scholarly journals Effect of Thermal Ageing on the Impact Damage Resistance and Tolerance of Carbon-Fibre-Reinforced Epoxy Laminates

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 160 ◽  
Author(s):  
Irene García-Moreno ◽  
Miguel Caminero ◽  
Gloria Rodríguez ◽  
Juan López-Cela
Keyword(s):  
Carbon Fibre ◽  
Residual Strength ◽  
Composite Structures ◽  
Impact Resistance ◽  
Thermal Ageing ◽  
Low Velocity Impact ◽  
Impact Tests ◽  
Compression After Impact ◽  
Structural Applications ◽  
The Impact

Composite structures are particularly vulnerable to impact, which drastically reduces their residual strength, in particular, at high temperatures. The glass-transition temperature (Tg) of a polymer is a critical factor that can modify the mechanical properties of the material, affecting its density, hardness and rigidity. In this work, the influence of thermal ageing on the low-velocity impact resistance and tolerance of composites is investigated by means of compression after impact (CAI) tests. Carbon-fibre-reinforced polymer (CFRP) laminates with a Tg of 195 °C were manufactured and subjected to thermal ageing treatments at 190 and 210 °C for 10 and 20 days. Drop-weight impact tests were carried out to determine the impact response of the different composite laminates. Compression after impact tests were performed in a non-standard CAI device in order to obtain the compression residual strength. Ultrasonic C-scanning of impacted samples were examined to assess the failure mechanisms of the different configurations as a function of temperature. It was observed that damage tolerance decreases as temperature increases. Nevertheless, a post-curing process was found at temperatures below the Tg that enhances the adhesion between matrix and fibres and improves the impact resistance. Finally, the results obtained demonstrate that temperature can cause significant changes to the impact behaviour of composites and must be taken to account when designing for structural applications.

Improvement of Biocomposite Performance under Low-Velocity Impact Test - A Review

2021 ◽  
Vol 893 ◽  
pp. 67-74
Author(s):  
Usha Kiran Sanivada ◽  
Gonzalo Mármol ◽  
Francisco P. Brito ◽  
Raul Fangueiro
Keyword(s):  
Composite Structures ◽  
Impact Test ◽  
Impact Resistance ◽  
Vital Role ◽  
Low Velocity Impact ◽  
Efficient Design ◽  
Low Velocity ◽  
Velocity Impact ◽  
Impact Tests ◽  
The Impact

The study of the impact energy and the composite behaviour plays a vital role in the efficient design of composite structures. Among the various categories of impact tests, it is essential to study low-velocity impact tests as the damage generated due to these loads is often not visible to the naked eye. The internal damages can reduce the strength of the composites and hence the impact behaviour must be addressed specifically for improving their applications in the transport industry. The main aim of this paper is to provide a comprehensive review of the work focusing on the assessment of biocomposites performance under low impact velocity, the different deformations, and damage mechanisms, as well the methods to improve the impact resistance.

scholarly journals Enhanced Impact-Resistance of Aeronautical Quasi-Isotropic Composite Plates Through Diffused Water Molecules in Epoxy

2020 ◽  
Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Mazhar Ul-Islam ◽  
Frédéric JACQUEMIN ◽  
Jung-Wuk Hong
Keyword(s):  
Carbon Fiber ◽  
Impact Resistance ◽  
Composite Plates ◽  
Hot Water ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Segmental Mobility ◽  
Impact Tests ◽  
Isotropic Composite ◽  
The Impact

Abstract In order to elucidate the hygroscopic effects on impact-resistance of carbon fiber/epoxy quasi-isotropic composite plates, low-velocity impact tests are conducted on dry and hygroscopically conditioned plates, respectively, under identical configurations. For the impact tests, plates were immersed in the hot water at 80 °C to absorb a different amount of moisture content (MC). Experimental results reveal that the presence of the MC plays a pivotal role by improving the impact-resistance of composite plates. Plates with higher percentage of MC could behave elastically to a larger strain, yielding larger deflection under impact loading. From SEM fractographies, it is observed that small disbanding grows at the interface of epoxy and carbon fiber due to absorbed MC. After absorbing MC, most of impact enegy is dissipated in hygroscopic conditioned composite plates throught elastic deformation and overall less damage is induced in wet composite plates compare to the dry plate. We can postulate that the presence of MC increases the elastic limit as well as ductility of the epoxy by promoting chain segmental mobility of the polymer molecules, which eventually leads to the enhancement of the impact-resistance of wet quasi-isotropic composite plates in comparison with the dry plate.

scholarly journals Experimental analysis of impact and post-impact behaviour of inserts in Carbon sandwich structures

2017 ◽  
Vol 21 (1) ◽  
pp. 135-153 ◽  
Author(s):  
Laurent Mezeix ◽  
Simon Dols ◽  
Christophe Bouvet ◽  
Bruno Castanié ◽  
Jean-Paul Giavarini ◽  
...  
Keyword(s):  
Sandwich Structures ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Failure Patterns ◽  
Impact Tests ◽  
Compression After Impact ◽  
Post Impact ◽  
Pull Through ◽  
Failure Scenario ◽  
The Impact

In aeronautics, honeycomb sandwich structures are widely used for secondary structures such as landing gear doors, flaps or floors, and for primary structures in helicopters or business jets. These structures are generally joined by using local reinforcements of the insert type. In the present study, 50 J low velocity impact tests were performed on inserts using a drop-weight device and the impact response and failure patterns were analysed. Impacted specimens were then pull-through tested to failure. Some of the tests were stopped before final failure in order to obtain precise details on the failure scenario. It was shown that, in the cases studied, the residual strength after impact was very high (about 90%) in comparison to the large reductions habitually observed in compression after impact tests.

scholarly journals Enhanced impact-resistance of aeronautical quasi-isotropic composite plates through diffused water molecules in epoxy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Furqan Ahmad ◽  
Fethi Abbassi ◽  
Mazhar Ul-Islam ◽  
Frédéric Jacquemin ◽  
Jung-Wuk Hong
Keyword(s):  
Carbon Fiber ◽  
Impact Resistance ◽  
Composite Plates ◽  
Hot Water ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Segmental Mobility ◽  
Impact Tests ◽  
Isotropic Composite ◽  
The Impact

AbstractIn order to elucidate the hygroscopic effects on impact-resistance of carbon fiber/epoxy quasi-isotropic composite plates, low-velocity impact tests are conducted on dry and hygroscopically conditioned plates, respectively, under identical configurations. For the impact tests, plates were immersed in the hot water at 80 °C to absorb a different amount of moisture content (MC). Experimental results reveal that the presence of the MC plays a pivotal role by improving the impact-resistance of composite plates. Plates with higher percentage of MC could behave elastically to a larger strain, yielding larger deflection under impact loading. From SEM fractographies, it is observed that small disbanding grows at the interface of epoxy and carbon fiber due to absorbed MC. After absorbing MC, most of impact energy is dissipated in hygroscopic conditioned composite plates through elastic deformation and overall less damage is induced in wet composite plates compare to the dry plate. We can postulate that the presence of MC increases the elastic limit as well as ductility of the epoxy by promoting chain segmental mobility of the polymer molecules, which eventually leads to the enhancement of the impact-resistance of wet quasi-isotropic composite plates in comparison with the dry plate.

Impact response of nanoparticle reinforced 3D woven spacer/epoxy composites at cryogenic temperatures

2021 ◽  
pp. 002199832110370
Author(s):  
Ferhat Yıldırım ◽  
Ahmet Caner Tatar ◽  
Volkan Eskizeybek ◽  
Ahmet Avcı ◽  
Mustafa Aydın
Keyword(s):  
Composite Structures ◽  
Impact Resistance ◽  
Low Velocity Impact ◽  
Woven Composites ◽  
Cryogenic Temperatures ◽  
Low Velocity ◽  
Impact Performance ◽  
Fiber Reinforced Polymer Composites ◽  
3D Woven Composites ◽  
The Impact

Fiber-reinforced polymer composites serving in harsh conditions must maintain their performance during their entire service. The cryogenic impact is one of the most unpredictable loading types, leading to catastrophic failures of composite structures. This study aims to examine the low-velocity impact (LVI) performance of 3D woven spacer glass-epoxy composite experimentally under cryogenic temperatures. LVI tests were conducted under various temperatures ranging from room temperature (RT) to −196°C. Experimental results reveal that the 3D composites gradually absorbed higher impact energies with decreasing temperature. Besides, the effect of multi-walled carbon nanotube and SiO2 nanofiller reinforcements of the matrix on the impact performance and the damage characteristics were further assessed. Nanofiller modification enhanced the impact resistance up to 30%, especially at RT. However, the nanofiller efficiency declined with decreasing temperature. The apparent damages were visually examined by scanning electron microscopy to address the damage formation. Significant outcomes have been achieved with the nanofiller modification regarding the new usage areas of 3D woven composites.

scholarly journals Effects of Hybridisation on the Low Velocity Falling Weight Impact and Flexural Properties of Flax-Carbon/Epoxy Hybrid Composites

Fibers ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 95 ◽  
Author(s):  
Matthew Chapman ◽  
Hom Nath Dhakal
Keyword(s):  
Carbon Fibre ◽  
Product Life Cycle ◽  
Material Selection ◽  
Hybrid Composites ◽  
Real Life ◽  
Low Velocity Impact ◽  
Flexural Properties ◽  
Low Velocity ◽  
Structural Applications ◽  
The Impact

The trend of research and adoption of natural plant-based fibre reinforced composites is increasing, with traditional synthetic fibres such as carbon and glass experiencing restrictions placed on their manufacture and use by legislative bodies due to their environmental impact through the entire product life cycle. Finding suitable alternatives to lightweight and high-performance synthetic composites will be of benefit to the automotive, marine and aerospace industries. This paper investigates the low-velocity impact (LVI) and flexural properties and damage characteristics of flax-carbon/epoxy hybrid composites to be used in structural lightweight applications. LVI, for example, is analogous to several real-life situations, such as damage during manufacture, feasibly due to human error such as the dropping of tools and mishandling of the finished product, debris strikes of aircraft flight, or even the collision of a vessel with another. Carbon fibre has been hybridised with flax fibres to achieve enhanced impact and flexural performance. The failure mechanisms of woven flax and flax-carbon epoxy hybrid composites have been further analysed using Scanning Electron Microscopy (SEM). It was observed from the experimental results that carbon fibre hybridisation has a significant effect on the impact and flexural properties and their damage modes. The results obtained from this study exhibited that the flexural strength and modulus of plain flax/epoxy composite increase significantly from 95.66 MPa to 425.87 MPa and 4.78 GPa to 17.90 GPa, respectively, with carbon fibre hybridisation. This significant improvement in flexural properties would provide designers with important information to make informed decisions during material selection for lightweight structural applications.

scholarly journals Effect of Uniaxial Fatigue Aging and Fabric Orientation on Low Impact Velocity Response of Glass Fibers/Elium Acrylic Composite Laminates

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4089
Author(s):  
Tomasz Libura ◽  
Rodrigue Matadi Boumbimba ◽  
Alexis Rusinek ◽  
Zbigniew L. Kowalewski ◽  
Tadeusz Szymczak ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Impact Energy ◽  
Composite Structures ◽  
Glass Fibers ◽  
Impact Resistance ◽  
Woven Fabric ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Engineering Structures ◽  
The Impact

Impact resistance is one of the most critical features of composite structures, and therefore, its examination for a new material has a fundamental importance. This paper is devoted to the characterization of the fully recyclable thermoplastic ELIUM acrylic resin reinforced by glass fabric woven, which belongs to a new category of materials requiring advanced testing before their application in responsible elements of engineering structures. Its high strength, low weight as well as low production cost give excellent opportunities for its wide application in the automotive industry as a replacement of the thermoset-based laminates. The study presents an experimental work concerning the effect of damage due to low and high cyclic fatigue aging of two groups of specimens, first with the woven fabric orientations of [0°/90°]4 and secondly with [45°/45°]4, on the low impact velocity properties. The impact resistance was measured in terms of load peak, absorbed energy, penetration threshold and damage analysis. The low velocity impact results indicate that the uniaxial cyclic loading (fatigue aging) of the material leads to the reduction of impact resistance, especially at the high impact energy levels. Scanning Electron Microscopy (SEM) and Computed Tomography (CT) scan observations reveal that the damage area grows with the increase of both strain amplitude and impact energy.

Development of a mathematical model to analyze residual strength of composites after low-velocity impact

2018 ◽  
Vol 53 (8) ◽  
pp. 738-745 ◽  
Author(s):  
Camila Medeiros Dantas de Azevedo ◽  
Rayane Dantas da Cunha ◽  
Raimundo Carlos Silverio Freire Junior ◽  
Wanderley Ferreira de Amorim Junior
Keyword(s):  
Residual Strength ◽  
Composite Laminates ◽  
Repair Process ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Velocity Impact ◽  
Three Point Bending ◽  
Compression After Impact ◽  
Strength And Stiffness ◽  
The Impact

This study aimed to develop a model to analyze the residual strength of composites after low-velocity impact, using three-point bending and compression after impact tests. Two types of composite laminates with an orthophthalic polymer matrix were used: one reinforced with bidirectional E-glass fabric and the other reinforced with bidirectional Kevlar-49 fabric. To that end, an equation was developed to assess loss of strength and stiffness after impact at different distances from the impact point, and this equation was not found in any previously searched article. The results demonstrate that the laminate based in glass fiber is more appropriate for the repair process.

Low Velocity Impact Resistance of CPVC Pipes Exposed to Natural Outdoor Weathering Conditions

2012 ◽  
Vol 445 ◽  
pp. 959-964
Author(s):  
Z. Khan ◽  
Necar Merah ◽  
A. Bazoune ◽  
S. Furquan
Keyword(s):  
Impact Resistance ◽  
Outdoor Exposure ◽  
Impact Testing ◽  
Low Velocity Impact ◽  
Pipe Material ◽  
Low Velocity ◽  
Impact Energies ◽  
The Impact ◽  
Impact Events ◽  
Outdoor Weathering

Low velocity drop weight impact testing of CPVC pipes was conducted on 160 mm long pipe sections obtained from 4-inch (100 mm) diameter schedule 80 pipes. Impact test were carried out for the base (as received) pipes and after their exposure to out door natural weathering conditions in Dhahran, Saudi Arabia. The results of the impact testing on the natural (outdoor exposure) broadly suggest that the natural outdoor exposures produce no change in the impact resistance of CPVC pipe material for the impact events carrying low incident energies of 10 and 20J. At the impact energies of 35 and 50J the natural outdoor exposures appear to cause appreciable degradation in the impact resistance of the CPVC pipe material. This degradation is noted only for the longer exposure periods of 12 and 18 months.

Low Velocity and Compression-After-Impact Response of Pin-Reinforced Sandwich Composites

1999 ◽  
Author(s):  
Uday K. Vaidya ◽  
Mohan V. Kamath ◽  
Mahesh V. Hosur ◽  
Anwarul Haque ◽  
Shaik Jeelani
Keyword(s):  
Impact Testing ◽  
Low Velocity Impact ◽  
Sandwich Composites ◽  
Low Velocity ◽  
Static Compression ◽  
Velocity Impact ◽  
Transverse Stiffness ◽  
Impact Studies ◽  
Compression After Impact ◽  
The Impact

Abstract In the current work, sandwich composite structures with innovative constructions referred to as Z-pins, or truss core pins are investigated, in conjunction with traditional honeycomb and foam core sandwich constructions, such that they exhibit enhanced transverse stiffness, high damage resistance and furthermore, damage tolerance to impact. While the investigations pertaining to low velocity impact have appeared recently in Vaidya et al. 1999, the current paper deals with compression-after-impact studies conducted to evaluate the residual properties of sandwich composites “with” and “without” reinforced foam cores. The resulting sandwich composites have been investigated for their low velocity (< 5 m/sec) impact loading response using instrumented impact testing at energy levels ranging from 5 J to 50 J impact energy. The transverse stiffness of the cores and their composites has also been evaluated through static compression studies. Compression-after-impact studies were then performed on the sandwich composites with traditional and pin-reinforcement cores. Supporting vibration studies have been conducted to assess the changes in stiffness of the samples as a result of the impact damage. The focus of this paper is on the compression-after-impact (CAI) response and vibration studies with accompanying discussion pertaining to the low velocity impact.

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