The study was published by the prestigious Composites Science and Technology, which is the second highest ranked scientific journal in the field of materials science and composites.
“The aim was to prepare several variants of sample with different distribution and density of reinforcing carbon fibre in relation to the initial polymeric matrix of Onyx. The samples were then tested using a 3-point bending test and subjected to microscopic examination to determine the real structure after printing. An important part of the process was also to compare the experimental results with different numerical modelling methods,” says Jiří Hajnyš, one of the authors of the publication, who is also the head of Protolab's 3D Printing Centre. The work, he says, builds on previous research on additively manufactured composite materials at the Faculty of Mechanical Engineering where Hajnyš is based. Specifically, this study was a collaboration between the Department of Applied Mechanics and the Department of Machining, Assembly and Engineering Metrology.
Components prepared by additive technologies are increasingly used thanks to their geometric freedom and new fibre reinforcement options. It is therefore important to investigate their mechanical properties and the possibilities in numerical simulations. Researchers from Ostrava have designed and verified a total of four types of model.
“Among other things, we found that the distribution of fibres is more important for the flexibility of the material than the amount of fibres in the sample. This is also related to the verification of the possibility of accurate numerical modelling of the investigated composites. Furthermore, it has been shown that after printing a number of air pockets appear in the structure, which affect the material properties. These findings will complement the existing findings of the scientific community on the subject. In practice, the testing and validation of different modelling methods as well as different variants of fibre reinforcement is beneficial for engineers involved in the design of structures made from these materials. At the same time, the published results can be an inspiration for the use of these advanced materials,” says Hajnyš to sum up the results of the team's work, which took roughly six months.