In situ consolidation of carbon fiber PAEK via laser-assisted automated fiber placement

Heathman, Nathaniel; Koirala, Pratik; Yap, Timothy; Emami, Anahita; Tehrani, Mehran

doi:10.1016/j.compositesb.2022.110405

Cited by 31 publications

(10 citation statements)

References 33 publications

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“…33 As Figure 9 and Figure 10 suggest, 24 h of vacuum hold times yield 0.44%, 0.72%, and 0.79% final void contents with a percentage change of 88%, 83% and 36% for Sample A, Sample B, and Sample C, respectively. These figures clearly illustrate the decrease of the void content to lower values than the autoclave post-processing and improved surface roughness with increasing vacuum hold time to 24 h. Moreover, in Figure 9, a resin-rich region within the tape can be observed at the zoom-in section of Sample C which is attributed to the incoming tape property, as illustrated by Heathman et al 5 Interestingly with low compaction with low lay-up velocity, Sample A, in VBO with longer pre-evacuation for 24 h, we obtained lower void content even better than autoclave (Figure 10(a)). However, low compaction with high lay-up velocity (Sample B), and high compaction with low lay-up velocity (Sample C), 24 h of a dwelling provided higher void contents due to the morphology of the voids at the AFP-fabricated samples compared to Sample A.…”

Section: Resultssupporting

confidence: 57%

“…The voids of AFP-fabricated composites can be categorized into two groups: intra-laminar and inter-laminar voids. Intra-laminar voids originate from incoming raw material (slit-tape), 5 while inter-laminar voids are correlated with AFP lay-up process parameters. 6 The effect of AFP lay-up process parameters like roller compaction force, lay-up velocity, and AFP head laser heat flux on the inter-laminar void content of thermoplastic components is the subject of many studies.…”

Section: Introductionmentioning

confidence: 99%

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A study of post-processing for AFP-fabricated thermoplastic composites with void content and air permeability characterization

Karimi

Yousefi-Louyeh

Barzegar

et al. 2023

Journal of Reinforced Plastics and Composites

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Improving the quality of fiber-reinforced composite laminates using out-of-autoclave techniques has been a challenge for a long time. The recent trends toward the replacement of autoclave processes with out-of-autoclave processes for thermoplastic composites still lack a compressive recipe. This study first develops an understanding of the integrated effect of the automated fiber placement (AFP) lay-up process parameters (compaction force and lay-up velocity) and the type of post-processing: i) autoclave and ii) vacuum bag only (VBO) processing with two vacuum hold times, 2 and 24 h. The void content results highlight the potential of the VBO process to replace the autoclave with an improved void content of VBO with 24 vacuum hold times. Then, this result has been correlated with the morphology of voids after the AFP lay-up as isolated or connected via air permeability characterization. This study reveals that the high air permeability to effective porosity ratio of samples after AFP lay-up which is achievable with low compaction force facilitates the air removal mechanism during the VBO process with sufficient vacuum hold times.

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Section: Resultssupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

A study of post-processing for AFP-fabricated thermoplastic composites with void content and air permeability characterization

Karimi

Yousefi-Louyeh

Barzegar

et al. 2023

Journal of Reinforced Plastics and Composites

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“…Currently, automated manufacturing techniques for composite components predominantly encompass Filament Winding (FW), Automated Tape Laying (ATL), and Automated Fiber Placement (AFP) 7–9 . Among them, AFP enables independent control of multiple prepreg fibers, which is suitable for the placement of complex surfaces, and the material utilization rate is higher 10,11 . The highly integrated AFP system has become the key to mass manufacturing in the aerospace industry 12 …”

Section: Introductionmentioning

confidence: 99%

“…AFP enables independent control of multiple prepreg fibers, which is suitable for the placement of complex surfaces, and the material utilization rate is higher. 10,11 The highly integrated AFP system has become the key to mass manufacturing in the aerospace industry. 12 During AFP, the roller presses the prepreg fiber to the mold surface with appropriate pressure.…”

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confidence: 99%

Modeling of contact mechanics and defects investigation in automated fiber placement

Miao,

Zhu,

Guo

et al. 2024

Polymer Composites

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The layup quality of prepreg fibers onto complex surfaces is the most concerned issue in automated fiber placement (AFP), which is intimately related to the contact stress in tractive rolling contact. An analytical model of tractive rolling contact is proposed in this paper to clarify the defects mechanism during the AFP process, which considers the mold curvatures, mechanical properties of contacted objects, and pose information to make it suitable for irregular surfaces and arbitrary conditions. Classical Hertz theory in this model is expanded to 3D contact area, and multi‐scale deformations are united in the accurate calculation of contact stress under geometric constraints. Based on the model, the phenomena of adhesion, microslip, and the transition between them in AFP are systematically analyzed. For engineering applications, a discrete processing strategy is proposed to quickly obtain the local curvatures of the mold. Additionally, an algorithm is designed to calculate the contact stress of any path. Experimental results on an aircraft component demonstrate the accuracy of the proposed model in restoring the contact stress distribution during AFP. In conjunction with specific layup information, this model exhibits utility in forecasting laying defects and parameter optimization.Highlights An analytical modeling approach based on Hertz theory is proposed to calculate the contact stress in automated fiber placement. A model‐based algorithm is designed and combined with the proposed discrete scheme to quickly restore the contact stress distribution. Contact states related to stress are systematically investigated and defects analysis based on computational mechanics results is illustrated.

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“…The assembly is then being consolidated in an autoclave or under a press, with applied pressures of 7–10 bar 9,10 . For economic reasons, in‐situ consolidation through ATP or the use of out‐of‐autoclave (OOA) devices, such as vacuum bag only (VBO) with lower pressures applied (~ 1 bar) 11 are now considered for this last step 12–14 . The goal of this consolidation step is to facilitate flow in the composite, which lowers the void content of the composite and in turn increases its mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Role of the inter‐ply microstructure in the consolidation quality of high‐performance thermoplastic composites

Arquier,

Sabatier,

Iliopoulos

et al. 2023

Polymer Composites

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Consolidation of Carbon Fiber (CF)/high‐performance thermoplastic composites is much less understood than the one of their thermoset counterparts. It is usually assumed that the consolidation quality is directly linked to the removal of voids within the sample during consolidation, leading to mechanical properties suitable for aerospace applications. A systematic study of the temporal evolution of CF/polyetherketoneketone (PEKK) samples' microstructure consolidated under low pressure in a rheometer is related to the increase in inter‐laminar shear strength. The results show that despite similar void contents well‐below 1 vol%, samples can present significant differences in ILSS values, from 80 to 95 MPa for cross‐ply samples, and from 98 to 112 MPa for unidirectional (UD) ones. A microstructural analysis shows that, for these materials, consolidation quality is rather related to a reorganization of the inter‐ply, a resin‐rich (~70 vol%) region of typical thickness 10 μm which is slowly repopulated in fibers during consolidation.Highlights Microstructure of CF/PEKK composites is characterized over consolidation time Contrary to thermosets void content cannot be used to predict mechanical properties ILSS increase over consolidation time is related to inter‐ply reorganization Inter‐ply microstructure and ILSS have a direct correlation The repopulation in fibers of the resin‐rich inter‐ply is a slow process

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In situ consolidation of carbon fiber PAEK via laser-assisted automated fiber placement

Cited by 31 publications

References 33 publications

A study of post-processing for AFP-fabricated thermoplastic composites with void content and air permeability characterization

A study of post-processing for AFP-fabricated thermoplastic composites with void content and air permeability characterization

Modeling of contact mechanics and defects investigation in automated fiber placement

Role of the inter‐ply microstructure in the consolidation quality of high‐performance thermoplastic composites

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