An acoustic-emission characterization of the failure modes in polymer-composite materials

Giordano, M.; Calabrò, Antonio; Esposito, C.; D’Amore, Alberto; Nicolais, L.

doi:10.1016/s0266-3538(98)00013-x

Cited by 150 publications

(73 citation statements)

References 7 publications

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“…Here, source models are geometrically approximated as point sources, while the dynamic of the source is either approximated from iterative refinement of model parameters to fit experimental data or is based on assumptions on the source dynamics derived from structural mechanics. Various stepfunction descriptions exist, which are used to describe the 3-dimensional spatial displacement of the crack surface during crack formation [7][8][9][10][11]. In particular, the rise-time of the initial crack surface displacement is an essential parameter to model the crack surface motion [12].…”

Section: Introductionmentioning

confidence: 99%

“…Instead the rise-time is typically estimated based on the elastic properties of the bulk material. This type of source modeling has been successfully applied to many cases, and the basic concept has been used within the generalized theory of acoustic emission by Ono and Ohtsu [8,13], the work of Scruby [14] and numerous other analytical descriptions [7,9,15,16]. In recent years it has become convenient to use numerical methods to model acoustic emission sources.…”

Section: Introductionmentioning

confidence: 99%

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Finite Element Modelling of Cracks as Acoustic Emission Sources

Sause

Richler

2015

J Nondestruct Eval

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This paper presents results for a new acoustic emission crack source model based on a finite element modelling approach which calculates the dynamic displacement field during crack formation. The specimen modelled is statically loaded until conditions for crack growth as defined by a failure criterion are fulfilled. Subsequently, crack growth is modelled by local degradation of the material stiffness utilizing a cohesive zone element approach. The displacements due to crack growth generate the acoustic emission signal and allow detailed examination of the principles of acoustic emission sources operation. Subsequent to crack growth signal propagation is modeled. The signal propagation is modeled superimposed on the static displacement field. The presented model comprises a multi-scale and multi-physics approach to consider the signal propagation from source to sensor, the piezoelectric conversion of the elastic wave to an electric signal and the interaction to the acquisition electronics. Validation of the modeling approach is done by investigating the acoustic emission signals of micromechanical experiments. Using a specifically developed load stage, carbon fiber filament failure and matrix cracking can be prepared as model sources. A comparison of the experimental signals to the modeled signals shows good quantitative agreement in signal amplitude and frequency content. A comparison between the present modeling work and analytical theories demonstrates the substantial differences not considered in previous modeling work of acoustic emission sources.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finite Element Modelling of Cracks as Acoustic Emission Sources

Sause

Richler

2015

J Nondestruct Eval

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“…This technique has been widely used on carbon or glass/polyester composites [4][5], carbon or glass/epoxy composites [6][7][8] or polymer reinforced composites [9]. Moreover, some recent studies introduce AE technique to analyse the behaviour of natural fibre composites [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

Bonnafous

Touchard

Chocinski–Arnault

2010

EPJ Web of Conferences

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Abstract. This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.

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“…Microcracking of the matrix is often the first sign of internal damage. When failure is initiated, a part of the total strain energy is released as a wave that propagates from the failure site throughout the structure 35) . In the case of fiber-reinforced structures, as the crack propagates from one fiber to another, the microcracks and fiber breakages can absorb energy and thus decrease the energy of the final fracture.…”

Section: Discussionmentioning

confidence: 99%

Effect of fiber-reinforced composites on the failure load and failure mode of composite veneers

et al. 2009

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This study compared the initial and final failure loads and failure modes of indirect resin composite laminate veneers with and without fiber reinforcement. Forty intact lower canines received standard laminate preparations and were randomly assigned into four test groups (n=10). In Group 1, indirect resin composite veneers were repaired with two layers of preimpregnated bidirectional glass fiber weave and a restorative composite; in Group 2, with a layer of preimpregnated unidirectional glass fibers and a restorative composite; and in Group 3, with an experimental semi-IPN matrix composed of multidirectional short glass fibers. Indirect resin composite veneers without any fiber reinforcement were used as control (Group 4). All specimens were thermocycled and tested with a universal testing machine. On the final failure load, there were no statistically significant differences (p>0.05) among the test groups. Within each group, pairwise comparison of initial and final failure loads revealed statistically significant differences (p<0.05), except for Group 4 (p>0.05). On failure mode, unreinforced specimens showed instantaneous failure, whereas reinforced specimens mostly demonstrated elongated failure.

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An acoustic-emission characterization of the failure modes in polymer-composite materials

Cited by 150 publications

References 7 publications

Finite Element Modelling of Cracks as Acoustic Emission Sources

Finite Element Modelling of Cracks as Acoustic Emission Sources

Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

Effect of fiber-reinforced composites on the failure load and failure mode of composite veneers

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