Statistical features of magnetic noise in mixed-type impact fracture

Danku, Zsuzsa; Lenkey, Gy. B.; Kun, Ferenc

doi:10.1063/1.4908184

Cited by 4 publications

(7 citation statements)

References 15 publications

(46 reference statements)

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“…7 for different durations W for all dimensions considered. It can be observed that, except for D = 1, the shape of avalanches obtained is similar to the experimental findings [6,7]. For D = 1 the stress concentration is so high at the tip of growing broken clusters that all steps of the breaking sequence have a size ∆ s = 1, since a larger number of breaking fibers would trigger a catastrophic avalanche.…”

Section: Temporal Profile Of Avalanchessupporting

confidence: 84%

“…In order to keep the problem numerically tractable for the dimensions D = 1, 2, 3, 4, 5, 6, 7, 8 the lattice size was set to L = 4084101, 2021, 159, 45, 21,13,9,7, which ensures nearly the same number of fibers in all dimensions. To obtain reliable results statistical averaging was done over K = 5000 simulations.…”

Section: Local Load Sharing Fiber Bundle Model In 1 To 8 Dimensionsmentioning

confidence: 99%

“…These investigations provided symmetric parabolic profiles mainly attributed to long range elastic forces acting along the crack front [6]. Measurements of magnetic noise induced by the dynamic fracture of steal revealed similar pulse profiles, however, with a right handed asymmetry [7,16]. The front propagation was modeled as the driven motion of an elastic line in a disordered environment of pinning centers.…”

Section: Introductionmentioning

confidence: 99%

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Avalanche dynamics in higher-dimensional fiber bundle models

2018

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We investigate how the dimensionality of the embedding space affects the microscopic crackling dynamics and the macroscopic response of heterogeneous materials. Using a fiber bundle model with localized load sharing computer simulations are performed from 1 to 8 dimensions slowly increasing the external load up to failure. Analyzing the constitutive curve, fracture strength and avalanche statistics of bundles we demonstrate that a gradual crossover emerges from the universality class of localized behavior to the mean field class of fracture as the embedding dimension increases. The evolution between the two universality classes is described by an exponential functional form. Simulations revealed that the average temporal profile of crackling avalanches evolves with the dimensionality of the system from a strongly asymmetric shape to a symmetric parabola characteristic for localized stresses and homogeneous stress fields, respectively.

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Section: Temporal Profile Of Avalanchessupporting

confidence: 84%

Section: Local Load Sharing Fiber Bundle Model In 1 To 8 Dimensionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Avalanche dynamics in higher-dimensional fiber bundle models

2018

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“…The jerky magnetic signals are similar in shape to the classical (magnetic field induced) Barkhausen noise, but they have a different origin: they are initiated by the phase transformation between the two structures with different magnetization [6,9] or by the rearrangement of the martensite variant structure in the martensitic state [10]. This phenomenon is called magnetic Barkhausen noise [9] or denoted as "magnetization transition spectra" [6,7], but we prefer to name it simply magnetic emission (ME), expressing the similarity to acoustic emission (AE), which also can be evoked by phase transformation [11], plastic deformation [12,13], rearrangement of martensite variant structure [14], fracture [15], etc.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous investigation of thermal, acoustic, and magnetic emission during martensitic transformation in single-crystallineNi2MnGa

et al. 2016

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Simultaneous thermal, acoustic, and magnetic emission (AE and ME) measurements during thermally induced martensitic transformation in Ni 2 MnGa single crystals demonstrate that all three types of the above noises display many coincident peaks and the same start and finish temperatures. The amplitude and energy distribution functions for AE and ME avalanches satisfy power-law behavior, corresponding to the symmetry of the martensite. At zero external magnetic field asymmetry in the exponents was obtained: their value was larger for heating than for cooling. Application of constant, external magnetic fields (up to B = 722 mT) leads to the disappearance of the above asymmetry, due to the decrease of the multiplicity of the martensite variants. Time correlations (i.e., the existence of nonhomogeneous temporal processes) within AE as well as ME emission events are demonstrated by deviations from the uncorrelated behavior on probability distributions of waiting times as well as of a sequence of number of events. It is shown that the above functions collapse on universal master curves for cooling and heating as well as for AE and ME noises. The analysis of the existence of temporal correlations between AE and ME events revealed that at short times the acoustic signals show a time delay relative to the magnetic one, due to the time necessary for the propagation of the ultrasound. At intermediate times, as expected, the magnetic signal is delayed, i.e., the magnetic domain rearrangement followed the steps of structural transformation. At much longer times the deviation from an uncorrelated (Poisson-type) behavior is attributed to the nonhomogeneity of the avalanche statistics.

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“…However, both the time evolution and the final outcome of fracture processes also depend on how the load is applied on the specimen. For instance, in the usual Charpy impact test of dynamic fracture [30][31][32][33], the specimen is clamped at the ends and a hammer attached to the arm of a pendulum hits it in the middle resulting in a dynamic three point bending. Under such boundary and loading conditions, the damage localizes to a relatively thin layer of the specimen giving rise to a single growing crack.…”

Section: Introductionmentioning

confidence: 99%

Impact induced transition from damage to perforation

Batool,

Pál,

Kun

2020

Preprint

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We investigate the impact induced damage and fracture of a bar shaped specimen of heterogeneous materials focusing on how the system approaches perforation as the impact energy is gradually increased. A simple model is constructed which represents the bar as two rigid blocks coupled by a breakable interface with disordered local strength. The bar is clamped at the two ends and the fracture process is initiated by an impactor hitting the bar in the middle. Our calculations revealed that depending on the imparted energy, the system has two phases: at low impact energies the bar suffers damage but keeps its integrity, while at sufficiently high energies, complete perforation occurs. We demonstrate that the transition from damage to perforation occurs analogous to continuous phase transitions. Approaching the critical point from below, the intact fraction of the interface goes to zero, while the deformation rate of the bar diverges according to power laws as function of the distance from the critical energy. As the degree of disorder increases, further from the transition point the critical exponents agree with their zero disorder counterparts, however, close to the critical point a crossover occurs to a higher exponent.

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Statistical features of magnetic noise in mixed-type impact fracture

Cited by 4 publications

References 15 publications

Avalanche dynamics in higher-dimensional fiber bundle models

Avalanche dynamics in higher-dimensional fiber bundle models

Simultaneous investigation of thermal, acoustic, and magnetic emission during martensitic transformation in single-crystallineNi2MnGa

Impact induced transition from damage to perforation

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