ORALS

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: 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).

SESSION: GeomechanicsWedPM1-R9	2nd Intl Symp on Geomechanics & Applications for Sustainable Development
Wed. 30 Nov. 2022 / Room: Similan 2
Session Chairs: Stephane Bordas; Avraam Konstantinidis; Session Monitor: TBA

14:50: [GeomechanicsWedPM107] OL Keynote
Studying the statistics of landslide phenomena for mitigating their impact
Avraam Konstantinidis¹ ; ¹Aristotle University of Thessaloniki, Thessaloniki, Greece;
Paper Id: 305 [Abstract]

A statistical study of precursor activity in rain- as well as earthquake-induced landslides by means of spring block models enhanced with displacement gradients and stochasticity is performed. This way, a robust 2D model can be formulated for studying triggered landslides. A cellular automaton is utilized, in order to examine the dynamic behavior and the stability of rock/soil slopes due to neighboring heavy rainfall or earthquake activity. The type and nature of the failure plane, as well as the triggering mechanism is studied. Moreover, the different dynamic evolution modes of the slope can be mapped to specific shape parameters of the corresponding distributions of the incremental displacements. These parameters are calibrated through comparison with statistical data on landslides events available in the literature. The calibrated model can then be used as a means for understanding, predicting and mitigating the impact of catastrophic landslides and its theoretical predictions are compared with the respective predictions of alternative techniques for studying slope stability.