Experimental study of the effect of automated fiber placement induced defects on performance of composite laminates

Croft, Kaven; Lessard, Larry; Pasini, Damiano; Hojjati, Mehdi; Chen, Jihua; Yousefpour, Ali

doi:10.1016/j.compositesa.2011.01.007

Cited by 240 publications

(155 citation statements)

References 14 publications

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“…For instance, Sawicki and Minguet [2] explored the effect of aligned and isolated gaps in 90° plies in a compression strength test, Turoski [3] systematically studied the effects of isolated gaps and interacting gaps with different stagger repeats on the strength of unnotched and notched quasi-isotropic laminates in both tension and compression tests. Croft et al [4] have investigated the influence of a gap, an overlap and a half gap/overlap located at the through-thickness symmetry plane in a laminate by tension, compression and in-plane shear tests. These works provide very informative results; however, compared with the large number of different and complex combinations and permutations for gap and overlap defect types in aerospace structures, they represent only a small subset of the possible configurations that can occur.…”

Section: Introductionmentioning

confidence: 99%

Modelling the effect of gaps and overlaps in automated fibre placement (AFP)-manufactured laminates

Hallett

Wisnom

2015

Science and Engineering of Composite Materials

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Abstract:In automated fibre placement (AFP) process, gaps and overlaps parallel to the fibre direction can be introduced between the adjoining tapes. These gaps and overlaps can cause a reduction in strength compared with pristine conditions. Finite element modelling is an effective way to understand how the size and distribution of such gaps and overlaps influences the strength and failure development. Many modelling work showed that out-ofplane waviness and ply thickness variations caused by gaps and overlaps play an important role in inducing the strength knock-down; however, there has been a lack of effective way to explicitly model the ply waviness, which constrained the relevant research. In this work, 3D meshing tools were developed to automatically generate ply-byply models with gaps and overlaps. Intra-ply and inter-ply cohesive elements are also automatically inserted in the model to capture the influence of splitting and delamination. Out-of-plane waviness and ply thickness variations caused by gaps and overlaps are automatically modelled. Models with various sizes and distribution of gaps and overlaps were built to predict the reduction of strength as a function of the magnitude and type of the defects. Results of gap and overlap models will be used to guide future experimental characterization of simulated AFP process defects, manufactured by hand layup from prepreg tape.

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Section: Introductionmentioning

confidence: 99%

Modelling the effect of gaps and overlaps in automated fibre placement (AFP)-manufactured laminates

Hallett

Wisnom

2015

Science and Engineering of Composite Materials

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“…These procedures require high-end textile processing capabilities, which are expensive, time consuming, and labour-intensive. The automated fiber placement (AFP) technique [6][7][8], is an innovative way of overcoming many preforming problems. The process utilizes a robotic arm, which deposits dry fibers onto a complex mold, potentially overcoming any fabric structure variability and variations in local fiber volume fraction, while draping in complex or tight corners.…”

Section: Introductionmentioning

confidence: 99%

Transverse permeability of dry fiber preforms manufactured by automated fiber placement

Aziz

Ali

Zeng

et al. 2017

Composites Science and Technology

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This work presents a correlation between the transverse permeability of a preform and the process variability of the automated dry fiber placement manufacturing technique. In this study, an experimental and numerical analysis of the dry tape preform, with a focus on its through-thickness permeability, has been undertaken. Geometric models, containing flow channels of two different width dry tape carbon preforms, have been created in the TexGen modeller. A Computational fluid dynamics (CFD) simulation has been undertaken to obtain the predicted through-thickness-permeability of the dry tape preform. A parametric study on the effect of different dry tape gap sizes on the permeability of the preform is presented. An in-situ compaction study, carried out in an X-CT machine, revealed that the gap sizes were irregular throughout the manufactured preforms. In addition, an experimental investigation of the through-thickness permeability, which is based on a saturated flow condition at a thickness corresponding to full vacuum pressure, is also presented. The permeability prediction based on the X-CT re-constructed geometric model has been validated using the experimental data. A further parametric study has revealed that the process variablity in automated dry fibre placement influences the through-thickness permeability by a factor of upto 5.

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“…In the past [17,18], some investigations have been performed addressing the effects of gaps and overlaps on the mechanical properties of carbon-epoxy components. More recent results [18] show the performance of gap and overlap configurations in composite materials, providing the conclusions that the ultimate strength is less affected by the different defect configurations at the lamina level (fibre tension, fibre compression, and in-plane shear) as opposed to the laminate level (open hole tension and open hole compression).…”

Section: Introductionmentioning

confidence: 99%

Detection and Evaluation of Pre-Preg Gaps and Overlaps in Glare Laminates

Nardi

Abouhamzeh

Leonard³

et al. 2018

Appl Compos Mater

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Gaps and overlaps between pre-preg plies represent common flaws in composite materials that can be introduced easily in an automated fibre placement manufacturing process and are potentially detrimental for the mechanical performances of the final laminates. Whereas gaps and overlaps have been addressed for full composite material, the topic has not been extended to a hybrid composite material such as Glare, a member of the family of Fibre Metal Laminates (FMLs). In this paper/research, the manufacturing, the detection, and the optical evaluation of intraply gaps and overlaps in Glare laminates are investigated. As part of an initial assessment study on the effect of gaps and overlaps on Glare, only the most critical lay-up has been considered. The experimental investigation started with the manufacturing of specimens having gaps and overlaps with different widths, followed by a nondestructive ultrasonic-inspection. An optical evaluation of the gaps and overlaps was performed by means of microscope image analysis of the cross sections of the specimens. The results from the non-destructive evaluations show the effectiveness of the ultrasonic detection of gaps and overlaps both in position, shape, width, and severity. The optical inspections confirm the accuracy of the non-destructive evaluation also adding useful insights about the geometrical features due to the presence of gaps and overlaps in the final Glare laminates. All the results justify the need for a further investigation on the effect of gaps and overlaps on the mechanical properties.

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Experimental study of the effect of automated fiber placement induced defects on performance of composite laminates

Cited by 240 publications

References 14 publications

Modelling the effect of gaps and overlaps in automated fibre placement (AFP)-manufactured laminates

Modelling the effect of gaps and overlaps in automated fibre placement (AFP)-manufactured laminates

Transverse permeability of dry fiber preforms manufactured by automated fiber placement

Detection and Evaluation of Pre-Preg Gaps and Overlaps in Glare Laminates

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