Assistant Professor
Department of Physics
It is been over three decades now that statistical physicists started paying continual attention to the failure and breakdown properties of disordered materials. Primarily its importance lies in the extreme nature of the statistics, translating into safety and integrity issues for large as well as small structures. It also has the fascinating aspect of universality in its response statistics that opened up new applications of concepts of phase transition and criticality in this field [Phil. Trans. Royal Society A, vol 377, Issue 2136 (2018)]. One of the interesting questions in this regard is the forewarning of breakdown [Sci. Rep. vol 5, no 13259 (2015)]. Other than the nature of the acoustic signals [Phys. Rev. Lett. 73, 3423 (1994)] (Fig.1) emitted prior to a breakdown, even simply the duration of such signals is crucially important. It is well known that a higher disordered sample has more prior warnings of its imminent breakdown. A brittle material (like glass), on the other hand, will have an understandably shorter time window for such signals. The system size scaling, and the probability distribution functions of the failure times of disorder materials have been actively pursued questions.
During my Ph.D. (with Prof. Purusattam Ray) I have extensively explored statistical disordered systems, focusing on their rheological response under external stress and predict the nature of failure (brittle vs ductile), to eventually provide a warning of catastrophic events. Using methods such as Monte Carlo and Molecular Dynamics simulations, I was able to explain the mode of failure [Europhysics Letters, Volume 112, Number 2, pp 26004 (2015), Phys. Rev. E 96, 042142 (2017)] and spatial correlation of damage during crack propagation in a discrete or continuum media [Phys. Rev. E 91, 050105(R) (2015), Front. Phys. 9, 752086 (2021), Phys. Rev. E 105, 055003 (2022)]. We exposed the existence of two main parameters, (i) strength of disorder and (ii) stress release range, that control the dynamics and determine if the failure process is brittle or ductile as well as if it is nucleating or percolating [Phys. Rev. E 96, 063003 (2017), Physica A 569, 125782 (2021)] (Fig.2). Above two parameters has a significant role as the formal depends on material property like crystal defects, impurities, micro-crack, etc., while the latter is related to the span of fracture process zone and the stress concentration. These papers provided a through understanding of fracturing and failure at the microscopic scales.
We used the combination of computational and experimental techniques to develop a novel thermodynamic framework for flow through porous media [Front. Phys. 8, 4 (2020)] which is consistent with theoretical and experimental data of relative permeability [Transport in Porous Media 143, 69 (2022)], the main characteristic of flow in porous media used in the industry. This framework is highly relevant and thus highly useful for the upscaling process (Fig.7) that links pore-scale, Darcy scale and field scale to each other.
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