Implementing 3D Digital Image Correlation to Study the Dynamics of Globally-Coupled Multistable Structures
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Mechanical and Aerospace Engineering Honors Theses; 2019
Modern structural systems that employ slender structures to minimize cost and weight may undergo nonlinear dynamics that can be harmful to long-term structural integrity. For example, slender aerostructures employed for future hypersonic aircraft may experience detrimental dynamic behaviors due to combined loads of hypersonic flight. Skin buckling is a result of the combined loads and leads to wear on structural components, and failure. The skin buckling is evidence of multistability, a condition analogous to an array of coupled, bistable beams, that each contain two stable equilibrium configurations. While the influences of local coupling between adjacent bistable beams on the system dynamic behaviors has previously been assessed, the more expansive global coupling mechanisms have not been investigated. Global coupling influences are those that provide direct connection between one bistable component and a non-nearest neighbor by way of interfaces that are shared throughout the system. This research seeks to establish an experimental approach to uncover first insights on global coupling mechanisms that influence the resulting dynamic behaviors of multistable structures. An array of cantilevered beams that share a common overhang boundary is fabricated to allow control over a simplified form of global coupling. Once fabricated, the system is configured with attractive magnets near the end of the beams to induce bistable states and thus a multistable structure. A new experimental infrastructure based on the three-dimensional digital image correlation (3D DIC) method is implemented to provide full-field motion mapping of the system displacements. Then, experiments investigate how global coupling parameters influence the dynamic behavior of the beam system when subjected to harmonic mechanical loads. The results of this research will guide development of future investigations to analyze the influences of global coupling in multistable structures in a complementary theoretical framework.
Academic Major: Mechanical Engineering