Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

Pishvar, Maya; Amirkhosravi, Mehrad; Altan, M. Cengiz

doi:10.3791/57254

Cited by 5 publications

(4 citation statements)

References 41 publications

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“…The visual demonstration of the composite lay-up preparation using the WLVB process can be found in Ref. [33]. Briefly, the steps are as follows: the 38.1 × 25.4 cm 2 area of 400-series stainless steel tool plate was covered by a release film for easy removal of the laminate.…”

Section: Methodsmentioning

confidence: 99%

“…Accordingly, a cost-effective, flexible method to apply sufficiently high consolidation pressure in WLVB processes can have certain benefits in the manufacture, repair, and maintenance of large composite parts. Towards this goal, Neodymium Iron Boron (NdFeB) permanent magnets have been recently used to generate up to 0.8 MPa compaction pressure on the vacuum bag lay-up [31,32,33,34]. It was shown that by the stationary placement of permanent magnets during cure of the glass/epoxy laminates, both the flexural strength and modulus increased in excess of 46% due to a 70% reduction in void content to less than 2% and a 55% increase in fiber volume fraction.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool

et al. 2018

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This study presents a novel method to fabricate high-quality, large composite parts which can be used in a wet lay-up/vacuum bag (WLVB) process. The new method utilizes a commercial lifting magnet, which is commonly used for transporting ferrous plates, to apply a magnetic consolidation pressure on the WLVB composite lay-up. The pressure is applied on a large area of the laminate by slowly sliding the magnet over the vacuum bag surface, which leads to an improved laminate quality. When further improvement is desirable, multiple passes of the magnet can be performed, where each pass successively compacts the lay-up. To explore the feasibility of implementing this technique, random mat and plain weave glass/epoxy laminates were fabricated, and their properties compared to conventional WLVB laminates. The effects of the number of moving passes of the lifting magnet on the laminate microstructure and properties are also investigated. As a result of multiple passes, the fiber volume fraction in random mat and plain weave laminates increases to 34% and 53%, representing 80% and 16% improvements, respectively. In addition, the void volume fraction reduces almost by 60% to a very low level of 0.7% and 1.1%, respectively. Consequently, the flexural properties considerably enhance by 20–81%, which demonstrates the potential of the proposed method to produce WLVB parts with substantially higher quality. It is also shown that there exists an optimal number of passes, depending on the fabric type where additional passes induce new voids as a result of excessive resin removal.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool

et al. 2018

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“…Recently, NdFeB magnets were used to apply consolidation pressure during wet lay-up/vacuum bag process and out-of-autoclave prepreg curing to improve laminate properties. [30][31][32] In the present study, two sets of magnets, magnetized through the thickness, were used for inducing different levels of pressure. The first set (A) includes N52-2.54 Â 2.54 Â 1.27 cm 3 NdFeB magnets with a surface magnetic field of 0.49 T. The second set (B) contains N52-2.54 Â 2.54 Â 5.08 cm 3 NdFeB magnets, which are thicker and can generate a stronger surface magnetic field of 0.71 T. The pull force generated by one magnet placed on a top steel plate is measured as a function of the gap from a bottom steel plate using a mechanical testing machine.…”

Section: Neodymium Permanent Magnetmentioning

confidence: 99%

Void reduction in VARTM composites by compaction of dry fiber preforms with stationary and moving magnets

Amirkhosravi

Pishvar

Altan

2018

Journal of Composite Materials

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Voids are the most common process-induced defects in composite laminates fabricated by vacuum assisted resin transfer molding (VARTM). Reduction or total elimination of these defects is essential for the improved performance and long-term durability of the structural composites. This study introduces a novel method that reduces the void content in VARTM laminates to below 1% by compacting the fibrous mat before infusion. The compaction is achieved by applying magnetic pressure on the vacuum bag by either stationary or moving magnets which are removed before the resin infusion. To assess the effectiveness of the proposed method, 6-, 12-, and 18-ply random mat glass/epoxy laminates are fabricated by VARTM using compacted and uncompacted mats and their properties are compared. In addition, different sets of magnets are used to investigate the effect of compaction levels on the resin flow and the quality of the final part. The placement of stationary magnets on the entire vacuum bag surface is practical for fabrication of small parts. For medium to large parts, however, magnets with a smaller footprint can be moved to apply the compaction pressure over a larger vacuum bag surface. The results show that by applying compaction pressure of 0.2 MPa or higher either by stationary or moving magnets on the dry preforms, the void volume fraction was decreased by 65%–95% to 0.1%–0.8% in all laminates.

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“…Both offer numerous benefits such as multifunctional design, production, and structural flexibility and tailoring [11,12]. Biomedical devices [13,14], field-assisted fabrication [15][16][17], surgical [18,19], electronics and sensing [20][21][22][23][24][25], and soft robotics/actuators/stiffening [26][27][28][29][30][31][32][33] are amongst the most common applications for magnetic composite materials. Investigations have been conducted to provide a description of the mechanical properties affected by a magnetic field [34,35].…”

Section: Introductionmentioning

confidence: 99%

Low Magnetic Field Induced Extrinsic Strains in Multifunctional Particulate Composites: An Interrupted Mechanical Strengthening in 3D-Printed Nanocomposites

Mucolli,

Midmer,

Manolesos

et al. 2024

J. Compos. Sci.

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The current paper reports on the quantification of the effect of magnetic fields on the mechanical performance of ferromagnetic nanocomposites in situ during basic standard tensile testing. The research investigates altering the basic mechanical properties (modulus and strength) via the application of a contact-less magnetic field as a primary attempt for a future composites strengthening mechanism. The nanocomposite specimens were fabricated using filament-based 3D printing and were comprised of ferromagnetic nanoparticle-embedded thermoplastic polymers. The nanoparticles were iron particles dispersed at 21 wt.% (10.2 Vol.%) inside a polylactic acid (PLA) polymer, characterised utilising optical microscopy and 3D X-ray computed tomography. The magnetic field was stationary and produced using permanent neodymium round-shaped magnets available at two field strengths below 1 Tesla. The 3D printing was a MakerBot Replicator machine operating based upon a fused deposition method, which utilised 1.75 mm-diameter filaments made of iron particle-based PLA composites. The magnetic field-equipped tensile tests were accompanied by a real-time digital image correlation technique for localized strain measurements across the specimens at a 10-micron pixel resolution. It was observed that the lateral magnetic field induces a slight Poisson effect on the development of extrinsic strain across the length of the tensile specimens. However, the effect reasonably interferes with the evolution of strain fields via the introduction of localised compressive strains attributed to accumulated magnetic polarisation at the magnetic particles on an extrinsic scale. The theory overestimated the moduli by a factor of approximately 3.1. To enhance the accuracy of its solutions for 3D-printed specimens, it is necessary to incorporate pore considerations into the theoretical derivations. Additionally, a modest 10% increase in ultimate tensile strength was observed during tensile loading. This finding suggests that field-assisted strengthening can be effective for as-received 3D-printed magnetic composites in their solidified state, provided that the material and field are optimally designed and implemented. This approach could propose a viable method for remote field tailoring to strengthen the material by mitigating defects induced during the 3D printing process.

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Magnet Assisted Composite Manufacturing: A Flexible New Technique for Achieving High Consolidation Pressure in Vacuum Bag/Lay-Up Processes

Cited by 5 publications

References 41 publications

Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool

Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool

Void reduction in VARTM composites by compaction of dry fiber preforms with stationary and moving magnets

Low Magnetic Field Induced Extrinsic Strains in Multifunctional Particulate Composites: An Interrupted Mechanical Strengthening in 3D-Printed Nanocomposites

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