The decade-long international collaboration resulted in the issuance of U.S. patent 10,618,262 on April 14th 2020. The U.S.-owned patent is for a composite material fabrication process which has shown improvements in toughness and fracture-resistant material properties, technology that has the potential to lead to reduced crack propagation in the Future Vertical Lift Army modernisation priority area.
In the patent, our researchers note that as the use of composite materials increases in manufacturing, so do the demands on the material and the ways in which it is used, necessitating a stronger, but barely heavier, material. The patented composite material fabrication process uses polymer "islands” – inkjet-printed polymer dots – placed precisely on laminate layers. A different, thermoplastic polymer is applied between layers prior to curing of the composite material. The different polymers interact to prevent cracks from propagating in the composite. For Dr. Patrick Smith, senior lecturer in the Department of Mechanical Engineering at the University of Sheffield, “the key appeal lies in improving the properties of carbon fibre composites whilst maintaining their weight-saving advantage.”
The inventors’ initial contact was with the U.S. Air Force Office of Scientific Research – International in 2010 and resulted in an international research grant in 2011. Further collaborative research, facilitated by CCDC Atlantic, was funded by the AFOSR European Office of Aerospace Research and Development and CCDC AvMC via a second international grant in 2014 and a cooperative agreement in 2016, respectively. CCDC AvMC, which incorporates innovative technology solutions, cutting-edge science and technology, and partnerships to provide rapid, cost-effective solutions to complex aviation and missile challenges, contributed more than $150,000 to the research.
Dr Patrick Smith says that the research illustrates: “the breadth of research undertaken by us here at the department of Mechanical Engineering and underlines the need to fund speculative research. All of this came about by asking ‘what if?’”