Yannis P Korkolis

Yannis P Korkolis

Associate Professor
Graduate Program Coordinator

Credentials

Ph.D. – Engineering Mechanics, The University of Texas at Austin, 2009
M.Sc. – Computational Mechanics, National Technical University of Athens, Greece, 2002
5-year Diploma – Mechanical Engineering, National Technical University of Athens, Greece, 1998

Prof. Korkolis joined the department in Fall 2009. He is trained as a mechanical engineer with emphasis on mechanical constructions and on manufacturing, while his graduate studies are in solid mechanics. He also has 2 years of industrial experience. His research aims at interfacing mechanics of materials, constitutive modeling and failure, using numerical methods and experimental techniques. It is motivated by – but not limited to – actual manufacturing problems, such as those encountered in sheet metal forming and tube hydroforming. He has worked on constitutive modeling of advanced aluminum alloys, formability and failure prediction, modeling of machining operations, tube hydroforming and microforming processes.

Prof. Korkolis is the recipient of a 2012 CAREER Award from the National Science Foundation (NSF). His research is further supported by grants from NSF, Office of Naval Research, Dept. of Commerce, Ford Motor Company and the Auto/Steel Partnership.  

Since 2015, Prof. Korkolis is an Associate Editor for the ASME Journal of Manufacturing Science and Engineering (JMSE). He served as a Guest Editor of a Special Issue of JMSE, on Forming and Joining of Lightweight and Multi-material Systems

Prof. Korkolis has taught ME 542 - Mechanical Dissection and Design Analysis, ME 643 – Machine Design, ME 795/895 - Materials Processing in Manufacturing, ME 777/877 - Computer-Aided Engineering, ME 927 - Theory of Plasticity and ME 795/995 - Experimental Mechanics while at UNH.

For more details, please take a look at Prof. Korkolis' C.V

Research Areas

Prof. Korkolis' areas of reasearch are the following:

  • Plasticity and constitutive modeling of materials.
  • Ductile fracture and formability. Instabilities and wrinkling.
  • Forming of light-weight materials (e.g., high rate forming processes, sheet metal forming, tube hydroforming).

His present research efforts are summarized below:

Area I: Mechanics of Materials Processing and Forming

  • Deformation and failure of solids under pulsed loads
  • Ductility enhancement by continuous-bending-under-tension
  • Deformation-induced heating
  • Isothermal tension testing
  • Degradation of elastic properties with plastic deformation, for springback analyses in sheet metal forming
  • Mircostructurally-informed constitutive modeling and mircoformability
  • Mircotube bursting and formability
  • Surface roughening with accumulated plastic deformation
  • Cruciform specimen testing adn optimal geometry
  • Cavitation erosion

Area II: Process Innocation

  • Tube hydroforming (THF) and pulsed THF
  • Pan forming and the effect of strain path on formability
  • Mircoplate and mircotube bending
  • Mircotube hydroforming
  • High-strain-rate deformation - electrohydraulic forming
  • Surface treatment by hypervelocity water droplets

Publications

M. Zecevic, Y.P. Korkolis, T. Kuwabara, M. Knezevic, “Dual-phase steel sheets under cyclic tension-compression to large strains: Experiments and crystal plasticity modeling” (submitted)

P. Knysh and Y.P. Korkolis, “Identification of the post-necking hardening response of rate- and temperature-dependent metals” (submitted)

O. Majidi, F. Barlat, M.-G. Lee, Y.P. Korkolis and J.W. Fu, “Thermal effects on the enhanced ductility in non-monotonic uniaxial tension of DP780” (submitted)

Y.P. Korkolis, N. Deng and T. Kuwabara, “On the non-linear unloading behavior of a biaxially loaded dual-phase steel sheet” (in preparation)

P. Knysh and Y.P. Korkolis, “The role of quasi-constant and evolving stress triaxialities on the ductile fracture of an austenitic stainless steel” (in preparation)

Y.P. Korkolis, B. Brownell, S. Coppieters and H. Tian, "Hole-expansion of anisotropic AA 6022-T4 sheets using a flat-headed punch", (in preparation)


H. Tian, B. Brownell, M. Baral and Y.P. Korkolis, "Earing in cup-drawing of anisotropic Al-6022-T4 sheets", International Journal of Materials Forming, (in press).

M. Zecevic, T.J. Roemer, M. Knezevic, Y.P. Korkolis and B.L. Kinsey, "Residual Ductility and Microstructural Evolution in Continuous-Bending-under-Tension of AA-6022-T4", Materials (Special Issue: Forming of Light Weight Materials), 9 (2016) 130.

H.Y. Gong, S. Wang, P. Knysh and Y.P. Korkolis, "Experimental investigation of the mechanical response of laser-welded dissimilar blanks from advanced- and ultra-high-strength steels", Materials & Design, 90 (2016) 1115-1123.

P.W. Ripley and Y.P. Korkolis, "Multiaxial Deformation Apparatus for Testing of Microtubes Under Combined Axial-Force and Internal-Pressure", Experimental Mechanics, 56 (2016) 273-286.

C.P. Dick and Y.P. Korkolis, "Anisotropy of thin-walled tubes by a new method of combined tension and shear loading", International Journal of Plasticity, 71 (2015) 87-112.

C.P. Nikhare, Y.P. Korkolis and B.L. Kinsey "Formability enhancement in titanium tube-flaring by manipulating the deformation path”, Journal of Manufacturing Science and Engineering-ASME, 137 (2015), 051006-1 to -9.

P. Knysh and Y.P. Korkolis, "Determination of the fraction of plastic work converted into heat in metals", Mechanics of Materials 86 (2015), 71-80.

N. Deng, T. Kuwabara and Y.P. Korkolis, “Cruciform specimen design and verification for constitutive identification of anisotropic sheets”, Experimental Mechanics 55 (2015), 1005-1022.

C.P. Dick and Y.P. Korkolis, “Strength and ductility evaluation of cold-welded seams in aluminum tubes extruded through porthole dies”, Materials & Design 67 (2015), 631-636.

M.G. Lee, Y.P. Korkolis and J.H. Kim, “Recent Developments in Hydroforming Technology”, Proceedings of Institution of Mechanical Engineers (UK) – Journal of Engineering Manufacture, 229 (2015) 572–596 – Opening/review article for the special issue on TubeHydro 2013 Conference.

M. Knezevic, M. Jahedi, Y.P. Korkolis and I.J. Beyerlein, “Material based design of the extrusion of bimetallic tubes”, Computational Materials Science 95 (2014), 63-73.

N.H. Moser, T.S. Gross and Y.P. Korkolis, “Martensite formation in conventional and isothermal tension of 304 austenitic stainless steel measured by x-ray diffraction”, Metallurgical and Materials Transactions - A 45 (2014), 4891-4896.

C.P. Dick and Y.P. Korkolis, “Mechanics and full-field deformation study of the ring hoop tension test”, International Journal of Solids and Structures, 51 (2014), 3042-3057.

J.F. Wilson, B.L. Kinsey and Y.P. Korkolis, “Development of a biaxial loading frame for sheet metal”, Journal of Manufacturing Processes–SME, 15 (2013), 580-585.

N. Deng and Y.P. Korkolis, “Numerical study of the lateral crushing and reinflation of stainless steel and aluminum tubes”, Journal of Manufacturing Processes – SME, 15 (2013), 242-255.

G.W. Cullen and Y.P. Korkolis, “Ductility of 304 stainless steel under pulsed uniaxial loading”, International Journal of Solids and Structures, 50 (2013), 1621-1633.

L. Wang, Y.P. Korkolis and B.L. Kinsey, “Investigation of strain gradients and magnitudes during microbending”, Journal of Manufacturing Science and Engineering-ASME, 134 (2012), 041011-1/-9.

Y.P. Korkolis and S. Kyriakides, “Hydroforming of anisotropic aluminum tubes. Part II: analysis”, International Journal of Mechanical Sciences, 53 (2011), 83-90.

Y.P. Korkolis and S. Kyriakides, “Hydroforming of anisotropic aluminum tubes. Part I: experiments”, International Journal of Mechanical Sciences, 53 (2011), 75-82.

T. Giagmouris, S. Kyriakides, Y.P. Korkolis and L.-H. Lee, “On the localization and failure in aluminum shells due to crushing-induced bending and tension”, International Journal of Solids and Structures, 47 (2010), 2680-2692.

Y.P. Korkolis, S. Kyriakides, T. Giagmouris and L.-H. Lee, “Constitutive modeling and rupture predictions of Al-6061-T6 tubes under biaxial loading paths”, Journal of Applied Mechanics-ASME, 77 (2010), 064501-1/-5.

Y.P. Korkolis and S. Kyriakides, “Path-dependent failure of inflated aluminum tubes”, International Journal of Plasticity, 25/11 (2009) 2059-2080.

Y.P. Korkolis and S. Kyriakides, “Inflation and burst of anisotropic aluminum tubes, part II: an advanced yield function including deformation-induced anisotropy”, International Journal of Plasticity, 24/9 (2008) 1625-1637.

Y.P. Korkolis and S. Kyriakides, “Inflation and burst of anisotropic aluminum tubes for hydroforming applications”, International Journal of Plasticity, 24/3 (2008) 509-543.

Yannis Korkolis
Kingsbury Hall W131
Phone: 
(603) 862-2772