PSI - Issue 54

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Wojciech Skarka et al. / Procedia Structural Integrity 54 (2024) 506–513 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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After analysing the sources, the design shown above (Pentakis dodecahedron) was selected as the shield to be used in the project. Its advantages over the other designs are the ability to easily scale it as it requires only changing the length of used tubes, connectors (Fig. 2a and 2b) stay the same and it is made of 12 identical segments that make repairing any damages or disassembly easy and fast.

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Fig. 2. (a) Centre connector, (b) Edge connector

The material of the connecting rods was selected among different types of materials such as steel, fiberglass, and carbon fiber [6]. The best (considering best availability to price ratio) would be balloon tubes made of LDPE. The rods were attached to the connectors by tight fit and cyanoacrylate glue. The kinematics of the connection between the cage and the drone was taken from the kinematics concept of a gyroscope. Connection in gyroscope segments was accomplished by the use of specially designed 3D printing and easy assembly connectors. 3.2. Drone cage strength analysis The simulation was conducted on one segment of the drone cage. The mesh consists of elements of the HEX20 and to a lesser extent of the TET10 with dimensions not exceeding 5mm (Fig.3b). It was generated automatically by the program with a given upper limit. The materials used in the simulation are: • Low-density polyethylene (LDPE) for tubes • PET-G (polyethylene terephthalate glycol) for connectors

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Fig.3. (a)CAD model of cage segment, (b) Mesh on cage segment

The simulation was conducted with boundary conditions such as: • Fixing connectors at the edge, they were only allowed to move a maximum of 5 mm along the z axis, with the vector directed to the minus side, which allowed for imitating a real connection of the segments. • Standard Earth Gravity: 9806.6 mm/s². • A load of 0.226 kg = 2.2163029N is intended to imitate the remaining 11 cage segments which were omitted for the purposes of the simulation in order to simplify the computational model.