Bridging effect on mode I fatigue delamination behavior in composite laminates

Yao, Liaojun; Alderliesten, R.C.; Zhao, Minghua; Benedictus, Rinze

doi:10.1016/j.compositesa.2014.04.007

Cited by 90 publications

(88 citation statements)

References 24 publications

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“…To this end the use of initial quasi-static loading or via fatigue loading has been studied. The experimental data presented in [13,14] revealed that these two different approaches can yield different delamination FCG rate curves. The conclusion reached in this study was:…”

Section: Effect Of Pre-crack Lengthmentioning

confidence: 99%

“…This failure locus also appears be a function of the length of the delamination [13,14]. The need to determine the functional dependence of the fatigue threshold ΔG thr on the mode-mix may be of importance in assessing the criterion for 'growth/no growth' of delaminations found in operational aircraft.…”

Section: Analysis Of the Measured Fcg Datamentioning

confidence: 99%

“…(a-a 0 ), is aptly illustrated in Figure 10. This figure presents the da/dN versus ∆√G curves given in [13] for DCB tests where prior to the actual fatigue test the pre-crack delamination was grown from the initial film-insert a distance of (a-a 0 ) of values of 4.1, 12.7 and 51.3 mm, i.e. before measurements associated with the subsequent fatigue test were taken.…”

Section: Effect Of Pre-crack Lengthmentioning

confidence: 99%

“…The apparent increase in fracture toughness due to fibre-bridging, measured using the Mode I DCB test subjected to quasi-static loading, has led several authors [4,13,14,42] to express the apparent toughness, G CR , as a function the length, a, of the advancing delamination by the amount by which the delamination exceeds its initial length, a 0 . The proposed expressions are of the form shown below, and it should be noted that these present discussions are all concerned with Mode I failure, and hence, the subscript 'I' has been omitted for clarity:…”

Section: Dcb Quasi-static Testsmentioning

confidence: 99%

“…The use of Mode I DCB tests is the most common approach employed to characterise delamination growth as a function of the energy release-rate, G [2,4,5,19,26,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][76][77][78]. However, a major problem with this method is the large retardation that can develop due to fibres bridging the delamination [4,5,13,14,36,42,49]. (A detailed review of the effects of fibre-bridging and the current test standards is given in [78].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Delamination growth in polymer-matrix fibre composites and the use of fracture mechanics data for material characterisation and life prediction

Jones

Kinloch

Michopoulos

et al. 2017

Composite Structures

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The growth of delaminations in polymer-matrix fibre composites under cyclic-fatigue loading in operational aircraft structures has always been a very important factor which has the potential to significantly affect the service-life of such structures. The recent introduction by the Federal Aviation Administration (FAA) of a 'slow growth' approach to the certification of composites has further focused attention on the experimental data and the analytical tools needed to assess the growth of delaminations under fatigue loads. Specific attention is given to the test and data-reduction procedures required to determine a 'valid' rate of fatigue crack growth (FCG), da/dN, versus the range of the energy release-rate, ΔG, (or the maximum energy release-rate, G max , in a cycle) relationship (a) to characterise and compare different types of composites, and (b) for designing and lifing in-service composite structures. Now, fibre-bridging may occur behind the tip of the advancing delamination and may cause very significant retardation of the FCG rate. Such retardation effects cannot usually be avoided when using the Mode I double-cantilever beam test to ascertain experimentally the fatigue behaviour of composites, so that a means of estimating a valid (i.e. ideally a 'retardation-free' or, at least, a very low-retardation) relationship is needed. The present paper presents a novel methodology, that is based on a variant of the Hartman-Schijve equation, to ascertain a valid, 'retardation-free', upper-bound FCG rate curves.

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Section: Effect Of Pre-crack Lengthmentioning

confidence: 99%

Section: Analysis Of the Measured Fcg Datamentioning

confidence: 99%

Section: Effect Of Pre-crack Lengthmentioning

confidence: 99%

Section: Dcb Quasi-static Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Delamination growth in polymer-matrix fibre composites and the use of fracture mechanics data for material characterisation and life prediction

Jones

Kinloch

Michopoulos

et al. 2017

Composite Structures

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Dependance of stress ratio on the Mode I fatigue delamination growth in woven carbon–epoxy composites

et al. 2018

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This study analyzes crack growth behavior of woven carbon fiber reinforced plastics under tension–tension fatigue varying the stress ratio (R). The composite studied here is 3K‐70‐P carbon fiber plain weave with EPOLAM 2015® epoxy resin, manufactured by vacuum bagging procedure. The modified París’ law for composites is used to estimate the delamination crack growth (da/dN) in terms of interlaminar fracture toughness ratio (Gmax/GIC). Delamination's dependence on R factor is discussed, as crack growth rate increases when stress ratio becomes higher. Also, fractographic examination is provided, as fatigue striation density is inversely dependent on fatigue stress ratio.

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Interlaminar toughening of carbon fiber/epoxy composites via interleaving co‐polyamide (Co‐PA) veils

Alshrif,

Peng,

Yang

et al. 2024

Polymer Composites

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Thermoplastic veil interlayers offer a promising approach to improve interlaminar reinforcement in composite materials. This study investigates co‐polyamide (Co‐PA) interleaved veils, fabricated through the hot melt adhesive (HMA) technique. These veils are then applied with varying areal weight densities as interleaves to simultaneously toughen and strengthen carbon fiber/epoxy (CF/EP) composites, utilizing the vacuum‐assisted resin infusion (VARI) method. Integrating Co‐PA veils with a low melting point in the interlaminar of CF/EP composites improves compatibility and promotes strong adhesion between thermoplastics and epoxy resins. As result, The Co‐PA laminates exhibited significant improvements compared with the untoughened composites, with a maximum enhancement of 148.1% and 67.8% for Mode‐I (GIC) and Mode‐II (GIIC), respectively. Moreover, ILSS, tensile strength, and flexural strength improvements were also 20.9%, 34.9%, and 14.5%, respectively. The fracture surface analysis via scanning electron microscopy directly revealed the crack propagation on the fracture surfaces of Mode‐I and Mode‐II specimens. This analysis revealed that Co‐PA demonstrated excellent compatibility with epoxy resin, melts during the stage of epoxy curing, and undergoes phase separation in the later stage, resulting in the formation of “bead‐like” structures within the fibrous network. Remarkably, this structure significantly enhanced the toughness of the CF/EP composites. The Co‐PA veils can improve the interlaminar toughness of CF/EP composites due to their compatibility with the epoxy matrix and high inherent toughness and strength. This method is straightforward to manage and can be utilized for manufacturing large‐scale composite materials incorporating CF fabrics, demonstrating promise for industrial applications.Highlights With its low melting point, co‐polyamide helps prevent structural failure or excessive damage and is proposed to be utilized in composites to enhance the interlaminar fracture toughness properties. The effects of Co‐PA veils of different areal densities on the mechanical characteristics of interlaminar composites were examined. Co‐polyamide particles with fiber‐carbon laminates offer superior fatigue properties and an optimum carbon fiber‐bridging mechanism. Co‐polyamide veils with CF/EP laminates are feasible for structural use in high‐tech automotive applications.

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Bridging effect on mode I fatigue delamination behavior in composite laminates

Cited by 90 publications

References 24 publications

Delamination growth in polymer-matrix fibre composites and the use of fracture mechanics data for material characterisation and life prediction

Delamination growth in polymer-matrix fibre composites and the use of fracture mechanics data for material characterisation and life prediction

Dependance of stress ratio on the Mode I fatigue delamination growth in woven carbon–epoxy composites

Interlaminar toughening of carbon fiber/epoxy composites via interleaving co‐polyamide (Co‐PA) veils

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