ABSTRACT
In this study, protective clothing for firefighters is analyzed using 4D body scanning and 3D hand scanning, with a focus on the experimental analysis of ergonomic comfort. In particular, German firefighting clothing is examined to discuss the possibilities and limitations of current scanning technologies for capturing firefighting clothing. For this purpose, various movements are recorded in the 4D scanner. In addition, a method for determining position changes of protective clothing at identified limits is presented. The initial results illustrated that the analysis of protective clothing for firefighters using 4D scanning is problematic due to specific materials, reflections, and surface properties. Improvements in the scanning process and optimization of algorithms are required to achieve more detailed and precise results. Concerning the ergonomic comfort related to the mobility under firefighting clothing use conditions, this methodical case study highlights the limits of current approaches, with a focus on the limitations of 4D scanning and potential improvements.
ABSTRACT
Many users relate additive manufacturing (AM) directly with fast and high-quality prototyping and manufacturing. Nevertheless, already within the different printing techniques there are significant printing time differences for the same polymer printed objects. For AM, there are currently two main known methods to three-dimensional (3D) print objects: One is the vat polymerization process using liquid crystal display (LCD) polymerization, also known as masked stereolithography (MSLA). The other is material extrusion, known as fused filament fabrication (FFF) or fused deposition modeling. Both processes can be found in the private sector (desktop printers) or in industry. The FFF and MSLA processes apply material layer by layer to 3D print objects, but both processes are different in their printing techniques. The different printing methods result in different printing speeds for the same 3D printed object. Geometry models are used to investigate which design elements affect the printing speed without changing the actual printing parameters. Support and infill are also taken into account. The influencing factors will be shown to optimize the printing time. With the assistance of the different slicer software, the influence factors were calculated and the different variants are pointed out. The determined correlations help to find the suitable printing technique to make optimum use of the printing performance of both technologies.
ABSTRACT
This paper presents a geometrical modelling principle for the modelling of yarns at the fibre level. The woven and the knitted textile structures are built of yarns, which on the other side, are fibrous assemblies. In many yarn and fabric modelling works, yarns are considered as a single line element; however, most yarns are composed of a number of staple or filament fibres. It is then very important to understand the yarn at the micro level for a better understanding, production and application of the above structures. The current paper aims to present the modelling and implementation of yarn structures at the fibre level using the algorithmic geometrical modelling principle. The research work uses basic assumptions for the building of the models and various implementation issues, connected with the proper representation of the single multi-filament yarns, plied yarns and finally the staple fibre yarns. Except for visualization, the generated yarn models are prepared as a basis for mechanical, thermal, fluid flow and other simulations of textile structures using FEM, CFD and other numerical tools.
