Gerassimos Spathis
Professor
Section of Mechanics
National Techical University of Athens
Date of Birth: 4/4/1949
Business Address: 5 Heroes of Polytechnion Av.,
Zografou Campus, Athens 15773, Greece, National Technical University of
Athens (NTUA), School of Applied Mathematical and Physical Sciences,
Section of Mechanics.
Education: 1975, PhD, under the title:
Renormalisation Group Fixed Points Near the Origin" University of
Sussex, England 1972, Diploma , Department of Physics, Athens
University (8 5/11)
Professional Carreer:
Present Position: 2005- Professor , Section of Mechanics, NTUA.
Previous positions: 1980-1982: Researcher at the Laboratory for TESTING MATERIALS NTUA.
1982-1985: Lecturer at the Section of
Mechanics, NTUA.
1985-1995, Assistant Professor, Section of Mechanics, NTUA.
1995-2005, Associate Professor, Section of
mechanics, NTUA
Research interests
Mechanics and Physics of polymers and polymeric composite materials, in
terms of theoretical and experimental analysis. Study of a variety of
polymeric systems, such as amorphous glassy polymers, semicrystalline,
vulcanized elastomers, fiber and particulate polymer composites.
Introduction of theoretical expressions which describe the elastic
modulus of polymer composites. Constitutive description of vulcanized
elastomers, (pure and reinforced with carbon black). Theoretical study
of nonlinear viscoelasticity (stress relaxation, creep, monotonic
loading). Experimental and theoretical study of plastic
behaviour (yield, strain softening, strain hardening, rate effect)
of amorphous glassy polymers.
Experimental and theoretical description of polymeric composites
(particulate, unidirectional fiber composites). Constitutive laws for
strain hardening.
Theoretical description of the rate of plastic deformation of the
polymeric structure. Free-volume distribution, statistical description
and its relation to the onset of yielding in the polymeric structure.
Participation in Research Projects: Coordinator / partner in international and national projects.
Publications: about 50 journal papers, about 30 presentations in national and international conferences. Chapter in book
Science Citation Index: About 400 references.
Teaching Activities:
1980 - Now: Mechanics of Deformable
Body, Linear Viscoelasticity, Introduction to Plasticity, Mechanics and
Physics of Polymers and Polymeric Composites (undergraduate
level), Materials science, Nonlinear Viscoelasticity,
Anelastic Behaviour of Materials (postgraduate level).
Administration activities:
-
Head of the Department of the Section of Mechanics: 1998-2000
- Dean of the School of Applied Mathematical and Physical Sciences: 2000-2006
- Vice Rector of the National Technical University of Athens: 2006-2010
LIST OF PUBLICATIONS
1. G.Spathis, "Z Boson Effects in Electron-Positron Scattering at EPIC Energies at 14 Gev", Nuclear Physics B87, p.351, 1975.
2. D.Bailin, A.Love and G.D.Spathis, Renormalization group fixed points in Yukawa theories, Nuclear Physics B 93, p.165, 1975.
3. D.Bailin, A.Love and G.D.Spathis, "Nonleptonic Decays in
Asymptotically nearly-free Theories", Nuclear Physics B 3 ), p.865,
1977.
4. G.C.Papanicolaou, P.S.Theocaris and G.D.Spathis, "Adhesion
Efficiency Between Phases in Fibre-Reinforced Polymers by Means of the
Concept of Boundary Interphase", Colloid and Polymer Sci. Vol.258, p.
12' ) 1, 1980.
5. P.S.Theocaris, G.C.Papanicolaou and G.D.Spathis, "Physical Model for
the Thermal Expansion Behaviour of Fibre-Reinforced Viscoelastic
Composites", Fibre Science and Technology, Vol. 15, p.187, 1981.
6. G.D.Spathis, E.P.Sideridis and P.S.Theocaris, "Adhesion Efficiency
and Volume Fraction of the Boundary Interphase in Metal-Filled
Epoxies", Int.J.Adhesion and Adhesives, Vol. I , p. 195, 1981.
7. P.S.Theocaris, G.Spathis and E.Sideridis, Elastic and viscoelastic
properties of fibre-reinforced composite materials, Fibre Science and
Technology, Vol. 17, p.169, 1981.
8. P.S.Theocaris and G.Spathis, "Glass-Transition Behaviour of Particle
Composites Modelled on the Concept of Interphase", Jnl.of Applied
Polymer Sci., Vol. 27, 1982.
9. P.S.Theocaris, G.Spathis and V. Kefalas, "The Adhesion Coefficient
of Fiber-Reinforced Polymers Evaluated by Dynamic Measurements",
Colloid and Polymer Science, Vol.260, 1982.
10. P.S.Theocaris,V.Kefalas and G.Spathis, "Retardation Spectra for the
Existence of Interphase in Fiber Composites", Jnl. of Applied Polym.
Sci., Vol.28, p.3641, 1983.
11. G.Spathis,B.Kefalas and P.S.Theocaris "The loss Tangent Behaviour
at the interphase of fiber compsites" Interrelations between Processing
Structure and Properties of Polymeric Materilas, edited by J.C.Seferis
and P.S.Theocaris 1984.
12. G.Spathis, E.Kontou and P.S.Theocaris, 'Dynamic Mechanical
Properties of an Iron-epoxy Particulate Composite", Journal of
Rheology, Vol. 28(2), p.161, 1984.
13. G.Spathis, E.Kontou and P.S.Theocaris, "Network Structure of
Plasticized Epoxy Resins by Dynamic Measurements", Rheologica Acta,
Vol.24, p.63, 1985.
14. E.Kontou, G.Spathis and P.S.Theocaris, "The Heterogeneity of the
Network Structure of Epoxy Polymers Studied by Dynamic and DSc-Tests",
Journal of Polymer Science,Vo. 23, p.1493, 1985.
15. J.Milios and G.Spathis, Dynamic behaviour of two-phase viscoelastic
materials, Composites Science and Technology, Vol.25, p.301, 1986.
16. G.Spathis, E.Kontou and P.S.Theocaris, "Network Characterization of
a Polyfunctional Crosslinked System", Journal of Macromolecular
Science-Physics, B26(4), P.509, 1987.
17. G.Spathis, E.Kontou and P.S.Theocaris, "Structural Changes in
Glassy Polymers Studied by Thermal Analysis and Dynamic Mechanical
Tests", Journal of Polymer Science, part A 25, p.1285, 1987.
18. J.Milios and G.Spathis, "Dynamic Interaction of a Propagating Crack
with a Hole Boundary", Acta Mechanics, Vol.72, p.283, 1988.
19. P.S.Theocaris, V.Kefalas and G.Spathis, "Evaluation of Interfacial
Grafting Between Matrix and Gel Inclusions in High Impact
Polystyrene",Journal of Reinforced Plastics and Composites, Vol.7,
p.66, 1988.
20. J.Milios, V.Kefalas, E.Sideridis and G.Spathis, “Dynamic Properties
of Epoxy Resins” Handbook of Ceramics and Composites, Vol.1, p.137,
Marcel Dekker Inc.1989
21. Kontou and G.Spathis, "Elastic Behaviour of Natural Rubber Filled
Vulcanizates", Journal of Applied Polymer Sci., Vol.39, p.649-654, 1990.
22. G.Spathis, E.Kontou and V.KefalasL.Apekis, C.Christodoulides and
P.Pissis M.011ivon and S.Quinquenet" Relaxation Phenomena and
Morphology of Polyurethane Block Copolymers", Journal of Macromolecular
Science-Physics, B29(1), p.31-48, 1990.
23. E.Kontou, G.Spathis, M.Niaounakis and V.Kefalas, "Physical and
Chemical Crosslinking Effects in Polyurethane Elastomers", Colloid and
Polymer Science, Vol.268, p.66, 1990.
24. G.Spathis, "Polyurethane Elastomers Studied by the Mooney-Rivlin
Equation for Rubbers", Jnl.Applied Polym. Sci., Vol.43, p.613-620, 1991.
25. G.Spathis, E.Kontou and A.Saklabani, "The Effect of Accelerator on
the Crosslink-Density and Mechanical Behaviour of an SBR-Filled
Elastomer", Jnl. of Reinforced Plastics and Composites, Vol. 10(4),
p.391-399, 1991.
26. G.Spathis, E.Kontou and G.Bourkas, "A New Equation of the
Relaxation Process in the Nonequilibrium State: Application to Creep
and Dynamic Hxperiments in Epoxy Resins", The Society of Rheology,
Vol.3 5(8),,p. 148 1 - 1497, 1991.
27. L.Apekis, P.Pissis, C.Chiistodoulides, G.Spathis, M.Niaounakis,
E.Kontou, E.Schlosser, A.Schonals and H.Goering, "Physical and Chemical
Network Effects in Polyurethane Elastomers", Colloid and Polymer
Science, Vol.90,p.144-150, 1992.
28. G.Spathis, Relaxation behaviour in the transition region of glassy systems, Polymer, Vol. 35(4), p.791-795, 1994.
29. G.Spathis, M.Niaounakis, E.Kontou, L.Apekis, P.Pissis and
C.Christodoulides, Morphological Changes in Segmented Polyurethane
Elastomers by Varying the NCO/OH Ratio", Jnl. Applied Polym.Sci.,
Vol.54, p.831-842, 1-842, 1994.
30. G.Spathis, Non-Gaussian stress-strain constitutive equation for crosslinked elastomers, Polymer,Vol. 36(2),p.309, 1995.
31. G.Spathis and E.Kontou, "Viscoelastic Response of Elastomers in
Large Deformations", Polymer Gels and Networks, Vol.3,p.209-220, 1995.
32. E.Kontou, G.Spathis and C.Kavadias, "Viscoplastic Behaviour of PMMA
blends - The Effect of Moisture Absorption", Jnl. of Reinforced
Plastics and Composites, vol 16(4),p.306, 1997.
33. G. Spathis and C.Maggana, A non-linear viscoelastic model for
predicting the yield stress of amorphous polymers, Polymer, 38,
pp.2371-2377, (1997).
34. G.Spathis, "Theory for the plastic deformation of glassy polymers", Jnl. of Materials Science, 32, pp. 194' )- 1950 (1997).
35. G.Spathis Non-linear constitutive equations for viscoelastic
behaviour of elastomers at large deformations Polymer Gels and
Networks, 5,(1997) 55-68.
36. G.Spathis and E.Kontou, Experimental and theoretical description of
the plastic behaviour of semicrystalline polymers,Polymer, Vol.39,
Nr(1),pp 135-142,(1998).
37. E.Kontou and G.Spathis "Structural Rearrangements During Yielding
of Glassy Polymers" Polymer Engineering and Science, vol. 38(9),
p.1443-1449,(1998).
38. G.Spathis and E.Kontou "An Experimental and Analytical Study of the
Large Strain Response of Glassy Polymers With a Non-Contact
Laserextensometer",Journal of Applied Polymer Science, vol.71, p.2007,
(1999)
39. M. Blanas, E.Kontou and G.Spathis "A Mechanical Model for the
Prediction of the Elastic properties of Polymeric Resins Reinforced
With Liduid Crystal Polymers"Journal of Reinforced Plastics and
Composites, vol. I 8(5),p.3 90-412 (1999).
40. P. Farasoglou, E.Kontou and G. Spathis,J.L.Gomez-Ribelles,and
G.Gallego Ferrer "Processing Conditions and Compatibilizing effects on
reinforcement of Polypropylene Liquid Crystalline polymer
blends",Polymer Composites, Polymer Composites, vol.21 (1), p.84-95,
2000.
41. G.Spathis,G.Bourkas,V.Kytopoulos and E.Sideridis `Elastic Modulus
of Particulate Composites using a Multiphase Model' Jnl of Reinforced
Plastics and Composites, vol. 1 9(l 1),p.883-910, (2000).
42. G.Spathis and E.Kontou Mechanism of Plastic Deformation for
Polycarbonate under Compression by a Laserextensometer Technique'Jnl of
Applied Polymer Science,vol.79,p.2534-2542, (2000)
43. G.Spathis and E.Kontou `Non-Linear Viscoelastic and Viscoplastic
Response of Glassy Polymers' Polymer Engineering and Science ,
vol.41(8), p. 1337, 2001.
44. E.Kontou, M.Niaounakis and G.Spathis Thermomechanical behavior of
metallocene ethylene-α-olefin copolymers, European Polymer Journal,
38(2002) 8(2002) 2477-2487
45. E.Kontou and G.Spathis, "Interrelation between Long Term
Viscoelasticity and Viscoplastic Response of Semicrystalline Polymers"
,accepted for in press, J.Applied Polymer Science (2003)
46. G. Spathis and E.Kontou Non-linear viscoplastic behavior of fiber
reinforced polymer composites, Journal of Composites Science and
Technology 64, 2333-2340, (2004).
47. G.Spathis and E.Kontou A non-linear Viscoelastic Model for the
Prediction of Double Yielding in a LLDPE film" J. Appl. Pol. Sci, in
press (2004).
48. E.Kontou, G.Spathis, Application of finite strain viscoplasticity
to polymeric fiber composites, International Journal of Plasticity,
Vol. 22, p. 1287-1303, (2006).
49. Pandermarakis, Z.G., Spathis, G., Tsamasphyros,G., Constructing a
modulus map for linear elastic composites: The case of rigid
reinforcements ‘Polymer Composites Vol.28, pp. 593-604 (2007).
http://onlinelibrary.wiley.com/doi/10.1002/pc.20271/abstract
50. G. Spathis, E. Kontou, “Modeling of non-linear viscoelasticity at
large deformations”, J. Mater. Sci., vo 43(6), p.2046-2052,
(2008). http://www.springerlink.com/content/6uw7675u15625w31/
51. G,Spathis, E.Kontou, Strain inhomogeneity effect on yielding of polymer nanocomposites, Polymer, vol.49,p. 4462-4468 (2008).
CONFERENCES
1. V.Kefalas, G.Spathis and E.Kontou, “Dynamic
Mechanical Analysis of High Impact Polystyrene”, Proc.Comp. 86,
Engineering Applications of New Composites, The University of Patras
25-29 August 1986, Patras Greece, Omega Scientific,
England (1988).
2. L.Apekis, P.Pissis and C.Christodoulides,
G.Spathis, E.Kontou and V.Kefalas, “Dielectric Properties of
Polyurethane Block Copolymers”, Proceedings of the
6th International Symposium on Electrets, Oxford, England, (1988).
3. L.Apekis, C.Christodoulides, P.Pissis, G.Spathis,
E.Kontou and V.Kefalas, “Dielectric Study of Polyurethane Block
Copolymers”,
4. E.Kontou, G.Spathis, V.Kefalas, L.Apekis,
C.Christodoulides and P.Pissis,“Structure-Property Interrelation in
Thermoplastic Polyurethanes”, Comp 88, Phase Interaction in Composite
Materials, Second International Symposium, Patras
Greece, August (1988).
5. L.Apekis, C.Christodoulides, P.Pissis, G.Spathis,
E.Kontou and V.kefalas, “Thermally Stimulated Depolarization Current
Measurements in Polyurethane Block Copolymers”,
Sixth International Seminar on Polymer Physics,
Gomodingen (W.Germany) October (1988).
6. L.Apekis, C.Christodoulides, P.Pissis, G.Spathis,
E.Kontou,V.Kefalas, ‘ Study of glass transition of polymers by
dielectric and thermomechanical methods’ Hellenic Conference of Solid
State Physics, Xanthi, September 1989.
7. L.Apekis, P.Pissis, C.Christodoulides, G.Spathis, E.Kontou,
V.Kefalas, M.Niaounakis‘Study of the structure-properties relationship
by dielectric and thermomechanical methods’ Conference on new advanced
technology materials in Greece, Athens, December 1989.
8. G.Spathis and E.Kontou, Viscoelastic response of elastomers in large
deformations, 2nd International Discussion Meeting on Relaxation in
Complex Systems, 28 June-8 July, Alicante Spain, (1993).
9. E.Kontou, G.Spathis, F.Romero Colomer, M.Lopez Torres and J.L.Gomez
Ribelles, “Thermomechanical Behaviour of
Polypropylene-Liquid Crystalline Blends”, J.MED.CAT ‘97, Universitat de
les Illes Balears, June 24-27, (1997).
10. C.Maggana, G.Spathis, E.Kontou and P.Pissis,“Water Effect to the
a-Relaxation Process of Epoxy Resin Systems ”Proceedings of the
5th European Conference on Advanced Materials and Processes and
Applications, Materials, Functionality and Design,Edited by L.A.J.L.
Sarton and H.B. Zeedijk, Maastricht-NL, 21-23 April 1997.
11. M.Lopez, F.Romero, J.L.Gomez, M.Monleon, E.Kontou, G.Spathis,
P.Farasoglou, P.Pissis and A.Kiritsys, “Morphology and Mechanical
Properties of Blends of Polypropylene and a Main Chain Liquid Crystal
Polymer”,International Symposium on Polymeric Materials, Terrassa, 8-10
September 1997, Spain
12 Ε.Κontou and G.Spathis ‘Theoretical and Experimental Investigation
of non-linear viscoelastic and viscoplastic response of amorphous
polymers’3nd International Meeting of the Hellenic Society of Rheology
, Patras,Greece , June 10-14 ,(2001).
13. E.Kontou,M.Niaounakis,G.Spathis Thermomechanical Behavior and
Morphology of Metallocene Ethylene –a- olefin Copolymers’ 4th
International Discussion Meeting on Relaxation in Complex
Systems, 17-23 June, Crete, (2001).
14. G.Spathis, E.Kontou, “ Strain Localization Effect on Yielding of G;assy Polymers” ICSAM-2007, September 2007, Patras