Viscoelastic response of dry and wet fibrous materials during infusion processes

Kelly, Piaras; Umer, Rehan; Bickerton, Simon

doi:10.1016/j.compositesa.2005.02.008

Cited by 141 publications

(137 citation statements)

References 20 publications

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“…It is well known that, fiber reinforcements exhibit viscoelastic compaction response [12][13][14]. Tape compression through AFP rollers also play a significant role in determining the final part quality, given that the first ply will be compressed several times, while the last ply will be compressed only once and the resulting preform may be non-homogeneous in the through-thickness direction.…”

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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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

Self Cite

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“…Each 100 mm × 100 mm sample was loaded up to 5 MPa in a 100 kN electromechanical Zwick test machine at a compaction rate of 1 mm/min to avoid any fiber relaxation. 21 The applied load was measured using the load indictor of the test machine; the displacement was an average measurement from a pair of Micro-Epsilon ILD1700-100 laser-optical displacement sensors. Figure 2 shows the compaction measurement fixture.…”

Section: Consolidation Measurementsmentioning

confidence: 99%

Resource-friendly carbon fiber composites: combining production waste with virgin feedstock

Kratz

Low

Fox

2017

Advanced Manufacturing: Polymer & Composites Science

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“…The experimental studies highlight at the same time the phase of compression and the phase of relaxation which are represented on the same figures [11]. Kelly [12] proposed interesting model inspired from the work of Saunders [13] which treats simultaneously the phases of compression and of relaxation. The objective of this work is to propose two approaches for the modelling of the compressibility.…”

Section: Introductionmentioning

confidence: 99%

Compressibility and relaxation models for fibrous reinforcements in Liquid Composites Moulding

2008

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: Liquid composites moulding processes are now widely used in the aeronautical and the aerospace fields. For the automobile sector, this type of processes is more and more used and still has very high potential. Optimizing moulding parameters, particularly the time cycle and improving the quality of the obtained parts, are key to increasing use of this type of process. When closing the mould in the LCM processes, the compression phase followed by the reinforcements' relaxation are important stages that influence all process parameters. This work presents a theoretical modelling based on two approaches. The results are compared to the experimental ones obtained within our laboratory. In the experimental results, the compressibility behaviour of the reinforcements according to their type; number of ply, lubrication and compression speed were studied. The test results highlight the influence of these parameters on the compressibility and the relaxation of the reinforcements and identify the nesting and the anisotropy as being two important factors. For the theoretical modelling, two approaches are proposed. In the first one, based on the equation of continuity, Darcy's law and the Terzhagui model; the total stress in the mould is equal to a viscous stress due to the fluid flow and an elastic stress due to the fibers response. The equation of Chen and Al, used to model elastic stress allows us to predict the compressibility of the impregnated reinforcements. The second approach is a rheological one where the models of Zener, Burger and Maxwell are used. The results analysis highlights the influence of some moulding parameters and fibrous reinforcement's compression rules. A good agreement is noted between the experimental and the theoretical compression curves of the fibrous reinforcements. The rheological model of Maxwell gives the best prediction of reinforcements behaviour in both compression and relaxation phase.

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Viscoelastic response of dry and wet fibrous materials during infusion processes

Cited by 141 publications

References 20 publications

Transverse permeability of dry fiber preforms manufactured by automated fiber placement

Transverse permeability of dry fiber preforms manufactured by automated fiber placement

Resource-friendly carbon fiber composites: combining production waste with virgin feedstock

Compressibility and relaxation models for fibrous reinforcements in Liquid Composites Moulding

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