2023
Friedel, Andreas; Heimbs, Sebastian; Horst, Peter; Schmidt, Carsten; Timmermann, Marc
In: Composites Part C, Ausg. 10, 2023.
Abstract | Links | BibTeX | Schlagwörter: fuzz ball, Process Monitoring, representative structural element
@article{Friedel2023,
title = {Representative structural element approach for assessing the mechanical properties of automated fibre placement-induced defects},
author = {Andreas Friedel and Sebastian Heimbs and Peter Horst and Carsten Schmidt and Marc Timmermann},
url = {https://www.sciencedirect.com/science/article/pii/S2666682023000063?via%3Dihub},
doi = {https://doi.org/10.1016/j.jcomc.2023.100350},
year = {2023},
date = {2023-02-15},
urldate = {2023-02-15},
journal = {Composites Part C},
issue = {10},
abstract = {In this paper, a 3D finite element modelling approach is presented to assess the effects of manufacturing defects within composite structures. The mesoscale modelling approach derives the stress-strain response of a composite structure from a representative structural element. A set of tensile and bending loads is used to compute its ABD-Matrix. The boundary conditions of the model are described in detail as is the extraction of the strain and curvature response. The derived stiffness from the presented modelling approach is compared to the classical lamination theory and the models' shortcomings are discussed. Finally, the influence of a gap, an overlap and two different-sized fuzzballs on the macroscopic mechanical properties of a composite structure are evaluated using the presented multiscale modelling approach, thereby providing stiffness matrices influenced by the defects for the use in global models of composite parts.},
keywords = {fuzz ball, Process Monitoring, representative structural element},
pubstate = {published},
tppubtype = {article}
}
2021
Denkena, Berend; Schmidt, Carsten; Timmermann, Marc; Friedel, Andreas
In: Production Engineering, 2021.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring
@article{Denkena2021c,
title = {An optical-flow-based monitoring method for measuring translational motion in infrared-thermographic images of AFP processes},
author = {Berend Denkena and Carsten Schmidt and Marc Timmermann and Andreas Friedel},
doi = {10.1007/s11740-021-01084-w},
year = {2021},
date = {2021-10-19},
journal = {Production Engineering},
abstract = {This paper presents a novel method for a precise localization of the automated-fiber-placement head, without the need for a data access to the machine control. It is based on a sub-pixel accurate optical-flow-algorithm which determines information about the heads movement by means of the material flow in sequences of IR images. Using local curvatures in the temperature field of the IR images, feature matrices are created which can locally be compared to the features of successive images. Thus, the translation between images become visible. This enables the possibility to perform an accurate (16.8μm) and self-sufficient process monitoring that additionally is capable of capturing the motion and position information of the AFP system and can be linked to existing algorithms for defect detection and classification.},
keywords = {Automated Fiber Placement, Process Monitoring},
pubstate = {published},
tppubtype = {article}
}
2020
Hocke, Tristan
Klassifizierung und Untersuchung von thermografisch erfassten Fertigungsfehlern im Automated-Fiber-Placement-Prozess Promotionsarbeit
Leibniz Universität Hannover, 2020, ISBN: 978-3-95900-503-6.
Abstract | Links | BibTeX | Schlagwörter: Process Monitoring
@phdthesis{Hocke2020,
title = {Klassifizierung und Untersuchung von thermografisch erfassten Fertigungsfehlern im Automated-Fiber-Placement-Prozess},
author = {Tristan Hocke},
url = {https://www.tewiss-verlag.de/script/pdfviewer.php?pdf=978-3-95900-503-6.pdf},
isbn = {978-3-95900-503-6},
year = {2020},
date = {2020-11-04},
school = {Leibniz Universität Hannover},
abstract = {In dieser Arbeit ist eine thermografische Überwachung für den Automated-Fiber-Placement-Prozess entwickelt und umgesetzt worden, die Fertigungsfehler in den thermischen Prozessbildern mittels neuronaler Faltungsnetzwerke detektiert und klassifiziert. Zudem können die Temperaturen von fehlerfrei abgelegten Tows nach der Kompaktierung in Abhängigkeit von vier Prozessparametern berechnet werden. Folglich lassen sich aus den thermischen Prozessbildern Differenzbilder berechnen, in denen das thermische Temperaturverhalten der Tows aufgrund des AFP-Prozesses kompensiert wird. Die Zusammenführung der Fehlerklassifizierung mit der Differenzbildanalyse die Segmentierung der detektierten Fehler, um auf Grundlage der thermischen Prozessbilder geometrische und thermische Fehlereigenschaften zu bestimmen.},
keywords = {Process Monitoring},
pubstate = {published},
tppubtype = {phdthesis}
}
2019
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}
}
2018
Völtzer, Klaas
Online-Prozessüberwachung von Automated Fiber Placement Prozessen auf Basis der Thermografie Buch
2018.
Abstract | BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring
@book{Völtzer2018,
title = {Online-Prozessüberwachung von Automated Fiber Placement Prozessen auf Basis der Thermografie},
author = {Klaas Völtzer},
year = {2018},
date = {2018-06-08},
series = {Dissertation Leibniz Universität Hannover, Institut für Fertigungstechnik und Werkzeugmaschinen},
abstract = {Der steigende Einsatz von kohlenstofffaserverstärkten Kunststoffen (CFK), vor allem in der Luftfahrtindustrie, führt zu einer zunehmenden Bedeutung der CFK-Fertigungsverfahren, wie dem Automated Fiber Placement Prozess (AFP). Eine manuelle Überwachung dieses Prozesses ist aufgrund des geringen Kontrasts zwischen den einzelnen Laminatlagen erschwert und damit zeitintensiv und ineffizient. In dieser Arbeit wird eine neuartige Überwachungsmethode auf Basis der Thermografie vorgestellt und erforscht. Eine integrierte Infrarotkamera direkt hinter der Andruckeinheit des AFP-Legekopfes wertet dabei den Temperaturkontrast zwischen dem unmittelbar abgelegten Faser-Matrix-Halbzeug und dem Untergrund sowie die generelle Temperaturverteilung aus. Über eine Detektion der Halbzeugkanten können Positionierungsfehler identifiziert werden. Ebenso können über eine Auswertung der Oberflächentemperaturen Anbindungsfehler oder Fremdkörper anhand von Temperaturanomalien detektiert werden. Mit einem prototypischen Überwachungssystem werden die Systemgrenzen aufgezeigt und die Funktionsfähigkeit anhand eines Beispielprozesses demonstriert. },
keywords = {Automated Fiber Placement, Process Monitoring},
pubstate = {published},
tppubtype = {book}
}
Völtzer, Klaas
Online-Prozessüberwachung von Automated Fiber Placement Prozessen auf Basis der Thermografie Promotionsarbeit
Leibniz Universität Hannover, 2018.
Abstract | Links | BibTeX | Schlagwörter: Process Monitoring
@phdthesis{Völtzer2018b,
title = {Online-Prozessüberwachung von Automated Fiber Placement Prozessen auf Basis der Thermografie},
author = {Klaas Völtzer},
url = {https://www.researchgate.net/profile/Klaas-Voeltzer/publication/325415549_Online-Prozessuberwachung_von_Automated_Fiber_Placement_Prozessen_auf_Basis_der_Thermografie/links/5b0cee924585157f871cce28/Online-Prozessueberwachung-von-Automated-Fiber-Placement-Prozessen-auf-Basis-der-Thermografie.pdf},
year = {2018},
date = {2018-04-12},
school = {Leibniz Universität Hannover},
abstract = {Der steigende Einsatz von kohlenstofffaserverstärkten Kunststoffen (CFK), vor allem in der Luftfahrtindustrie, führt zu einer zunehmenden Bedeutung der CFK-Fertigungsverfahren, wie dem Automated Fiber Placement Prozess (AFP). Eine manuelle Überwachung dieses Prozesses ist aufgrund des geringen Kontrasts zwischen den einzelnen Laminatlagen erschwert und damit zeitintensiv und ineffizient. In dieser Arbeit wird eine neuartige Überwachungsmethode auf Basis der Thermografie vorgestellt und erforscht. Eine integrierte Infrarotkamera direkt hinter der Andruckeinheit des AFP-Legekopfes wertet dabei den Temperaturkontrast zwischen dem unmittelbar abgelegten
Faser-Matrix-Halbzeug und dem Untergrund sowie die generelle Temperaturverteilung aus. Über eine Detektion der Halbzeugkanten können Positionierungsfehler identifiziert werden. Ebenso können über eine Auswertung der Oberflächentemperaturen Anbindungsfehler oder Fremdkörper anhand von Temperaturanomalien detektiert werden. Mit einem prototypischen Überwachungssystem werden die Systemgrenzen aufgezeigt und die Funktionsfähigkeit anhand eines Beispielprozesses demonstriert.},
keywords = {Process Monitoring},
pubstate = {published},
tppubtype = {phdthesis}
}
Faser-Matrix-Halbzeug und dem Untergrund sowie die generelle Temperaturverteilung aus. Über eine Detektion der Halbzeugkanten können Positionierungsfehler identifiziert werden. Ebenso können über eine Auswertung der Oberflächentemperaturen Anbindungsfehler oder Fremdkörper anhand von Temperaturanomalien detektiert werden. Mit einem prototypischen Überwachungssystem werden die Systemgrenzen aufgezeigt und die Funktionsfähigkeit anhand eines Beispielprozesses demonstriert.
2017
Schmidt, Carsten; Denkena, Berend; Hocke, Tristan; Völtzer, Klaas
1st CIRP Conference on Composite Materials Parts Manufacturing, 2017.
Links | BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Quality Assurance, Thermal Imaging
@conference{Schmidt2017b,
title = {Influence of AFP process parameters on the temperature distribution used for thermal in-process monitoring},
author = {Carsten Schmidt and Berend Denkena and Tristan Hocke and Klaas Völtzer},
editor = {Procedia CIRP 66},
doi = {10.1016/j.procir.2017.03.220},
year = {2017},
date = {2017-06-07},
booktitle = {1st CIRP Conference on Composite Materials Parts Manufacturing},
pages = {68-73},
keywords = {Automated Fiber Placement, Process Monitoring, Quality Assurance, Thermal Imaging},
pubstate = {published},
tppubtype = {conference}
}
Brüning, Jan; Denkena, Berend; Dittrich, Marc-Andre; Hocke, Tristan
Machine Learning Approach for Optimization of Automated Fiber Placement Processes Konferenz
2017.
Links | BibTeX | Schlagwörter: Automated Fiber Placement, Industry 4.0, Process Monitoring
@conference{Brüning2017b,
title = {Machine Learning Approach for Optimization of Automated Fiber Placement Processes},
author = {Jan Brüning and Berend Denkena and Marc-Andre Dittrich and Tristan Hocke},
editor = {Procedia CIRP 66},
doi = {10.1016/j.procir.2017.03.295},
year = {2017},
date = {2017-06-07},
pages = {74-78},
keywords = {Automated Fiber Placement, Industry 4.0, Process Monitoring},
pubstate = {published},
tppubtype = {conference}
}
Schmidt, Carsten; Denkena, Berend; Hocke, Tristan; Völtzer, Klaas
Thermal imaging as a solution for reliable monitoring of AFP processes Konferenz
3rd ACM Automated Composites Manufacturing, Montreal, Canada, 2017.
BibTeX | Schlagwörter: Automated Fiber Placement, Industry 4.0, Manufacturing Quality, Process Monitoring, Thermal Imaging
@conference{Schmidt2017,
title = {Thermal imaging as a solution for reliable monitoring of AFP processes},
author = {Carsten Schmidt and Berend Denkena and Tristan Hocke and Klaas Völtzer},
year = {2017},
date = {2017-04-20},
booktitle = {3rd ACM Automated Composites Manufacturing},
address = {Montreal, Canada},
keywords = {Automated Fiber Placement, Industry 4.0, Manufacturing Quality, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {conference}
}
Brüning, Jan; Schmidt, Carsten; Denkena, Berend
Erhöhung der Prozesssicherheit von Automated-Fiber-Placement-Prozessen Artikel
In: Ingenieurspiegel, Bd. 1, S. 29-31, 2017.
Abstract | BibTeX | Schlagwörter: Composite Structures, Process Monitoring, Thermal Imaging
@article{Brüning2017,
title = {Erhöhung der Prozesssicherheit von Automated-Fiber-Placement-Prozessen},
author = {Jan Brüning and Carsten Schmidt and Berend Denkena},
year = {2017},
date = {2017-01-16},
journal = {Ingenieurspiegel},
volume = {1},
pages = {29-31},
abstract = {In der Luftfahrtindustrie ist Automated Fiber Placement (AFP) eine der führenden Fertigungstechnologien für die kosteneffektive Serienproduktion von hochqualitativen Leichtbaustrukturen. Allerdings bieten sowohl die automatisierten Fertigungssysteme als auch die Prozessplanungssysteme noch ungenutzte Verbesserungspotenziale hinsichtlich Zuverlässigkeit und Effizienz.},
keywords = {Composite Structures, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
2016
Schmidt, Carsten; Völtzer, Klaas; Hocke, Tristan; Brüning, Jan
Bahnplanung für Automated-Fiber-Placement-Prozesse Artikel
In: Lightweight Design, Bd. 4, 2016.
BibTeX | Schlagwörter: Automated Fiber Placement, Path Planning, Process Monitoring, Thermal Imaging
@article{Schmidt2016b,
title = {Bahnplanung für Automated-Fiber-Placement-Prozesse},
author = {Carsten Schmidt and Klaas Völtzer and Tristan Hocke and Jan Brüning},
year = {2016},
date = {2016-09-15},
journal = {Lightweight Design},
volume = {4},
keywords = {Automated Fiber Placement, Path Planning, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
Denkena, Berend; Schmidt, Carsten; Völtzer, Klaas; Hocke, Tristan
POTENTIAL OF THERMAL INLINE MONITORING IN AUTOMATED FIBER PLACEMENT PROCESS FOR AEROSPACE APLICATIONS Konferenz
7th International Symposium on Composites Manufacturing for High Performance Applications - ISCM, Braunschweig, 2016.
BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Thermal Imaging
@conference{Denkena2016b,
title = { POTENTIAL OF THERMAL INLINE MONITORING IN AUTOMATED FIBER PLACEMENT PROCESS FOR AEROSPACE APLICATIONS},
author = {Berend Denkena and Carsten Schmidt and Klaas Völtzer and Tristan Hocke},
year = {2016},
date = {2016-08-25},
booktitle = {7th International Symposium on Composites Manufacturing for High Performance Applications - ISCM},
address = {Braunschweig},
keywords = {Automated Fiber Placement, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {conference}
}
Schmidt, Carsten; Denkena, Berend; Völtzer, Klaas; Hocke, Tristan
Thermal Image-Based Monitoring for the Automated Fiber Placement Process Konferenz
10th CIRP Conference on Intelligent Computation in Manufacturing Engineering, Neapel, Italien, 2016.
BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Thermal Imaging
@conference{Schmidt2016b,
title = {Thermal Image-Based Monitoring for the Automated Fiber Placement Process},
author = {Carsten Schmidt and Berend Denkena and Klaas Völtzer and Tristan Hocke},
year = {2016},
date = {2016-07-20},
booktitle = {10th CIRP Conference on Intelligent Computation in Manufacturing Engineering},
address = {Neapel, Italien},
keywords = {Automated Fiber Placement, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {conference}
}
Denkena, Berend; Schmidt, Carsten; Völtzer, Klaas; Hocke, Tristan
Thermographic online monitoring system for Automated Fiber Placement processes Artikel
In: Composite Part B, Bd. Vol. 97, S. 239-243, 2016.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Thermal Imaging
@article{Denkena2016,
title = {Thermographic online monitoring system for Automated Fiber Placement processes},
author = {Berend Denkena and Carsten Schmidt and Klaas Völtzer and Tristan Hocke},
doi = {10.1016/j.compositesb.2016.04.076},
year = {2016},
date = {2016-07-17},
journal = {Composite Part B},
volume = {Vol. 97},
pages = {239-243},
abstract = {Automated Fiber Placement processes are commonly used to manufacture lightweight structures e. g. for highly demanding aerospace applications. In general, quality inspection is usually carried out manually and it is considerably time consuming in terms of high lot sizes and huge part dimensions. An online AFP process monitoring based on thermal camera combined with process depending image processing is presented. The visible temperature difference between the laid-up tow and its surface underneath is analyzed and information of lay-up defects such as overlaps, gaps, twisted tows and bridging derived. This monitoring system can reduce the efforts in quality inspection and will help to increase process reliability significantly.},
keywords = {Automated Fiber Placement, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
Schmidt, Carsten; Völtzer, Klaas; Hocke, Tristan; Windels, Lars
Automated path planning and thermographic monitoring for automated fibre placement Artikel
In: JEC Composites Magazine, Bd. No. 104, 2016.
BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Thermal Imaging
@article{Schmidt2016b,
title = {Automated path planning and thermographic monitoring for automated fibre placement},
author = {Carsten Schmidt and Klaas Völtzer and Tristan Hocke and Lars Windels},
year = {2016},
date = {2016-04-01},
journal = {JEC Composites Magazine},
volume = {No. 104},
keywords = {Automated Fiber Placement, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {article}
}
2015
Denkena, Berend; Schmidt, Carsten; Völtzer, Klaas
Online Monitoring of Automated Fiber Placement Processes by Thermal Imaging Konferenzbeitrag
In: ACM - Automated Composite Manufacturing, Montreal, 2015.
Abstract | BibTeX | Schlagwörter: Automated Fiber Placement, Process Monitoring, Thermal Imaging
@inproceedings{Denkena2015,
title = {Online Monitoring of Automated Fiber Placement Processes by Thermal Imaging},
author = {Berend Denkena and Carsten Schmidt and Klaas Völtzer},
year = {2015},
date = {2015-04-24},
booktitle = {ACM - Automated Composite Manufacturing},
address = {Montreal},
abstract = {Automated fiber placement processes are commonly used to manufacture lightweight structures e.g. for highly demanding aerospace applications. Quality inspection usually is done manually and in terms of high part numbers and huge part sizes it is a very time consuming process. An online AFP-process monitoring through a thermal camera combined with process depending image processing is presented.
Thermoset prepreg tows need to be kept cool inside the fiber placement head to prevent fouling. A mayor quality aspect of the placed tow is the tack between tow and surface. To ensure a good tack, surface and tows are heated right before the placement and compacted under specific pressure. Right behind the compaction-roller, the surface temperature of the placed tow shows a lower temperature than the surrounding surfaces. This temperature difference can be detected by a thermal camera. It is shown that by evaluating specific regions behind the roller and by applying an edge detection algorithm the tow geometry and position can be extracted and monitored. This information reveals many placing faults like overlaps, gaps, twisted tows and spliced tows. Furthermore, the bond influences heat transfer from the substrate to the tow surface. Therefore, the temperature of the placed tow can be used as a quality indicator of the bond.
The temperature of the heated surface behind the compaction-roller depends on the heat absorption, the heat transfer into the tooling, and the convection. A homogeneous temperature distribution is expected. If there are inhomogeneous sections in the placed laminate, their temperature differs from the surrounding surface temperature. These hot or cold spots indicate anomalies like bridging faults or foreign objects. Knowing the normal temperature picture of the actual process, hot and cold spots can be detected by dynamic thresholds depending on the actual process.
The presented results add to reduce above-mentioned efforts in quality inspection and will help to increase process reliability significantly.},
keywords = {Automated Fiber Placement, Process Monitoring, Thermal Imaging},
pubstate = {published},
tppubtype = {inproceedings}
}
Thermoset prepreg tows need to be kept cool inside the fiber placement head to prevent fouling. A mayor quality aspect of the placed tow is the tack between tow and surface. To ensure a good tack, surface and tows are heated right before the placement and compacted under specific pressure. Right behind the compaction-roller, the surface temperature of the placed tow shows a lower temperature than the surrounding surfaces. This temperature difference can be detected by a thermal camera. It is shown that by evaluating specific regions behind the roller and by applying an edge detection algorithm the tow geometry and position can be extracted and monitored. This information reveals many placing faults like overlaps, gaps, twisted tows and spliced tows. Furthermore, the bond influences heat transfer from the substrate to the tow surface. Therefore, the temperature of the placed tow can be used as a quality indicator of the bond.
The temperature of the heated surface behind the compaction-roller depends on the heat absorption, the heat transfer into the tooling, and the convection. A homogeneous temperature distribution is expected. If there are inhomogeneous sections in the placed laminate, their temperature differs from the surrounding surface temperature. These hot or cold spots indicate anomalies like bridging faults or foreign objects. Knowing the normal temperature picture of the actual process, hot and cold spots can be detected by dynamic thresholds depending on the actual process.
The presented results add to reduce above-mentioned efforts in quality inspection and will help to increase process reliability significantly.
2014
Schmidt, Carsten; Schultz, Cedric; Weber, Patricc; Denkena, Berend
In: Composites PArt B: Engineering, Bd. 56, S. 109-116, 2014.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Composite Structures, Eddy Current Testing, Process Monitoring, Quality Assurance
@article{Schmidt2014,
title = {Evaluation of eddy current testing for quality assurance and process monitoring of automated fiber placement},
author = {Carsten Schmidt and Cedric Schultz and Patricc Weber and Berend Denkena},
url = {http://dx.doi.org/10.1016/j.compositesb.2013.08.061},
year = {2014},
date = {2014-01-01},
journal = {Composites PArt B: Engineering},
volume = {56},
pages = {109-116},
abstract = {Standards in energy and cost efficiency are higher the ever especially in the aerospace industry. While structures made from carbon-fiber reinforced plastics (CFRP) show significant advantages in regards to specific strength and lightweight design, further improvements in their production processes are essential in order for CFRP to be competitive in the future. The authors present eddy current (EC) testing as a means for quality assurance (QA) and process monitoring for CFRP parts produced by automatic fiber placement (AFP), which is one the most prevalent production methods in aerospace industry. Eddy current testing shows the potential for highly automated process monitoring that can reduce error correction and cycle time in AFP.},
keywords = {Automated Fiber Placement, Composite Structures, Eddy Current Testing, Process Monitoring, Quality Assurance},
pubstate = {published},
tppubtype = {article}
}