Consolidation and Interlaminar Fracture Properties of Unidirectional Commingled CF/PEEK Composites

Beehag, Andrew; Ye, Lin

doi:10.1177/089270579600900203

Cited by 16 publications

(5 citation statements)

References 20 publications

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“…This was also supported by the appearance of the matrix failure in Mode I fracture ( Figure 9). Shear deformation of the matrix was also seen, Figure 15, but this was not as extensive as in previous work on other thermoplastic matrix composites such as CF/PEEK [17]. It is possible that hydrolysis may account for some of the brittleness seen in the matrix.…”

Section: Mode IImentioning

confidence: 63%

“…The manufacturing and mechanical properties of commingled thermoplastic composites have been studied extensively by Svensson et al [12,13]. Previous work on interlaminar fracture of commingled thermoplastic composites has focused on unidirectional laminates, either carbon fiber/poly ether ether ketone composites (CF/PEEK) [14][15][16][17] or glass fiber/polypropylene composites (GF/PP) [18][19][20], in Mode I and/or Mode II. However, Ye and Friedrich [21] determined the Mode I and Mode II fracture toughnesses of woven biaxial commingled glass fiber/polyethylene terephthalate (GF/PET) laminates.…”

Section: Introductionmentioning

confidence: 99%

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Interlaminar Fracture of Commingled GF/PET Composite Laminates

Svensson¹,

Shishoo

Gilchrist

1998

Journal of Composite Materials

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The Mode I, Mode II and mixed mode (Mode I:II ratios of 4:1, 1:1 and 1:4) fracture behavior of novel textile glass fiber reinforced polyethylene terephthalate (GF/PET) laminates has been investigated. The laminates were manufactured by compression molding two different fabrics produced by weaving and warp knitting commingled GF/PET yarns. The initiation fracture toughnesses of the woven laminates in pure Mode I and Mode II were slightly higher than those of the warp knitted laminates. For the mixed modes, the difference between the fracture toughnesses of the two materials was smaller. An extensive scanning electron microscopy (SEM) investigation of the fracture surfaces was conducted to identify any characteristic failure mechanisms. The main fractographic features of the Mode I dominated failures were a brittle matrix failure and large amounts of fiber pull-out. As the Mode II loading component increased, the amount of fiber pull-out was reduced and the matrix had a more sheared appearance. A relatively large amount of cusps were found in pure Mode II and mixed mode I:II=1:4; such features are seldom seen in thermoplastic matrix composites. A general mixed mode failure criterion, which accounts for the appearance of the fracture surface, was evaluated and was seen to give a good fit to the experimental fracture toughness values.

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Section: Mode IImentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Interlaminar Fracture of Commingled GF/PET Composite Laminates

Svensson¹,

Shishoo

Gilchrist

1998

Journal of Composite Materials

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“…2(d) shows the evolution of the fracture toughness G IC over crack growth a i (up to a maximum of about 30 mm, which corresponds to the AOI) as a crack resistance R-curve for the different methods described in the introduction and determined with the displacement and crack growth measurement via DIC (except for PC method). Since the initiation value can be influenced by the specimen production process of placing a Teflon film between the plies [8], no conclusions will be drawn at this point. It can be seen that all methods presented show crack propagation bounded by the area method (maximum) and the pure compliance method (minimum) predictions.…”

Section: Methodsmentioning

confidence: 99%

Measurements of Mode I Interlaminar Properties of Carbon Fiber Reinforced Polymers Using Digital Image Correlation

Merzkirch

Powell

Foecke

2017

KEM

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Numerical models based on cohesive zones are usually used to model and simulate the mechanical behavior of laminated carbon fiber reinforced polymers (CFRP) in automotive and aerospace applications and require different interlaminar properties. The current work focuses on determining the interlaminar fracture toughness (GIC) under Mode I loading of a double cantilever beam (DCB) specimen of unidirectional CFRP, serving as prototypical material. The novelty of this investigation is the improvement of the testing methodology by introducing digital image correlation (DIC) as an extensometer and this tool allows for crack growth measurement, phenomenological visualization and quantification of various material responses to Mode I loading. Multiple methodologies from different international standards and other common techniques are compared for the determination of the evolution of GIC as crack resistance curves (R-curves). The primarily metrological sources of uncertainty, in contrast to material specific related uncertainties, are discussed through a simple sensitivity analysis. Additionally, the current work offers a detailed insight into the constraints and assumptions to allow exploration of different methods for the determination of material properties using the DIC measured data. The main aim is an improvement of the measurement technique and an increase in the reliability of measured data during static testing, in advance of future rate dependent testing for crashworthiness simulations.

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“…The influence of a TC interphase on the mechanical properties of the composite is actively and controversially discussed in the literature [26,[28][29][30][31][32]. Clark et al [16] report on polyamide (PA)/GF or PA/carbon fiber (CF) composites with higher strength but lower toughness in the case of transcrystallinity.…”

Section: The Tc Interphase and Its Impact On The Micromechanics And C...mentioning

confidence: 99%

“…Occasionally, the term "transcrystallization" is used in the literature in connection with another phenomenon [25,26]. By applying a shear stress along the fiber axis, a columnar superstructure is formed even at T > T cr,trans which resembles a TC layer.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Transcrystalline Interphases in Polypropylene/Glass Fiber Composites Using Micromechanical Tests

Brodowsky

Mäder

2018

Fibers

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In composites, a strong interphase between the components is essential for mechanical properties. By using a suitable sizing (i.e., surface modification) of the fiber, the interphase may be varied, e.g., by suppressing or promoting heterogeneous nucleation of a thermoplastic matrix. In the latter case, three-dimensional transcrystallized interphases with properties differing from those of the bulk matrix are formed. Polypropylene-glass fiber composites are prepared as single-fiber model composites with (a) sizings either inducing or suppressing a transcrystalline interphase, (b) different amounts of modifier maleic acid anhydride grafted polypropylene, and (c) different molecular weights of the matrix polymer. These are studied in quasi-static or cyclic load tests. Static tests permit insights in the interfacial characteristics such as critical interface energy release rate, adhesion strength and frictional stress. Cyclic tests on these model composites can be used to study the nature of dissipative processes and the damage behavior. Atomic Force Microscopy (AFM) investigations of the fiber fracture surfaces provide supplementary information. The transcrystalline layer can indeed improve the mechanical parameters (a 70–100% increase of strength and a 25 or 125% increase in toughness, depending on the molecular weight (MW) of the matrix polymer at low modifier concentration). However, the effect is partially neutralized by an opposing effect: high nucleation in the bulk in samples with commonly used concentrations of modifier.

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Consolidation and Interlaminar Fracture Properties of Unidirectional Commingled CF/PEEK Composites

Cited by 16 publications

References 20 publications

Interlaminar Fracture of Commingled GF/PET Composite Laminates

Interlaminar Fracture of Commingled GF/PET Composite Laminates

Measurements of Mode I Interlaminar Properties of Carbon Fiber Reinforced Polymers Using Digital Image Correlation

Investigation of Transcrystalline Interphases in Polypropylene/Glass Fiber Composites Using Micromechanical Tests

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