EMI-avskärmning, Värmeavledning och Strukturella Egenskaper hos Additivt Tillverkade Stöt- och Vibrationsutsatta Cellulärstrukturer

Additive manufacturing is a manufacturing technology that slices CAD models into multiple layers and reconstructs them layer by layer. Originally, additive manufacturing was exclusively used for rapid prototype-making but advancements in the field have expanded its usage to also include production. One of these advancements, and as of late, the focus of additive manufacturing, are cellular structures. These complex structures possess high strength and energy absorption properties while maintaining low weight and can increase EMI shielding, heat dissipation and structural integrity, all important qualities for equipment in the military field. As a result of this, additively manufactured cellular structures will be incorporated in the redesign and assessed within the context of a rugged voltage adapter for field radios. The framework for the evaluation is primarily the IEC 60950-1 as well as the MIL-STD 810H and 461F standards. With the support of the stakeholder MilDef, this thesis therefore aims to study how and if the additive manufactured cellular structures, BCC, star kagome, and gyroid, can provide a lower weight while maintaining adequate heat dissipation, EMI shielding and structural integrity when exposed to shock and vibrations. To answer the research question, an iterative design phase followed by a case study of simulations in ANSYS Workbench and ANSYS Electrical was carried out. The findings demonstrate that, at present, there is not sufficient evidence to support all of the research question's claims. Due to a lack of reliable results regarding EMI shielding and vibration resilience, no conclusions on these topics could be drawn. However, it is true that all lattice structures provided a lower weight than that of the solid infill and that they all passed the high- and low-temperature operations but marginally failed the maximum surface temperature test. It is believed though that this could be remedied with some small modifications. As for the exposure to shock, the cellular structures had an equivalent performance to the solid infill during deformation but the gyroid was an outlier in the stress performances. The cause of this is at present unknown. In all other cases, the infills’ performances could be rated, from the most optimal to the least optimal, as follows: solid, gyroid, BCC and star kagome. Areas which have been highlighted as future work are: a result-generating analysis of the infills’ EMI shielding abilities, the inclusion of thicker solid walls, the need for more accurate and quantitative input data, optimisation of the unit cell architecture, simulations with other materials and other cellular structures, and either the use of a more powerful computer or the implementation of physical tests.