In a significant stride towards enhancing the durability of composite materials, researchers have developed a novel hybrid laminate that combines thermoset and thermoplastic carbon fiber reinforcements, demonstrating improved crack resistance. This breakthrough, published in the open-access journal ‘Composites Part C: Open Access’ (translated to ‘Composites Part C: Open Access’), could have profound implications for industries like energy, where structural integrity is paramount.
The study, led by Kay A. Weidenmann from the University of Augsburg’s Institute of Materials Resource Management (MRM) and Delft University of Technology’s Aerospace Structures and Materials (ASM), explores the potential of hybrid laminates made from alternating layers of polyetherimide (PEI) and epoxy matrices. These materials are manufactured via hot pressing and tested using double-cantilever beam (DCB) tests, a standard method for evaluating crack propagation resistance.
“We were inspired by the enhanced crack propagation resistance seen in fiber-metal laminates,” Weidenmann explained. “Our goal was to transfer this concept to purely carbon fiber reinforced plastic (CFRP) based laminates.”
The results were promising. The hybrid laminates outperformed both constituent materials when crack initiation started in the tougher CFR-PEI layer and the laminate layup was 0/90°. “The energy dissipating mechanisms we observed were crack jumping and the formation of several parallel cracks,” Weidenmann noted. “This suggests that crack resistance in such hybrids might be controlled in the future by adjusting the crack resistance of the constituents as well as the laminate architecture.”
For the energy sector, these findings could translate into more robust and reliable structures. Wind turbine blades, for instance, often face fatigue and crack propagation issues due to their constant exposure to dynamic loads and environmental stresses. Hybrid laminates with improved crack resistance could extend the lifespan of these structures, reducing maintenance costs and downtime.
Moreover, the potential to tailor crack resistance by adjusting the laminate architecture opens up new avenues for design and optimization. “This could lead to more efficient and safer structures, not just in energy, but in aerospace, automotive, and construction industries as well,” Weidenmann suggested.
The study also included microstructural investigations and fractography on crack surfaces, providing a comprehensive understanding of the material behavior. This holistic approach could pave the way for further advancements in composite materials, shaping the future of structural design and engineering.
As the world continues to demand more from its materials, innovations like these hybrid laminates offer a glimpse into a future where structures are not just stronger, but also more adaptable and resilient. With further research and development, these materials could become a cornerstone of modern engineering, driving progress across multiple sectors.