Compression molding of chopped woven thermoplastic composite flakes

Research output: ThesisPhD Thesis - Research UT, graduation UTAcademic

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Abstract

Continuous fiber reinforced composites with high-performance thermoplastic polymer matrices have an enormous potential in terms of performance, production rate, cost efficiency and recyclability. The use of this relatively new class of materials by the aerospace and automotive industry has been growing steadily during the last decade. However, the use of continuous reinforcements limit the complexity of the shape of the end products, as defects such as wrinkles can form during processing. Moreover, a significant amount of process waste is generated, which lowers the efficiency of the conventional production processes involving a prepreg cutting stage and/or final trimming stages. The overall efficiency of the manufacturing value chain of composites can be improved by adjoining a complementary manufacturing process that utilizes the process waste incurred in the primary process. The discontinuous form of reinforcements in the reclaimed material will provide a means to manufacture complex 3D geometries with near-net edges and at the same time use the raw material efficiently. However, the discontinuities in the reinforcing phase lead to a reduced mechanical performance compared to continuous reinforcements. Suitable applications include semi-structural parts and non-load bearing structures. This thesis focuses on the processing of planar discontinuous reinforcements and the associated mechanical performance. Chopped thermoplastic semi-preg with a woven fabric reinforcement, referred to as flakes, is considered as a standalone molding compound in this study. A compression molding process is chosen to manufacture parts, as it allows for complex geometries while retaining a long fiber length. Although processing of different types of discontinuous reinforcements has been studied in the past, the processing of the specific class of planar reinforcements with a woven architecture and high fiber content has not been explored so far. The principal objective is to develop a strategy for manufacturing woven-flake reinforced parts with good quality and consistent mechanical properties. For achieving this goal, the flow behavior of chopped woven material, process induced jamming of the material and the mechanical properties of molded plates are experimentally investigated and are explained with theoretical models. The work presented in the thesis shows the multidisciplinary nature of the problem, with strong correlations between the material, process and the design of the part leading to the final part performance. Therefore, a processing strategy is proposed which takes into consideration the aforementioned three basic blocks to manufacture consistent parts. Finally, the proposed strategy is validated by manufacturing a full-scale part with typical design features, which successfully demonstrates the processing capabilities of the material and the developed process.
Original languageEnglish
Awarding Institution
  • University of Twente
Supervisors/Advisors
  • Akkerman, R., Supervisor
  • Govaert, Leonard Eduard, Supervisor
  • Visser, H.A., Advisor
Award date15 Jul 2016
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-4151-0
DOIs
Publication statusPublished - 15 Jul 2016

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Compression molding
Thermoplastics
Reinforcement
Composite materials
Processing
Fibers
Bearings (structural)
Mechanical properties
Sheet molding compounds
Trimming
Geometry
Aerospace industry
Jamming
Polymer matrix
Automotive industry
Raw materials
Defects
Costs

Keywords

  • METIS-317137
  • IR-100622

Cite this

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title = "Compression molding of chopped woven thermoplastic composite flakes",
abstract = "Continuous fiber reinforced composites with high-performance thermoplastic polymer matrices have an enormous potential in terms of performance, production rate, cost efficiency and recyclability. The use of this relatively new class of materials by the aerospace and automotive industry has been growing steadily during the last decade. However, the use of continuous reinforcements limit the complexity of the shape of the end products, as defects such as wrinkles can form during processing. Moreover, a significant amount of process waste is generated, which lowers the efficiency of the conventional production processes involving a prepreg cutting stage and/or final trimming stages. The overall efficiency of the manufacturing value chain of composites can be improved by adjoining a complementary manufacturing process that utilizes the process waste incurred in the primary process. The discontinuous form of reinforcements in the reclaimed material will provide a means to manufacture complex 3D geometries with near-net edges and at the same time use the raw material efficiently. However, the discontinuities in the reinforcing phase lead to a reduced mechanical performance compared to continuous reinforcements. Suitable applications include semi-structural parts and non-load bearing structures. This thesis focuses on the processing of planar discontinuous reinforcements and the associated mechanical performance. Chopped thermoplastic semi-preg with a woven fabric reinforcement, referred to as flakes, is considered as a standalone molding compound in this study. A compression molding process is chosen to manufacture parts, as it allows for complex geometries while retaining a long fiber length. Although processing of different types of discontinuous reinforcements has been studied in the past, the processing of the specific class of planar reinforcements with a woven architecture and high fiber content has not been explored so far. The principal objective is to develop a strategy for manufacturing woven-flake reinforced parts with good quality and consistent mechanical properties. For achieving this goal, the flow behavior of chopped woven material, process induced jamming of the material and the mechanical properties of molded plates are experimentally investigated and are explained with theoretical models. The work presented in the thesis shows the multidisciplinary nature of the problem, with strong correlations between the material, process and the design of the part leading to the final part performance. Therefore, a processing strategy is proposed which takes into consideration the aforementioned three basic blocks to manufacture consistent parts. Finally, the proposed strategy is validated by manufacturing a full-scale part with typical design features, which successfully demonstrates the processing capabilities of the material and the developed process.",
keywords = "METIS-317137, IR-100622",
author = "{Abdul Rasheed}, {Mohammed Iqbal}",
year = "2016",
month = "7",
day = "15",
doi = "10.3990/1.9789036541510",
language = "English",
isbn = "978-90-365-4151-0",
publisher = "Universiteit Twente",
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}

Compression molding of chopped woven thermoplastic composite flakes. / Abdul Rasheed, Mohammed Iqbal.

Enschede : Universiteit Twente, 2016. 152 p.

Research output: ThesisPhD Thesis - Research UT, graduation UTAcademic

TY - THES

T1 - Compression molding of chopped woven thermoplastic composite flakes

AU - Abdul Rasheed, Mohammed Iqbal

PY - 2016/7/15

Y1 - 2016/7/15

N2 - Continuous fiber reinforced composites with high-performance thermoplastic polymer matrices have an enormous potential in terms of performance, production rate, cost efficiency and recyclability. The use of this relatively new class of materials by the aerospace and automotive industry has been growing steadily during the last decade. However, the use of continuous reinforcements limit the complexity of the shape of the end products, as defects such as wrinkles can form during processing. Moreover, a significant amount of process waste is generated, which lowers the efficiency of the conventional production processes involving a prepreg cutting stage and/or final trimming stages. The overall efficiency of the manufacturing value chain of composites can be improved by adjoining a complementary manufacturing process that utilizes the process waste incurred in the primary process. The discontinuous form of reinforcements in the reclaimed material will provide a means to manufacture complex 3D geometries with near-net edges and at the same time use the raw material efficiently. However, the discontinuities in the reinforcing phase lead to a reduced mechanical performance compared to continuous reinforcements. Suitable applications include semi-structural parts and non-load bearing structures. This thesis focuses on the processing of planar discontinuous reinforcements and the associated mechanical performance. Chopped thermoplastic semi-preg with a woven fabric reinforcement, referred to as flakes, is considered as a standalone molding compound in this study. A compression molding process is chosen to manufacture parts, as it allows for complex geometries while retaining a long fiber length. Although processing of different types of discontinuous reinforcements has been studied in the past, the processing of the specific class of planar reinforcements with a woven architecture and high fiber content has not been explored so far. The principal objective is to develop a strategy for manufacturing woven-flake reinforced parts with good quality and consistent mechanical properties. For achieving this goal, the flow behavior of chopped woven material, process induced jamming of the material and the mechanical properties of molded plates are experimentally investigated and are explained with theoretical models. The work presented in the thesis shows the multidisciplinary nature of the problem, with strong correlations between the material, process and the design of the part leading to the final part performance. Therefore, a processing strategy is proposed which takes into consideration the aforementioned three basic blocks to manufacture consistent parts. Finally, the proposed strategy is validated by manufacturing a full-scale part with typical design features, which successfully demonstrates the processing capabilities of the material and the developed process.

AB - Continuous fiber reinforced composites with high-performance thermoplastic polymer matrices have an enormous potential in terms of performance, production rate, cost efficiency and recyclability. The use of this relatively new class of materials by the aerospace and automotive industry has been growing steadily during the last decade. However, the use of continuous reinforcements limit the complexity of the shape of the end products, as defects such as wrinkles can form during processing. Moreover, a significant amount of process waste is generated, which lowers the efficiency of the conventional production processes involving a prepreg cutting stage and/or final trimming stages. The overall efficiency of the manufacturing value chain of composites can be improved by adjoining a complementary manufacturing process that utilizes the process waste incurred in the primary process. The discontinuous form of reinforcements in the reclaimed material will provide a means to manufacture complex 3D geometries with near-net edges and at the same time use the raw material efficiently. However, the discontinuities in the reinforcing phase lead to a reduced mechanical performance compared to continuous reinforcements. Suitable applications include semi-structural parts and non-load bearing structures. This thesis focuses on the processing of planar discontinuous reinforcements and the associated mechanical performance. Chopped thermoplastic semi-preg with a woven fabric reinforcement, referred to as flakes, is considered as a standalone molding compound in this study. A compression molding process is chosen to manufacture parts, as it allows for complex geometries while retaining a long fiber length. Although processing of different types of discontinuous reinforcements has been studied in the past, the processing of the specific class of planar reinforcements with a woven architecture and high fiber content has not been explored so far. The principal objective is to develop a strategy for manufacturing woven-flake reinforced parts with good quality and consistent mechanical properties. For achieving this goal, the flow behavior of chopped woven material, process induced jamming of the material and the mechanical properties of molded plates are experimentally investigated and are explained with theoretical models. The work presented in the thesis shows the multidisciplinary nature of the problem, with strong correlations between the material, process and the design of the part leading to the final part performance. Therefore, a processing strategy is proposed which takes into consideration the aforementioned three basic blocks to manufacture consistent parts. Finally, the proposed strategy is validated by manufacturing a full-scale part with typical design features, which successfully demonstrates the processing capabilities of the material and the developed process.

KW - METIS-317137

KW - IR-100622

U2 - 10.3990/1.9789036541510

DO - 10.3990/1.9789036541510

M3 - PhD Thesis - Research UT, graduation UT

SN - 978-90-365-4151-0

PB - Universiteit Twente

CY - Enschede

ER -