Universal mechanical instabilities in the energy landscape of amorphous solids: Evidence from athermal quasistatic expansion

Dattani, Umang A.; Karmakar, Smarajit; Chaudhuri, Pinaki

doi:10.1103/physreve.106.055004

Cited by 6 publications

(4 citation statements)

References 45 publications

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“…The solid at T = 0.01 is quenched to T = 0 by conjugate gradient energy minimization. The solid is then subjected to athemal quasistatic expansion (AQE) [24,26,29] where, in each step, a constant volume strain is applied on the system by rescaling the length of the box by a factor (1 + ) along with affine transformation of particle coordinates, followed by minimization of the energy of this strained configuration using the conjugate gradient algorithm. We used = 5 × 10 −5 .…”

Section: Athermal Quasistatic Expansion (Aqe)mentioning

confidence: 99%

“…Not much has been explored in the context of cavitation in such materials under uniform expansion or uniaxial deformation process. There are a handful of numerical studies that recently focused on understanding the microscopic mechanisms of how cavitation occurs during volumetric strain [22][23][24][25], wherein the emergence of the cavities has been demonstrated as a yielding process [26]. In fact, it has been shown [26] that cavitation instability under uniform volumetric expansion in a athermal quasistatic limit is a saddle-node bifurcation in the potential energy landscape where a stable minimum becomes unstable by merging with the nearest saddle during the expansion process.…”

Section: Introductionmentioning

confidence: 99%

“…There are a handful of numerical studies that recently focused on understanding the microscopic mechanisms of how cavitation occurs during volumetric strain [22][23][24][25], wherein the emergence of the cavities has been demonstrated as a yielding process [26]. In fact, it has been shown [26] that cavitation instability under uniform volumetric expansion in a athermal quasistatic limit is a saddle-node bifurcation in the potential energy landscape where a stable minimum becomes unstable by merging with the nearest saddle during the expansion process. Such a process manifests itself via vanishing of an eigenvalue of an appropriate dynamical matrix (Hessian matrix) of the energy function.…”

Section: Introductionmentioning

confidence: 99%

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Cavitation instabilities in amorphous solids via secondary mechanical perturbations

Dattani¹,

Sharma²,

Karmakar³

et al. 2023

Preprint

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Amorphous solids are known to fail catastrophically and in some situations, nano-scaled cavities are believed to play a significant role in the failure. In a recent work, using numerical simulations, we have shown the correspondence between cavitation under uniform expansion of amorphous solids and the yielding under shear. In this study, we probe the stability of spatially-homogeneous states sampled from expansion trajectories to alternate modes of driving, viz. macroscopic cyclic shear or local random deformation via activity. We find that, under cyclic shear and activity, the cavitation instabilities can occur in expanded states at much higher densities than under pure uniform-expansion, and the shift in density is determined by the magnitude of the secondary deformation. We also show that barriers to cavitation on the energy landscape are much smaller for cyclic-shear and activity than seen under expansion. Further, we also analyse the spatial manifestation of cavitation and investigate whether large scale irreversible plasticity can set in due to the combination of expansion and the secondary deformation. Overall, our study reveals the interplay between expansion and other deformation modes leading to cavitation instabilities and the existence of abundant relaxation pathways for such processes.

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Section: Athermal Quasistatic Expansion (Aqe)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cavitation instabilities in amorphous solids via secondary mechanical perturbations

Dattani¹,

Sharma²,

Karmakar³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…It could also be thought of as a stand-alone method for annealing, alongside techniques like Physical Vapour Deposition (PVD) [26], swap Monte Carlo [27], in-silico vapour deposition [28], and, of course, annealing via oscillatory shearing [29][30][31]. We previously alluded to these annealing effects of activity in our work dealing with the formation of cavities in glasses [32].…”

Section: Introductionmentioning

confidence: 99%

Activity-Induced Annealing leads to Ductile-to-Brittle Transition in Amorphous Solids

Karmakar,

Sharma

2024

Preprint

Self Cite

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Active glasses are dense and disordered systems consisting of motile particles, capturing the phenomenology observed in many biological systems. We investigate motility-driven annealing and fluidization in these systems, offering new perspectives on cellular ageing and maturation. Our study establishes a correspondence between the yielding behavior of glassy systems under active dynamics and their yielding under oscillatory shear, revealing strikingly similar phase diagrams with areas of annealing and fluidization. The yielded region of the phase diagram may correlate with tissue fluidization, while the annealing region may explain age-related maturation and stiffening. This suggests that some mechanical changes observed in ageing tissues may partially stem from processes analogous to enhanced ageing observed in active glasses. Furthermore, by studying the mechanical response to tension in such systems, we establish that the degree of annealing alone cannot elicit a brittle response; the sample's geometry, particularly its ability to accommodate a shear band, is crucial. Thus, one must consider the embedding geometry for a complete picture of yielding and mechanical response in biological matter. Additionally, we explore the interplay between imposed and internal time scales in active glasses, shedding light on their complex mechanical responses.

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Athermal quasistatic cavitation in amorphous solids: Effect of random pinning

Dattani,

Karmakar,

Chaudhuri

2023

The Journal of Chemical Physics

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Amorphous solids are known to fail catastrophically via fracture, and cavitation at nano-metric scales is known to play a significant role in such a failure process. Micro-alloying via inclusions is often used as a means to increase the fracture toughness of amorphous solids. Modeling such inclusions as randomly pinned particles that only move affinely and do not participate in plastic relaxations, we study how the pinning influences the process of cavitation-driven fracture in an amorphous solid. Using extensive numerical simulations and probing in the athermal quasistatic limit, we show that just by pinning a very small fraction of particles, the tensile strength is increased, and also the cavitation is delayed. Furthermore, the cavitation that is expected to be spatially heterogeneous becomes spatially homogeneous by forming a large number of small cavities instead of a dominant cavity. The observed behavior is rationalized in terms of screening of plastic activity via the pinning centers, characterized by a screening length extracted from the plastic-eigenmodes.

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Universal mechanical instabilities in the energy landscape of amorphous solids: Evidence from athermal quasistatic expansion

Cited by 6 publications

References 45 publications

Cavitation instabilities in amorphous solids via secondary mechanical perturbations

Cavitation instabilities in amorphous solids via secondary mechanical perturbations

Activity-Induced Annealing leads to Ductile-to-Brittle Transition in Amorphous Solids

Athermal quasistatic cavitation in amorphous solids: Effect of random pinning

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