation,” Journal of Applied Physics, 101, 063514-063520, 2007.
• Ahn, D. C., P. Sofronis, and R. Minich, “On the Micromechanics of Void Growth by Prismatic Dislocation Loop Emission,” Journal of the Mechanics and Physics of Solids, 54, 735-755, 2006.
• Robertson, I. M., A. Beaudoin, K. Al-Fadhalah, C-M. Li, J. Robach, B. D. Wirth, A. Arsenlis, D. Ahn, and P. Sofronis, “Dislocation-Obstacle Interactions: Dynamics Experiments to Continuum Modeling,” Materials Science and Engineering A., 400-401, 245-250, 2005.
• Clark, B. G., I. M. Robertson, L. M. Dougherty, D. C. Ahn, and P. Sofronis, “High-Temperature Dislocation-Precipitate Interactions in Al Alloys: An In Situ Transmission Electron Microscopy Deformation Study,” Journal of Materials Research, 20, 1792-1801, 2005.
• Subramanian, S., P. Sofronis, and P. Ponte Castaneda, “Void Growth in a Power-law Creeping Solids: Effect of Surface Diffusion and Surface Energy,” International Journal of Solids and Structures, 42, 6202-6225, 2005.
• Liang, Y. and P. Sofronis, “Numerical Simulation of Hydrogen-Induced Intergranular Fracture in Alloy 690,” Journal of Engineering Materials and Technology, ASME, 126, 368-377, 2004.
• Liang, Y., P. Sofronis, and R. Dodds, “Interaction of Hydrogen with Crack Tip Plasticity in the Presence of T-Stress: Effects on Void Growth,” Materials Science and Engineering A, 366, 397-411, 2004.
• Liang, Y. and P. Sofronis, “Micromechanics and Numerical Modeling of the Hydrogen-Particle-Matrix Interactions in Nickel-Base Alloys,” Modeling and Simulation in Materials Science and Engineering, 11, 523-551, 2003.
• Liang, Y. and P. Sofronis, “Toward a Phenomenological Description of Hydrogen-Induced Decohesion at Particle/Matrix Interfaces,” Journal of Mechanics and Physics of Solids, 51, 1509-1531, 2003.
• Liang, Y., P. Sofronis, and N. Aravas, “On the Effect of Hydrogen on Plastic Instabilities in Metals,” Acta Materialia, 51, 2717-2730, 2003.
• Mishin, Y., P. Sofronis, and J. L. Bassani, “Thermodynamic and Kinetic Aspects of Interfacial Decohesion,” Acta Materialia, 50, 3609-3622, 2002.
• Sofronis, P. and I. M. Robertson, “Transmission Electron Microscopy Observations and Micromechanical/Continuum Models for the Effects of Hydrogen on the Mechanical Behavior of Metals,” Philosophical Magazine A, 82, 3405-3413, 2002.
• Subramanian, S. J. and P. Sofronis, “Calculation of a Constitutive Potential for Isostatic Powder Compaction,” International Journal of Mechanical Sciences, 44, 2239-2262, 2002.
• Sofronis, P., Y. Liang, and N. Aravas, “Hydrogen Induced Shear Localization of the Plastic Flow in Metals and Alloys,” European Journal of Mechanics A/Solids, 20, 857-872, 2001.
• Subramanian, S. J. and P. Sofronis, “Modeling the Interaction Between Densification Mechanisms in Powder Compaction,” International Journal of Solid and Structures, 38, 7899-7918, 2001.
• Sofronis, P., Editorial Statement, Engineering Fracture Mechanics, 68, 617, 2001.
• Taha, A. and P. Sofronis, “A Micromechanics Approach to the Study of Hydrogen Transport and Embrittlement,” Engineering Fracture Mechanics, 68, 803-837, 2001.
• Lufrano, J. and P. Sofronis, “Micromechanics of Hydride Formation and Cracking in Zirconium Alloys,” Computer Modeling in Engineering Science, 1:2, 119-131, 2000.
• Sofronis, P. and J. Lufrano, “Interaction of Local Elastoplasticity with Hydrogen: Embrittlement Effects,” Materials Science Engineering A, 260, 41-47, 1999.
• Lufrano, J., P. Sofronis, and H. K. Birnbaum, “Elastoplastically Accommodated Hydride Formation and Embrittlement,” Journal of Mechanics and Physics of Solids, 46, 1497-1520, 1998.
• Lufrano, J. and P. Sofronis, “Enhanced Hydrogen Concentrations Ahead of Rounded Notches and Cracks-Competition Between Plastic Strain and Hydrostatic Stress,” Acta Materialia, 46, 1519-1526, 1998.
• Lufrano, J., D. Symons, and P. Sofronis, “Hydrogen Transport and Large Strain Elastoplasticity Near a Notch in Alloy X-750,” Engineering Fracture Mechanics, 59, 827-845, 1998.
• Casagranda, A. and P. Sofronis, “Numerical Observations of Scaling Laws in the Consolidation of Powder Compacts,” Acta Materialia, 45, 4835-4845, 1997.
• Nimmagadda, P. B. R. and P. Sofronis, “On the Calculation of the Matrix/Reinforcement Interface Diffusion Coefficient in Diffusional Relaxation of Composite Materials at High Temperatures,” Acta Metallurgica et Materialia, 44, 2711-2716, 1996.
• Nimmagadda, P. B. R. and P. Sofronis, “Creep Strength of Fiber and Particulate Composite Materials: The Effect of Interface Slip and Diffusion,” Mechanics of Materials, 23, 1-19, 1996.
• Lufrano, J. and P. Sofronis, “Numerical Analysis of the Interaction of Solute Hydrogen Atoms with the Stress Field of a Crack,” International Journal of Solids and Structures, 33, 1709-1723, 1996.
• Lufrano, J., P. Sofronis, and H. K. Birnbaum, “Modeling of Hydrogen Transport and Elastically Accommodated Hydride Formation Near a Crack Tip,” Journal of Mechanics and Physics of Solids, 44, 179-205, 1996.
• Sofronis, P., “The Influence of Mobility of Dissolved Hydrogen on the Elastic Response of a Metal,” Journal of Mechanics and Physics of Solids, 43, 1385-1407, 1995.
• Sofronis, P. and H. K. Birnbaum, “Mechanics of the Hydrogen-Dislocation-Impurity Interactions: Part I-Increasing Shear Modulus,” Journal of Mechanics and Physics of Solids, 43, 49-90, 1995.
• Birnbaum, H. K. and P. Sofronis, “Hydrogen Enhanced Localized Plasticity—A Mechanism for Hydrogen Related Fracture,” Materials Science and Engineering, A176, 191-202, 1994.
• Sofronis, P. and R. M. McMeeking, “The Effect of Interface Diffusion and Slip on the Creep Resistance of Particulate Composite Materials,” Mechanics of Materials, 18, 55-68, 1994.
• Sofronis, P. and R. M. McMeeking, “Creep of a Power Law Material Containing Spherical Voids,” Journal of Applied Mechanics, 59, 88-95, 1992.
• Sofronis, P. and R. M. McMeeking, “Numerical Analysis of Hydrogen Transport Near a Blunting Crack Tip,” Journal of Mechanics and Physics of Solids, 37, 317-350, 1989.

Professional Societies

• Member, TMS (Minerals, Materials, Metals)
• National Associate Member, The Art Institute of Chicago
• Member, New York Academy of Science
• Member, American Academy of Mechanics
• Member, The American Society of Mechanical Engineers
• Member, Association of Mechanical Engineers of Greece

Teaching Honors

• Campus Award for Excellence in Graduate and Professional Teaching, 2009
• Listed in the Daily Illini's “Incomplete List of Instructors Rated as Excellent by Their Students,” for Spring 1993, Fall 1994, Spring 1995, Fall 1997, Spring 1998, Spring 1999, Spring and Fall 2000, Spring and Fall 2002, Spring and Fall 2003, Spring and Fall 2004, Spring 2005 and Fall 2005, Spring 2006, Fall 2007, Spring 2008, Fall 2008, Spring 2009, Spring 2010, Fall 2010, Spring 2011, Fall 2011, Spring 2012, Fall 2012, Spring 2013, Spring 2014, Fall 2014, Spring 2015, Spring 2016, Fall 2016, Fall 2017, Spring 2019, Fall 2019, Fall 2020, Spring 2021, Fall 2021, Spring 2022