prof. Yannis John F Dafalias

Department:  Department D 4 - Impact and Waves in Solids
Room:  Externista
Location:  Extern,
Publications: Search in ASEP Database
WoS Researcher ID:

SCOPUS ID:  7006538110


Employment Record

2017–now: Leading Researcher, Institute of Thermomechanics, CAS, Prague, Czech Republic

2021–now: Distinguished Professor Emeritus, University of California, CEE Department, U.C. Davis

2013–2021: Distinguished Professor, University of California, CEE Department, U.C. Davis

1985–2013: Professor, Department of Civil and Environ. Engineering, University of California, Davis

1987–2013: Professor, Department of Mechanics, School of Applied Math. and Phys. Sciences, NTUA

1980–1985: Associate Professor, Department of Civil Engineering, University of California, Davis

1975–1980: Assistant Professor, Department of Civil Engineering, University of California, Davis

1974–1975: Research Engineer and Junior Specialist, Dept. of Civil Eng., U.C. Berkeley

1973–1974: Research Assistant, Department of Civil Engineering, University of California, Berkeley

1970–1971: Research Assistant, Division of Engineering, Brown University


Honors and Awards

2018: Prize for the 13th Outstanding Paper Award by the China Civil Engineering Society, third tier, 2018, for the paper: “DEM study of fabric features governing undrained post-liquefaction shear deformation of sand”, Acta Geotechnica, 2016, by R. Wang, P. Fu, J.M. Zang, and Y.F. Dafalias.

2012: Norman Medal, ASCE, for the paper “SANISTEEL: Simple anisotropic steel plasticity model”, J. Structural Engineering, ASCE, 137(2), 185–194, 2011.

2012: Nathan M. Newmark Medal, Engineering Mechanics Institute (EMI) and Structural Engineering Institute (SEI) of ASCE.

2012: FP7_IDEAS Advanced Grant Award of 1.9 million euro from the European Research Council; IDEAS advanced grants are given only to top researchers in Europe.

1991: Foreign Researcher Shield Plate, Japanese Society of Soil Mechanics and Foundation Eng.

1987: Walter L. Huber Civil Engineering Research Prize, ASCE.


Selected Papers

Taiebat, M., Dafalias, Y.F., and Peek, R., “A Destructuration Theory and its Application to SANICLAY Model”, International Journal for Numerical and Analytical Methods in Geomechanics, Vol. 34 (10), pp. 1009–1040, 2010.

Plesek, J., Feigenbaum, H.P., and Dafalias, Y.F., “Convexity of Yield Surface with Directional Distortional Hardening Rules”, J. Eng. Mechanics, ASCE, Vol. 136(4), pp. 477–484, 2010.

Feigenbaum, H.P, Dugdale, J., Dafalias, Y.F., Kourousis, K.I., and Plesek, J., “Multiaxial Ratcheting with Advanced Kinematic and Directional Distortional Hardening Rules”, Int. J. of Solids and Structures, Vol. 49, pp. 3063–3076, 2012.

Dafalias, Y.F., and Taiebat, M., “Anatomy of Rotational Hardening in Clay Plasticity”, Geotechnique, Vol. 63(16), pp. 1406–1418, DOI: 10.1680/geot.12.P.197, 2013.

Dafalias, Y.F., and Taiebat, M., “Rotational hardening with and without anisotropic fabric at critical state”, Geotechnique, Vol. 64, No.6, pp. 507–511, 2014.DOI: 10.1680/geot.13.T.035, 2014.

Feigenbaum H.P., and Dafalias, Y.F., “Directional Distortional Hardening at large plastic deformations”, Int. J. of Solids and Structures, Vol. 51, pp. 3904–3918, 2014.

Marek, R., Plesek, J., Hruby, Z., Parma, A., Feigenbaum, H.P., and Dafalias, Y.F., “Numerical implementation of a model with Directional Distortional Hardening”, J. of Eng. Mechanics, ASCE, Vol. 141(12), pp. 04015048-1-10 DOI: 10.1061/(ASCE)EM.1943-7889.0000954, 2015.

Dafalias, Y.F., “Must Critical State Theory Be Revisited to Include Fabric Effects?”, Acta Geotechnica, Vol. 11(3), pp. 479–491, DOI 10.1007/s11440-016-0441-0, 2016.

Welling C.A, Marek R., Feigenbaum H.P, Dafalias Y.F., Plesek J., Hruby Z., and Parma S., “Numerical Convergence in Simulations of Multiaxial Ratcheting with Directional Distortional Hardening”, International Journal of Solids and Structures (IJSS), vol. 127-127, pp. 105–121, 2017.

Parma S., Plesek, J., Marek R., Hruby Z., Feigenbaum H., and Dafalias, Y.F., “Calibration of a simple directional distortional hardening model for metal plasticity”, International Journal of Solids and Structures, Vol. 143, pp. 113–124, 2018.

Emmanouil Vairaktaris, Alexandros I. Theocharis, and Yannis F. Dafalias, “Correlation of fabric tensors for granular materials using 2D DEM”, Acta Geotechnica, Published online, DOI: 10.1007/s11440-018-0755-1, 2018.

Petalas A.L., Dafalias, Y.F., and Papadimitriou A.G., “SANISAND-FN: An evolving fabric-based sand model accounting for stress principal axes rotation”, Int. J. Num. Anal. Meth. Geomechanics, Vol. 43 (1), pp. 97–123, 2019.

Alexandros L. Petalas and Yannis F. Dafalias, “Implicit integration of incrementally non-linear, zero-elastic range, bounding surface plasticity”, Computers and Geotechnics, Vol. 112, pp. 386–402, 2019.

F. Dafalias, M. Taiebat, F. Rollo, and A. Amorosi, “On convergence of rotational hardening with bounds in clay plasticity”, Geotechnique Letters, Vol. 9, pp. 1–4, 2019.

Andres R. Barrero, Mahdi Taiebat, and Yannis F. Dafalias, “Modelling cyclic shearing of sands in the semifluidized state”, Int. J. Num. Anal. Meth. Geomechanics, Vol. 44, pp. 371–388, 2020.

Ehsan Badakhshan, Ali Noorzad, Abdelmalek Bouazza, and Yannis F. Dafalias, “Load recovery mechanism of arching within piled embankments using discrete element method and small-scale tests”, Powder Technology, Vol. 359, pp. 59–75, 2020.

Angelo Amorosi, Fabio Rollo and Yannis F. Dafalias, “Relating elastic and plastic fabric anisotropy of clays”, Geotechnique,, 2020.

Triantafyllos, P. K., Georgiannou, V.N., Pavlopoulou, E.M., Dafalias, Y.F. “Strength and and dilatancy of sand before and after stabilization with colloidal-silica gel”, Geotechnique,, 2021.

An Zhang, Yannis F. Dafalias, and Mingjing Jiang, “A bounding surface plasticity model for cemented sand under monotonic and cyclic loading”, Geotechnique,, 2021.

Rahman, M. M and Dafalias, Y. F., “Modelling undrained behavior of sand with fines and fabric anisotropy”, Acta Geotechnica,, 2021.

Chara Prassa, Sotiris Alevizos, Manolis Veveakis, and Yannis F. Dafalias, “The influence of anisotropy on compaction bands: The case of coaxiality between stress and fabric anisotropy tensors”, Int. J. Num. Anal. Meth. Geomechanics, Vol. 46(1), pp. 68–88, DOI: 10.1002/nag.3291, 2022.

Yannis F. Dafalias, “Split stress rate plasticity formulation”, International Journal of Solids and Structures, in press, 2022.


2023–2025GA23-05338SMechanical and structural properties of additively manufactured AlSi10Mg alloy with effect of powder recycling