PSI - Issue 63

Dominik Gřešica et al. / Procedia Structural Integrity 63 (2024) 7– 12

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The technology of applying cement mixtures using robotic arms or gantry systems has been known for almost 15 years and is gaining ground in many forms (Cuevas et al., 2021). On the other hand, the usability of 3D printing from metal or polymer-based material for structural load-bearing purposes is not widely represented and is a topic that has not been explored much. A smaller number of research teams focused on the use of 3D printing of metal materials for joints, where the goal is to optimize topologies or to focus on non-traditional architectural shapes (Buchanan and Gardner, 2019). An interesting possibility is the application of 3D printing to known and problematic details such as the joints of structures that do not have to have a repeating shape, for example membranes. Membrane or rope constructions generally present a challenge in the need to prepare the ideal inclination, shape or size of the connection at high tensile forces. It is also interesting to note the prevalence of the topic of 3D printing in the scientific literature, where more than 1000 publications have been published in the last 10 years (Nguyen et al., 2023). 1.1. 3D printing 3D printing is an additive process that adds material to the final desired shape (Su and Al’Aref, 2018). So there is a difference to machine tools, where material is removed from the whole block until only the desired shape remains. When we talk about the construction industry we must not forget the so-called concrete printing (Federowicz et al., 2023), which has already found its place and provides interesting results and applications. However, if we return to the history of 3D printing, we must focus on plastics. The most used technology for 3D printing of plastics is Fused Deposition Modeling (FDM), which works very simply (Garzon-Hernandez et al., 2020). The object is created layer by layer by melting a thin strip of plastic (or metal) material. There are also a number of other technologies, of which there are nearly 30 (Ghanbari-Ghazijahani et al., 2022; Pagac et al., 2021; Ritter et al., 2023). The advantages of FDM include high simplicity, minimal waste, easy design of models of various sizes, usability of a wide range of materials, and applicability to very cheap printers. On the other hand, the disadvantages are lower quality of print detail, large thickness of each layer, imperfections, and ambiguity in the lifetime of the product itself (Kozior et al., 2024). Looking at these disadvantages, construction professionals must ask themselves whether this technology is suitable. There is no simple answer, of course, but there is certainly room for evaluating the appropriate use of FDM technology in the construction industry and the like. The hypothesis that another material, such as a metal, is more suitable for the construction industry needs to be evaluated here. Metallic materials such as carbon steel, stainless steel and aluminium are widely used in the construction industry, but the products are usually manufactured using traditional techniques such as hot rolling, cold forming, and extrusion. This naturally leads to structural elements that are very austere and simple. The application of 3D printing can help create more complex shapes and structural elements that make better use of the topology of the element with respect to internal stress distribution for metals, Powder Bed Fusion (PBF) and Directed Energy Deposition (DED) are most commonly used. These methods also have advantages and disadvantages that need to be evaluated in the future. 1.2. 3D printing in construction As mentioned above 3D concrete printing already has its place assured (Federowicz et al., 2023), and is being used despite many challenges around the world. In contrast, 3D printing of other materials in the construction industry is limited. We can find few real-world examples that show a strong commitment to interesting design and a modern take on the industry (Kanyilmaz et al., 2022; Mechtcherine et al., 2018; Paolini et al., 2019; Skoratko and Katzer, 2021). A key opportunity that additive manufacturing offers over traditional manufacturing processes is geometric flexibility at both macro and micro scales, allowing for highly optimized structures and engineering materials. This idea has led to the research presented here, which primarily focuses on membrane structures and, in particular, their connection to other structural elements.