Finite Element Modelling of Cracks as Acoustic Emission Sources

Sause, Markus G. R.; Richler, Stefan

doi:10.1007/s10921-015-0278-8

Cited by 66 publications

(68 citation statements)

References 18 publications

(28 reference statements)

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“…Furthermore, the approach followed in this article differs from prior analytical and computational approaches in the area of AE modeling (Hora et al, 2013;Sause and Richler, 2015;Uhnáková et al, 2010), primarily because it does not impose a damage source for the generation of the fracture-related stress waves. The geometry investigated is that of a Compact Tension (CT) specimen of an aluminum alloy (Al2024) with 6 mm thickness and subjected to Mode I loading, as shown in Fig.…”

Section: Computational Modelmentioning

confidence: 99%

Energy dissipation via acoustic emission in ductile crack initiation

et al. 2016

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This article presents a modeling approach to estimate the energy release due to ductile crack initiation in conjunction to the energy dissipation associated with the formation and propagation of transient stress waves typically referred to as Acoustic Emission. To achieve this goal, a ductile fracture problem is investigated computationally using the Finite Elements Method based on a compact tension geometry under Mode I loading conditions. To quantify the energy dissipation associated with Acoustic Emission, a crack increment is produced given a pre-determined notch size in a 3D cohesive-based extended finite element model. The computational modeling methodology consists of defining a damage initiation state from static simulations and linking such state to a dynamic formulation used to evaluate wave propagation and related energy redistribution effects.The model relies on a custom traction separation law constructed using full field deformation measurements obtained experimentally using the Digital Image Correlation method. The amount of energy release due to the investigated first crack increment is evaluated through three different approaches both for verification purposes and to produce an estimate of the portion of the energy that radiates away from the crack source in the form of transient waves. The results presented herein propose an upper bound for the energy dissipation associated to Acoustic Emission, which could assist the interpretation and implementation of relevant nondestructive evaluation methods and the further enrichment of the understanding of effects associated with fracture.

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Section: Computational Modelmentioning

confidence: 99%

Energy dissipation via acoustic emission in ductile crack initiation

et al. 2016

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“…Similar numerical analyses coupled with circuit models have been performed in related fields, e.g. for cracks as acoustic emission sources [32][33][34]. Such multiphysics models are also highly advantageous for improvements and optimisations of the sensor design.…”

Section: Eme Source Descriptionmentioning

confidence: 96%

“…Considering crack propagation velocities of the order of 10 3 m/s and crack lengths in the range of a few µm the crack propagation times are expected to be in the nanosecond range. In a more detailed approach Sause et al [32], combining AE measurements and FEM modelling of single fibre fracture, obtained a total crack duration of 1.2 ns for carbon fibres with comparable diameter. Therefore, an acquisition board with an appropriate bandwidth and sample rate is needed to measure these fast processes.…”

Section: Fibre Fracture Testsmentioning

confidence: 99%

Measurement and Study of Electromagnetic Emission Generated by Tensile Fracture of Polymers and Carbon Fibres

Gade

Sause

2016

J Nondestruct Eval

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Electromagnetic emission (EME) signals generated by tensile fracture of four different types of polymers and three different carbon fibre types are presented and discussed. A suitable set-up for the detection of the electric field component of EME generated by fracture of solids is proposed. Basic theoretical considerations are made about the coupling between these field components and the capacitive sensors used to directly measure the short ranged and low frequency (kHz-MHz) electric fields emitted by the generation of free surface charges and their spatial movement as dictated by the vibrational motion of the crack walls. Special focus is put on solids with low conductivity, where the influences of the material on the emitted fields is small and the detected electric signals almost solely depend on the source dynamics and the sensor characteristics. Analysis of the influence of the acquisition circuit is presented. The discussion of the electric signals emitted by tensile fracture of carbon fibres and polymer specimens comprises the influences of the material properties on the signals as well as correlations between the signals and the crack dynamics, including the crack propagation velocities.

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“…This is a level of detail that is typically not accounted for in modeling approaches used to describe crack formation by means of cohesive zone elements, extended finite element methods, or similar implementations. New source model description presented herein using dynamic changes of the source geometry based on fracture mechanics (c) (reprinted from [13])…”

Section: Ae Source Model Implementation For Fiber Reinforced Materialsmentioning

confidence: 99%

“…This is typically done by phenomenological observations [6], by comparative measurement of test specimens with known types of AE sources [7,8] or subsequent microscopy [9]. Recent advances also allow the forward prediction of the emitted AE signal of a specific source type by analytical methods [10] or finite element modeling (FEM) [11][12][13].…”

mentioning

confidence: 99%