Date of Award

2021

Document Type

Campus Access Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Vijaya V. N. Sriram Malladi

Committee Member 1

Jason Blough

Committee Member 2

Andrew Barnard

Abstract

Recent research in vibration isolation focuses on designing metastructures with structural bandgaps; however, experimentally demonstrating bandgaps in low-frequency bandwidths is challenging. This research focuses on creating metastructures consisting of a composite compliant bistable unit with low-frequency bandgaps. Geometric nonlinearity in the design of unit cells enables adaptive stiffness of the lattice structures. Tuning the stiffness of unit cells facilitates the design of structural bandgaps in the desired range. Multiple design iterations that led to the final design are discussed. The buckled structures are fabricated for testing using 3D printing. The experimental frequency response functions (FRFs) are determined for the in-plane stacking configurations. As a modal shaker excites the base, the response is measured on the top surface using a laser vibrometer. LMS SCADAS data acquisition system analyzes the data and generates FRFs, and structural bandgaps are then identified by using them. Two analytical models are developed to predict and validate the bandgaps achieved by the structure. The analytical models are coded using MATLAB, and the parameters for simulation are obtained from measurements and mathematical optimizations. The accuracy of the models in predicting the bandgap is studied, and the future scope for this research is presented.

Available for download on Monday, August 01, 2022

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