Experimental setup and method for the characterization of ply-ply adhesion for fiber-reinforced thermoplastics in melt

Rens Pierik*, Thijs Rouwmaat, Wouter Grouve, Sebastiaan Wijskamp, Remko Akkerman

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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Process simulation software for hot press forming is a vital tool for the development of complex continuous fiber-reinforced thermoplastic parts for structural applications. The simulation tools need to be accurate to truly facilitate the design stage, which in turn requires accurate material characterizations and constitutive models. The material forming behavior is composed of different deformation mechanisms, one of which is the separation of adjacent plies or delamination. Currently, the resistance against delamination or ply-ply adhesion is modeled as a constant tensile stress that needs to be overcome, the value of which is based on an educated guess. To date, no standard exists to characterize this material property for thermoplastic matrix composites (TPC) in melt. Hence, we discuss and evaluate several methods to measure ply-ply adhesion of TPCs. The most promising approach, a so-called probe test, was further pursued and a setup was designed and manufactured for the use in a rheometer. Subsequently, we measured the required normal force to separate two C/LM-PAEK tapes in melt. Repeated tests on the same specimen resulted in an increasing adhesive peak force, which we relate to a change in the amount and distribution of the matrix material at the ply’s surface. The peak force increased also with increasing compression time and pressure. We found a reasonable correlation of the average measured peak force with the values currently assumed in simulation software.

Original languageEnglish
Title of host publicationMaterial Forming
Subtitle of host publicationThe 26th International ESAFORM Conference on Material Forming – ESAFORM 2023
EditorsLukasz Madej, Mateusz Sitko, Konrad Perzynsk
PublisherAssociation of American Publishers
Number of pages10
ISBN (Print)9781644902462
Publication statusPublished - 2023
Event26th International ESAFORM Conference on Material Forming, ESAFORM 2023 - Kraków, Poland
Duration: 19 Apr 202321 Apr 2023
Conference number: 26

Publication series

NameMaterials Research Proceedings
ISSN (Print)2474-3941
ISSN (Electronic)2474-395X


Conference26th International ESAFORM Conference on Material Forming, ESAFORM 2023
Abbreviated titleESAFORM 2023


  • Hot Press Forming
  • Ply-Ply Adhesion
  • Thermoplastic Matrix Composites (TPC)


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