Mass reduction of a conceptual microsatellite aluminum structure via employing perforation patterns

Mass reduction is a primary design goal pursued in satellite structural design, since the launch cost is proportional to their total mass. The most common mass reduction method currently employed is to introduce honeycomb structures, with space qualified composite materials as facing materials, into the structural design, especially for satellites with larger masses. However, efficient implementation of these materials requires significant expertise in their design, analysis, and fabrication processes; moreover, the material procurement costs are high, therefore increasing the overall program costs. Thus, the current work proposes a low-cost alternative approach through the design and implementation of geometrically-shaped, parametrically-defined metal perforation patterns, fabricated by standard processes. Four geometric shapes (diamonds, hexagons, squares, and triangles) were designed parametrically, and hence implemented onto several components of a structural design for a conceptual sub-100 kg microsatellite. Subsequently, a parametric design space was defined by developing two scale factor and also two aspect ratio variations on the four baseline shape designs. The change in the structure’s fundamental natural frequency, as a result of implementing each pattern shape and parameter variation, was the selection criterion, due to its importance during the launcher selection process. The best pattern from among the four alternatives was selected, after having validated the computational methodology. This validation was achieved through implementing experimental modal analysis on a scaled-down physical model of a primary load-bearing component of the structural design. The selected pattern design was hence refined iteratively, to yield the same value of fundamental natural frequency, but with significant mass reduction. From the findings, a significant mass reduction percentage of 23.15%, from 84.48 kg to 62.42 kg, utilizing the proposed perforation concept, was achieved in the final parametric design iteration. This reduction was relative to the baseline unperforated case, while maintaining the same fundamental natural frequency. Dynamic loading analyses were also performed, namely, quasi static, random, and shock loading analyses, utilizing both the baseline and the finalized perforated designs. These analyses investigated the contrast in the capabilities of the two design to withstand the nominal dynamic launch loads. The findings showed that the final perforated design did have the capacity to withstand the launch loads without yield failure, as indicated by the computed positive yield margins of safety for each loading type. With these encouraging outcomes, the perforated design concept proved that it could provide an opportunity to develop low-cost satellite structural designs with reduced mass, and with reasonably good structural performance.

Text 114885.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18199

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