Flexural response of composite beams made by Automated Fiber Placement process: Effect of fiber tow gaps

Ghayour, Mohammadhossein; Ganesan, Rajamohan; Hojjati, Mehdi

doi:10.1016/j.compositesb.2020.108368

Cited by 11 publications

(9 citation statements)

References 36 publications

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“…It can also cause local stress relaxation in the composite plies due to the presence of the relatively large resin pocket, which might lead to damage initiation at certain loading conditions. 17 The performance of the IDLM method for the structures under out-of-plane loading was examined by comparing the obtained results with the experimental results. 17 It is important to note that the tow gap defects are not necessarily induced in the whole length of the fiber tows in real applications.…”

Section: Multiscale Analysis Of Defective Composite Laminatesmentioning

confidence: 99%

“…18 It was shown that the periodic gaps between the fiber courses with an average width of 2.0 mm could affect the impact response, damage threshold load, and also delamination pattern of the impacted plates. The flexural behavior study 17 of the Carbon/Epoxy composite beams shows that the induced gap can initiate the delamination in the beams under out-of-plane shear loading. It can also decrease the interlaminar shear strength and flexural strength of the thin composite beams by 13% and 35%, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…It might have a different impact on the mechanical performance of the structures for different scenarios of loading conditions. The experimental studies can be categorized by the works performed on tensile, [10][11][12] compressive, [11][12][13][14][15][16] flexural, 17 and impact 18,19 loadings, and also fatigue loading 20 cases of the defective composite laminates.…”

Section: Introductionmentioning

confidence: 99%

“…But, the method implements an elastic homogenization technique that restricts the method to the linear elastic analysis of composite structures with defects. However, failure strength's reduction [11][12][13] and accelerating of damage initiation 17,20 are the primary issues of the existence of the gaps in the structures rather than the local reduction of the elastic properties. Thus, up to the knowledge of the authors, there is still no practical method that can assess the structural integrity of the composite structures in the presence of the automated manufacturing induced-gaps under general loading conditions.…”

Section: Introductionmentioning

confidence: 99%

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Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Ghayour

Hojjati

Ganesan

2021

Journal of Composite Materials

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Automated manufacturing defects are new types of composite structure defects induced during fiber deposition by robots. Fiber tow gap is one of the most probable types of defects observed in the Automated Fiber Placement (AFP) technique. This defect can affect the structural integrity of structures by reducing structural strength and stiffness. The effect of this defect on the mechanical response of the composite laminates has been investigated experimentally in the literature. However, there is still no efficient numerical/analytical method for damage assessment of composite structures with distributed induced gaps manufactured by the AFP technique. The present paper aims to develop the Induced Defect Layer Method (IDLM), a new robust meso-macro model for damage analysis of the composite laminates with gaps. In this method, a geometrical parameter, Gap Percentage (GP), is implemented to incorporate the effect of induced-gaps in the elastic, inelastic, and softening behavior at the material points. Thus, while the plasticity and failure of the resin pockets in conjunction with intralaminar composite damages can be evaluated by this method, the defective areas are not required to be defined as resin elements in the Finite Element (FE) models. It can also be applied for any arbitrary distributions of the defects in the multi-layer composite structures, making it a powerful tool for continuum damage analysis of large composite structures. Results indicate that the proposed method can consider the effect of gaps in both elastic and inelastic behavior of the composite laminate with defects. It also provides good agreement with the experimental results.

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Section: Multiscale Analysis Of Defective Composite Laminatesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Ghayour

Hojjati

Ganesan

2021

Journal of Composite Materials

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“…Ghayour et al used short and long flexural specimens to examine the effect of tow gaps. They found a reduction in apparent shear strength of 13% and a drop in flexural stiffness of 35% (due to thickness reduction), compared with a hand lay-up reference, when gaps were present [ 24 ]. However, to date there has been very little work to characterize the presence of defects in AFP composites using a fracture mechanics approach.…”

Section: Introductionmentioning

confidence: 99%

Influence of Embedded Gap and Overlap Fiber Placement Defects on Interlaminar Properties of High Performance Composites

Cartié¹,

Lan

Davies

et al. 2021

Materials

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Automated fiber placement (AFP), once limited to aerospace, is gaining acceptance and offers great potential for marine structures. This paper describes the influence of manufacturing defects, gaps, and overlaps, on the out-of-plane properties of carbon/epoxy composites manufactured by AFP. Apparent interlaminar shear strength measured by short beam shear tests was not affected by the presence of defects. However, the defects do affect delamination propagation. Under Mode I (tension) loading a small crack arrest effect is noted, resulting in higher apparent fracture energies, particularly for specimens manufactured using a caul plate. Under Mode II (in-plane shear) loading there is a more significant effect with increased fracture resistance, as stable propagation for specimens with small gaps changes to arrest with unstable propagation for larger gaps.

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Experimental study on flexural behavior of T‐shaped reinforced concrete laminated beams with defects

Feng,

Ye,

et al. 2023

Structural Concrete

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To study the influence of the defects on the flexural behavior of laminated T‐beams, full‐scale beam tests of three reinforced concrete laminated T‐beams with incomplete bonding and one non‐defective reinforced concrete laminated T‐beam were conducted under monotonic loading. The results showed that the failure modes and crack patterns of the defective beams were similar to those of beams without defects. However, horizontal cracks appeared in these defects. Although the peak loads of the four specimens were relatively close, the difference in the maximum deflection was distinct. The deflection span ratio of each specimen exceeded 1/17, and the displacement ductility ratio exceeded 15. The results indicate that internal defects have only a slight influence on the flexural capacity of laminated beams but significantly influence their ductility.

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Flexural response of composite beams made by Automated Fiber Placement process: Effect of fiber tow gaps

Cited by 11 publications

References 36 publications

Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Induced defect layer method to characterize the effect of fiber tow gaps for the laminates manufactured by automated fiber placement technique

Influence of Embedded Gap and Overlap Fiber Placement Defects on Interlaminar Properties of High Performance Composites

Experimental study on flexural behavior of T‐shaped reinforced concrete laminated beams with defects

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