2016
Koch, Simon-F.; Barfuss, Daniel; Bobbert, Mathias; Groß, Lukas; Grützner, Raik; Riemer, Matthias; Stefaniak, Daniel; Wang, Zhen
Intrinsic hybrid composites for lightweight structures: New Process Chain Approaches Konferenz
Proceedings of 2016 WGP Congress, 2016.
Abstract | BibTeX | Schlagwörter: Automated Fiber Placement, Composite Structures, Intrinsic Hybridisation, Multilayer Insert
@conference{Koch2016,
title = {Intrinsic hybrid composites for lightweight structures: New Process Chain Approaches},
author = {Simon-F. Koch and Daniel Barfuss and Mathias Bobbert and Lukas Groß and Raik Grützner and Matthias Riemer and Daniel Stefaniak and Zhen Wang},
year = {2016},
date = {2016-08-25},
booktitle = {Proceedings of 2016 WGP Congress},
abstract = {This publication describes new process chain approaches for the manufacturing of intrinsic hybrid composites for lightweight structures. The introduced process chains show a variety of different part and sample types, like insert technology for fastening of hollow hybrid shafts and profiles. Another field of research are hybrid laminates with different layers of carbon fiber reinforced plastics stacked with aluminum or steel sheets. The derived process chains base on automated fiber placement, resin transfer molding, deep drawing, rotational molding and integral tube blow molding.},
keywords = {Automated Fiber Placement, Composite Structures, Intrinsic Hybridisation, Multilayer Insert},
pubstate = {published},
tppubtype = {conference}
}
Behr, Matthias; Schmidt, Carsten
Systematic Production Planning Method for CFRP Structures Artikel
In: Advanced Materials Research, Bd. Vol. 1140, S. S. 328-334, 2016.
Abstract | BibTeX | Schlagwörter: Composite Structures, Preliminary design, Production Planning
@article{Behr2016,
title = {Systematic Production Planning Method for CFRP Structures},
author = {Matthias Behr and Carsten Schmidt},
year = {2016},
date = {2016-08-25},
booktitle = {Proceedings of 2016 WGP Congress},
journal = {Advanced Materials Research},
volume = {Vol. 1140},
pages = {S. 328-334},
abstract = {A production planning method is presented which allows to systematically build process chains based on a preliminary design of a composite structure. The method uses the specific sequences of procedural steps that occur in the production of carbon fibre reinforced plastic (CFRP) structures, to build sub process chains for each sub component of the structure. Process restrictions are considered to evaluate the suitability of different production processes. To obtain the whole process chain of the structure, different joining methods are applied in addition to combine the sub components and it sub chains. The results of the presented method are used in a superior development procedure to investigate resulting impacts on the solution. Possible impacts could be the production costs or the material characteristics.},
keywords = {Composite Structures, Preliminary design, Production Planning},
pubstate = {published},
tppubtype = {article}
}
Denkena, Berend; Schmidt, Carsten; Behr, Matthias
Systematische Erstellung von Prozessketten in frühen Phasen der Produktentwicklung von CFK-Strukturen Konferenz
WGP Kongress 2016, 2016.
BibTeX | Schlagwörter: Composite Structures, Preliminary design, Production Planning
@conference{Denkena2016b,
title = {Systematische Erstellung von Prozessketten in frühen Phasen der Produktentwicklung von CFK-Strukturen},
author = {Berend Denkena and Carsten Schmidt and Matthias Behr},
year = {2016},
date = {2016-08-25},
booktitle = {WGP Kongress 2016},
keywords = {Composite Structures, Preliminary design, Production Planning},
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; Weber, Patricc; Völtzer, Klaas; Deniz, Onur
Self-Configurable Production of CFRP Aerospace Components Based on Multi-Criteria Structural Optimization Konferenzbeitrag
In: CFK-Valley Convention, 2016.
Abstract | BibTeX | Schlagwörter: Composite Structures, Industry 4.0, Self Configurable Production
@inproceedings{Schmidt2016,
title = {Self-Configurable Production of CFRP Aerospace Components Based on Multi-Criteria Structural Optimization },
author = {Carsten Schmidt and Patricc Weber and Klaas Völtzer and Onur Deniz},
year = {2016},
date = {2016-06-17},
booktitle = {CFK-Valley Convention},
abstract = {Increased utilization of composite materials in a wide range of applications and industries due to their specific properties such as strength-to weight ratio, damage tolerance, reduced maintenance costs and flexibility let to advanced requirements on production methodologies and increased demands on lightweight construction. To be well prepared for tomorrow´s market, lightweight industries must be able to response quickly to customer needs as well as controlling costs and manufacturing quality. Accompanying challenges of manufacturing individually designed lightweight components with predominantly small lot sizes have to be met with flexible production systems in a quick reconfigurable production environment. Process reliability particularly in single part production is a big challenge. To minimize the risk associated therewith, criteria like component producibility already have to be considered in the design phase and monitoring of the manufacturing process becomes more relevant to ensure desired material properties.
Within the interdisciplinary research project “High Performance Production of CFRP-Structures” (HP CFK), a generic approach for simultaneously developing lightweight aerospace components, automated fiber placement system and processes is developed. This presentation introduces the new multicriteria optimization framework that efficiently involves corresponding manufacturing analysis of developed aerospace composite structures with respect to production costs, producibility and material characteristics. In addition, a newly developed reconfigurable automated fiber placement system with adaptive force controlled compaction unit, whose technical characteristics are represented within the optimization framework, and an online thermal imaging system for monitoring fiber placement manufacturing processes are presented. It is shown, how component topologies easily improve and adapt themselves to the corresponding production technology due to returned process knowledge and manufacturing restrictions and hereby avoiding time consuming redesign iterations. The coupling of optimization framework and manufacturing system lead to a self-configuration of automated fiber placement processes and an individually parametrization of the monitoring system for part specific online quality control.
},
keywords = {Composite Structures, Industry 4.0, Self Configurable Production},
pubstate = {published},
tppubtype = {inproceedings}
}
Within the interdisciplinary research project “High Performance Production of CFRP-Structures” (HP CFK), a generic approach for simultaneously developing lightweight aerospace components, automated fiber placement system and processes is developed. This presentation introduces the new multicriteria optimization framework that efficiently involves corresponding manufacturing analysis of developed aerospace composite structures with respect to production costs, producibility and material characteristics. In addition, a newly developed reconfigurable automated fiber placement system with adaptive force controlled compaction unit, whose technical characteristics are represented within the optimization framework, and an online thermal imaging system for monitoring fiber placement manufacturing processes are presented. It is shown, how component topologies easily improve and adapt themselves to the corresponding production technology due to returned process knowledge and manufacturing restrictions and hereby avoiding time consuming redesign iterations. The coupling of optimization framework and manufacturing system lead to a self-configuration of automated fiber placement processes and an individually parametrization of the monitoring system for part specific online quality control.
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}
}
Herwig, Alexander; Groß, Lukas; Serna, Jonathan; Denkena, Berend; Schmidt, Carsten
Entwicklung eines mehrlagigen Inserts für dünnwandige Hochleistungs-CFK- Strukturen Artikel
In: Lightweight Design, Bd. 9, Nr. 1, S. 22-27, 2016, ISSN: 1865-4819.
Abstract | Links | BibTeX | Schlagwörter: Composite Structures, Intrinsic Hybridisation, Multilayer Insert
@article{Herwig2016,
title = {Entwicklung eines mehrlagigen Inserts für dünnwandige Hochleistungs-CFK- Strukturen},
author = {Alexander Herwig and Lukas Groß and Jonathan Serna and Berend Denkena and Carsten Schmidt},
editor = {Wolfgang Siebenpfeifer Springer Vieweg},
doi = {10.1007/s35725-015-0064-7},
issn = {1865-4819},
year = {2016},
date = {2016-01-01},
journal = {Lightweight Design},
volume = {9},
number = {1},
pages = {22-27},
abstract = {Hochbelastete Verbindungen von dünnwandigen Strukturen werden im Flugzeug- und Automobilbau häufig als Klebungen oder als Überlappungsfügung mit Bolzen realisiert. Durch den zunehmenden Einsatz von Faser-Kunstoff-Verbunden (FKV) entsteht der Bedarf neuer Verbingungstechnologien, die ein faser- und belastungsgerechtes Fügen der Strukturen erlauben. Konventionelle Nietverbindungen und eingebrachte Metallstrukturen wie Gewindeeinsätze oder bigHeads bilden eine überprüfbare formschlüssige Verbindung. Die Krafteinteilung erfolgt über die Kontaktflächen der Metallstruktur in die angrenzenden Schichten des Laminats. Typische Ausführungen von Verbindungselementen sind in Bild 1 dargestellt. Das Einbringen dieser Inserts als Fremdkörper in ein Laminat bedingt eine lokale Aufdickung und führt zu einer Störung des Faserverlaufs und damit zu einer Schwächung des Bauteils. Dieser Problematik Multilayer-Inserts (MLI). Der erarbeitete Ansatz verfolgt eine lokale intrinsische Hybridisierung des Laminats bereits während der Ablage der CFK-Einzelschichten durch dünne Metallschichten ersetzt werden.},
keywords = {Composite Structures, Intrinsic Hybridisation, Multilayer Insert},
pubstate = {published},
tppubtype = {article}
}
2015
Deniz, Onur; Horst, Peter; Schmidt, Carsten
In: 11th World Congress on Structural and Multidisciplinary Optimisation, Sydney, 2015.
Abstract | Links | BibTeX | Schlagwörter: Composite Structures, Evolutionary strategies, Surrogate Model
@inproceedings{Deniz2015,
title = {Production-based Multi-criteria Design Optimisation of an Unconventional Composite Fuselage Side Panel by Evolutionary Strategies and a Surrogate Model of Manufacturability Analysis},
author = {Onur Deniz and Peter Horst and Carsten Schmidt},
url = {http://web.aeromech.usyd.edu.au//WCSMO2015/papers/1421_paper.pdf},
year = {2015},
date = {2015-06-07},
booktitle = {11th World Congress on Structural and Multidisciplinary Optimisation},
address = {Sydney},
abstract = {This paper introduces a novel multi-criteria optimisation framework that efficiently combines manufacturing analysis of composite structures with respect to various production criteria such as manufacturability and limitation of process-based material deviations. These criteria include gaps induced by fibre placement systems as well as structural constraints regarding material failure, stability and damage tolerance. Within this optimisation framework, evolutionary algorithms are coupled with an in-house parametric FE-Model generation tool, which exhibits an extensive design scope comprising various unconventional stiffener topologies, evaluates buckling modes and obtains composite specific failure criteria according to multiple load cases.
This work focuses on multi-criteria optimisation of a newly developed lattice-stiffened fuselage panel with novel double-curved stiffeners aiming for minimum weight based on a reference structure. Composite related design parameters such as number of layers and orientations of fibres are efficiently optimized in conjunction with a wide range of geometric parameters by applying a layup table based strategy regarding manufacturable layup combinations.
Within the optimization framework, an interface to the production concept is introduced, which evaluates quantitative information based on manufacturability analysis and estimation of tow gaps according to geometric topology of the stiffeners regarding machine parameters of AFP system. In context of the investigation manufacturability outputs are approximated using radial basis functions in order to increase the optimization efficiency in terms of computation time. Both structural responses and manufacturability values of the each individual are converted into one fitness value generated by the in-house evolutionary algorithm. This fitness evolution leads to more efficiently producible unconventional configurations and adequate mechanical performance with significant weight savings and limited material deviations based on production criteria at the each new generation.
Main characteristics of the optimized new panel are respectively, adaptation of the unconventional stiffener topologies to various loading conditions and innovative window configurations offering considerably large space. The final design is compared with an optimised reference composite panel with the same weight objective under identical loading conditions.},
keywords = {Composite Structures, Evolutionary strategies, Surrogate Model},
pubstate = {published},
tppubtype = {inproceedings}
}
This work focuses on multi-criteria optimisation of a newly developed lattice-stiffened fuselage panel with novel double-curved stiffeners aiming for minimum weight based on a reference structure. Composite related design parameters such as number of layers and orientations of fibres are efficiently optimized in conjunction with a wide range of geometric parameters by applying a layup table based strategy regarding manufacturable layup combinations.
Within the optimization framework, an interface to the production concept is introduced, which evaluates quantitative information based on manufacturability analysis and estimation of tow gaps according to geometric topology of the stiffeners regarding machine parameters of AFP system. In context of the investigation manufacturability outputs are approximated using radial basis functions in order to increase the optimization efficiency in terms of computation time. Both structural responses and manufacturability values of the each individual are converted into one fitness value generated by the in-house evolutionary algorithm. This fitness evolution leads to more efficiently producible unconventional configurations and adequate mechanical performance with significant weight savings and limited material deviations based on production criteria at the each new generation.
Main characteristics of the optimized new panel are respectively, adaptation of the unconventional stiffener topologies to various loading conditions and innovative window configurations offering considerably large space. The final design is compared with an optimised reference composite panel with the same weight objective under identical loading conditions.
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.
Biel, Andreas
Simulative Bauteil- und Prozessoptimierung im Composite Bereich Konferenzbeitrag
In: 1. Niedersächsisches Symposium Materialtechnik, Clausthal-Zellerfeld, 2015.
BibTeX | Schlagwörter: Composite Structures, Draping Simulation
@inproceedings{Biel2015,
title = {Simulative Bauteil- und Prozessoptimierung im Composite Bereich},
author = {Andreas Biel},
year = {2015},
date = {2015-02-13},
booktitle = {1. Niedersächsisches Symposium Materialtechnik},
address = {Clausthal-Zellerfeld},
keywords = {Composite Structures, Draping Simulation},
pubstate = {published},
tppubtype = {inproceedings}
}
2014
Engel, Kevin; Horst, Peter; Hundt, Tobias; Schmidt, Carsten; Denkena, Berend
Effect of manufacturing process induced fiber waviness on mechanical properties of composite structures by example of a prepreg forming process Konferenzbeitrag
In: ECCM16 - 16TH European Conference on Composite Materials, Seville, 2014.
Abstract | BibTeX | Schlagwörter: Composite Structures, Fiber Waviness
@inproceedings{Engel2014,
title = {Effect of manufacturing process induced fiber waviness on mechanical properties of composite structures by example of a prepreg forming process},
author = {Kevin Engel and Peter Horst and Tobias Hundt and Carsten Schmidt and Berend Denkena},
year = {2014},
date = {2014-06-22},
booktitle = {ECCM16 - 16TH European Conference on Composite Materials},
issuetitle = {ECCM16 - 16TH European Conference on Composite Materials},
address = {Seville},
abstract = {In this paper an approach to include the effects of a forming process on preimpregnated fibers into the design of composite structures by analysis of the resulting fiber waviness is presented. Therefore the influence of the forming process and a measurement method for fiber waviness is discussed. Fiber waviness in formed composite parts is characterized by the power spectral density and the resulting fiber angle distribution. This modeled using a discrete inverse fast Fourier transformation. Subsequently the mechanical properties are calculated based on these fiber angle distributions in a finite element analysis. An additional comparative experimental analysis of a specimen manufactured with and without the influence of the forming process is presented. The measured fiber angle distributions are analyzed and resulting first ply failure for both cases is predicted using the presented method.},
keywords = {Composite Structures, Fiber Waviness},
pubstate = {published},
tppubtype = {inproceedings}
}
Deniz, Onur; Horst, Peter; Weber, Patricc; Schmidt, Carsten; Denkena, Berend
Design optimization of an unconventinal cfrp aircraft panel stiffner based on manufacturability criteria of integrated fiber placement processes Konferenzbeitrag
In: 16th European Conference on Composite Materials, Seville, 2014.
Abstract | BibTeX | Schlagwörter: Automated Fiber Placement, Composite Structures, Design Optimization
@inproceedings{Deniz2014,
title = {Design optimization of an unconventinal cfrp aircraft panel stiffner based on manufacturability criteria of integrated fiber placement processes},
author = {Onur Deniz and Peter Horst and Patricc Weber and Carsten Schmidt and Berend Denkena},
year = {2014},
date = {2014-06-22},
booktitle = {16th European Conference on Composite Materials},
address = {Seville},
abstract = {This paper introduces a global optimization methodology that comprises structural analysis in conjunction with manufacturability examination of the aircraft components based on in-house developed automated fiber placement (AFP) system. Target point of the investigation is an unconventional grid stiffened carbon fiber reinforced plastic (CFRP) fuselage panel with additional multi-curved local stabilizers (stiffener peaks) that are located between diagonal grid stiffeners. The optimization task is formulated to reach global minimum weight of the panel under combined loading scenarios with respect to composite material failures, stability and manufacturability of stiffener peaks based on AFP system. Presented methodology solves the multi-disciplinary problem and offers producible unconventional configurations with adequate mechanical performance and weight savings based on production limits and objectives.},
keywords = {Automated Fiber Placement, Composite Structures, Design Optimization},
pubstate = {published},
tppubtype = {inproceedings}
}
Kriglsteiner, Joscha; Horst, Peter; Schmidt, Carsten
Optimization of fiber-reinforced stiffener profiles for aircraft fuselage preliminary structural design Konferenzbeitrag
In: 16th European Conference on Composite Materials, Seville, 2014.
Abstract | BibTeX | Schlagwörter: Composite Structures, Fuselage, Preliminary design, Stiffener Profiles
@inproceedings{Kriglsteiner2014,
title = {Optimization of fiber-reinforced stiffener profiles for aircraft fuselage preliminary structural design},
author = {Joscha Kriglsteiner and Peter Horst and Carsten Schmidt},
year = {2014},
date = {2014-06-22},
booktitle = {16th European Conference on Composite Materials},
address = {Seville},
abstract = {This paper presents a characterization module for stiffener profiles. It is part of a modellig and analysis tool for stiffened structures in aircraft fuselage design. The module offers options to determine mechanical characteristics of a given section such as mass, stiffness, and failure loads for strength and local stability. For the characterization, analytical approaches and the Finite Element Method (FEM) are used. Both ways are presented and the results are compared as part of the verification of the module. Furthermore, how the module can be used for a basic comparison of design concepts is described.},
keywords = {Composite Structures, Fuselage, Preliminary design, Stiffener Profiles},
pubstate = {published},
tppubtype = {inproceedings}
}
Hundt, Tobias; Schmidt, Carsten; Denkena, Berend; Engel, Kevin; Horst, Peter
Variable forming tool and process for thermoset prepregs with simulation verified part quality Artikel
In: Key Engineering Materials, Bd. 611-612, S. 391-398, 2014.
Abstract | BibTeX | Schlagwörter: Composite Structures, Variabel Forming Tool
@article{Hundt2014,
title = {Variable forming tool and process for thermoset prepregs with simulation verified part quality},
author = {Tobias Hundt and Carsten Schmidt and Berend Denkena and Kevin Engel and Peter Horst},
year = {2014},
date = {2014-05-01},
journal = {Key Engineering Materials},
volume = {611-612},
pages = {391-398},
abstract = {In this paper a new variable forming tool concept and associated numerical methods for calculating optimal actuator layout and estimating CFRP part quality are presented. The concept of the tool features a modular design and active control of the forming process to achieve the desired geometry. Initially the laminate is placed on the flat top layer of the forming tool. There it is fixed and compacted using vacuum bagging. After compacting, it is heated up to increase the performance of the forming process using water based tempering of the forming tool’s top layer. The heated laminate is then formed, pulling the tool’s top layer into the desired geometry using the actuators. Finally, the formed laminate is cooled and transferred into a mold for curing. The position of the forming tool’s actuators on the base plates is variable. Numerical optimization in combination with finite element (FE) technologies is utilized, to approximate the tool surface within given error margins, with as few actuators as possible. In addition, results of a numerical method for part quality estimation are shown. The influence of the forming process on mechanical properties due to fiber waviness is taking into account using a self-developed method that includes manufacturing characteristics in FE modeling of the part. The method is based on mathematical descriptions of fiber waviness, which are implemented into a FE model. Therefore a structure discretization assuming perfect fiber orientations is realized and the expected fiber waviness induced by the forming process is applied element-wise.},
keywords = {Composite Structures, Variabel Forming Tool},
pubstate = {published},
tppubtype = {article}
}
Schmidt, Carsten
Klebrigkeit optimierenund Prozesssicherheit erhöhen: Neue Methode misst Anhaftungsverhalten von CFK-Materialien Artikel
In: TI-Magazin, 2014.
BibTeX | Schlagwörter: Prepreg, Tack, Thermoset
@article{Schmidt2014b,
title = {Klebrigkeit optimierenund Prozesssicherheit erhöhen: Neue Methode misst Anhaftungsverhalten von CFK-Materialien},
author = {Carsten Schmidt},
year = {2014},
date = {2014-02-01},
journal = {TI-Magazin},
keywords = {Prepreg, Tack, Thermoset},
pubstate = {published},
tppubtype = {article}
}
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}
}
2013
Denkena, Berend; Schmidt, Carsten; Hundt, Tobias; Köller, Marian
In: S. 855-859, 2013.
Abstract | Links | BibTeX | Schlagwörter: Composite Manufacturing, Manufacturing Quality, Tooling Costs
@article{Denkena2013b,
title = {Bewertung mehrstufiger CFK-Fertigungsprozesse: Analyse der Zusammenhänge zwischen Formwerkzeugkosten und Bauteilqualität bei der Herstellung von CFK-Bauteilen},
author = {Berend Denkena and Carsten Schmidt and Tobias Hundt and Marian Köller},
url = {Direct Link: http://www.zwf-online.de/ZW111034},
year = {2013},
date = {2013-11-01},
pages = {855-859},
abstract = {Die Bewertung von Bauteilqualität und Herstellkosten der Formwerkzeuge bei der Fertigung von CFK-Bauteilen ist ein wichtiger Faktor zur Auslegung von Prozessketten. Form- und Lageabweichungen von CFK-Bauteilen korrelieren mit den Material- und Oberflächeneigenschaften der Formwerkzeuge, die ihrerseits Einfluss auf die Kosten der Formwerkzeugfertigung haben. In diesem Beitrag wird der Zusammenhang zwischen den Kosten des Formwerkzeugs und der Bauteilqualität mit verschiedenen am IFW entwickelten Bewertungsansätzen für mehrstufige Fertigungsprozesse analysiert.},
keywords = {Composite Manufacturing, Manufacturing Quality, Tooling Costs},
pubstate = {published},
tppubtype = {article}
}
Denkena, Berend; Horst, Peter; Schmidt, Carsten; Behr, Matthias; Krieglsteiner, Joscha
Efficient production of CFRP lightweight structures on the basis of manufacturing considerations at an early design stage Konferenzbeitrag
In: Machining Innovation Conference , Hannover, 2013.
Abstract | BibTeX | Schlagwörter: Aerospace, Composite Structures, Fuselage, Preliminary design
@inproceedings{Denkena2013,
title = {Efficient production of CFRP lightweight structures on the basis of manufacturing considerations at an early design stage},
author = {Berend Denkena and Peter Horst and Carsten Schmidt and Matthias Behr and Joscha Krieglsteiner},
year = {2013},
date = {2013-09-18},
booktitle = {Machining Innovation Conference },
address = {Hannover},
abstract = {Success in development of lightweight structures is determined by the three disciplines of design, materials, and manufacturing. Focusing on design leads to expensive lightweight structures while overrating production makes it hard to reach structural performance goals. The global optimum of structural performance and cost can only be reached if all three disciplines are equally taken into account. It can be observed that this optimum gets increasingly important for major strategic decisions in lightweight construction industry, e.g. the material concept in future aircraft structures: carbon fiber-reinforced plastics (CFRP) vs. aluminum.
While development of metallic structures is industrially performed and broadly researched, fiber-reinforced plastics do present new challenges. Design work with homogeneous and isotropic metallic structures is mainly done on a level of part shape and sizing. For composites, the inner heterogeneous and orthotropic structure has to be engineered as well. Therefore, structure development usually has to deal with a higher number of design parameters, raising the need for simulation tools and optimization algorithms. In addition to more sophisticated design procedures, production planning for composite structures gets more challenging as well. For metallic structures, manufacturing usually starts with semi-finished parts having material properties mostly set as in the final product. The material properties of composites are mainly determined by the manufacturing processes. Properties such as fiber volume fraction or fiber orientation and imperfections like fiber undulations or inclusions are highly dependent on manufacturing. Therefore process stability has a large impact on structural characteristics. Design mostly accounts for the resulting uncertainties with high knock-down factors for assumed material properties, i.e. decreased lightweight potential.},
keywords = {Aerospace, Composite Structures, Fuselage, Preliminary design},
pubstate = {published},
tppubtype = {inproceedings}
}
While development of metallic structures is industrially performed and broadly researched, fiber-reinforced plastics do present new challenges. Design work with homogeneous and isotropic metallic structures is mainly done on a level of part shape and sizing. For composites, the inner heterogeneous and orthotropic structure has to be engineered as well. Therefore, structure development usually has to deal with a higher number of design parameters, raising the need for simulation tools and optimization algorithms. In addition to more sophisticated design procedures, production planning for composite structures gets more challenging as well. For metallic structures, manufacturing usually starts with semi-finished parts having material properties mostly set as in the final product. The material properties of composites are mainly determined by the manufacturing processes. Properties such as fiber volume fraction or fiber orientation and imperfections like fiber undulations or inclusions are highly dependent on manufacturing. Therefore process stability has a large impact on structural characteristics. Design mostly accounts for the resulting uncertainties with high knock-down factors for assumed material properties, i.e. decreased lightweight potential.
Biel, Andreas; Ziegmann, Gerhard; Meiners, Dieter; Deniz, Onur; Horst, Peter
Optimization of the Structure and the Infusion Process of a CFRP Fuselage Stiffener, according to the Fiber Reorientation by the Draping Process Konferenzbeitrag
In: SETEC, 2013.
Abstract | BibTeX | Schlagwörter: Composite Structures, Draping Simulation, Fuselage, Infusion Process
@inproceedings{Biel2013,
title = {Optimization of the Structure and the Infusion Process of a CFRP Fuselage Stiffener, according to the Fiber Reorientation by the Draping Process},
author = {Andreas Biel and Gerhard Ziegmann and Dieter Meiners and Onur Deniz and Peter Horst},
year = {2013},
date = {2013-09-11},
booktitle = {SETEC},
abstract = {Design optimization plays a vital role in Aerospace Industry due to its challenging requirements that are not only based on mechanical aspects but also in manufacturing processes. Besides, manufacturing processes cause imperfections and variations on the structure which could be estimated by advanced simulations that result in expensive computation processes. On the other hand, it has been an issue to obtain global optima of the objective function of structures such as CFRP stiffened fuselage panels whose mechanical system responses are generally evaluated by Finite Element calculations.
This paper proposes a global optimization process on an innovative CFRP fuselage panel which simultaneously covers stability criterion and draping simulation of fiber textiles that is considered as a manufacturing effect. Genetic algorithms were chosen as an optimization technique to reach global optima. A parametric FEM model generator was developed under periodic boundary conditions in order to obtain buckling modes and corresponding failure criterions during the parameter variation. The shear angles of the fibers arising due to the draping process were considered as production constraint and represented with the surrogate model by RBF-ANN in the optimization loop. Different infusion strategies are simulated in a final step to find the optimal resin infusion process for the obtained fuselage stiffener.
This method presents an optimization frame that covers the production failures of draping process and its influence on structural design. Furthermore this optimization process can be modified with other undetermined production constraints that are predicted by simulation.},
keywords = {Composite Structures, Draping Simulation, Fuselage, Infusion Process},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper proposes a global optimization process on an innovative CFRP fuselage panel which simultaneously covers stability criterion and draping simulation of fiber textiles that is considered as a manufacturing effect. Genetic algorithms were chosen as an optimization technique to reach global optima. A parametric FEM model generator was developed under periodic boundary conditions in order to obtain buckling modes and corresponding failure criterions during the parameter variation. The shear angles of the fibers arising due to the draping process were considered as production constraint and represented with the surrogate model by RBF-ANN in the optimization loop. Different infusion strategies are simulated in a final step to find the optimal resin infusion process for the obtained fuselage stiffener.
This method presents an optimization frame that covers the production failures of draping process and its influence on structural design. Furthermore this optimization process can be modified with other undetermined production constraints that are predicted by simulation.