Composites with a thermoplastic matrix, so-called thermoplastic composites (TPC), are increasingly used in key industries due to their lightweight design potential. Due to their re-meltability and short cycle times, they offer the opportunity to make an important contribution to the environmental compatibility and competitiveness of new products. Continuous fiber-reinforced thermoplastic composites (eTPC) are playing a special role. Thanks to their excellent mechanical properties, they are particularly suitable for use in structural load-bearing components. An application obstacle is the frequent lack of fully comparable and efficiently calculated material properties for complex load cases. However, these are relevant for the component design.
Goal of the project Chara-TPC is developing new, efficient characterization methods for complex loading cases of eTPC to generate comparable material properties which allows the mechanical potential of this material class to be fully exploited as well as the hurdles for a large series application to be lowered.
During the project period from January 2020 to September 2022, methods for the characterization of short-term dynamic, multi-axial and long-term loads of high performance components out of eTPC as well as joints of hybrid components with eTPC have been developed. In a step preceding the method development the production of plates in a static pressing process, the production of tube specimens in an innovative tape laying process and the preparation of specimens with regard to efficiency and quality are also investigated (Figure 1).
For the characterization of the long-term behavior, the focus is on the development of creep tests for different load cases. The test methodology for the description of the short-term behavior includes the determination of the energy absorption capacity of eTPC in crash tests as well as the description of the tensile, shear and flexural behavior in dynamic tensile testing (Figure 2). The characterization of hybrid joints focuses on the connection of short-/long-fiber reinforced TPC to eTPC and metal to eTPC. To describe the multi-axial loading behavior of eTPC, a test methodology that efficiently determines the material-specific fracture curve, i.e. with little experimental material input, is being developed. For this purpose, the load cases under superimposed tensile and shear loading as well as compression and shear loading are considered in detail. Tube specimens are used for this purpose (Figure 3). The developed test methods are optimized in each case by simulation and are experimentally validated using two industry-relevant tape reference materials as examples. For validation, a glass fiber reinforced polypropylene (GF-PP) and a carbon fiber reinforced polycarbonate (CF-PC) tape material were selected.
The project „Chara-TPC – Establishing a material characterization center for thermoplastic composites (TPC) in Rhineland-Palatinate“ is funded by the European Regional Development Fund (ERDF) and the Ministry of Economics, Transport, Agriculture, and Viticulture (MWVLW; Funding reference: 84005413).
Florian Mischo, Dipl.-Ing.
Research Assistent Crash & Energy Absorption
Institut für Verbundwerkstoffe GmbH
Telephone: +49 (0) 631/2017-407
Sebastian Schmeer, Dr.-Ing.
Deputy Research Director Component Development & Manager Crash & Energy Absorption Institut für Verbundwerkstoffe GmbH
Telephone: +49 (0) 631/2017-322