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Reducing NDT Effort by Coupled Monitoring and Simulation of Liquid Composite Molding Processes

Liebers, Nico and Bertling, Dominic (2019) Reducing NDT Effort by Coupled Monitoring and Simulation of Liquid Composite Molding Processes. In: NDT & E INTERNATIONAL. 11TH SYMPOSIUM ON NDT IN AEROSPACE, 13.-15. Nov. 2019, Paris, Frankreich.

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Liquid Composite Molding (LCM) is a manufacturing technique which could reduce material and process costs in comparison to the widely used prepreg processes. The raw materials are less expensive and easier to store and geometrical complex parts can be manufactured. But LCM requires more sophisticated process design due to its sensitivity to deviations in the raw materials or process setup. Gaps for example can lead to race tracking which often results in trapped gas inside of the component. Such gas inclusions can lead to porosity or even larger dry spots and thus an unusable part. The DLR Institute of Composite Structures and Adaptive Systems developed flexible low cost ultrasonic sensors for LCM monitoring. The sensors do not require direct contact to the part and therefore do not affect the part surface or mold. Due to enhanced signal analysis not only the flowfront arrival can be detected, but also its flow speed. Further the moments of wetting of the mold surface and the infiltration through the part thickness can be distinguished. The sensor system is also able to perform cure monitoring including the detection of gelation and vitrification points. These sensor inputs are coupled with a fast flow simulation where the model parameters are adapted to match the measurement by a sophisticated optimization algorithm. The most important model parameters are the permeability and gap sizes. By adapting the simulation the pointwise monitoring results are transformed into a 2.5-dimensional representation of the flowfront that enables the prediction of its further course. The results are used to detect possible gas inclusions and areas of high porosity. If none of these defects are detected the NDT process could be omitted. In the case of detected defects only these areas would have to be tested potentially.

Item URL in elib:https://elib.dlr.de/131056/
Document Type:Conference or Workshop Item (Speech)
Title:Reducing NDT Effort by Coupled Monitoring and Simulation of Liquid Composite Molding Processes
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Liebers, Niconico.liebers (at) dlr.dehttps://orcid.org/0000-0002-0124-896X
Bertling, DominicDominic.Bertling (at) dlr.dehttps://orcid.org/0000-0003-1851-3333
Date:November 2019
Journal or Publication Title:NDT & E INTERNATIONAL
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Keywords:Liquid Composite Molding, Ultrasonic Process Monitoring, Process Simulation, NDT reduction
Event Location:Paris, Frankreich
Event Type:international Conference
Event Dates:13.-15. Nov. 2019
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:fixed-wing aircraft
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Structures and Materials
Location: Braunschweig
Institutes and Institutions:Institute of Composite Structures and Adaptive Systems > Composite Technology
Deposited By: Liebers, Nico
Deposited On:25 Nov 2019 09:12
Last Modified:25 Nov 2019 09:12

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