ORALS

SESSION: ModellingMaterialsWedPM1-R6	Modelling, Materials & Processes Interdisciplinary symposium for sustainable development
Wed. 30 Nov. 2022 / Room: Andaman 1
Session Chairs: Elias Aifantis; Michael Zaiser; Session Monitor: TBA

14:00: [ModellingMaterialsWedPM105] OL Plenary
Newton / Hooke, Fick / Fourier, and Coulomb / Maxwell revisited
Elias Aifantis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 349 [Abstract]

The talk ventures to describe a high-risk proposal to extend classical laws of mechanics and physics by enhancing them with a Laplacian term accounting for nonlocality and underlying heterogeneity effects. The approach is motivated by a robust gradient model of the classical theory of elasticity which in the last two decades has been shown very useful in eliminating undesirable singularities and interpreting size effects. Implications to a variety of unsettled questions across scales and disciplines are outlined.

References:
E.C. Aifantis, Internal length gradient (ILG) material mechanics across scales & disciplines, Adv. Appl. Mech. 49, 1-110 (2016).
E.C. Aifantis, Gradient extension of classical material models: From nuclear & condensed matter scales to earth & cosmological scales, In: E. Ghavanloo, S.A. Fazelzadeh, F. Marotti de Sciarra (eds), Size-Dependent Continuum Mechanics Approaches. Springer Tracts in Mechanical Engineering, Springer, pp. 417-452 (2021).

SESSION: ModellingMaterialsWedPM1-R6	Modelling, Materials & Processes Interdisciplinary symposium for sustainable development
Wed. 30 Nov. 2022 / Room: Andaman 1
Session Chairs: Elias Aifantis; Michael Zaiser; Session Monitor: TBA

14:25: [ModellingMaterialsWedPM106] OL Plenary
Newton / Hooke, Fick / Fourier, and Coulomb / Maxwell revisited [K]
Elias Aifantis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 374 [Abstract]

The talk ventures to describe a high-risk proposal to extend classical laws of mechanics and physics by enhancing them with a Laplacian term accounting for nonlocality and underlying heterogeneity effects. The approach is motivated by a robust gradient model of the classical theory of elasticity which in the last two decades has been shown very useful in eliminating undesirable singularities and interpreting size effects. Implications to a variety of unsettled questions across scales and disciplines are outlined.

References:
E.C. Aifantis, Internal length gradient (ILG) material mechanics across scales &disciplines, Adv. Appl. Mech. 49, 1-110 (2016).
E.C. Aifantis, Gradient extension of classical material models: From nuclear & condensed matter scales to earth & cosmological scales, In: E. Ghavanloo, S.A. Fazelzadeh, F. Marotti de Sciarra (eds), Size-Dependent Continuum Mechanics Approaches. Springer Tracts in Mechanical Engineering, Springer, pp. 417-452 (2021).

SESSION: MultiscaleTuePM1-R8	Horstemeyer International Symposium (7th Intl. symp. on Multiscale Material Mechanics & Sustainable Applications)
Tue. 29 Nov. 2022 / Room: Similan 1
Session Chairs: Elias Aifantis; Lev Rapoport; Session Monitor: TBA

14:00: [MultiscaleTuePM105] OL
Gradient enhancing classical quantum mechanical and empirical interatomic potentials [K]
Elias Aifantis¹ ; Avraam Konstantinidis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 375 [Abstract]

A proposal is advanced for enhancing classical quantum mechanical and empirical potentials with a Laplacian term incorporating nonlocal effects. It is shown that this results to a “repulsive” branch, in addition to its classical “attractive” branch derived by rigorous quantum mechanical considerations. By properly choosing the gradient coefficient (or internal length) multiplying the Laplacian term, it is shown that the gradient-enhanced London potential recovers the structure of the empirical Lennard-Jones potential, and the same holds for the Stillinger-Weber potential. In the sequel, an attempt is made to address the role of such gradient enhancement for the case of Baskes embedded atom method (EAM) to determine whether or not the Laplacian term can account for non pair-wise interactions and angular/orientation effects. Finally, the role of bi-Laplacian and fractional/fractal effects is briefly discussed.

References:
K. Parisis, F. Shuang, P. Hu, A. Konstantinidis, A. Giannakoudakis and E.C. Aifantis, From gradient elasticity to gradient interatomic potentials: The case-study of gradient London potential, J. Appl. Math. Phys. 8, 1826-1837, 2020.
K. Parisis and E.C. Aifantis, Gradients, singularities and interatomic potentials, in: TMS 2021 150th Annual Meeting & Exhibition Supplementary Proceedings, pp. 793-800, 2021.
E.C. Aifantis, Gradient Extension of Classical Material Models: From Nuclear & Condensed Matter Scales to Earth & Cosmological Scales, Springer Tracts in Mechanical Engineering, pp. 417–452, 2021.

SESSION: MultiscaleTuePM2-R8	Horstemeyer International Symposium (7th Intl. symp. on Multiscale Material Mechanics & Sustainable Applications)
Tue. 29 Nov. 2022 / Room: Similan 1
Session Chairs: Bernhard Schrefler; Konstantinos Parisis; Session Monitor: TBA

16:45: [MultiscaleTuePM211] OS Keynote
Gradient enhancing classical quantum mechanical and empirical interatomic potentials
Konstantinos Parisis¹ ; Elias Aifantis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 300 [Abstract]

A proposal is advanced for enhancing classical quantum mechanical and empirical potentials with a Laplacian term incorporating nonlocal effects. It is shown that this results in a “repulsive” branch, in addition to its classical “attractive” branch derived by rigorous quantum mechanical considerations. By properly choosing the gradient coefficient (or internal length) multiplying the Laplacian term, it is shown that the gradient-enhanced London potential recovers the structure of the empirical Lennard-Jones potential, and the same holds for the Stillinger-Weber potential. In the sequel, an attempt is made to address the role of such gradient enhancement for the case of Baskes embedded atom method (EAM) to determine whether or not the Laplacian term can account for non pairwise interactions and angular/orientation effects. Finally, the role of bi-Laplacian and fractional/fractal effects is briefly discussed.

References:
K. Parisis, F. Shuang, P. Hu, A. Konstantinidis, A. Giannakoudakis and E.C. Aifantis, From gradient elasticity to gradient interatomic potentials: The case-study of gradient London potential, J. Appl. Math. Phys. 8, 1826-1837, 2020.
K. Parisis and E.C. Aifantis, Gradients, singularities and interatomic potentials, in: TMS 2021 150th Annual Meeting & Exhibition Supplementary Proceedings, pp. 793-800, 2021.
E.C. Aifantis, Gradient Extension of Classical Material Models: From Nuclear & Condensed Matter Scales to Earth & Cosmological Scales, Springer Tracts in Mechanical Engineering, , pp. 417–452, 2021.

SESSION: ModellingWedPM1-R8	Trovalusci International Symposium (17th Intl. Symp. on Multiscale & Multiphysics Modelling of 'Complex' Material (MMCM17) )
Wed. 30 Nov. 2022 / Room: Similan 1
Session Chairs: Sotos Generalis; Session Monitor: TBA

14:00: [ModellingWedPM105] OL Keynote
Combined Gradient – Stochastic Models for Composites [K]
Avraam Konstantinidis¹ ; Elias Aifantis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 376 [Abstract]

The deterministic internal length gradient (ILG) mechanics framework for elasticity and plasticity is extended to account for internal stress fluctuations due to stochastic effects associated with deformation-induced microstructures. Various existing approaches are first briefly reviewed and then an integrated discussion is provided. The role of probability density functions (PDFs) is examined in terms of existing experimental data. Emphasis is placed on Tsallis q-statistics and the related modification of classical PDFs (e.g. q-Gaussian, q-exponential). Then some example problems from the composites’ literature are discussed.

References:
E.C. Aifantis, Internal length gradient (ILG) material mechanics across scales &disciplines, Adv. Appl. Mech. 49, 1-110 (2016).
A.A. Konstantinidis, K.E. Aifantis and J.Th.M. De Hosson, Capturing the stochastic mechanical behavior of micro and nanopillars, Mater. Sci. Eng. A 597, 89-94 (2014).
A.A. Konstantindis, X. Zhang and E.C. Aifantis, On the combined gradient-stochastic plasticity model: Application to Mo-micropillar compression, AIP Conf. Proc. 1646, 3-9 (2015).
A.A. Konstantinidis and K.E. Aifantis, Capturing slip band formation in Ni3Al nanocubes during compression, Mater. Sci. Technol. 35, 571-576 (2019).