Flexural behavior of carbon and glass fiber composite laminates reinforced with Nylon 6,6 electrospun nanofibers (original) (raw)
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Journal of Reinforced Plastics and Composites, 2015
Nylon 6,6 nanofibers were interleaved in the mid-plan of glass fiber/epoxy matrix composite laminates for Mode I and II fracture mechanic tests. The present study investigates the effect of the nanofibers on the laminates' mechanical response. Results showed that Nylon 6,6 nanofibers improved specimen's fracture mechanic behaviour: the initial energy release rates G IC and G IIC increased 62% and 109% respectively when nanofibrous interlayer was used. Scanning Electron Microscope (SEM) micrographs showed that nanofiber bridging mechanism enhances performances of the nanomodified specimens, still able to link the layers when the matrix is broken.
Composite Structures, 2014
The necessity to produce modern composites with an acceptable impact resistance is an essential task in automobile and aerospace industry that needs to be satisfied. This capability is addressed by noteworthy energy absorption augmentation which is the most vital characteristic of such composite materials. In this paper, nanofibers are applied as interleaves to modify the delamination strength with a minimum rise in weight and thickness of the high-modulus polypropylene/epoxy composites. Nylon 6,6 nanofibers are produced by the electrospinning method. The distribution of nanofibers across the mats is examined by SEM. Innegra fabrics have been applied in composite layers production. The proper hand lay-up manufacturing of the laminates has been assured by the assistance of a hydraulic press. The energy absorption capacity at the onset of breakdown and impact resistance of the nanomodified and non-modified laminates were determined by quasistatic three-point flexural for the former and low-velocity impact tests for the latter. The obtained results were compared. The results showed a 6.2 and 16.9% increase in the energy absorption capacity of nanomodified laminates in quasi-static three-point flexural test and low-velocity impact tests, respectively. In addition, low-velocity impact tests revealed 16 and 26% improvement in maximum load capacity.
Authors Figures Multimedia References Cited By Keywords Application of electrospun nanofibers for the improvements in mode-i fracture toughness of fiberglass composites Delamination is a major mode of failure in laminated composites. This paper addresses development of advanced delamination resistant composites using interlaminar SiO nanoflbers. The SiO nanoflbers were manufactured using Tetra Ethyl Orthosilicate (TEOS) sol gel. The sol gel viscosity of 100-200 cps Voltage of 18kV and distance between spinneret and grounded collector plate of 80 mm were found to be suitable for maximizing production of electrospun fibers. It was observed that typical electrospun fibers were of 300 nm diameter after they were sintered at 600 degrees C. These SiO nanoflbers produced using electrospinning were then integrated into fiber glass Epon 862 resin matrix composites. During mechanical characterization of these three phase (fiber glass+Epon 862+SiO nanoflbers) composites, extensive experimentation was carried out as per the ASTM D 5528 standard to study the influence of electrospun SiO nanoflbers on the Mode I fracture toughness of fiber glass composites. Other characterization studies were related to determining the effect of SiO nanoflbers on short beam shear strength, flexure properties, and tensile properties of three phase composites.
Ultra-thin electrospun nanofibers for development of damage-tolerant composite laminates
Materials Today Chemistry, 2019
The present article overcomes existing challenges ahead of inter-laminar toughening of novel multifunctional fibre-reinforced polymer composites via development and embedment of highly stretched, ultra-thin electrospun thermoplastic nanofibers made of polyamide 6.6. The nanofibers have exhibited significant enhancement of the composite laminate's structural integrity with almost zero weight penalty via ensuring a smooth stress transfer throughout the plies and serving tailoring mechanical properties in desired directions, with no interference with geometric features e.g. thickness. The findings for 1.5 grams per square meter (gsm) electrospun nanofibers have demonstrated, on test coupons specimens, improvements up to 85% and 43% in peak load and crack opening displacement, respectively, with significant improvement (> 25%) and no sacrifice of fracture toughness at both initiation and propagation phases. The initial stiffness for the modified specimens was improved by nearly 150%. The enhancement is mainly due to nano-fibres contributing to the stiffness of the resin rich area at the crack tip adjacent to the Polytetrafluoroethylene (PTFE) film. Glass fibre-reinforced woven phenolic preimpregnated composite plies have been modified with the nano-fibres (each layer having an average thickness of <1 micron) at 0.5, 1.0, 1.5, 2.0 and 4.0 gsm, electrospun at room temperature on each ply, and manufactured via autoclave vacuum bagging process. Inter-laminar fracture toughness specimens were manufactured for Mode I (double cantilever beam, DCB) fracture tests. It was found that there is threshold for electrospun nanofibers density, at which an optimum performance is reached in modified composite Manuscript File
Effect of Electrospun Nanofibers on the Short Beam Strength of Laminated Fiberglass Composite
2014
High specific modulus and strength are the most desirable properties for the material used in structural applications. Composite materials exhibit these properties and over the last decade, their usage has increased significantly, particularly in automotive, defense, and aerospace applications. The major cause of failures in composite laminates is due to delaminations. Delamination in composite laminates can occur due to fatigue, low velocity impact and other loadings modes. Conventional methods like “through-the-thickness stitching” or “Z-Pinning” have limitations for improving flexural and interlaminar properties in woven composites due to the fact that while improving interlaminar properties, the presence of stitches or Z pins affects inplane properties. This study investigates the flexural behavior of fiberglass composites interleaved with non-woven Tetra Ethyl Orthosilicate(TEOS) electrsopsun nanofibers(ENFs). TEOS ENFs were manufactured using an electrospinning technique and t...
Electrospun nanofibers as reinforcement for composite laminates materials - A Review
Composite Structures
In the last few decades nanofibers have been developed and introduced in a vast number of industrial and research applications. One of their most effective use is as interleaved reinforcement for composite laminate materials against delamination. Nanofibrous mats have the ideal morphology to be embedded between two plies of a laminate, and a vast and deep research has been carried out investigating their effect on the global behaviour of a composite laminate. This review is the first of its kind to date which presents a detailed state-ofthe-art on the effect of nanofibrous interleaves into composite laminates with focus on the mechanical performances and behaviours of nanomodified materials. A detailed description of the working mechanisms of the nanointerleave under different load cases is presented, and a comparative analysis between papers in literature will provide readers with a powerful tool to understand and use nanofibers for reinforcing purposes.
Impact Damage Resistance and Tolerance of Polymer Nanofiber Interleaved Composite Laminates
53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference<BR>20th AIAA/ASME/AHS Adaptive Structures Conference<BR>14th AIAA, 2012
The primary limitation of fiber reinforced composite laminates is their poor interlaminar strength and fracture toughness that result in poor impact damage resistance and tolerance. A number of methods have been tried to address this limitation. These methods are limited by factors such as increase in cost, weight, or loss of in-plane properties. A promising approach which does not degrade the in-plane properties is interleaving. Thermoplastic particle interleaving has been applied to reinforce laminates but the primary concern of in-plane properties degradation has not been addressed. Polymer nano-fiber interleaving was investigated in this dissertation as an alternative approach to particle interleaving. The concept showed promise because of the very high surface area to volume ratio and high strain to fracture of the interleaving Nylon-66 nanofibers. The objectives of the work were to determine the relationship between the electric field and the polymer flow-rate, to improve the electrospinning process, to assess lowvelocity impact damage resistance and tolerance, and to compare the performance of the base laminate to the interleaved laminate. An electrospinning setup with a collector current management technique was developed to match the electric field to the flow-rate. Twenty-four ply quasi-isotropic base and interleaved AS4/3501-6 composite laminates were produced. Interleaving was achieved with 0.7 g/m 2 nano-fabric. The impacted
A Review of Electrospun Nanofiber Interleaves for Interlaminar Toughening of Composite Laminates
polymers, 2023
Recently, polymeric nanofiber veils have gained lot of interest for various industrial and research applications. Embedding polymeric veils has proven to be one of the most effective ways to prevent delamination caused by the poor out-of-plane properties of composite laminates. The polymeric veils are introduced between plies of a composite laminate, and their targeted effects on delamination initiation and propagation have been widely studied. This paper presents an overview of the application of nanofiber polymeric veils as toughening interleaves in fiber-reinforced composite laminates. It presents a systematic comparative analysis and summary of attainable fracture toughness improvements based on electrospun veil materials. Both Mode I and Mode II tests are covered. Various popular veil materials and their modifications are considered. The toughening mechanisms introduced by polymeric veils are identified, listed, and analyzed. The numerical modeling of failure in Mode I and Mode II delamination is also discussed. This analytical review can be used as guidance for veil material selection, for estimation of the achievable toughening effect, for understanding the toughening mechanism introduced by veils, and for the numerical modeling of delamination.
Composites Part B: Engineering, 2015
This work simulates numerically Double Cantilever Beam and End Notched Flexure experiments on Carbon Fiber Epoxy Resin specimens that have been performed by some of the authors in a previous work. Specimens have been nanomodified by interleaving plies with a layer of electrospun nanofibers in the delaminated interface. Eight different configurations of nanofibers have been used as interleave, for a total of 9 configurations (8 nanomodified plus the virgin one) to be simulated for both kind of tests to identify the cohesive zone parameters corresponding to the effect of nanofiber diameter, nanolayer thickness and nanofiber orientation on the delamination behaviour of the composite. Results showed that a bilinear damage law is necessary for almost all nanomodified configurations, and presented a clear relationship between nanomat layer parameters and the cohesive energy of the interface.
Delivering interlaminar reinforcement in composites through electrospun nanofibres
Advanced Manufacturing: Polymer & Composites Science, 2019
Electrospun nonwoven veils comprising thermoplastic fibres (average diameter 400-600 nm) based on polysulfone (PSU), polyamide (PA-6,6), and polyetherimide (PEI) have been fabricated and used as interlaminar reinforcements in carbon fibre composites containing a commercial epoxy resin (8552/IM7). Samples were tested for their interlaminar properties and improvements were observed in the initial mode I interlaminar toughness of 30% (PA-6,6), 36% (PEI), and 44% (PSU), while improvements of 7% (PSU) and 8% (PEI) were observed in the propagation of the mode I interlaminar toughness. A reduction of 11% was observed for the propagation of the mode I interlaminar toughness for PA-6,6. Post-testing analysis of the cross-section and the fracture surface revealed that the crack front avoids the reinforcement significantly for PA-6,6. For mode II, however, this failure mechanism leads to improvements of 30% in interlaminar toughness for the PA-6,6, whereas the other reinforcements display negligible (PEI) and 31% reduction (PSU) interlaminar toughness.