Non‐destructive self‐healing design for carbon fiber/epoxy composites

Carbon composites are susceptible to invisible damage development such as matrix cracking, fiber kinking, and interfacial debonding upon external transverse loading. These incipient damages may interact to evolve into life‐limiting delamination propagating both in in‐plane and transverse directions. This study addressed that by interleaving carbon/epoxy composites with electrospun nylon 6 nanofibers adopting a double infusion method. Damage resistance results showed that the optimum nanofiber areal weight (17.35 g/m2) offered a 27% improvement in specific total toughness. The emergence of pseudo‐ductility substantially enhanced the plastic toughness (46.15%) of interleaved composites. The load required for initial matrix cracking was 65.49% higher, and number of matrix cracking events was suppressed by 84.11% at the optimum areal weight of interleave. Fractography revealed frequent interlaminar crossings and delamination crack bridging as two major toughness mechanisms. Both the external damage area and delaminated area increased with increment in nanofiber areal weight.Highlights Electrospun nanofibre interleaved carbon/epoxy composites were fabricated through a double infusion method to characterize damage resistance. Acoustic data of matrix cracking was rationalized to show the effectiveness of nanofiber interleaves in suppressing this damage type. Microstructural factors and mechanisms contributing to the improved toughness of optimally interleaved composites were identified. External damage/delaminated areas of interleaved composites were correlated with nanofiber areal weights.

Section: Introductionmentioning

confidence: 74%

Electrospun nanofiber interleaving through double infusion method to induce pseudo‐ductile damage resistance response in carbon/epoxy composites

Shakil,

Hassan,

Yahya

et al. 2024

“…Where CNTs can improve the electrical conductivity of composites, and the incorporation of CNTs in the shell of nanofibers enhances the self-healing and mechanical properties. 25 Tensile and flexural tests were conducted to evaluate the composite under different failure modes, and real-time resistance changes were collected and analyzed for in-situ damage monitoring. Furthermore, cyclic three-point bending experiments were performed on composites to evaluate the self-healing properties, and the damaged specimens were subjected to resistive heating during the healing process to expedite the healing process.…”

Section: Introductionmentioning

confidence: 99%

Carbon fiber reinforced composites with self‐sensing and self‐healing capabilities enabled by CNT‐modified nanofibers

Wan,

Shen,

Tang

et al. 2024

Self Cite

Carbon fiber reinforced polymer (CFRP) composites with self‐sensing and self‐healing capabilities was developed in this work. Uniform dispersion of CNTs within a core‐shell nanofiber structure was achieved through a combination of electrospinning and subsequent surface spraying of CNTs. The resulting core‐shell nanofibers were incorporated into CFRP composites using a vacuum‐assisted resin transfer molding process. Mechanical testing demonstrated improved mechanical properties in the composites treated with CNT spraying. Real‐time, precise monitoring of structural damage was enabled through the measurement of electrical signal changes caused by composite deformation in static loading experiments. Furthermore, self‐healing experiments demonstrated that the thermally conductive network formed by CNTs facilitated more uniform heat transfer within the composites. During the healing process, resistive heating of damaged specimens was applied, resulting in a remarkable healing efficiency of 95.2%. The experiments indicate that the composite developed in this paper possess excellent self‐sensing and self‐healing capabilities.Highlights Damage self‐sensing and self‐healing CFRP composites were developed. CNTs‐modified nanofibers were applied to endow the composite specific abilities. Resistivity signals were collected for real‐time damage monitoring. The self‐healing efficiency of the designed composite reached up to 95.2%. Self‐sensing and self‐healing occurred autonomously within closed‐loop structure.

“…After five cycles of bending tests, the residual bending strength of the samples still reached 75% of the original strength. Similarly, Wan et al 35 added carbon nanotubes (CNTs) into PAN core–shell nanofibers, and the flexural strength of the composites containing 1 wt% CNTs increased by 10% compared to the specimens without CNTs. Furthermore, the bending strength recovered to 93.57% after the first repair.…”

Section: Introductionmentioning

confidence: 99%

Low‐velocity impact response and post‐impact assessment of self‐healing composites with different stacking configurations of core–shell nanofibers

Cai,

Gan,

Chen

et al. 2023

This work investigates the low‐velocity impact (LVI) and self‐healing behavior of carbon fiber composite laminates interlaced with electrospun polyacrylonitrile core–shell nanofibers (PAN@CFRP). The main goal is to investigate the influence of different stacking configurations of core–shell nanofibers on the impact resistance and self‐healing properties of composite laminates. To achieve the purpose, three different stacking configurations were designed and tested alongside virgin specimens. The damage mechanism and self‐healing of laminates following LVI were determined using ultrasonic C‐scan and cross‐sectional microscopy examinations. At an impact energy of 14.1 J, the flexural strength of the post‐healing PAN‐3@CFRP specimen reached 95.0% of the initial value, whereas at an impact energy of 21.8 J, severe impact damage was observed in the laminates with different configurations. Among the laminates, the PAN‐1@CFRP specimen had the highest flexural strength after healing, which reached 80.1% of its pre‐impact strength. As observed, the impact resistance and self‐healing capacity of composites could be significantly enhanced by optimizing the distribution configuration of core–shell nanofibers for various impact energies.Highlights The introduction of electrospun core–shell nanofibers has not significantly compromised the mechanical properties of the composites, but rather enhanced their toughness. The addition of core–shell nanofibers significantly enhances the impact resistance of the composites and imparts excellent self‐healing properties to the material. The flexural strength of impact‐damaged specimens with different stacking configurations can be restored up to 95% of the undamaged specimen after repair treatment. Significantly improved impact resistance and self‐healing ability of laminates by optimizing the distribution configuration of core–shell nanofibers between composite layers.