2020
Herwig, Alexander; Schmidt, Carsten; Horst, Peter
Investigation of Asymmetrical Fiber Metal Hybrids Used as Load Introduction Element for Thin-Walled CFRP Structures Vortrag
Gulf of Naples, Italy, 15.07.2020.
Abstract | BibTeX | Schlagwörter: Multilayer Insert
@misc{Herwig2020,
title = {Investigation of Asymmetrical Fiber Metal Hybrids Used as Load Introduction Element for Thin-Walled CFRP Structures},
author = {Alexander Herwig and Carsten Schmidt and Peter Horst},
editor = {CIRP ICME ’20 - 14th CIRP Conference on INTELLIGENT COMPUTATION IN MANUFACTURING ENGINEERING},
year = {2020},
date = {2020-07-15},
booktitle = {14th CIRP Conference on Intelligent Computation in Manufacturing Engineering
},
address = {Gulf of Naples, Italy},
abstract = {Due to the industrial success of fiber reinforced plastic (FRP) light-weight components, the demand for joining methods suitable for FRP also increases. Conventional joining elements like rivets and screws or a simple clamping are not designed for an application in FRP components. Thus, fail to consider the orthotropic fiber properties, which, in most cases, leads to poor results and an inferior joint. Therefore, this investigation presents the concept of a layered local metal-hybrid area that can be used as a load introduction element. The design of the hybrid area is discussed for several stacking options. Furthermore, the sensitivity to geometrical design variables and asymmetrical stackings are investigated by a simplified two-dimensional finite element model. The deduced parameter relations are discussed in the context of an application in an automated fiber placement process in order to formulate a parameter recommendation.},
keywords = {Multilayer Insert},
pubstate = {published},
tppubtype = {presentation}
}
Due to the industrial success of fiber reinforced plastic (FRP) light-weight components, the demand for joining methods suitable for FRP also increases. Conventional joining elements like rivets and screws or a simple clamping are not designed for an application in FRP components. Thus, fail to consider the orthotropic fiber properties, which, in most cases, leads to poor results and an inferior joint. Therefore, this investigation presents the concept of a layered local metal-hybrid area that can be used as a load introduction element. The design of the hybrid area is discussed for several stacking options. Furthermore, the sensitivity to geometrical design variables and asymmetrical stackings are investigated by a simplified two-dimensional finite element model. The deduced parameter relations are discussed in the context of an application in an automated fiber placement process in order to formulate a parameter recommendation.
Reichert, Lisa; Schmidt, Carsten; Horst, Peter
A Methodology for Strategic Individualization of Stiffened CFRP Structures Vortrag
Gulf of Naples, Italy, 15.07.2020.
Abstract | BibTeX | Schlagwörter: Composite Manufacturing, Design Method
@misc{Reichert2020,
title = {A Methodology for Strategic Individualization of Stiffened CFRP Structures},
author = {Lisa Reichert and Carsten Schmidt and Peter Horst},
editor = {CIRP ICME ’20 - 14th CIRP Conference on INTELLIGENT COMPUTATION IN MANUFACTURING ENGINEERING},
year = {2020},
date = {2020-07-15},
booktitle = {14th CIRP Conference on Intelligent Computation in Manufacturing Engineering},
address = {Gulf of Naples, Italy},
abstract = {The design process for stiffened lightweight structures faces many challenges. Current design goals, especially in the aircraft industry, demand significant decrease in structural weight while keeping development and manufacturing costs low. Therefore, more complex design choices are investigated and show promising potential. The resulting increase in computational effort presents a remaining challenge. A novel approach for the design of stiffened lightweight structures, that enables strategic application of individualization and therefore allocates computational effort to areas of a structure where high benefits can be expected, is presented. Starting from a structure with common parts, the concept of individualization, i.e. adapting the design to local loads, is applied iteratively to selected parts of the structure. The methodology of strategic individualization is explained in detail before being applied to an example structure. This application shows the general capability of the methodology to design lightweight structures with less computational effort compared to a conventional approach.},
keywords = {Composite Manufacturing, Design Method},
pubstate = {published},
tppubtype = {presentation}
}
The design process for stiffened lightweight structures faces many challenges. Current design goals, especially in the aircraft industry, demand significant decrease in structural weight while keeping development and manufacturing costs low. Therefore, more complex design choices are investigated and show promising potential. The resulting increase in computational effort presents a remaining challenge. A novel approach for the design of stiffened lightweight structures, that enables strategic application of individualization and therefore allocates computational effort to areas of a structure where high benefits can be expected, is presented. Starting from a structure with common parts, the concept of individualization, i.e. adapting the design to local loads, is applied iteratively to selected parts of the structure. The methodology of strategic individualization is explained in detail before being applied to an example structure. This application shows the general capability of the methodology to design lightweight structures with less computational effort compared to a conventional approach.
Weykenat, Jannik; Herwig, Alexander; Serna, Jonathan; Schmidt, Carsten
Local Fiber-Metal-Laminate used as Load Introduction element for Thin-Walled CFRP Structures Vortrag
26.05.2020.
BibTeX | Schlagwörter: Fiber-Metal Laminate, Intrinsic Hybridisation, Multilayer Insert
@misc{Weykenat2020,
title = {Local Fiber-Metal-Laminate used as Load Introduction element for Thin-Walled CFRP Structures},
author = {Jannik Weykenat and Alexander Herwig and Jonathan Serna and Carsten Schmidt},
editor = {4th Internation Conference Hybrid 2020 – Materials and Structures, Karlsruhe, Deutschland},
year = {2020},
date = {2020-05-26},
keywords = {Fiber-Metal Laminate, Intrinsic Hybridisation, Multilayer Insert},
pubstate = {published},
tppubtype = {presentation}
}
Budelmann, Dennis; Schmidt, Carsten; Meiners, Dieter
Prepreg tack: A review of mechanisms, measurement, and manufacturing implication Artikel
In: Polymer Composites, Bd. 2020, S. 1-19, 2020, ISSN: 1548-0569.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Tack
@article{Budelmann2020,
title = {Prepreg tack: A review of mechanisms, measurement, and manufacturing implication},
author = {Dennis Budelmann and Carsten Schmidt and Dieter Meiners},
doi = {10.1002/pc.25642},
issn = {1548-0569},
year = {2020},
date = {2020-05-23},
journal = {Polymer Composites},
volume = {2020},
pages = {1-19},
abstract = {The stickiness of prepregs (tack) is considered a decisive material property for the success of high-quality composite manufacturing by automated lay-up processes such as automated fiber placement (AFP) or automated tape laying (ATL). Adverse control of prepreg tack can easily result in laminate defects or machine breakdown, which are highly undesirable considering the tremendous machinery and material costs of these processes. Prepreg tack is governed by a complex interaction of adhesive and cohesive phenomena that are influenced by machine and environmental parameters of the production process
as well as by intrinsic properties of the prepreg material itself. This review aims at providing a condensed insight into the current state of research on prepreg tack. Therefore, experimental studies including the discussion of utilized tack measurement methods as well as model approaches to prepreg tack are reviewed. The findings are discussed against the background of fundamental mechanisms, the strong interdependency of influencing parameters and the challenge of translating measured tack data into an enhanced AFP/ATL process stability by process adjustment.},
keywords = {Automated Fiber Placement, Tack},
pubstate = {published},
tppubtype = {article}
}
The stickiness of prepregs (tack) is considered a decisive material property for the success of high-quality composite manufacturing by automated lay-up processes such as automated fiber placement (AFP) or automated tape laying (ATL). Adverse control of prepreg tack can easily result in laminate defects or machine breakdown, which are highly undesirable considering the tremendous machinery and material costs of these processes. Prepreg tack is governed by a complex interaction of adhesive and cohesive phenomena that are influenced by machine and environmental parameters of the production process
as well as by intrinsic properties of the prepreg material itself. This review aims at providing a condensed insight into the current state of research on prepreg tack. Therefore, experimental studies including the discussion of utilized tack measurement methods as well as model approaches to prepreg tack are reviewed. The findings are discussed against the background of fundamental mechanisms, the strong interdependency of influencing parameters and the challenge of translating measured tack data into an enhanced AFP/ATL process stability by process adjustment.
as well as by intrinsic properties of the prepreg material itself. This review aims at providing a condensed insight into the current state of research on prepreg tack. Therefore, experimental studies including the discussion of utilized tack measurement methods as well as model approaches to prepreg tack are reviewed. The findings are discussed against the background of fundamental mechanisms, the strong interdependency of influencing parameters and the challenge of translating measured tack data into an enhanced AFP/ATL process stability by process adjustment.
Berg, David C.
An Innovative Approach for Simultaneous Measurement of Cure Shrinkage and Thermal Expansion of Reactive Liquids Promotionsarbeit
Technische Universität Clausthal, 2020, ISBN: 978-3-86948-718-2.
BibTeX | Schlagwörter: Cure shrinkage
@phdthesis{Berg2020,
title = {An Innovative Approach for Simultaneous Measurement of Cure Shrinkage and Thermal Expansion of Reactive Liquids},
author = {David C. Berg},
isbn = {978-3-86948-718-2},
year = {2020},
date = {2020-04-01},
school = {Technische Universität Clausthal},
keywords = {Cure shrinkage},
pubstate = {published},
tppubtype = {phdthesis}
}
2019
Schmidt, Carsten; Fix, Johann; Timmermann, Marc; Werner, Simon
Flexible Produktion individualisierter CFK-Strukturen Artikel
In: lightweight.design, Bd. 12, Nr. 6, S. 58-63, 2019, ISSN: 2192-8738.
Abstract | BibTeX | Schlagwörter: Continuous Wet Draping, Draping Simulation, Light Weight Construction
@article{Schmidt2019c,
title = {Flexible Produktion individualisierter CFK-Strukturen},
author = {Carsten Schmidt and Johann Fix and Marc Timmermann and Simon Werner},
issn = {2192-8738},
year = {2019},
date = {2019-12-19},
journal = {lightweight.design},
volume = {12},
number = {6},
pages = {58-63},
abstract = {Das Forschungsprojekt FlexProCFK adressiert die anlagen- und materialtechnischen Herausforderungen, die bei der Herstellung komplexer CFK-Strukturen entstehen. Aus der Vision, bionische Strukturen im Flugzeugbau zu etablieren, ist eine Legetechnologie entstanden, die die bisherige Bandbreite automatisiert herstellbarer Bauteile signifikant erweitert.},
keywords = {Continuous Wet Draping, Draping Simulation, Light Weight Construction},
pubstate = {published},
tppubtype = {article}
}
Das Forschungsprojekt FlexProCFK adressiert die anlagen- und materialtechnischen Herausforderungen, die bei der Herstellung komplexer CFK-Strukturen entstehen. Aus der Vision, bionische Strukturen im Flugzeugbau zu etablieren, ist eine Legetechnologie entstanden, die die bisherige Bandbreite automatisiert herstellbarer Bauteile signifikant erweitert.
Budelmann, Dennis; Reichert, Lisa; Schmidt, Carsten; Meiners, Dieter
Design und Herstellung unkonventionell versteifter Flugzeugstrukturen Artikel
In: Sonderprojekte ATZ/MTZ, Bd. 24, Nr. 2, S. 46-48, 2019, ISSN: 2509-4610.
Abstract | Links | BibTeX | Schlagwörter: Continuous Wet Draping, Design Optimization, Light Weight Construction
@article{Budelmann2019b,
title = {Design und Herstellung unkonventionell versteifter Flugzeugstrukturen},
author = {Dennis Budelmann and Lisa Reichert and Carsten Schmidt and Dieter Meiners},
doi = {10.1007/s41491-019-0045-8},
issn = { 2509-4610},
year = {2019},
date = {2019-12-18},
journal = {Sonderprojekte ATZ/MTZ},
volume = {24},
number = {2},
pages = {46-48},
abstract = {Am gemeinsamen Forschungsstandort in Stade entwickeln die TU Clausthal, die TU Braunschweig und die Leibniz Universität Hannover eine Fertigungstechnologie zur Herstellung komplex gekrümmter Faserverbundbauteile. Als individuelle Versteifungsstrukturen im Flugzeugrumpf ermöglichen diese Bauteile die notwendige Gewichtsreduktion im Flugzeugbau.},
keywords = {Continuous Wet Draping, Design Optimization, Light Weight Construction},
pubstate = {published},
tppubtype = {article}
}
Am gemeinsamen Forschungsstandort in Stade entwickeln die TU Clausthal, die TU Braunschweig und die Leibniz Universität Hannover eine Fertigungstechnologie zur Herstellung komplex gekrümmter Faserverbundbauteile. Als individuelle Versteifungsstrukturen im Flugzeugrumpf ermöglichen diese Bauteile die notwendige Gewichtsreduktion im Flugzeugbau.
Meiners, Dieter; Budelmann, Dennis
Materialcharakterisierung von Prepregs für automatisierte Legeprozesse Artikel
In: Jahresmagazin Kunststofftechnik, 2019, ISSN: 1619-8357.
Abstract | Links | BibTeX | Schlagwörter: Continuous Wet Draping, Rheometer, Tack
@article{Meiners2019,
title = {Materialcharakterisierung von Prepregs für automatisierte Legeprozesse},
author = {Dieter Meiners and Dennis Budelmann },
editor = {Institut für Wissenschaftliche Veröffentlichungen IWV},
url = {http://institut-wv.de/jahresmagazin-ingenieurwissenschaften-im-fokus-kunststofftechnik/},
issn = {1619-8357},
year = {2019},
date = {2019-10-17},
journal = {Jahresmagazin Kunststofftechnik},
abstract = {Die Herstellung von großflächigen, faserverstärkten Hochleistungsbauteilen für die Luft- und
Raumfahrt erfolgt durch automatisiertes Ablegen von Kohlenstofffaser-Prepregs. Der aus Sicht
des verarbeiteten Materials wichtigste Parameter für den Herstellungsprozess ist seine Klebrigkeit (Tack). Um die Robustheit der automatisierten Prozesse zu erhöhen, fehlt es sowohl an Kenntnis der komplexen Wechselwirkungen zwischen Halbzeugeigenschaften und Prozess als auch einer standardisierten Messmethode zur Quantifizierung des Prepreg-Tacks. Das Institut für Polymerwerkstoffe und Kunststofftechnik der TU Clausthal nimmt sich dieser Herausforderung an.},
keywords = {Continuous Wet Draping, Rheometer, Tack},
pubstate = {published},
tppubtype = {article}
}
Die Herstellung von großflächigen, faserverstärkten Hochleistungsbauteilen für die Luft- und
Raumfahrt erfolgt durch automatisiertes Ablegen von Kohlenstofffaser-Prepregs. Der aus Sicht
des verarbeiteten Materials wichtigste Parameter für den Herstellungsprozess ist seine Klebrigkeit (Tack). Um die Robustheit der automatisierten Prozesse zu erhöhen, fehlt es sowohl an Kenntnis der komplexen Wechselwirkungen zwischen Halbzeugeigenschaften und Prozess als auch einer standardisierten Messmethode zur Quantifizierung des Prepreg-Tacks. Das Institut für Polymerwerkstoffe und Kunststofftechnik der TU Clausthal nimmt sich dieser Herausforderung an.
Raumfahrt erfolgt durch automatisiertes Ablegen von Kohlenstofffaser-Prepregs. Der aus Sicht
des verarbeiteten Materials wichtigste Parameter für den Herstellungsprozess ist seine Klebrigkeit (Tack). Um die Robustheit der automatisierten Prozesse zu erhöhen, fehlt es sowohl an Kenntnis der komplexen Wechselwirkungen zwischen Halbzeugeigenschaften und Prozess als auch einer standardisierten Messmethode zur Quantifizierung des Prepreg-Tacks. Das Institut für Polymerwerkstoffe und Kunststofftechnik der TU Clausthal nimmt sich dieser Herausforderung an.
Schmidt, Carsten; Hocke, Tristan; Denkena, Berend
Artificial intelligence for non-destructive testing of CFRP prepreg materials Artikel
In: Production Engineering, S. 1-10, 2019.
Abstract | Links | BibTeX | Schlagwörter: Artificial Intelligence, Automated Fiber Placement, Composite Manufacturing, Composite Structures, Defects, Prepreg, Quality Assurance, Thermal Imaging
@article{Schmidt2019,
title = {Artificial intelligence for non-destructive testing of CFRP prepreg materials},
author = {Carsten Schmidt and Tristan Hocke and Berend Denkena},
url = {https://link.springer.com/article/10.1007%2Fs11740-019-00913-3},
doi = {https://doi.org/10.1007/s11740-019-00913-3},
year = {2019},
date = {2019-07-02},
journal = {Production Engineering},
pages = {1-10},
abstract = {This paper presents a concept of the quality assurance for CFRP prepreg materials and focusses on the classification of thermographic images using convolution neural networks (CNNs). The method for non-destructive testing of CFRP prepreg materials combines a laser-triangulation sensor and an infrared camera to monitor both, the geometry and the impregnation of the prepreg material. The aim is to ensure a high material quality excluding any defective material in an early stage of the process chain of the production of CFRP components. As a result, the reliability of Automated-Fiber-Placement processes utilizing this previously tested material increases. Therefore, an artificial intelligence is set up to classify the thermal images of the CFRP material. Two different architectures of CNN are trained and validated with data sets consisting of thermal images of several prepreg materials and different material defects, such as geometric deviations and varying fiber-matrix-ratios caused by an incorrect impregnation. The CNNs are able to differentiate prepreg materials and to detect and classify certain material-independent defects for known and trained prepreg materials.},
keywords = {Artificial Intelligence, Automated Fiber Placement, Composite Manufacturing, Composite Structures, Defects, Prepreg, Quality Assurance, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
This paper presents a concept of the quality assurance for CFRP prepreg materials and focusses on the classification of thermographic images using convolution neural networks (CNNs). The method for non-destructive testing of CFRP prepreg materials combines a laser-triangulation sensor and an infrared camera to monitor both, the geometry and the impregnation of the prepreg material. The aim is to ensure a high material quality excluding any defective material in an early stage of the process chain of the production of CFRP components. As a result, the reliability of Automated-Fiber-Placement processes utilizing this previously tested material increases. Therefore, an artificial intelligence is set up to classify the thermal images of the CFRP material. Two different architectures of CNN are trained and validated with data sets consisting of thermal images of several prepreg materials and different material defects, such as geometric deviations and varying fiber-matrix-ratios caused by an incorrect impregnation. The CNNs are able to differentiate prepreg materials and to detect and classify certain material-independent defects for known and trained prepreg materials.
Serna, Jonathan; Herwig, Alexander; Weykenat, Jannik; Schmidt, Carsten; Horst, Peter; Meiners, Dieter; Denkena, Berend
Intrinsische Hybridverbunde zur Krafteinleitung in dünnwandige Hochleistungs-CFK-Strukturen Vortrag
28.06.2019.
BibTeX | Schlagwörter: Fiber-Metal Laminate, Intrinsic Hybridisation, Multilayer Insert
@misc{Serna2019,
title = {Intrinsische Hybridverbunde zur Krafteinleitung in dünnwandige Hochleistungs-CFK-Strukturen},
author = {Jonathan Serna and Alexander Herwig and Jannik Weykenat and Carsten Schmidt and Peter Horst and Dieter Meiners and Berend Denkena},
editor = {23. Internationales Dresdner Leichtbausymposium},
year = {2019},
date = {2019-06-28},
keywords = {Fiber-Metal Laminate, Intrinsic Hybridisation, Multilayer Insert},
pubstate = {published},
tppubtype = {presentation}
}
Krieglsteiner, Joscha; Horst, Peter; Schmidt, Carsten
In: Aircraft Engineering and Aerospace Technology , Bd. 91, Nr. 4, S. 607-619, 2019.
Abstract | Links | BibTeX | Schlagwörter: Composite Structures, Design Method, Preliminary design
@article{Krieglsteiner2019b,
title = {Definition and Representation of Stiffened Shell Structures in the Context of an Integrated Development Process},
author = {Joscha Krieglsteiner and Peter Horst and Carsten Schmidt},
url = {https://doi.org/10.1108/AEAT-07-2018-0205},
doi = {10.1108/AEAT-07-2018-0205},
year = {2019},
date = {2019-03-28},
journal = {Aircraft Engineering and Aerospace Technology },
volume = {91},
number = {4},
pages = {607-619},
abstract = {Purpose A novel development process aims at finding solutions for lightweight stiffened shell structures and their efficient production. To respect the strong interdependency of structural design and production planning, particularly observed for composite structures, it is of high interest to start considering production effects in early development phases. This integrated approach requires an integrated representation of structure and production. The purpose of this study is to investigate the scope of relevant data and to find a structure for its representation. Design/methodology/approach The development task is analyzed and a system of so-called solution dimensions is presented, which covers all important aspects of stiffened shell structures and their production. An integrated product data model is developed to cover all of the solution dimensions. Findings The product data model consists of five coherent partial models. It is explained how these models are defined and how they are connected to each other. An academic example of an aircraft fuselage panel is used to demonstrate the definition process. It is shown how even complex structural concepts are defined systematically. Practical implications It is explained how this integrated product data model is used in a software project for the development of aircraft fuselage structures. Originality/value The presented approach for the definition and representation of stiffened shell structures enables the developer, e.g. of aircraft fuselage, to respect the crucial criterion of manufacturability from early development phases on. Further, new design approaches, e.g. as inspired by topology optimization, can be considered.},
keywords = {Composite Structures, Design Method, Preliminary design},
pubstate = {published},
tppubtype = {article}
}
Purpose A novel development process aims at finding solutions for lightweight stiffened shell structures and their efficient production. To respect the strong interdependency of structural design and production planning, particularly observed for composite structures, it is of high interest to start considering production effects in early development phases. This integrated approach requires an integrated representation of structure and production. The purpose of this study is to investigate the scope of relevant data and to find a structure for its representation. Design/methodology/approach The development task is analyzed and a system of so-called solution dimensions is presented, which covers all important aspects of stiffened shell structures and their production. An integrated product data model is developed to cover all of the solution dimensions. Findings The product data model consists of five coherent partial models. It is explained how these models are defined and how they are connected to each other. An academic example of an aircraft fuselage panel is used to demonstrate the definition process. It is shown how even complex structural concepts are defined systematically. Practical implications It is explained how this integrated product data model is used in a software project for the development of aircraft fuselage structures. Originality/value The presented approach for the definition and representation of stiffened shell structures enables the developer, e.g. of aircraft fuselage, to respect the crucial criterion of manufacturability from early development phases on. Further, new design approaches, e.g. as inspired by topology optimization, can be considered.
Schmidt, Carsten; Hocke, Tristan; Denkena, Berend
Deep learning-based classification of production defects in automated-fiber-placement processes Artikel
In: Production Engineering, Bd. 13, 3-4, S. 501-509, 2019.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Industry 4.0, Thermal Imaging
@article{Schmidt2019,
title = {Deep learning-based classification of production defects in automated-fiber-placement processes},
author = {Carsten Schmidt and Tristan Hocke and Berend Denkena},
url = {http://link.springer.com/article/10.1007/s11740-019-00893-4},
doi = {https://doi.org/10.1007/s11740-019-00893-4},
year = {2019},
date = {2019-03-15},
journal = {Production Engineering},
volume = {13, 3-4},
pages = {501-509},
abstract = {This paper presents a deep learning-based approach for the detection and classification of production defects that comple-
ments an existing thermographic online monitoring system for Automated-Fiber-Placement (AFP) processes. The detection
and classification procedure is performed in two stages. In the first stage, the system monitors each tow individually and
classifies its process status. Furthermore, it detects and classifies production defects that affect individual tows such as a
tow-twist. In the second stage, the system monitors the total width of the faultless tows. In this stage, production defects
effecting multiple tows, for example gaps or overlaps, are detected and classified. Twelve different deep convolution neural
networks (CNN) with three various architectures are learned supervised relating to different data sets. The performance of
both identification stages is explored separately before the entire system will be set up. Therefore, the thermal images of the
data sets are superimposed by noise to test the performance of the selected CNN.},
keywords = {Automated Fiber Placement, Industry 4.0, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
This paper presents a deep learning-based approach for the detection and classification of production defects that comple-
ments an existing thermographic online monitoring system for Automated-Fiber-Placement (AFP) processes. The detection
and classification procedure is performed in two stages. In the first stage, the system monitors each tow individually and
classifies its process status. Furthermore, it detects and classifies production defects that affect individual tows such as a
tow-twist. In the second stage, the system monitors the total width of the faultless tows. In this stage, production defects
effecting multiple tows, for example gaps or overlaps, are detected and classified. Twelve different deep convolution neural
networks (CNN) with three various architectures are learned supervised relating to different data sets. The performance of
both identification stages is explored separately before the entire system will be set up. Therefore, the thermal images of the
data sets are superimposed by noise to test the performance of the selected CNN.
ments an existing thermographic online monitoring system for Automated-Fiber-Placement (AFP) processes. The detection
and classification procedure is performed in two stages. In the first stage, the system monitors each tow individually and
classifies its process status. Furthermore, it detects and classifies production defects that affect individual tows such as a
tow-twist. In the second stage, the system monitors the total width of the faultless tows. In this stage, production defects
effecting multiple tows, for example gaps or overlaps, are detected and classified. Twelve different deep convolution neural
networks (CNN) with three various architectures are learned supervised relating to different data sets. The performance of
both identification stages is explored separately before the entire system will be set up. Therefore, the thermal images of the
data sets are superimposed by noise to test the performance of the selected CNN.
Hocke, Tristan
Künstliche Intelligenz in der Fertigungsüberwachung von CFK-Bauteilen im Flugzeugbau Vortrag
12.02.2019.
BibTeX | Schlagwörter: Artificial Intelligence, Automated Fiber Placement, Process Monitoring
@misc{Hocke2019,
title = {Künstliche Intelligenz in der Fertigungsüberwachung von CFK-Bauteilen im Flugzeugbau},
author = {Tristan Hocke},
editor = {Künstliche Intelligenz in der Automatisierungstechnik - Automatisierungsforum Westküste},
year = {2019},
date = {2019-02-12},
keywords = {Artificial Intelligence, Automated Fiber Placement, Process Monitoring},
pubstate = {published},
tppubtype = {presentation}
}
Budelmann, Dennis; Detampel, Hendrik; Schmidt, Carsten; Meiners, Dieter
In: Composites Part A, Bd. 117, S. 308-316, 2019.
Abstract | Links | BibTeX | Schlagwörter: Tack
@article{Budelmann2019,
title = {Interaction of process parameters and material properties with regard to prepreg tack in automat-ed lay-up and draping processes},
author = {Dennis Budelmann and Hendrik Detampel and Carsten Schmidt and Dieter Meiners},
url = {https://doi.org/10.1016/j.compositesa.2018.12.001},
year = {2019},
date = {2019-01-15},
journal = {Composites Part A},
volume = {117},
pages = {308-316},
abstract = {Selectively adjusting the tackiness of epoxy pre-impregnated carbon fibers is considered mandatory in terms of process stability of automated lay-up and draping. This experimental study investigates the influence of crucial process and material parameters such as temperature, compaction force, debonding rate and ageing on prepreg tack using a rheometer as a test apparatus. Accompanying material characterization is conducted in terms of cure kinetics and rheology to establish a profound understanding of tack-determining mechanisms and material behavior. Two evaluated tack indicators are found to be sensitive to temperature and steadily increased as a function of compaction stress. The maximum tack plateau of progressively aged prepreg shifts towards higher temperatures. Material is still processable after tack life with tack properties exceeding the adhesive performance of fresh prepreg when being processed at elevated temperatures. Tackiness of impregnated tape for automated draping and aerospace epoxy prepreg differs in both quantitative extent and pivotal mechanisms.},
keywords = {Tack},
pubstate = {published},
tppubtype = {article}
}
Selectively adjusting the tackiness of epoxy pre-impregnated carbon fibers is considered mandatory in terms of process stability of automated lay-up and draping. This experimental study investigates the influence of crucial process and material parameters such as temperature, compaction force, debonding rate and ageing on prepreg tack using a rheometer as a test apparatus. Accompanying material characterization is conducted in terms of cure kinetics and rheology to establish a profound understanding of tack-determining mechanisms and material behavior. Two evaluated tack indicators are found to be sensitive to temperature and steadily increased as a function of compaction stress. The maximum tack plateau of progressively aged prepreg shifts towards higher temperatures. Material is still processable after tack life with tack properties exceeding the adhesive performance of fresh prepreg when being processed at elevated temperatures. Tackiness of impregnated tape for automated draping and aerospace epoxy prepreg differs in both quantitative extent and pivotal mechanisms.
Krieglsteiner, Joscha; Horst, Peter; Schmidt, Carsten
An Integrated Development Process for Stiffened Shell Lightweight Structures Artikel
In: Proceedings of ICoRD, Bd. 1, S. 834-844, 2019.
Links | BibTeX | Schlagwörter: Design Method, Preliminary design
@article{Krieglsteiner2019,
title = {An Integrated Development Process for Stiffened Shell Lightweight Structures},
author = {Joscha Krieglsteiner and Peter Horst and Carsten Schmidt},
doi = {10.1007/978-981-13-5974-3_72},
year = {2019},
date = {2019-01-15},
journal = {Proceedings of ICoRD},
volume = {1},
pages = {834-844},
keywords = {Design Method, Preliminary design},
pubstate = {published},
tppubtype = {article}
}
2018
Engel, Kevin
Berücksichtigung prozessinduzierter Effekte in der Auslegung von Faser-Kunststoff-Verbunden Buch
2018, ISBN: 978-3947623150.
Abstract | BibTeX | Schlagwörter: Auslegung; Effects of Defects
@book{Engel2018,
title = {Berücksichtigung prozessinduzierter Effekte in der Auslegung von Faser-Kunststoff-Verbunden},
author = {Kevin Engel},
isbn = {978-3947623150},
year = {2018},
date = {2018-12-17},
abstract = {In der Produktentwicklung und speziell im Leichtbau, ist die Kenntnis über den verwendeten Werkstoff entscheidend. Je größer das Wissen über den Werkstoff, wie er unter unterschiedlichen Bedingungen reagiert, umso präziser kann die Auslegung des Produktes auf die gestellten Anforderungen hin geschehen. Faser-Kunststoff-Verbunde (FKV) sind, wie der Name bereits verrät, ein Verbund aus zwei Werkstoffen, der Faser und der Matrix, welche sich im Verbund ergänzen. Die resultierenden Eigenschaften eines Verbundwerkstoffes hängen demnach von den Eigenschaften der Verbundpartner, der Konstituenten, ab. Neben den Eigenschaften der Konstituenten beeinflusst auch ihre Zusammensetzung und eine Reihe von Qualitätsparametern, wie Lufteinschlüsse und die Welligkeit der Fasern, die resultierenden Werkstoffeigenschaften. Die Qualitätsparameter von FKV werden maßgeblich von deren Fertigungsprozessen beeinflusst, weshalb es wichtig ist die Zusammenhänge zwischen den Fertigungsprozessen und den Werkstoffeigenschaften zu kennen.
Aus diesem Grund wird in dieser Arbeit eine Methode entwickelt, welche die systematische Integration prozessinduzierter Einflüsse in die Berechnung von Strukturen aus FKV ermöglicht. Die Qualitätsparameter bilden dabei das Bindeglied zwischen den Prozessen und den Eigenschaften des FKV. Die Einflüsse der Qualitätsparameter fließen innerhalb eines Multiskalenmodells zur Berechnung von Laminaten ein, was eine Integration der Prozesse in die Auslegung ermöglicht.
Die Arbeit zeigt das Vorgehen der Methode anhand von Faserwelligkeiten, Gaps und Lagenwelligkeiten in Laminaten aus FKV. Die Faserwelligkeiten werden auf Ebene der FKV integriert, indem effektive Steifigkeiten und Festigkeiten für den beeinflussten Verbundwerkstoff bestimmt werden. Dabei werden auch die inhärenten Zufälligkeiten der Faserwelligkeiten berücksichtigt. Gaps, und die daraus resultierenden Lagenwelligkeiten, werden auf der Laminatebene modelliert und deren Einflüsse auf die Laminatsteifigkeiten und Versagenslasten der Laminate analysiert. Alle untersuchten Fertigungseinflüsse werden zudem mittels experimenteller Untersuchungen analysiert und zu den Erkenntnissen der simulativen Untersuchungen referenziert. Die Methode wird schließlich, mit den gewonnenen Erkenntnissen, an der Berechnung eines Hautfeldes eines Flugzeugrumpfs exemplarisch demonstriert.},
keywords = {Auslegung; Effects of Defects},
pubstate = {published},
tppubtype = {book}
}
In der Produktentwicklung und speziell im Leichtbau, ist die Kenntnis über den verwendeten Werkstoff entscheidend. Je größer das Wissen über den Werkstoff, wie er unter unterschiedlichen Bedingungen reagiert, umso präziser kann die Auslegung des Produktes auf die gestellten Anforderungen hin geschehen. Faser-Kunststoff-Verbunde (FKV) sind, wie der Name bereits verrät, ein Verbund aus zwei Werkstoffen, der Faser und der Matrix, welche sich im Verbund ergänzen. Die resultierenden Eigenschaften eines Verbundwerkstoffes hängen demnach von den Eigenschaften der Verbundpartner, der Konstituenten, ab. Neben den Eigenschaften der Konstituenten beeinflusst auch ihre Zusammensetzung und eine Reihe von Qualitätsparametern, wie Lufteinschlüsse und die Welligkeit der Fasern, die resultierenden Werkstoffeigenschaften. Die Qualitätsparameter von FKV werden maßgeblich von deren Fertigungsprozessen beeinflusst, weshalb es wichtig ist die Zusammenhänge zwischen den Fertigungsprozessen und den Werkstoffeigenschaften zu kennen.
Aus diesem Grund wird in dieser Arbeit eine Methode entwickelt, welche die systematische Integration prozessinduzierter Einflüsse in die Berechnung von Strukturen aus FKV ermöglicht. Die Qualitätsparameter bilden dabei das Bindeglied zwischen den Prozessen und den Eigenschaften des FKV. Die Einflüsse der Qualitätsparameter fließen innerhalb eines Multiskalenmodells zur Berechnung von Laminaten ein, was eine Integration der Prozesse in die Auslegung ermöglicht.
Die Arbeit zeigt das Vorgehen der Methode anhand von Faserwelligkeiten, Gaps und Lagenwelligkeiten in Laminaten aus FKV. Die Faserwelligkeiten werden auf Ebene der FKV integriert, indem effektive Steifigkeiten und Festigkeiten für den beeinflussten Verbundwerkstoff bestimmt werden. Dabei werden auch die inhärenten Zufälligkeiten der Faserwelligkeiten berücksichtigt. Gaps, und die daraus resultierenden Lagenwelligkeiten, werden auf der Laminatebene modelliert und deren Einflüsse auf die Laminatsteifigkeiten und Versagenslasten der Laminate analysiert. Alle untersuchten Fertigungseinflüsse werden zudem mittels experimenteller Untersuchungen analysiert und zu den Erkenntnissen der simulativen Untersuchungen referenziert. Die Methode wird schließlich, mit den gewonnenen Erkenntnissen, an der Berechnung eines Hautfeldes eines Flugzeugrumpfs exemplarisch demonstriert.
Aus diesem Grund wird in dieser Arbeit eine Methode entwickelt, welche die systematische Integration prozessinduzierter Einflüsse in die Berechnung von Strukturen aus FKV ermöglicht. Die Qualitätsparameter bilden dabei das Bindeglied zwischen den Prozessen und den Eigenschaften des FKV. Die Einflüsse der Qualitätsparameter fließen innerhalb eines Multiskalenmodells zur Berechnung von Laminaten ein, was eine Integration der Prozesse in die Auslegung ermöglicht.
Die Arbeit zeigt das Vorgehen der Methode anhand von Faserwelligkeiten, Gaps und Lagenwelligkeiten in Laminaten aus FKV. Die Faserwelligkeiten werden auf Ebene der FKV integriert, indem effektive Steifigkeiten und Festigkeiten für den beeinflussten Verbundwerkstoff bestimmt werden. Dabei werden auch die inhärenten Zufälligkeiten der Faserwelligkeiten berücksichtigt. Gaps, und die daraus resultierenden Lagenwelligkeiten, werden auf der Laminatebene modelliert und deren Einflüsse auf die Laminatsteifigkeiten und Versagenslasten der Laminate analysiert. Alle untersuchten Fertigungseinflüsse werden zudem mittels experimenteller Untersuchungen analysiert und zu den Erkenntnissen der simulativen Untersuchungen referenziert. Die Methode wird schließlich, mit den gewonnenen Erkenntnissen, an der Berechnung eines Hautfeldes eines Flugzeugrumpfs exemplarisch demonstriert.
Engel, Kevin
Berücksichtigung prozessinduzierter Effekte in der Auslegung von Faser-Kunststoff-Verbunden Promotionsarbeit
Technische Universität Braunschweig, 2018, ISBN: 978-3947623150.
Abstract | BibTeX | Schlagwörter: Fuselage, Manufacturing Quality
@phdthesis{Engel2018b,
title = {Berücksichtigung prozessinduzierter Effekte in der Auslegung von Faser-Kunststoff-Verbunden},
author = {Kevin Engel},
isbn = {978-3947623150},
year = {2018},
date = {2018-12-17},
school = {Technische Universität Braunschweig},
abstract = {In der Produktentwicklung und speziell im Leichtbau, ist die Kenntnis über den verwendeten Werkstoff entscheidend. Je größer das Wissen über den Werkstoff, wie er unter unterschiedlichen Bedingungen reagiert, umso präziser kann die Auslegung des Produktes auf die gestellten Anforderungen hin geschehen. Faser-Kunststoff-Verbunde (FKV) sind, wie der Name bereits verrät, ein Verbund aus zwei Werkstoffen, der Faser und der Matrix, welche sich im Verbund ergänzen. Die resultierenden Eigenschaften eines Verbundwerkstoffes hängen demnach von den Eigenschaften der Verbundpartner, der Konstituenten, ab. Neben den Eigenschaften der Konstituenten beeinflusst auch ihre Zusammensetzung und eine Reihe von Qualitätsparametern, wie Lufteinschlüsse und die Welligkeit der Fasern, die resultierenden Werkstoffeigenschaften. Die Qualitätsparameter von FKV werden maßgeblich von deren Fertigungsprozessen beeinflusst, weshalb es wichtig ist die Zusammenhänge zwischen den Fertigungsprozessen und den Werkstoffeigenschaften zu kennen. Aus diesem Grund wird in dieser Arbeit eine Methode entwickelt, welche die systematische Integration prozessinduzierter Einflüsse in die Berechnung von Strukturen aus FKV ermöglicht. Die Qualitätsparameter bilden dabei das Bindeglied zwischen den Prozessen und den Eigenschaften des FKV. Die Einflüsse der Qualitätsparameter fließen innerhalb eines Multiskalenmodells zur Berechnung von Laminaten ein, was eine Integration der Prozesse in die Auslegung ermöglicht. Die Arbeit zeigt das Vorgehen der Methode anhand von Faserwelligkeiten, Gaps und Lagenwelligkeiten in Laminaten aus FKV. Die Faserwelligkeiten werden auf Ebene der FKV integriert, indem effektive Steifigkeiten und Festigkeiten für den beeinflussten Verbundwerkstoff bestimmt werden. Dabei werden auch die inhärenten Zufälligkeiten der Faserwelligkeiten berücksichtigt. Gaps, und die daraus resultierenden Lagenwelligkeiten, werden auf der Laminatebene modelliert und deren Einflüsse auf die Laminatsteifigkeiten und Versagenslasten der Laminate analysiert. Alle untersuchten Fertigungseinflüsse werden zudem mittels experimenteller Untersuchungen analysiert und zu den Erkenntnissen der simulativen Untersuchungen referenziert. Die Methode wird schließlich, mit den gewonnenen Erkenntnissen, an der Berechnung eines Hautfeldes eines Flugzeugrumpfs exemplarisch demonstriert.},
keywords = {Fuselage, Manufacturing Quality},
pubstate = {published},
tppubtype = {phdthesis}
}
In der Produktentwicklung und speziell im Leichtbau, ist die Kenntnis über den verwendeten Werkstoff entscheidend. Je größer das Wissen über den Werkstoff, wie er unter unterschiedlichen Bedingungen reagiert, umso präziser kann die Auslegung des Produktes auf die gestellten Anforderungen hin geschehen. Faser-Kunststoff-Verbunde (FKV) sind, wie der Name bereits verrät, ein Verbund aus zwei Werkstoffen, der Faser und der Matrix, welche sich im Verbund ergänzen. Die resultierenden Eigenschaften eines Verbundwerkstoffes hängen demnach von den Eigenschaften der Verbundpartner, der Konstituenten, ab. Neben den Eigenschaften der Konstituenten beeinflusst auch ihre Zusammensetzung und eine Reihe von Qualitätsparametern, wie Lufteinschlüsse und die Welligkeit der Fasern, die resultierenden Werkstoffeigenschaften. Die Qualitätsparameter von FKV werden maßgeblich von deren Fertigungsprozessen beeinflusst, weshalb es wichtig ist die Zusammenhänge zwischen den Fertigungsprozessen und den Werkstoffeigenschaften zu kennen. Aus diesem Grund wird in dieser Arbeit eine Methode entwickelt, welche die systematische Integration prozessinduzierter Einflüsse in die Berechnung von Strukturen aus FKV ermöglicht. Die Qualitätsparameter bilden dabei das Bindeglied zwischen den Prozessen und den Eigenschaften des FKV. Die Einflüsse der Qualitätsparameter fließen innerhalb eines Multiskalenmodells zur Berechnung von Laminaten ein, was eine Integration der Prozesse in die Auslegung ermöglicht. Die Arbeit zeigt das Vorgehen der Methode anhand von Faserwelligkeiten, Gaps und Lagenwelligkeiten in Laminaten aus FKV. Die Faserwelligkeiten werden auf Ebene der FKV integriert, indem effektive Steifigkeiten und Festigkeiten für den beeinflussten Verbundwerkstoff bestimmt werden. Dabei werden auch die inhärenten Zufälligkeiten der Faserwelligkeiten berücksichtigt. Gaps, und die daraus resultierenden Lagenwelligkeiten, werden auf der Laminatebene modelliert und deren Einflüsse auf die Laminatsteifigkeiten und Versagenslasten der Laminate analysiert. Alle untersuchten Fertigungseinflüsse werden zudem mittels experimenteller Untersuchungen analysiert und zu den Erkenntnissen der simulativen Untersuchungen referenziert. Die Methode wird schließlich, mit den gewonnenen Erkenntnissen, an der Berechnung eines Hautfeldes eines Flugzeugrumpfs exemplarisch demonstriert.
Schmidt, Carsten; Weber, Patricc; Hocke, Tristan; Denkena, Berend
In: Procedia CIRP, Bd. 67, S. 422-427, 2018.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Material Aging, Prepreg
@article{Schmidt2018c,
title = {Influence of prepreg material quality on carbon fiber reinforced plastic laminates processed by automated fiber placement},
author = {Carsten Schmidt and Patricc Weber and Tristan Hocke and Berend Denkena},
doi = {https://doi.org/10.1016/j.procir.2017.12.236},
year = {2018},
date = {2018-10-15},
journal = {Procedia CIRP},
volume = {67},
pages = {422-427},
abstract = {In this paper, the influence of prepreg material quality to the mechanical properties of CFRP parts is presented. During the out life of prepreg slit tape, the processability changes by aging especially when storing the material at room temperature. Therefore, investigations are done with an in-house developed AFP machine and are monitored with a thermal monitoring system to determine the influence of material aging to mechanical properties and changes in the manufacturing process. The manufactured CFRP plates are finally tested by 3-point bending test.},
keywords = {Automated Fiber Placement, Material Aging, Prepreg},
pubstate = {published},
tppubtype = {article}
}
In this paper, the influence of prepreg material quality to the mechanical properties of CFRP parts is presented. During the out life of prepreg slit tape, the processability changes by aging especially when storing the material at room temperature. Therefore, investigations are done with an in-house developed AFP machine and are monitored with a thermal monitoring system to determine the influence of material aging to mechanical properties and changes in the manufacturing process. The manufactured CFRP plates are finally tested by 3-point bending test.
Denkena, Berend; Schmidt, Carsten; Werner, Simon
Continuous Draping of Double Curved Geometries – A Geometrical Approach to Describe an Automated Layup Process of Fabrics on Complex Surface Konferenz
Southampton, Vereinigtes Königreich, 2018.
Abstract | BibTeX | Schlagwörter: Continuous Wet Draping
@conference{Denkena2018,
title = {Continuous Draping of Double Curved Geometries – A Geometrical Approach to Describe an Automated Layup Process of Fabrics on Complex Surface},
author = {Berend Denkena and Carsten Schmidt and Simon Werner},
editor = {SAMPE Europe Conference 2018 Southampton},
year = {2018},
date = {2018-09-12},
pages = {8},
address = {Southampton, Vereinigtes Königreich},
abstract = {To achieve a higher grade of integral aircraft structure design, a new unconventionally stiffened lattice composite fuselage panel is developed allowing a co-curing process of fuselage skin and stiffening structure. For this purpose, a novel automated layup module is under development. Within this contribution, the geometrical behaviour of the fibre-fabric during continuous draping onto the mould surface is investigated. Based on experimental draping studies on occurring issues during fabric draping, a process model was created. The presented approach is based on geometrical boundary conditions and neglects specific material properties. To ensure proper draping results, the fabric has to be kept under tension. Thus, it must be dropped in dependence of the surface geometry at the resulting “draping-spline” (Figure 4). Simulation results are verified and discussed through three-dimensional measuring data of the layup process. Subsequently, the geometrical data of the “draping-spline” for different process situations is analysed to determine the workspace for the layup modules shape-replicating kinematics. Furthermore, possible kinematical configurations and needed degrees of freedom to replicate the shape-changing three-dimensional spline mechanically are discussed.},
keywords = {Continuous Wet Draping},
pubstate = {published},
tppubtype = {conference}
}
To achieve a higher grade of integral aircraft structure design, a new unconventionally stiffened lattice composite fuselage panel is developed allowing a co-curing process of fuselage skin and stiffening structure. For this purpose, a novel automated layup module is under development. Within this contribution, the geometrical behaviour of the fibre-fabric during continuous draping onto the mould surface is investigated. Based on experimental draping studies on occurring issues during fabric draping, a process model was created. The presented approach is based on geometrical boundary conditions and neglects specific material properties. To ensure proper draping results, the fabric has to be kept under tension. Thus, it must be dropped in dependence of the surface geometry at the resulting “draping-spline” (Figure 4). Simulation results are verified and discussed through three-dimensional measuring data of the layup process. Subsequently, the geometrical data of the “draping-spline” for different process situations is analysed to determine the workspace for the layup modules shape-replicating kinematics. Furthermore, possible kinematical configurations and needed degrees of freedom to replicate the shape-changing three-dimensional spline mechanically are discussed.
Serna, Jonathan
Multilayer-Inserts – MLI Krafteinleitung in dünnwandige CFK-Strukturen durch lokale Hybridisierung Konferenzbeitrag
In: Leichtbau, 5. Technologietag Hybrider (Hrsg.): Stuttgart, 2018.
BibTeX | Schlagwörter: Multilayer Insert
@inproceedings{Serna2018,
title = {Multilayer-Inserts – MLI Krafteinleitung in dünnwandige CFK-Strukturen durch lokale Hybridisierung},
author = {Jonathan Serna },
editor = {5. Technologietag Hybrider Leichtbau},
year = {2018},
date = {2018-07-31},
address = {Stuttgart},
keywords = {Multilayer Insert},
pubstate = {published},
tppubtype = {inproceedings}
}