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Open Access Thesis
Master of Science in Civil Engineering (M.S.C.E.)
Year Degree Awarded
Month Degree Awarded
The first portion of this thesis assesses the structural application of a bracing design inspired by the deep-sea sponge, Euplectella Aspergillum. Many studies have investigated the natural strength found in the unique skeletal structure of this species. The braced design inspired by the sponge features square frames with two sets of cross-braces that are offset from the corners of each frame, creating a pattern of open and closed cells. This study reports the results of multiple Finite Element Analysis (FEA) computations that compare the described bracing pattern to a more common bracing design used in structural design. The designs are compared in two configurations; the first is a simplified tall building design, and the second is a slender plate design. Results indicate that the sponge’s natural pattern produces considerable mechanical benefit when only considering elastic behavior. However, the same was not true when considering plastic material properties. In conclusion to these observations, the sponge-inspired lattice design is determined to be an efficient alternative to slender-solid plates but not for lateral-resisting systems intended for tall building design.
The second topic of discussion in this thesis concerns the stability of thin cylindrical shells with imperfections. The structural stability of these members is highly sensitive to the size and shape of an imperfection. An accurate prediction of the capacity of an imperfect cylindrical shell can be determined using non-destructive testing techniques. This method does require previous knowledge of the characteristics of the imperfection, which realistically is unknown. In the hope of creating a technique to find the location of an imperfection, this study analyzes the trends in the stability landscapes of the surrounding area of an imperfection. The imperfection of interest in this study has an amplitude equivalent to the thickness of the shell. Using FEA to simulate non-destructive probing tests, it is established that there is a distinct area surrounding the imperfection where the axial load and peak probe force curves show the influence of the imperfection. This area is referred to as the zone of influence and can be used to create an efficient process to locate an imperfection on a thin cylindrical shell.
Sanjay R. Arwade
Sloane, Zoe Y., "Euplectella Aspergillum’s Natural Lattice Structure for Structural Design & Stability Landscape of Thin Cylindrical Shells with Dimple Imperfections" (2022). Masters Theses. 1168.