2022
Budelmann, Dennis; Schmidt, Carsten; Meiners, Dieter
In: Polymer Testing, Bd. 114, Ausg. Volume 114, 2022, 2022.
Abstract | Links | BibTeX | Schlagwörter: Automated Fiber Placement, Prepreg, Tack
@article{nokey,
title = {Tack of epoxy resin films for aerospace-grade prepregs: Influence of resin formulation, B-staging and toughening},
author = {Dennis Budelmann and Carsten Schmidt and Dieter Meiners},
url = {https://www.sciencedirect.com/science/article/pii/S0142941822002318},
doi = {https://doi.org/10.1016/j.polymertesting.2022.107709},
year = {2022},
date = {2022-07-19},
urldate = {2022-07-19},
journal = {Polymer Testing},
volume = {114},
issue = {Volume 114, 2022},
abstract = {Aerospace-grade prepreg resin films based on multifunctional tetraglycidyl-4,4′-methylenedianiline (TGMDA), triglycidyl p-aminophenol (TGAP), Bisphenol A diglycidyl ether (DGEBA) and curing agent 4,4'diaminodiphenyl sulfone (DDS) are investigated in terms of tackiness by probe testing. The model epoxy systems are modified regarding the thermoplastic toughener content (polyethersulfone, PES) and the B-stage level, which is adjusted by cure prediction based on a model-free isoconversional method (Flynn-Wall-Ozawa). Additional DSC and rheological analysis are performed to study the thermal and viscoelastic material behavior in conjunction to its impact on temperature-dependent tack. Maximum achievable tack is found to decrease as a function of both degree of conversion and toughener content. Meanwhile, both influencing factors shift the tack maximum towards higher temperatures corresponding to increased flow characteristics attributed to evolving network formation and the incorporation of high molecular weight PES. In terms of absolute tack level and corresponding temperature, probe tack values similar to commercial prepreg systems (∼100 μJ mm−2) are recorded for TGMDA-based formulations containing 10 wt% PES at 20% pre-cure. Model formulations, which have neither been exposed to B-staging nor toughened, show exceptionally high tack below room temperature for all investigated epoxy prepolymers and are therefore not considered processable by automated fiber placement.},
keywords = {Automated Fiber Placement, Prepreg, Tack},
pubstate = {published},
tppubtype = {article}
}
2021
Budelmann, Dennis; Schmidt, Carsten; Meiners, Dieter
In: Composites Part C, Bd. 6, 2021.
Abstract | Links | BibTeX | Schlagwörter: Adhesion-cohesion, Tack
@article{Budelmann2021b,
title = {Adhesion-cohesion balance of prepreg tack in thermoset automated fiber placement. Part 1: Adhesion and surface wetting},
author = {Dennis Budelmann and Carsten Schmidt and Dieter Meiners},
doi = {https://doi.org/10.1016/j.jcomc.2021.100204},
year = {2021},
date = {2021-11-11},
journal = {Composites Part C},
volume = {6},
abstract = {The constitution of prepreg tack in automated fiber placement (AFP) is affected by a sensitive balance between adhesive interfacial bond strength and cohesive strength of the prepreg resin. In an effort to explore the role of interfacial liquid-solid interaction on the tack of commercial aerospace-grade epoxy prepreg, a surface wetting analysis was performed on AFP-related substrates. The standard test liquid combination water/diiodmethane and extracted neat epoxy resin were used for contact angle measurement employing the sessile drop method and the Owens-Wendt-Rabel-Kaelble (OWRK) model. Additional rheological and topographical analyses were carried out to account for viscous resin flow on surfaces of different roughness. The results from the material characterization are discussed against the background of tack measurement by probe tack testing utilizing a rheometer. Significant differences between the investigated surfaces in terms of both the maximum tack level and the onset temperatures of adhesion were found as a function of test parameters relevant for contact formation. General agreement with the experimental tack results was observed employing a topographically extended version of the Dahlquist criterion. For each substrate, a temperature-dependent critical storage modulus could be determined that conforms to the onset temperature of tackiness. Contact angle measurements revealed a correlation between the thermodynamic work of adhesion and maximum tack and, moreover, the tack onset in the adhesive regime when additionally incorporating surface topography. Matching ratios of polar and dispersive surface free energy and surface tension components were found to favor the molecular interaction at the interface between prepreg resin and substrate.},
keywords = {Adhesion-cohesion, Tack},
pubstate = {published},
tppubtype = {article}
}
Budelmann, Dennis; Meiners, Dieter
Haftungseigenschaften duromerer Kohlenstofffaser-Prepregs im Automated Fiber Placement Vortrag
26.02.2021, (4. Symposium Materialtechnik, Clausthal-Zellerfeld).
BibTeX | Schlagwörter: Automated Fiber Placement, Tack
@misc{Budelmann2021,
title = {Haftungseigenschaften duromerer Kohlenstofffaser-Prepregs im Automated Fiber Placement},
author = {Dennis Budelmann and Dieter Meiners},
editor = {4. Symposium Materialtechnik, Clausthal-Zellerfeld},
year = {2021},
date = {2021-02-26},
note = {4. Symposium Materialtechnik, Clausthal-Zellerfeld},
keywords = {Automated Fiber Placement, Tack},
pubstate = {published},
tppubtype = {presentation}
}
2020
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}
}
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.
2019
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}
}
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.
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}
}
2014
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}
}