HUN-REN-BME Research Group

Development of multi-functional, high performance pseudo-ductile hybrid composites

Project ID:
OTKA FK131882
Supported by:
Hungarian National Research, Development and Innovation Office (NKFIH)
1 December 2019 - 30 November 2023
Supervisor (BME):
Dr. Gergely Czél
Participant researchers (BME):
Marino Salvatore Giacomo
Dr. Molnár Kolos
Dr. Pölöskei Kornél
Dr. Romhány Gábor
Dr. Szebényi Gábor
Prof. Dr. Toldy Andrea

Project summary

One of the biggest challenges for the 21st century’s transportation sector is to improve fuel economy and reduce carbon footprint in case of traditional internal combustion engine driven vehicles. Since the energy storage elements of electric vehicles constitute a significant additional load, weight reduction is a key challenge for both constructions, while structural stiffness and passenger safety is to be maintained. High strength, low density yet safely failing structural materials could enable the development of the next economic and environmentally friendly generation of vehicles. High performance carbon or glass fibre reinforced polymer matrix composites offer exceptional specific modulus and strength, but suffer from sudden and brittle failure, with no warning and insufficient residual load-bearing capacity. Pseudo-ductile composites provide a safe alternative to conventional ones showing a progressive failure character and improved failure strains, similar to those of metals. Another significant benefit is a clear sign of damage before final failure. The principal investigator of the programme demonstrated pseudo-ductility in thin-ply uni- and multidirectional hybrid composites under tension recently. One objective of the project is the further development of the pseudo-ductile composites primarily by the modification of the layer interfaces. The other direction of the research is to add valuable functions such as damage indication and repairability which are of significant interest for safe operation and reduced lifecycle cost.

Project results

Section 1
1 December 2019 - 30 November 2020
Design, manufacturing and structural testing of a pseudo-ductile sandwich panel with additional visual overload sensing feature were completed according to the work plan. A 600x300x10 mm size panel with carbon fibre/epoxy composite skins and foam core was fabricated with a full layer of glass/epoxy-carbon/epoxy hybrid composite visual overload sensor integrated into the bottom skin. This rather large size was selected to demonstrate that the recently patented sensing technology is suitable for high performance, industrial-scale components. The sensing layer provided clearly visible signs of overload in the form of light stripes when the high modulus carbon reinforced sensing layer started to fragment and delaminated locally around the fractures at a pre-defined strain. 40 mm long electronic strain gauges were applied successfully and provided accurate strain reading over the highly variable strain field after the triggering of the overload sensing layer. The trigger strain of the visual overload sensor was in line with the expected failure strain of the sensing layer. Acoustic emission damage monitoring was able to detect the triggering of the visual overload sensor and the obtained data correlated well with the knee point after the initial linear part of the load-displacement diagrams and the small drops in the load signal from the test machine indicating the fragmentation of the sensing layer.
Pseudo-ductile, self-monitoring sandwich panel

Section 2
1 December 2020 - 30 November 2021
According to the work plan, the main task of the second period of the programme was to modify the layer interfaces of our hybrid composites to make them pseudo-ductile, improve their performance and extend the scope of the new materials. Successful experimental programme was designed and executed using (30 and 60 um thick) thermoset resin films and thermoplastic acrylonitrile butadiene styrene (ABS) films at the layer interfaces to increase the mode II interlaminar fracture toughness and stabilise the delamination in the hybrid laminates made with standard thickness carbon/epoxy layers sandwiched between glass/epoxy layers. Excellent results were achieved with another thermoplastic film: polyamide 12 (PA 12) which was not applied in film format before as an interleaf layer for toughening laminated composites. The hybrid laminate specimens, which failed with unstable delamination without the PA 12 film interleaves demonstrated favourable pseudo-ductile behaviour with 20 um PA 12 films at the glass/epoxy-carbon/epoxy layer interfaces. The carbon/epoxy layer fragmented with no visible delamination even at 3% strain, where the tests were stopped to prevent final failure. An additional interface modification approach was applied successfully to the layer interfaces of our hybrid laminates to make their failure pseudo-ductile. Electrospun nanofibrous layers made of polyamide 6 (PA 6) with two different concentrations were used as interleaf layers in different areal densities ranging from 2 to 20 g/m2 between the carbon/epoxy and the glass/epoxy composite layers of our hybrid laminates. The interleaved nanofibrous layers helped to control the thickness of a well-defined interlayer between the composite block with thicknesses in correlation with the areal densities of the applied interleaves. Interface modification led to significant increase in the mode II interfacial fracture toughness of our samples.
Scanning electron micrograph of an electrospun polyamide veil suitable for interfacial toughening

Section 3
1 December 2021 - 30 November 2022

Section 4
1 December 2022 - 30 November 2023

Project-related publications

  1. Marino S. G., Kuželová Košťáková E. , Czél G. : Development of pseudo-ductile interlayer hybrid composites of standard thickness plies by interleaving polyamide 6 nanofibrous layers. Composites Science and Technology, 234, 109924/1-109924/14 (2023) 10.1016/j.compscitech.2023.109924 IF=9.1 Q1
  2. Marton G. Zs., Mezey Z., Czél G.: Prepregből autoklávban gyártott kompozit lemezek rétegközi tulajdonságainak alakulása a térhálósítás során alkalmazott technológiai paraméterek függvényében. in 'XXXI. Nemzetközi Gépészeti Konferencia (OGÉT 2023) Temesvár, Románia. 2023.04.27-2023.04.30.,354-359 (2023)
  3. Marino S. G., Czél G. : Development and characterisation of reparable, film-interleaved, pseudo-ductile hybrid composites. Composites Part A (Applied Science and Manufacturing), 169, 107496/1-107496/13 (2023) 10.1016/j.compositesa.2023.107496 IF=8.7 Q1
  4. Czél G. , Bugár-Mészáros M., Wisnom M. R.: Combined effect of moisture and test temperature on the pseudo-ductility of thin-ply carbon/epoxy-glass/epoxy hybrid composites. Composites Part A (Applied Science and Manufacturing), 165, 107353/1-107353/11 (2023) 10.1016/j.compositesa.2022.107353 IF=8.7 Q1
  5. Czél G. : Development of bi-directional pseudo-ductile glass/carbon-epoxy hybrid composites for improved safety in structural applications. Composites Part B (Engineering), 231, 109546/1-109546/ (2022) 10.1016/j.compositesb.2021.109546 IF=13.1 D1
  6. Rev T., Wisnom M. R., Xu X., Czél G. : The effect of transverse compressive stresses on tensile failure of carbon fibre/epoxy composites. Composites Part A (Applied Science and Manufacturing), 156, 106894/1-106894/1-9 (2022) 10.1016/j.compositesa.2022.106894 IF=8.7 Q1
  7. He H., Molnár K.: Fabrication of 3D printed nanocomposites with electrospun nanofiber interleaves. Additive Manufacturing, 46, 102030/1-102030/11 (2021) 10.1016/j.addma.2021.102030 IF=11.632 D1
  8. He H., Guo J., Illés B., Géczy A., Istók B., Hliva V., Török D., Kovács J. G., Harmati I., Molnár K.: Monitoring multi-respiratory indices via a smart nanofibrous mask filter based on a triboelectric nanogenerator. Nano Energy, 89, 106418/1-106418/ (2021) 10.1016/j.nanoen.2021.106418 IF=19.069 D1
  9. Marino S. G., Czél G.: Improving the performance of pseudo-ductile hybrid composites by film-interleaving. Composites Part A (Applied Science and Manufacturing), 142, 106233/1-106233/16 (2021) 10.1016/j.compositesa.2020.106233 IF=9.463 Q1
  10. He H., Gao M., Illés B., Molnár K.: 3D Printed and Electrospun, Transparent, Hierarchical Polylactic Acid Mask Nanoporous Filter. International Journal of Bioprinting, 194, 108902/1-108902/11 (2020) 10.18063/ijb.v6i4.278 IF=6.638 Q1
  11. Wisnom M., Potter K., Czél G., Jalalvand M.: Strain overload sensor. GB2544792B, United Kingdom (2020)
  12. Kara Y., He H., Molnár K.: Shear‐aided high‐throughput electrospinning: A needleless method with enhanced jet formation. Journal of Applied Polymer Science, , e49104/1-e49104/13 (2020) 10.1002/app.49104 IF=3.125 Q2
  13. Marino S.G., Mayer F., Bismarck A., Czél G.: Effect of Plasma-Treatment of Interleaved Thermoplastic Films on Delamination in Interlayer Fibre Hybrid Composite Laminates. Polymers, 12, 2834/1-2834/24 (2020) 10.3390/polym12122834 IF=4.329 Q1
  14. He H., Gao M., Török D., Molnár K.: Self-feeding electrospinning method based on the Weissenberg effect. Polymer, 190, 122247/1-122247/9 (2020) 10.1016/j.polymer.2020.122247 IF=4.43 Q1
  15. He H., Wang Y., Farkas B., Nagy Zs. K., Molnár K.: Analysis and prediction of the diameter and orientation of AC electrospun nanofibers by response surface methodology. Materials & Design, 194, 108902/1-108902/11 (2020) 10.1016/j.matdes.2020.108902 IF=7.991 Q1

© 2014 BME Department of Polymer Engineering - Created by: Dr. Romhány Gábor