Effects of low-velocity impact on vibration behaviors of polyamide fiber-reinforced composites

Coskun, Taner; Yar, Adem; Demir, Okan; Şahi̇n, Ömer Sinan

doi:10.1007/s40430-021-03322-9

Cited by 5 publications

(4 citation statements)

References 26 publications

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“…F I G U R E 9 Compression after impact responses for the nonimpacted, one impacted and two-impacted composites. 8.69 kN for non-impacted, one-impacted and twoimpacted specimens, respectively. The greatest peak force has occurred for non-impacted specimens, and reductions in peak forces were observed due to the degradation in the structural integrity with ascending impact numbers.…”

Section: Resultsmentioning

confidence: 97%

“…Due to their unique properties, composite materials, which are made up of a combination of two or more different materials, have received a lot of attention in recent years. [1][2][3][4][5][6][7][8][9][10] Glass-fiber, carbon-fiber and basalt-fiber composites achieved by mixing fibers with polymeric resin can be demonstrated as the most common examples. [11][12][13][14][15][16] These fiber-reinforced composite materials are extensively utilized in many engineering fields such as aerospace, aviation and automobile due to their high strength, lightweight, stiffness, resistance to environmental and corrosive factors, design originality and production advantages.…”

Section: Introductionmentioning

confidence: 99%

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Residual compressive strength of polyamide fiber‐reinforced epoxy composites after low‐velocity impact

et al. 2023

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In this study, polyamide fibers, which stand out with their excellent plastic deformation and energy absorption capacity, were used as reinforcement materials, and in‐house manufactured composite specimens were subjected to low‐velocity impact (LVI), compression after impact (CAI) and tensile tests. Within this scope, one and two repeated drop tests were performed under 3 m/s velocity to determine LVI responses and how impact number affects the dynamic properties. CAI tests were also performed at a 1 mm/min crosshead speed, and mechanical properties for non‐impacted, one‐impacted, and two‐impacted specimens were determined. As a result of the outstanding plastic deformation capacity of thermoplastic fabrics, it is concluded that polyamide composites exhibited quite large strains. Furthermore, it was understood from the tensile responses that tensile stresses were carried by the thermoplastic fibers in two different regimes and significantly high toughness was obtained. Moreover, reductions in the maximum compression loads, critical buckling loads and axial stiffness were observed due to degradation in structural integrity after impact loads. Additionally, the utilization of recyclable thermoplastic polyamide fibers as reinforcement material instead of conventional reinforcement materials such as carbon and glass fibers provide more environmentally friendly products.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Residual compressive strength of polyamide fiber‐reinforced epoxy composites after low‐velocity impact

et al. 2023

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“…Inherent damping can be defined as the energy dissipation within the structure, 39 and thermoplastic materials exhibit relatively higher damping due to their chemical structure and excellent energy absorption capacity. 38 These materials also exhibit high plastic deformation and ductility due to chain slippage during impact, which allows most of the applied energy to be encountered by thermoplastic materials, thus preventing serious damage to synthetic fibers. The energy distribution in such composites is influenced by the fiber-matrix interfaces, layer properties and orientations, as well as the forming matrix's viscoelastic nature.…”

Section: Resultsmentioning

confidence: 99%

“…In the second or subsequent impacts, the impact energy is encountered by the fibers due to the consequent decrement in the energy absorption capacity of the matrix, causing serious damage mechanisms such as delamination, fiber rupture, penetration, and so forth.For all these reasons, composites generally exhibit higher stiffness after first impact loadings, and then peak force and structural stiffness gradually decrease due to fiber damages caused by subsequent impacts 36 . On the other hand, the utilization of thermoplastic materials as inter‐ply veils 37 or fiber material 38 results in an increment in delamination resistance, impact‐induced deformation‐hardening, toughness and bending stiffness. The results achieved from the current study revealed that structural stiffness and consequently natural frequencies ascended after the first LVI loadings for almost all configurations of the CFRP and GFRP composites.…”

Section: Resultsmentioning

confidence: 99%

The influences of low‐velocity impact loading on the vibration responses of the carbon/glass fiber‐reinforced epoxy composites interleaved with various non‐woven thermoplastic veils

Tarih

Coskun

Yar

et al. 2023

J of Applied Polymer Sci

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Time‐dependent variable stresses that occur in composites subjected to mechanical and dynamic loads have devastating impacts on the material properties. Since these stresses reduce the service life, it is critical to detect and enhance structural responses before and after dynamic loadings. Therefore, the present study aimed to increase the toughness and delamination resistance of the conventional fiber‐reinforced composites by means of thermoplastic veil interleaves, thereby improving the vibration responses both before and after low‐velocity impact (LVI). In this context, carbon fiber (CF) and glass fiber (GF) reinforced epoxy composites interleaved with five different thermoplastic veils as Polyamide (PA), Polyetheretherketone (PEEK), Polyetherimide (PEI), Polyimide (PI) and Poly‐Phenylene Sulphide (PPS) were manufactured, and machined in accordance with the LVI standard. Composite specimens were subjected to the LVI tests, and then vibration tests were carried out for the non‐impacted and impacted specimens to determine dynamic properties. As a result, although thermoplastic veils generally have favorable effects on damping ratios of the GF composites, it has been revealed that these veils other than PPS and PI cause deterioration in CF composites. On the other hand, since vibration reduction depends on inherent damping and structural stiffness, this study also examined the storage‐to‐loss modulus ratios which denote the loss factors. In this respect, it was discovered that, while PPS, PEEK, PA, and PI thermoplastic veils included among the GF laminates ascend the loss factors of composites, only PI and PPS thermoplastic veils were shown to be positively effective in CF laminates. Moreover, CF and GF reinforced composites interleaved with thermoplastic veils generally exhibited higher natural frequency and lower damping ratio compared to the entirely CF or GF laminated composites. These results show that composite specimens gained bending stiffness due to local deformation hardening, and improved dynamic properties thanks to thermoplastic veil interleaved was attributed to increased toughness and delamination resistance.

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Dynamic responses and damage/element composition analysis of thermoplastic polyamide reinforced epoxy composites exposed to HCI environment

Coskun,

Sozen,

Sahin

2024

Polymer Composites

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The present study aimed to examine how the corrosive environment affected the low‐velocity impact (LVI) characteristics and damage mechanisms of thermoplastic polyamide fiber‐reinforced polymer (PFRP) composites. In this regard, composite specimens were subjected to corrosive environment containing 10 wt.% diluted HCl for one week and one month before LVI tests. To investigate the hostile effects of the corrosive environment on the composites, scanning electron microscope (SEM) coupled with energy‐dispersive X‐ray system (EDX) analyses were carried out, and thus variations in the elemental composition and damage mechanisms for the composites were determined. According to the examinations, it was discovered that the degradation in LVI responses, such as contact stiffness, bending stiffness, and peak force, increased with longer aging time, as expected. Furthermore, when the aging effect was assessed based on absorbed energy, the specimens exposed to a corrosive environment for one month exhibited the highest energy absorption compared to the control and 1‐week‐immersed ones. The degrading effect of the HCI environment appeared as higher damage severity on the composites, which was also detected from the SEM images. According to the SEM analyses, matrix cracks, corrosion pits, and local surface imperfections caused by ion exchange are detected in 1‐week‐immersed specimens, while more serious damage mechanisms such as fiber breakage and fiber pull‐out are noted in specimens exposed to corrosive environment for 1 month. Furthermore, approximately 6.33 wt.% CI was identified in the composites after 1 month of aging, which was associated with the hydrolysis triggered by rise in the composite's damage severity.Highlights Aging effects in mechanical properties of PFRP composites were investigated LVI tests were conducted to determine dynamic responses of aged composites Longer aging time led to more severe damages such fiber rupture, delamination etc. PFRP composites absorbed at least 68% of impact energy.

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Effects of low-velocity impact on vibration behaviors of polyamide fiber-reinforced composites

Cited by 5 publications

References 26 publications

Residual compressive strength of polyamide fiber‐reinforced epoxy composites after low‐velocity impact

Residual compressive strength of polyamide fiber‐reinforced epoxy composites after low‐velocity impact

The influences of low‐velocity impact loading on the vibration responses of the carbon/glass fiber‐reinforced epoxy composites interleaved with various non‐woven thermoplastic veils

Dynamic responses and damage/element composition analysis of thermoplastic polyamide reinforced epoxy composites exposed to HCI environment

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