Synchrotron radiation computed tomography for experimental validation of a tensile strength model for unidirectional fibre-reinforced composites

Swolfs, Yentl; Morton, H.; Scott, A.E.; Gorbatikh, Larissa; Reed, P.A.S.; Sinclair, Ian; Spearing, S. Mark; Verpoest, Ignace

doi:10.1016/j.compositesa.2015.06.018

Cited by 98 publications

(159 citation statements)

References 63 publications

Supporting

Mentioning

144

Contrasting

Order By: Relevance

“…The results showed a progressively increasing rate of fibre fracture with load, which could be approximated by a power-law relationship, and an increasing tendency for fibre breaks to occur in clusters at high percentages of the failure load [19]. These observations were refined by Swolfs et al [20], who noted that the tendency for cluster formation at high strains (>1.6%) accounted for 50% of the total breaks detected, and also that the majority of the clusters were co-planar (70%) rather than diffuse (30%). However, the model proposed overestimated the accumulation of fibre breaks, underestimated the cluster formation, and also predicted diffuse rather than co-planar clusters in contrast with the experimental observations [20].…”

Section: A C C E P T E D Accepted Manuscriptsupporting

confidence: 52%

Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography

Garcea

Sinclair

Spearing

2016

Composites Science and Technology

Self Cite

View full text Add to dashboard Cite

Please cite this article as: Garcea SC, Sinclair I, Spearing SM, Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography, Composites Science and Technology (2016), doi: 10.1016/j.compscitech.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractIn situ fatigue experiments using synchrotron X-ray computed tomography (SRCT) are used to assess the underpinning micromechanisms of fibre failure in double edge notch carbon/epoxy coupons. Observations showed fibre breaks along the 0º ply splits, associated with the presence and failure of bridging fibres, as well as fibres failed in the bulk composite within the 0º plies. A tendency for cluster formation, with multiple adjacent breaks in the bulk composite was observed when higher peak loads were applied, exceeding 70% of the ultimate tensile stress. Ex situ fatigue tests were used to assess the accumulation and distribution of fibre breaks for different loading conditions, varying peak load and number of cycles. A direct comparison with the quasi-static case for an equivalent peak load, considering the same material system and geometry, hasshown that fatigue produces a significantly higher number of fibre breaks. This supports the hypothesis that fibre breaks are indeed caused by the load cycling.

show abstract

Section: A C C E P T E D Accepted Manuscriptsupporting

confidence: 52%

Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography

Garcea

Sinclair

Spearing

2016

Composites Science and Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…While interfacial debonding is often observed in single fibre fragmentation tests, there is no evidence of debonding occurring in composites with thousands or millions of 125 fibres [2]. In addition, recent x-ray tomography images [21,25] suggest that debonding may not occur during the formation of clusters; in fact, the prevalence of planar clusters appear to be incompatible with the formation of splits after each fibre breaks. In any case, debonding could potentially be included in the FE model by adding cohesive elements at the fibre-matrix interface.…”

Section: Geometry and Meshmentioning

confidence: 99%

“…1. This is based on SEM images of fracture surfaces [35] and recent x-ray tomographic observations of incipient failure which showed that 70% of clusters analysed had fibres broken in the same plane [25].…”

Section: Stress Redistribution Around Broken Fibresmentioning

confidence: 99%

“…For example, Swolfs et al [19] showed that modelling the fibres as transversely isotropic (instead of isotropic) results in higher stress concentrations; these results were obtained for fibres embedded in an elastic matrix and when matrix plasticity is included the effect of fibre anisotropy is reduced [15]. In 155 the literature, the matrix has been modelled with a variety of constitutive behaviours such as linear elastic [12,17,19,25], non-linear elastic [10], linear elastic perfectly-plastic [13,14,18] or linear elastic with linear strain hardening [38]. Results indicate that for the options enumerated above, matrix plasticity has a reduced effect on the stress concentration factor, but leads to longer recovery lengths [2].…”

mentioning

confidence: 99%

“…Accurately representing how stress redistribution varies with the size of the broken cluster is a critical component of models predicting the strength of fibre bundles, especially for those using a two-step simulation technique [18,[23][24][25]. With this approach, a deterministic model is first used to calculate the stress field around a single broken fibre.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Stress redistribution around clusters of broken fibres in a composite

St-Pierre

Martorell

Pinho

2017

Composite Structures

View full text Add to dashboard Cite

A key aspect of the longitudinal tensile failure of composites is the stress redistribution that occurs around broken fibres. Work on this topic has focussed mainly on the stress field surrounding a single broken fibre; however, this is an important limitation as unstable failure in carbon fibre bundles occurs when a cluster of about 16 or more broken fibres is formed.Therefore, we have developed a detailed Finite Element (FE) model to investigate how stress redistribution varies with the number of broken fibres in a cluster. The results show that both the recovery length and stress concentration factor increase significantly with increasing number of broken fibres in a cluster. We have also developed an analytical model, suitable to be included in existing or new fibre bundle models, that captures how the recovery length and stress concentration factor vary with the broken cluster size, and validated its predictions against our FE simulations. Finally, we extended our FE model to predict the survival probability of fibre bundles using Monte Carlo simulations, and found that these predictions were in good agreement with experimental and analytical results on microcomposites.

show abstract

Splitting failure of a composite under longitudinal tension

2022

View full text Add to dashboard Cite

Significant variation can be found in measurements for the longitudinal tensile strength of the same unidirectional (UD) composite. A splitting failure is one of the main reasons. It is shown in this paper that the shear stress component resulted from a longitudinal tension and a fiber misalignment can cause the matrix to fail before fiber break. The misalignment angle consists of an initial off-axial angle and a further fiber rotation during the loading. Based on the micromechanics Bridging Model and the matrix true stress theory established by the author, splitting failure has been analyzed and predicted rigorously in this paper, only using the fiber and matrix properties together with the fiber misalignment angle. The fiber initial misalignment angle of a unidirectional plate can be obtained from testing statistics, or deducing from measured longitudinal compression strength. Our research indicates that the longitudinal tensile strength and the relevant failure mode can be significantly affected by the fiber initial misalignment.

show abstract

Synchrotron radiation computed tomography for experimental validation of a tensile strength model for unidirectional fibre-reinforced composites

Cited by 98 publications

References 63 publications

Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography

Fibre failure assessment in carbon fibre reinforced polymers under fatigue loading by synchrotron X-ray computed tomography

Stress redistribution around clusters of broken fibres in a composite

Splitting failure of a composite under longitudinal tension

Contact Info

Product

Resources

About