February 4, 2021

LUT scientists will conduct research on composites on the British synchrotron

Once a year, the UK-based Diamond Light Source research center allocates funds for the most interesting research projects. This time, a project with the participation of our scientists received funding. The international team includes scientists from Lublin University of Technology, Lodz University of Technology and the University of Bath.

The scientists' task will be to investigate the effect of stresses on composite structures with thin walls, e.g. columns or open profiles. These types of composite structures are widely used in the load-bearing elements of airplanes, helicopters, but also in the automotive industry and wind turbines.

- We are planning an experimental measurement of residual stresses in thin-walled composite structures made of carbon fiber and the impact of these stresses on the stability and load-bearing capacity of the structure - says Prof. Tomasz Kubiak from the Department of Strength of Materials and Structures, Lodz University of Technology.

The scientists have already carried out a series of tests, but detailed structural studies are needed and they will consist of observing the composite structure in critical areas of the columns during progressive loading.

- Residual stresses arising in the composite production process can significantly affect its stiffness and work under load. The structure of the composite and the manufacturing conditions, including mainly thermal treatment, have a major impact on the behavior of the composite during loading. The tests have shown that in square cross-sections, composite columns get destroyed under a buckling load 40% greater than expected and exhibit significantly greater post-buckling stiffness than expected. The reason for this behavior are the residual stresses generated in the composite structure during the hardening process in the autoclave - explains Dr. Eng. Patryk Jakubczak from the Department of Materials Engineering at Lublin University of Technology.

The synchrotron works like a giant microscope, enabling measurements of all kinds of structures, from chemical analysis of fossil fuels and metal microstructures to virus research. The machine accelerates electrons almost to the speed of light and thanks to the diffraction phenomenon (bending of light rays) it can analyze the examined structures with a very high resolution, 10,000 times greater than with a traditional microscope.

The Polish team is composed of: Prof. Jarosław Bieniaś and Dr. Eng. Patryk Jakubczak from the Department of Materials Engineering at Lublin University of Technology as well as Prof. Tomasz Kubiak and his PhD student Paweł Czapski, MSc from the Department of Strength of Materials and Structures at Lodz University of Technology.