@article{HandwerkerKesslerMarzbani2021, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz}, title = {Comparison of hydrogen powertrains with the battery powered electric vehicle and investigation of small-scale local hydrogen production using renewable energy}, volume = {2}, journal = {Hydrogen}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {2673-4141}, doi = {https://doi.org/10.3390/hydrogen2010005}, pages = {76 -- 100}, year = {2021}, abstract = {Climate change is one of the major problems that people face in this century, with fossil fuel combustion engines being huge contributors. Currently, the battery powered electric vehicle is considered the predecessor, while hydrogen vehicles only have an insignificant market share. To evaluate if this is justified, different hydrogen power train technologies are analyzed and compared to the battery powered electric vehicle. Even though most research focuses on the hydrogen fuel cells, it is shown that, despite the lower efficiency, the often-neglected hydrogen combustion engine could be the right solution for transitioning away from fossil fuels. This is mainly due to the lower costs and possibility of the use of existing manufacturing infrastructure. To achieve a similar level of refueling comfort as with the battery powered electric vehicle, the economic and technological aspects of the local small-scale hydrogen production are being investigated. Due to the low efficiency and high prices for the required components, this domestically produced hydrogen cannot compete with hydrogen produced from fossil fuels on a larger scale.}, language = {en} } @article{HandwerkerKesslerMarzbani2021, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz}, title = {Review of mechanical properties of and optimisation methods for continuous fibre‑reinforced thermoplastic parts manufactured by fused deposition modelling}, volume = {6}, journal = {Progress in Additive Manufacturing}, number = {4}, publisher = {Springer Nature}, address = {Cham}, issn = {2363-9520}, doi = {https://doi.org/10.1007/s40964-021-00187-1}, pages = {663 -- 677}, year = {2021}, abstract = {A new way of manufacturing continuous fibre-reinforced plastics is the embedding of fibres in the filament of a 3D printer. This method could be used in manufacturing composite materials with a thermoplastic matrix containing glass, Kevlar and carbon fibres. This paper provides an overview of research on the mechanical and physical properties of these parts as well as optimisation approaches of additively manufactured thermoplastics. Furthermore, applicable testing and analysis methods and their corresponding standards are included. Several studies, which represent the current state of the art, are reviewed in detail for the analysis of the mechanical performance of different fibre reinforcements. In addition, an overview of different optimisation approaches is given. The ultimate tensile strength of Kevlar and glass fibre-reinforced parts are similar to those of common Aluminium alloys whereas the carbon fibre reinforced parts outperform their aluminium counterparts. Major performance limitations include a poor adhesion between layers as well as a high air void ratio.}, language = {en} } @article{HandwerkerKesslerMarzbanietal.2022, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz and Tetzlaff, Ulrich}, title = {Pressure and heat treatment of continuous fibre reinforced thermoplastics produced by fused filament fabrication}, volume = {8}, journal = {Progress in Additive Manufacturing}, number = {2}, publisher = {Springer}, address = {Cham}, issn = {2363-9520}, doi = {https://doi.org/10.1007/s40964-022-00315-5}, pages = {99 -- 116}, year = {2022}, abstract = {Fused filament fabrication allows for the additive manufacturing of complex geometries without requiring moulds. However, due to large air voids and poor layer adhesion, the mechanical properties of parts manufactured using fused filament fabrication lag behind those of parts manufactured using conventional techniques. A previous study found that the tensile strength and Young's modulus of such parts could be increased by a heat-treatment process. However, large air voids were still present after annealing. This study, therefore, investigates the influence of a post-pressure-treatment process on the mechanical performance and the air void ratio of continuous glass fibre-reinforced polyamide 6 in the directions perpendicular to the fibres. Without the treatment, Young's modulus on the plane parallel to the printing bed is eight times higher than Young's modulus perpendicular to it. Annealing at 1 MPa homogenises the material and leads to a significant increase of both the tensile strength (55 MPa) and Young's modulus (5 GPa). Increasing the pressure to 3 MPa only slightly increases the mechanical performance, whereas a further increase to 6 MPa causes no significant changes.}, language = {en} } @article{HandwerkerKesslerMarzbanietal.2021, author = {Handwerker, Michael and Kessler, J{\"o}rg and Marzbani, Hormoz and Tetzlaff, Ulrich}, title = {Annealing of chopped and continuous fibre reinforced polyamide 6 produced by fused filament fabrication}, volume = {2021}, pages = {109119}, journal = {Composites Part B: Engineering}, number = {223}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1879-1069}, doi = {https://doi.org/10.1016/j.compositesb.2021.109119}, year = {2021}, language = {en} }