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A Static and Snapthrough Analysis of an Innovative Bistable Composite Wing
Hijazi, Sara
Hijazi, Sara
Description
A Master of Science thesis in Mechanical Engineering by Sara Hijazi entitled, “A Static and Snapthrough Analysis of an Innovative Bistable Composite Wing”, submitted in December 2022. Thesis advisor is Dr. Samir Emam. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).
Abstract
This thesis presents a numerical analysis of the room-temperature shapes and snapthrough response of thermally induced hybrid bistable symmetric laminates. The bistable laminate is clamped at one end and free at the other end to extend the applications of bistable laminates to non-free-free boundary conditions. The hybrid layup resolves the issue of losing the bistability of the laminate when attached to a larger structure or clamped. Bidirectional (BD) glass-epoxy layers are symmetrically embedded in the laminate’s layup to trigger the bistability. An approximate analytical model that is based on the Rayleigh-Ritz method along with the ABAQUS Finite Element (FE) package are used in the analysis. The model is validated against the results available in the literature and a good agreement is obtained. The significance of the BD layers on the thermally induced room-temperature shapes and the snapthrough response is examined. Three parameters are considered: the BD layers’ width, thickness, and location from the laminate’s center. It is found out that the three parameters greatly affect the static equilibrium shapes and the snapthrough/snapback response. This analysis complements the ongoing research on the bistable laminates for morphing applications. The second part of this study is to propose an innovative design of a bistable wing which has a symmetric flat platform followed by a winglet that utilizes the modified hybrid symmetric bistable laminate. The snap-through and snap-back responses under concentrated load of the proposed design is investigated. The proposed design is referred to as an innovative hybrid bistable laminate i-HBSL throughout this thesis.