Fraunhofer Research Institution for Casting, Composite and Processing Technology IGCV

Transcription

1 Fraunhofer Research Institution for Casting, Composite and Processing Technology IGCV Correlation between micro- and macroscopic characterization of recycled carbon fibre materials Frank Manis, Ananda Schindler, Michael Sauer and Jakob Wölling

2 Fraunhofer IGCV Located in Augsburg 2

3 Fraunhofer IGCV We use synergies in these fields of research and development: Casting technology Molding materials Sand and gravity die casting processes Simulation and design of mold and cast components Composite technology Hybrid composite constructions Online process monitoring Materials and test engineering CFRP manufacturing engineering Processing technology Resource efficiency in factories Intelligent networked production Flexible production Networked modeling and simulation Recycling Additive manufacturing Efficiency and balancing 3

4 Possibilities for cooperation The Fraunhofer-Model 4

5

6 Motivation Energy and resource intense manufacturing Carbon fibers are a high energy and cost intensive raw material: Generally: recycling can be rewarding ecological and economical

7 Why do we need characterization technics? Price Optical Chemical Sustainability Impact Electrical Durability Mechanical Etc. Pyrolysed (550 C, 30 minutes dwell time) CFRP-Woven out of epoxy resin Tensile Bending Shear

8 Virgin vs. Recycled carbon fibres What is the difference? Fibre orientation Fibre length Fibre volume content Filament Interphase

9 Why do we need characterization technics? [CES Selector by Granta Design]

10 Why do we need characterization technics? Influences on properties by recycling

11 Microscopic characterization Single filament testing ASTM : Method for Tensile Strength and Young Modulus for High-Modulus Single-Filament Materials Carbon fibre Paper Resin / Glue σ xx = F xx A = F xx π R² Diameter Favimat-Single fibre tensile test

12 Microscopic characterization Single filament testing Statistic Diameter Fibre-manufacturer Testing Parameters

13 Microscopic characterization Interface Surface Groups and Adhesion Fibre Interphase Matrix

14 Microscopic characterization Interface Defects and roughness

15 Macroscopic characterization Structural and textural homogeneity

16 Macroscopic characterization Structural and textural homogeneity Explanation of measurement: Transmitted Light calcuation Calculation Ø, Calculation of average value over e.g. 10x10 Pixel Increasing of pixel size fence

17 Macroscopic characterization Structural and textural homogeneity (grey-value) Homogeneity in MD MD CD (Grey Value) Homogeneity in CD Stabw MD Stabw CD 16,14 11,59 4,61 6,15 7,12 7,02 10,34 34,2 Sigrafil 12mm 0.1 vcf SGL 12mm 1.1 vcf SGL 18mm 1.2 vcf SGL 36mm 1.3 Homogeneity in MD is good. Steady production direction Longer fibres result in worse homogeneities

18 Macroscopic characterization Structural and textural homogeneity Fibre-orientation Fibre-volume content Homogeneity and defects Microscopic and Macroscopic Proof of Technology mit CT Untersuchungen und zerstörenden Zugfestigkeitsmessungen in >= 10 Studien

19 Macroscopic characterization Structural and textural homogeneity Project Izi-Direct starts in 2018 Development of in- and online measurement of fibre orientation in recycled fibre production via eddy current measurement Application in textile processes (Wet- and Dry laid nonwovens)

20 Micro and Macroscopic view Clean doesn t mean clean Pyrolysed (550 C, 30 minutes dwell time) CFRP-Woven out of epoxy resin

21 Micro and Macroscopic view Clean doesn t mean clean Virgin Fibers 600 C 30 minutes pyrolysed 100 % N C 30 minutes oxidised 20,9 % O 2

22 rcfrp-characterization Correlations of fibres and couponds

23 rcfrp-characterization Correlations of fibres and couponds

24 rcfrp-characterization Correlations of fibres and couponds -2% -15% e.g. additional missorientation due handling -12% e.g. Char, voids, matrix rich regions, intra tow voids rcf/vcf strength (SF) rcf/vcf strength (rcfrp) -18% e.g. Char, voids, matrix rich regions, intra tow voids rcf/vcf strength [%] U (V) U/500/30 U/500/60 W (V) W/500/60 W/475/30 Materials Results and discussion Enhanced material failure effects Strength of composites as a function of single fibre degradation Char, voids, matrix rich regions, intra tow voids lead to increase failure Maximum rcfrp degradation -27,78 % on woven and -41,37 % on unidirectional material

25 SUMMARY AND OUTLOOK WHY DO WE NEED CHARACTERIZATION TECHNICS? Recycling of composites leads to new questions that are not answered at the moment Macroscopic properties are depending on microscopic effects like fibre properties, char content, voids, fibre defects New testing methologies has to be implmeneted for prodcuts out of rcf Online measurment of rcf properties necessary for future application

26 Recycling of Composites Contact us Fraunhofer IGCV Am Technologiezentrum Augsburg, Germany Dipl.-Ing. Frank Manis Phone / frank.manis@igcv.fraunhofer.de