Carbon fibre-reinforced materials are becoming more and more popular in various fields of industries because of their lightweight and perfect mechanical properties. Additive manufacturing technologies can be used for the production of complex parts from various materials including composites. Fused deposition modelling (FDM) is an excellent technology for the production of composite structures reinforced with short or continuous carbon fibre. In this study, modified FDM technology was used for the production of composites reinforced with continuous carbon fibre. The main aim of this study is to evaluate the shear strength of 3D-printed composite structures. The influence of printing layer height and line width on shear strength was analysed. Results showed that layer height has a significant influence on shear strength, while the influence of printing line width on shear strength is slightly smaller. Reduction of layer height from 0.4 mm to 0.3 mm allows increasing shear strength by about 40 percent. Moreover, the influence of the shear area and overlap length on shear force showed linear dependency, in which the shear area is increasing the shear force increasing proportionally. Finally, the results obtained can be used for the design and development of new 3D-printed composite structures.

Interlayer Adhesion Analysis of 3D-Printed Continuous Carbon Fibre-Reinforced Composites.

A layer-wise multi-defect detection system for powder bed monitoring: Lighting strategy for imaging, adaptive segmentation and classification

Additive manufacturing of oxide-dispersion strengthened alloys: materials, synthesis and manufacturing

Additive manufacturing of metal parts was investigated in this research work, which connects to the models' supports. The connection between the support and the model has a high impact on the mechanical fixturing, the heat conduction, the removability of the support and the success of printing. In this research work, some support and tooth parameters such as the top length, the hatch distance, and Z offset were investigated to create a model-support connection strength map. This knowledge makes it possible to select the most appropriate connection type between the support and the model by the requirements specified in different cases. The strength of the support-model connection was characterized by the shearing properties using the torsion test. The results are illustrated and compared by different support parameters and materials. The 316L stainless steel and Ti6Al4V alloy were investigated. Different failure modes were determined depending on the chosen parameters. 

Characterizing the strength of support-model connection in the case of laser powder bed fusion technology by torsion test

Laser ablation in liquids has been established as a scalable preparation method of nanoparticles for various applications. Particularly for materials prone to oxidation, it is established to suppress oxidation by using organic solvents as a liquid medium. While this often functionalizes the nanoparticles with a carbon shell, the related chemical processes that result from laserinduced decomposition reactions of the organic solvents remain uncertain. Using a systematic series of C6 solvents complemented by n-pentane and n-heptane during the nanosecond laser ablation of gold, the present study focuses on the solvent-dependent influence on gas formation rates, nanoparticle productivity, and gas composition. Both the permanent gas and hydrogen formation was found to be linearly correlated with ablation rate, ΔHvap, and pyrolysis activation energy. Based on this, a decomposition pathway linked to pyrolysis is proposed allowing the deduction of first selection rules for solvents that influence the formation of carbon or permanent gases.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/cphc.202300089

Dongdong Gu

Papers

On the selection and design of powder materials for laser additive manufacturing