scholarly journals Fibre Alignment and Void Assessment in Thermoplastic Carbon Fibre Reinforced Polymers Manufactured by Automated Tape Placement

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 473
Author(s):  
Tamer A. Sebaey ◽  
Mohamed Bouhrara ◽  
Noel O’Dowd
Keyword(s):  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Ct Scans ◽  
Void Content ◽  
Reinforced Polymers ◽  
Fibre Distribution ◽  
Thermoset Composites ◽  
The Matrix ◽  
Carbon Fibre Reinforced Polymers ◽  
Multiple Melting

Automated Tape Placement (ATP) technology is one of the processes that is used for the production of the thermoplastic composite materials. The ATP process is complex, requiring multiple melting/crystallization cycles. In the current paper, laser-assisted ATP was used to manufacture two thermoplastic composites (IM7/PEEK and AS4/PA12). Those specimens were compared to specimens that were made of thermoset polymeric composites (IM7/8552) manufactured while using a standard autoclave cycle. In order assess the quality, void content, fibre distribution, and fibre misalignment were measured. After manufacturing, specimens from the three materials were assessed using optical microscopy and computed tomography (CT) scans. The results showed that, as compared to the thermoset composites, thermoplastics that are manufactured by the ATP have a higher amount of voids. On the other hand, manufacturing using the ATP showed an improvement in both the fibre distribution inside the matrix and the fibre misalignment.

scholarly journals Ultrasonic welding of epoxy- to polyetheretherketone- based composites: Investigation on the material of the energy director and the thickness of the coupling layer

2020 ◽  
Vol 54 (22) ◽  
pp. 3081-3098 ◽  
Author(s):  
Eirini Tsiangou ◽  
Sofia Teixeira de Freitas ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Mechanical Performance ◽  
High Strength ◽  
Ultrasonic Welding ◽  
Thermoplastic Composite ◽  
Thermoset Composites ◽  
Excellent Candidate ◽  
The Matrix ◽  
Energy Director ◽  
Epoxy Systems ◽  
Composite Samples

Ultrasonic welding is a highly promising technique for joining thermoplastic to thermoset composites. A neat thermoplastic coupling layer is co-cured on the surface to be welded to make the thermoset composite ‘weldable’. A reliable bond is attained when miscible thermoplastic and thermoset materials are chosen. For welding carbon fibre/polyetheretherketone (PEEK) to thermoset composite samples, a PEEK film is not preferable due to its immiscibility with epoxy resins. On the other hand, polyetherimide is an excellent candidate, since it is known to be miscible to most epoxy systems at high temperatures and PEEK polymers. This study focusses on two main subjects; firstly, the nature of the material of the energy director, i.e. a flat thermoplastic film used to promote heat generation at the interface. In this case, the energy director can be either polyetherimide, as in the coupling layer or PEEK material, as in the matrix of the thermoplastic composite adherend. It was found that both materials can produce welds with similar mechanical performance. This study focusses secondly on the thickness of the coupling layer. Due to the high melting temperature of the PEEK matrix, a 60-µm-thick coupling layer was seemingly too thin to act as a thermal barrier for the epoxy resin for heating times long enough to produce fully welded joints. Such an issue was found to be overcome by increasing the thickness of the coupling layer to 250 µm, which resulted in high-strength welds.

On the Manufacturing Defects of Thermoplastic Carbon/Epoxy Composites Manufactured by Automated Tape Placement

2020 ◽  
Author(s):  
Tamer A. Sebaey ◽  
Noel O’Dowd
Keyword(s):  
Solidification Process ◽  
The Other ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Circular Statistics ◽  
Engineering Practice ◽  
Manufacturing Defects ◽  
Thermoset Composites ◽  
Manufacturing Techniques

Abstract Thermoplastic composites are highly recommended for structural application, not only for their superior characteristics derived from the fiber and matrix materials but also for their recycling possibilities, which is a major issue in the today’s engineering practice. The manufacturing techniques for thermoplastics are different from those for the well-established thermoset composites. This paper addresses the quality of the thermoplastic composites by assessing the distribution of the fiber, the void contents and the waviness of the fibers, compared to the thermoset composites. IM7/PEEK and AS4/PA12 are the two thermoplastic composite systems used for this study, whereas, IM7/8552 is the thermoset composite used as reference. The specimens were examined using optical microscopy and computed tomography (CT) and the results were statistically treated using circular statistics. Compared to the IM7/8552 composite, the analysis reveals that the IM7/PEEK and AS4/PA12 composites, manufactured by ATP result in a higher volume of voids. On the other hand, ATP processing improves the alignment of the fibers, as the solidification process occurs while the fibers are in tension. The microscopy studies also show that the ATP manufactured composites have an area in between the different layers of tape with a low number of fibers, compared to the other areas.

Mechanical Analysis of a Thermo-Hydroforming Fiber-Reinforced Composite Using Preferred Fiber Orientation Model and Considering Viscoelastic Properties

2021 ◽  
pp. 1-22
Author(s):  
Hyunchul Ahn ◽  
Taejoon Park ◽  
Yumeng Li ◽  
Sang Young Yeo ◽  
Farhang Pourboghrat
Keyword(s):  
Fiber Orientation ◽  
Matrix Material ◽  
Mechanical Analysis ◽  
Single Step ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Process Time ◽  
Analysis Model ◽  
Process Characteristics ◽  
The Matrix

Abstract Thermo-hydroforming (THF) process is a single-step process for thermoplastic composite forming, which has a great advantage in terms of the process time and mass production potential as compared to conventional processes. However, with THF processes, winkles and deformations are easily generated due to the process characteristics and process parameters. In this study, the matrix material was examined by considering viscoelasticity and changes in formability according to the forming speed. A THF analysis was performed based on the preferred fiber orientation (PFO) analysis model, which considers the viscoelasticity of the matrix. The deformation change and molding possibility were examined according to various forming speeds. The viscoelastic PFO model showed better analysis efficiency and stability than the primitive PFO model. This analysis will help improve the process of forming thermoplastic composites.

Quality Controlled UD Tape Production for the Individualised Production of Load Optimised Thermoplastic Composite Parts

2017 ◽  
Vol 742 ◽  
pp. 90-95
Author(s):  
Christian Hopmann ◽  
Christian Beste ◽  
Markus Hildebrandt ◽  
Arne Boettcher ◽  
Kai Fischer
Keyword(s):  
Manufacturing Process ◽  
Individual Component ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Quality Data ◽  
Fibre Distribution ◽  
Weight Content ◽  
Plastics Processing ◽  
Component Manufacturing ◽  
Joining Process

A flexible and individual component manufacturing process for thermoplastic composites (TPC) has been developed at the Institut fuer Kunststoffverarbeitung in Industrie und Handwerk an der RWTH Aachen (Institute of Plastics Processing (IKV) at RWTH Aachen University). The process consists of a quality controlled tape production and a combined forming and joining process with additive manufactured functional structures. This paper describes the requirements for the unidirectional (UD) tape properties and the quality controlled tape production line in order to allow for a flexible and individual component manufacturing of load optimised thermoplastic composite parts. Besides the UD tape geometry and fibre impregnation quality an even fibre distribution over the width of the UD tape is an important characteristic. Results of investigations regarding the online measured quality data (fibre distribution) and offline measured UD tape properties (local fibre weight content) are presented and discussed.

Manufacturing procedure to make flat thermoplastic composite laminates by automated fibre placement and their mechanical properties

2016 ◽  
Vol 30 (12) ◽  
pp. 1693-1712 ◽  
Author(s):  
Suong Van Hoa ◽  
Minh Duc Hoang ◽  
Jeff Simpson
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Composite Structures ◽  
High Speed ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Thermoset Composites ◽  
Material Deposition ◽  
Manufacturing Procedure ◽  
Composites Processing

Automated fibre placement (AFP) is a relatively new process for the manufacturing of composite structures. Among many attractive features, it provides high-speed of material deposition, more repeatability in terms of quality of the part, less labour intensive (as compared with traditional methods of manufacturing such as Hand Lay-Up), less waste and the ability to transition more seamlessly from design to manufacturing. AFP can be used to process both thermoset composites and thermoplastic composites. Thermoplastic composites processing holds many potential benefits. This is because if the process is done right in producing parts with good quality, it is fast since it does not require a second process such as curing in an autoclave or oven. For the purpose of comparison of performance and for design, it is necessary to determine the mechanical properties of laminates made using this process. However, there are challenges in making flat coupons for the purpose of testing for mechanical properties. This article presents these challenges and the procedure developed to make flat laminates using a simple AFP machine. Mechanical properties of these laminates are also determined and compared with those obtained from laminates made using conventional autoclave moulding.

scholarly journals Energy absorption capability of laminated plates made of fully thermoplastic composite

2018 ◽  
Vol 232 (8) ◽  
pp. 1389-1401 ◽  
Author(s):  
Simonetta Boria ◽  
Alessandro Scattina
Keyword(s):  
Energy Absorption ◽  
Laminated Plates ◽  
Thermoplastic Composite ◽  
Low Velocity Impact ◽  
Thermoplastic Composites ◽  
Fibre Reinforcement ◽  
Low Velocity ◽  
Wide Range ◽  
The Matrix ◽  
The Impact

The behaviour of composites materials, made of synthetic fibres embedded in a thermoplastic resin, subjected to low velocity impacts, was largely studied in the past. However, in the last years, the use of thermoplastic composites has been increased due to the considerable advantages in terms of recyclability of this family of materials. Thermoplastic composites are composed of polymers with different material’s structure if compared to the more traditional thermoset composite. Consequently, the behaviour of these materials can be different in some loading conditions. Moreover, considering the wide range of thermoplastic composites that have been developed in the last years, the study of the behaviour of these materials, in case of impact, has not been yet widely analysed, in particular considering materials where both the matrix and the reinforcement are made of thermoplastic. In this perspective, the goal of this work is to study the behaviour of a new thermoplastic composite (PURE thermoplastic) in conditions of low velocity impact. In this material, the matrix and the fibre reinforcement are made of polypropylene both. The paper presents the results of an experimental investigation. In particular, a series of impact tests with a drop dart equipment have been carried out on laminates made of PURE thermoplastic. Laminates with different thicknesses have been taken into consideration. The influence of the impact conditions on the material’s behaviour has been investigated and the capability of energy absorption has been studied. The PURE thermoplastic showed a different behaviour in terms of energy absorption and damage mechanisms if compared to the composites presented in the literature. The thickness of the laminate has had influence on the deformation and the damage mechanism of the specimens: with low thickness, the perforation of the specimen has been obtained, whereas, with the higher thickness, the specimens have shown a ductile behaviour and extended plasticity without crack tip. The contact force between the dart and the specimen has been influenced by the energy level of the impact, but with an opposite trend if compared to that of the composites studied in the literature.

scholarly journals Test Methods for Fibre/Matrix Adhesion in Cellulose Fibre-Reinforced Thermoplastic Composite Materials: A Critical Review

2020 ◽  
Vol 8 (2) ◽  
pp. 68-129
Author(s):  
J. Müssig ◽  
N. Graupner
Keyword(s):  
Composite Materials ◽  
Cellulose Fibre ◽  
Test Methods ◽  
Test Method ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Cellulose Fibres ◽  
Reinforced Polymers ◽  
Matrix Adhesion ◽  
Fibre Matrix

Due to the increasing discussion about sustainable and CO2-reduced materials, the demand for cellulose-based fibres as a reinforcing component in thermoplastic composites has increased considerably. Knowledge about the possibilities of modifying fibres for improved adhesion to the plastic matrix is essential in this context. The fibre/matrix adhesion in cellulose fibre-reinforced polymers is of considerable importance for the design of composite materials. Unfortunately, there are no standards for many essential methods to determine fibre/matrix adhesion. In this review article, various methods for measuring the interfacial shear strength between fibres and matrix, as an indirect characterisation of adhesion, are presented. Additionally, a brief overview of different methods for surface modification of cellulose fibres to improve the adhesion to a thermoplastic matrix is given. This review focuses on the fact that the parameters for the production of test specimens as well as the test method itself can vary considerably from study to study. Because of this, the comparison of data from different publications is not always possible. Therefore, in this article, the main influencing factors and differences in the methods are presented and discussed. Based on a systematic review and a clear description and discussion of the methods, the reader is given a broad basis for a better understanding of characteristic values for fibre/matrix adhesion.

scholarly journals Multi-Wall Carbon Nanotubes Chemically Grafted and Physically Adsorpted on Reinforcing Carbon Fibres

2008 ◽  
Vol 17 (3) ◽  
pp. 096369350801700 ◽  
Author(s):  
P. Karapappas ◽  
S. Tsantzalis ◽  
E. Fiamegou ◽  
A. Vavouliotis ◽  
K. Dassios ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Acid Solution ◽  
Matrix Material ◽  
Carbon Fibres ◽  
Reinforced Polymers ◽  
Reinforcing Effect ◽  
Multi Wall Carbon Nanotubes ◽  
The Matrix ◽  
Carbon Fibre Reinforced Polymers

Carbon nanotubes (CNTs) because of their properties are alleged to be the key candidate additives for improving the mechanical properties of polymers and carbon fibre reinforced polymers (CFRPs). Nevertheless in order for the reinforcing effect of the nanotubes to be of practical use, the CNTs have to be mixed with the matrix material. In the current work an effort was made to chemically graft Multi-Wall Carbon Nanotubes (MWCNTs) on the actual reinforcing Carbon Fibres (CFs) in order to skip the sometimes complex mixing stage. Two different solutions were used in order to treat/prepare the CNTs; a) an acid solution of H2SO4/HNO3 and, b) a toluene solution. The treated CFs were added to each solution, sonic bathed with deionised water and then dried in an oven. The resulting CFs were examined under SEM and both the solutions used proved to be reasonable successful with further investigation/optimisation to be necessary.

scholarly journals One Step Production of Bicomponent Yarns with Glass Fibre Core and Thermoplastic Sheath for Composite Applications

2017 ◽  
Vol 742 ◽  
pp. 506-511 ◽  
Author(s):  
Alexander Lüking ◽  
Robert Brüll ◽  
Thomas Köhler ◽  
Davide Pico ◽  
Gunnar Seide ◽  
...  
Keyword(s):  
Glass Fibre ◽  
Fibre Volume ◽  
Thermoplastic Composite ◽  
Infrared Heating ◽  
Thermoplastic Composites ◽  
Drawing Process ◽  
Polyamide 12 ◽  
Glass Fibres ◽  
Homogenous Distribution ◽  
The Matrix

The film stacking method is the industrial standard for the manufacturing of fibre reinforced thermoplastic composites (FRTCs). An alternative to this is commingling thermoplastic fibres with reinforcement fibres, e. g. glass fibres, into hybrid yarns. However, the composites produced by the use of film-stacking or hybrid yarns cannot achieve an optimal impregnation of reinforcement fibres with the matrix polymer. This stens from the high melt viscosity of thermoplastics, which prevents a uniform wetting of the reinforcement fibres. Leaving some fibers is unconnected to the matrix. This leads to composite lower strength than theoretically possible. The aim of the research is the coating of a single glass filament in the glass fibre nozzle drawing process to achive a homogenous distribution of glass fibres and matrix in the final composite. The approach uses particles with a diameter from 5 to 25 μm of polyamide 12 (PA 12) which are electrostatically charged and blown at an Eglass filament in the nozzle drawing process as seen in. The particles adhering to the filament are melted by infrared heating and winded afterwards. This development will allow the homogenous distribution of fibres and the matrix in a thermoplastic composite allowing a higher fibre volume content leading to improved mechanical properties. Even though the glass filaments could be coated with PA 12, a homogenous sheath could not be achieved in this investigation. Therefore, further research will focus on an improved homogeneity by reducing the agglomeration of PA 12, using dried PA12 and enhancing the coating setup.

Void reduction of high-performance thermoplastic composites via oven vacuum bag processing

2017 ◽  
Vol 51 (30) ◽  
pp. 4219-4230 ◽  
Author(s):  
Danning Zhang ◽  
Dirk Heider ◽  
John W Gillespie
Keyword(s):  
Carbon Fiber ◽  
Composite Laminates ◽  
High Performance ◽  
Single Layer ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Void Content ◽  
Plane Flow ◽  
Reduction Mechanisms ◽  
Air Diffusion

In this study, void reduction mechanisms during oven vacuum bag processing of high-performance carbon fiber thermoplastic composites are investigated. Entrapped air exists within the prepreg tape and between layers during lay-up and must be removed during processing to achieve aerospace quality (<1% void content) Key void reduction mechanisms during oven vacuum bag processing include through-thickness air diffusion and in-plane flow to the laminate edges through the permeable interlayer regions created by the prepreg surface roughness. Interlayer permeability between unidirectional and cross-ply laminates is measured experimentally and is sufficiently high for effective air removal during oven vacuum bag processing. Thick 72-layer carbon fiber/PEEK (poly (ether ether ketone)) laminates were fabricated with oven vacuum bag process under different edge sealing conditions. Void reduction in the laminate with sealed perimeter is dominated by air diffusion through the entire laminate thickness, and the laminate exhibits very high void content levels after oven vacuum bag processing. In the laminates with edges open to vacuum, air diffusion through a single layer and flow through the permeable interlayer lead to essentially void-free laminates. The findings show the importance of the interlayer permeability and edge conditions on the void reduction, and demonstrate that low void content can be achieved in thick section thermoplastic composite laminates via cost effective oven vacuum bag processing.

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