Spatial correlation and temporal evolution of plastic heterogeneity in sheared granular materials

Ma, Gang; Zou, Yuxiong; Chen, Yuan; Tang, Longwen; Ng, Tang‐Tat; Zhou, Wei

doi:10.1016/j.powtec.2020.09.053

Cited by 29 publications

(7 citation statements)

References 61 publications

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“…According to amorphous plasticity, the serrated flow is attributed to the localized plastic zones undergoing irreversible rearrangements and their long‐range interactions through elasticity (Denisov et al, 2016; Leishangthem et al, 2017; Ma et al, 2021; Niiyama et al, 2019). The most significant drops often result from the localized plastic zones that would span the entire system.…”

Section: Resultsmentioning

confidence: 99%

Size Polydispersity Tunes Slip Avalanches of Granular Gouge

Zou

Gao

et al. 2020

Geophysical Research Letters

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Granular materials have frequently been used as representations of natural fault gouges. Although they can reproduce proper avalanche behaviors, the universality of the scaling exponent of avalanche size remains debatable. As a core issue in both amorphous plasticity and geophysics, avalanche universality may help reconcile the avalanche behaviors of earthquake and granular materials into the same universality class. We examine numerically the signatures of stress avalanches emerging from quasi-static shear of granular materials with different size polydispersity. A persistent serrated plastic flow phenomenon is observed in our models with varying polydispersity. The stress drop is well defined by a truncated power law distribution P(s)~s −τ exp(−s/s max). The exponent τ and cutoff stress drop s max show a clear dependence on polydispersity, which reflects a tuned criticality. We further calculate the effective temperature from the statistics of energy fluctuations. The effective temperature volatility can be used to explain the tuned critical behaviors of granular gouge. Plain Language Summary Granular materials are ubiquitous in nature and important to a wide range of industrial processes. When driven at slow rates, granular materials deform via intermittent dynamics which alternates slow elastic loading with rapid slips. Such serrated behaviors have attracted attentions from researchers in material science, process engineering and powder technology. They have aroused great interest for geoscientists since key clues may be offered for the origin of earthquake physics. The avalanche-like slip events of granular materials reveal a strong statistical similarity with earthquakes, having made granular materials widely adopted as an ideal laboratory model material for the study of earthquake physics. Different granular systems subjected to different loading conditions present similar scaling laws, such as the power law distributions of event size. However, the scaling exponents describing avalanche distributions vary greatly in range, posing challenges to the existence of universal scaling across diverse granular systems. In this study, we examined granular systems with varying size polydispersity from monosized spheres to highly polydisperse packings and found the signature of tunable avalanche statistics. We further use size polydispersity as a control parameter to generate continuously adjustable avalanche statistics.

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Section: Resultsmentioning

confidence: 99%

Size Polydispersity Tunes Slip Avalanches of Granular Gouge

Zou

Gao

et al. 2020

Geophysical Research Letters

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“…The corresponding DEM simulations comfirmed that the microslip event rate correlates well with large slip event onset (Ferdowsi et al, 2013). Microslip or local avalanche is essentially a result of the localized particle rearrangements (Ma et al, 2021). Due to the disordered structure of granular materials, a microslip may trigger nearby microslips, and the accumulation of these microslips may give rise to a global stress avalanche (Castellanos & Zaiser, 2018;Cao et al, 2019).…”

Section: Introductionmentioning

confidence: 68%

“…The microslips that occurred during the recharge and drop events are manifested as irreversible particle rearrangements which are hereby quantified by the nonaffine particle displacements 2 min D (see Text S1) (Ma et al, 2021). It should be noted that many other quantities, such as local displacement, local energy fluctuation (Barés et al, 2017;Zheng et al, 2018), granular temperature (Ma et al, 2018(Ma et al, , 2019, local acoustic emission (Trugman et al, 2020), force chain bulking (Gao et al, 2019;Liu et al, 2020) can also be used for characterizing microslips.…”

Section: Statistical and Spatial Characteristics Of Microslipsmentioning

confidence: 99%

“…The spatial distributions of microslips that occurred during the recharge and drop stage can be further quantified using the normalized spatial correlation function (see Text S2) (Ma et al, 2019(Ma et al, , 2021. We group the recharge and drop events according to the magnitude and sign of stress fluctuation.…”

Section: Statistical and Spatial Characteristics Of Microslipsmentioning

confidence: 99%

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Machine learning bridges microslips and slip avalanches of sheared granular gouges

Mei

Gao

et al. 2022

Earth and Planetary Science Letters

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“…上述物理试验大都采用声发射技术探测体系内出现的微滑事件, 并用声发射信号的强度表征微滑事件的大小, 但现有的声发射技术难以将微滑事件定位到颗粒级别. Ma 等 [36] 采用连续-离散耦合分析方法进行了如图 1 所示的颗粒断层泥数值剪切试验, 采采用空间相关性函数来刻画塑性行为的空间相关性 [37] : 与热系统相比, 颗粒物质内微滑事件的成因要复杂的多 [36] 。如图 4 所示, 在小应变间隔下, 微滑事件大多发生在应力波动较大的颗粒及其附近, 也即力链屈曲失稳和断裂失效是微滑事件的主要原因; 在较大应变间隔时, 微滑事件与结构熵变化之间存在较强的相关性, 表明较大应变间隔时体系具有明显的自由体积重分布 [38] . 自由体积的重分布导致多余自由体积的变化, 并通过已激活塑性区附近的局部屈服进一步促进应变局部化, 从而产生更大的微滑事件.…”

Section: 基于微观动力学的粘滑运动机制解释unclassified