Validation of Microscopy Measured Porosity in Carbon Fibbers Composites

AbstractOne of the most common defects in carbon fibre reinforced plastics (CFRP) is porosity. Too much of those defects could be serious problems to mechanical properties, which directly take effect on elements safety, like aircrafts. Therefore, the evaluation of porosity is very important test. Microscopic observations are widely used as a quality instrument in materials and constructions inspections. Cross section image of a material is easy to prepare and analyse. Porosity of a carbon fibre reinforced plastic can be clearly spot in such kind of images. Study shows that in the most cases porosity appear between layers of fibres, rather between fibres. Unfortunately, image from microscope is only 2D picture from a small representative region. Because of that, comparison of 2D image to a real porosity distribution in all volume of a material is very difficult. To verify 2D microscopic observation method is necessary to perform another kind of tests. In this article, authors focused on non-destructive (NDT) and destructive testing methods. 2D porosity images from light microscope were compared with three different testing methods: ultrasonic test (UT), computed tomography (CT) test and constituent content of composite materials standard test method according to ASTM D3171 – 15, procedure B. Porosity results obtained from dissolution of resin from the carbon-epoxy resin sample.

Download Full-text

Damage assessment of carbon fibre reinforced plastic using acoustic emission technique: experimental and numerical approach

Structural Health Monitoring ◽

10.1177/1475921720946438 ◽

2020 ◽

pp. 147592172094643

Author(s):

Claudia Barile ◽

Caterina Casavola ◽

Giovanni Pappalettera ◽

Vimalathithan Paramsamy Kannan

Keyword(s):

Finite Element ◽

Acoustic Emission ◽

Carbon Fibre ◽

Crack Length ◽

Research Work ◽

Numerical Approach ◽

Acoustic Energy ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Carbon Fibre Reinforced Plastic

In this research work, the acoustic emission results obtained from testing double cantilever beam specimens with carbon fibre reinforced plastic laminates are analysed. The acoustic emission descriptors such as amplitude, frequency centroid, counts, duration and risetime are clustered using k-means++ algorithm. An unconventional and innovative way of using the acoustic emission descriptors, after the clustering, is introduced. This method can favourably be used for relating the different damage progression modes in fibre reinforced plastics. Apart from this, the cumulative acoustic energy is used for predicting the crack length of the specimens. The predicted crack length is almost identical to the actual crack length opening recorded in each specimen. Finally, analytical and finite element models are used for validating the experimental results under the mode I delamination. The finite element studies are carried out using cohesive zone modelling in Comsol Multiphysics® platform.

Download Full-text

Engineering of three-dimensional near-net-shape weave structures for high technical performance in carbon fibre–reinforced plastics

Journal of Engineered Fibers and Fabrics ◽

10.1177/1558925019861239 ◽

2019 ◽

Vol 14 ◽

pp. 155892501986123

Author(s):

Stefan Schindler ◽

Hans-Jürgen Bauder ◽

Jürgen Wolfrum ◽

Jürgen Seibold ◽

Nemanja Stipic ◽

...

Keyword(s):

Carbon Fibre ◽

Material Flow ◽

Three Dimensional ◽

Cost Accounting ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Weaving Technology ◽

Near Net Shape ◽

Carbon Fibre Reinforced Plastic ◽

Carbon Fibre Reinforced Plastics

To tap the full potential of reinforcing fibres for lightweight construction of sustainable carbon fibre–reinforced plastic components, woven three-dimensional reinforcement structures open up innovative approaches by integrating functional features. In this work, a novel three-dimensional shuttle weaving technology was taken advantage of to study carbon reinforcement structures with uninterrupted load trajectories from three points of view. Mechanical principals, economic and environmental issues were focused to provide an overall picture. Near-net-shape reinforcement fabrics with load trajectory–compliant yarn paths and interconnected layers that are interwoven in thickness direction were objects of investigation. The effects of a closed fabric selvedge, only producible by shuttle weaving, were investigated too. The here presented novel technology enables complex woven reinforcement structures that otherwise would demand several fabric layers leading to limited properties and lower performance of the carbon fibre–reinforced plastics due to missing interconnections between the layers. The studies on exemplary rods revealed a close relationship between different three-dimensional weave structures and the carbon fibre–reinforced plastic’s mechanical properties. The three-dimensional structures were woven in a single-step process and subsequently infiltrated with epoxy resin in the Vacuum Assisted Process (VAP®) and mechanically tested. Rounding off, universal guidelines for the layout of three-dimensional fabrics for rods were derived therefrom. The economic and environmental aspects of the complete process line were compared to the conventional manufacturing procedures for carbon fibre–reinforced plastic by material flow cost accounting. Looking at sustainability, material flow cost accounting showed that lightweight three-dimensional components with integrated features can be produced cost-effectively with less environmental impact by the novel weaving technology. Its capability for high-quality serial production of three-dimensional reinforcement structures is evident, which was one major result of the work.

Download Full-text

Study of thermophysics during diamond drilling of fibreglass and carbon fibre-reinforced polymer composites

Proceedings of Irkutsk State Technical University ◽

10.21285/1814-3520-2021-3-290-299 ◽

2021 ◽

Vol 25 (3) ◽

pp. 290-299

Author(s):

A. S. Dudarev ◽

E. Kh. Gumarov

Keyword(s):

Composite Materials ◽

Carbon Fibre ◽

Polymer Composite ◽

Polymer Composite Materials ◽

Temperature Fields ◽

Comsol Multiphysics ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Carbon Fibre Reinforced Plastic ◽

Carbon Fibre Reinforced Plastics

This paper examines thermophysics of the drilling process of polymeric composite materials, such as carbon-fibre-reinforced plastics (CFRP) and fibreglass by tubular diamond drill bits. Features of the COMSOL Multiphysics engineering software package were used. We employed Fourier heat equations, which express the intensity of heat gain by a mobile source in a moving coordinate system. The research was performed using the proprietary method of modelling spatial thermal action upon drilling polymer composite materials (fibreglass and carbon-fibre-reinforced plastics) in the COMSOL Multiphysics software environment. A tubular diamond drill bit with a diameter of 10 mm with two slots was chosen as a model cutting tool. Solid plates with a thickness of 5.5 mm made of layered fibrous polymer composite materials (fibreglass, carbon-fibre-reinforced plastic) were used as a preform. As a result of computer calculations, we obtained temperature fields of fibreglass and carbon-fibre-reinforced plastic during diamond drilling with a tubular tool. When studying the thermal behaviour of fibreglass and carbon-fibre-reinforced plastics, maximum temperature fields were located. The study revealed that the temperature reaches 413.6 and 448.7 K during CFRP and fibreglass drilling, respectively. It was shown that the distance of heat transfer from the edge of the hole into the preform was 6.42 and 6.40 mm for CFRP and fibreglass, respectively. A method of modelling the thermal effects when cutting polymer composite materials developed in the COMSOL Multiphysics environment allows complex analytical calculations of temperatures induced by drilling to be simplified. In addition, its use prevents overheating of a preform during drilling, allows assessing the depth of heat distribution inside the preform from the edge of the formed hole in different polymer composite materials. These measures increase the machining quality of polymer composite materials.

Download Full-text

Adhesive behaviour of carbon fibre reinforced plastic panels manufactured using woven and unidirectional tape after ultraviolet laser surface treatment

Journal of Composite Materials ◽

10.1177/0021998317718614 ◽

2017 ◽

Vol 52 (7) ◽

pp. 853-865 ◽

Cited By ~ 5

Author(s):

Marta Botana-Galvín ◽

Ginesa Blanco ◽

Leandro González-Rovira ◽

Miguel A Rodríguez ◽

Francisco J Botana

Keyword(s):

Carbon Fibre ◽

Surface Treatment ◽

Laser Treatment ◽

Photoelectron Spectroscopy ◽

Adhesive Bonding ◽

Processing Parameters ◽

Ultraviolet Laser ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Carbon Fibre Reinforced Plastic

This paper describes the results obtained when ultraviolet laser treatment was performed as a surface treatment prior to adhesive bonding for two aeronautical carbon fibre-reinforced plastics based on an epoxy resin prepreg. Different laser-processing parameters were employed, and their effect on the surfaces was analysed through morphological characterisation and wettability studies. X-ray photoelectron spectroscopy measurements were performed to determine the cleaning and activation effects of the treatment. The strength of the bonded joint was studied for laser-treated and manually ground samples. Samples processed under the selected laser conditions exhibited better adhesive behaviour than the manually treated samples, thereby suggesting that ultraviolet laser treatment could be used as an alternative method for surface activation of aeronautical composites based on epoxy resins.

Download Full-text

Studying a grinding method of sapphire pipes using two grinders

Proceedings of Irkutsk State Technical University ◽

10.21285/1814-3520-2021-3-320-331 ◽

2021 ◽

Vol 25 (3) ◽

pp. 320-331

Author(s):

I. V. Savitsky ◽

V. A. Voytenko

Keyword(s):

Composite Materials ◽

Carbon Fibre ◽

Polymer Composite ◽

Polymer Composite Materials ◽

Temperature Fields ◽

Comsol Multiphysics ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Carbon Fibre Reinforced Plastic ◽

Carbon Fibre Reinforced Plastics

This paper examines the thermophysics of a drilling process of polymeric composite materials such as carbonfibre-reinforced plastics (CFRP) and fibreglass by tubular diamond drill bits. Features of the COMSOL Multiphysics engineering software package were used. We employed Fourier heat equations, which express the intensity of heat gain by a mobile source in a moving coordinate system. The research was performed using the proprietary method of modelling spatial thermal action upon drilling polymer composite materials (fibreglass and carbon-fibre-reinforced plastics) in the COMSOL Multiphysics software environment. A tubular diamond drill bit with a diameter of 10 mm with two slots was chosen as a model cutting tool. Solid plates with a thickness of 5.5 mm made of layered fibrous polymer composite materials (fibreglass, carbon-fibre-reinforced plastic) were used as a preform. As a result of computer calculations, we obtained temperature fields of fibreglass and carbon-fibre-reinforced plastic during diamond drilling with the tubular tool. When studying the thermal behaviour of fibreglass and carbon-fibre-reinforced plastics, maximum temperature fields were located. The study revealed that the temperature reaches 413.6 K and 448.7 K during CFRP and fibreglass drilling, respectively. It was shown that the distance of heat transfer from the edge of the hole into the preform was 6.42 and 6.40 mm for CFRP and fibreglass, respectively. A method of modelling the thermal effects when cutting polymer composite materials developed in the COMSOL Multiphysics environment allows complex analytical calculations of temperatures induced by drilling to be simplified. In addition, it helps avoid overheating of a preform during drilling, allows the depth of heat distribution inside the preform from the edge of the formed hole in different polymer composite materials to be assessed. These measures lead to increasing the machining quality of polymer composite materials.

Download Full-text

Thermo-Mechanical Monitoring of Composite Materials during the Pyrolysis of C/C Composites

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.425.95 ◽

2010 ◽

Vol 425 ◽

pp. 95-105 ◽

Cited By ~ 2

Author(s):

Bernhard Wielage ◽

Daisy Weber ◽

Tobias Müller ◽

Heike Steger

Keyword(s):

Carbon Fibre ◽

Structural Properties ◽

Ambient Pressure ◽

Pyrolysis Process ◽

Reinforced Plastics ◽

Reinforced Plastic ◽

Mechanical And Structural Properties ◽

Carbon Fibre Reinforced Plastic ◽

Tan Δ ◽

Short Time

Conventional mechanical and structural properties allow to describe the complete composite material. They do, however, not describe the reaction during the pyrolysis process. The dynamic mechanical thermal analysis (DMTA) is a technique which is used to characterize materials. In particular, the DMTA method is used to observe the viscoelastic nature of polymers. Another interesting application area of the DMTA is the simulation of pyrolysis experiments to obtain carbon/carbon composites (C/C composites). The pyrolysis process of carbon-fibre-reinforced plastics (CFRP) was performed by means of inert gas (Ar, ambient pressure) under a defined time-temperature profile or alternatively approached by short time sweeps in a DMTA. So the temperature dependence of the elastic modulus (E-modulus) and of the internal damping (tan δ) are determined starting from the cured carbon-fibre-reinforced plastic to the transformed C/C composites. The analyses were applied for different matrix resins. The shown method improves the access to usually hidden mechanical and structural properties and requires further investigation of the entire polymerization and pyrolysis processes.

Download Full-text