Date of Award

5-2023

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Committee Chair/Advisor

Oliver Myers

Committee Member

Gang Li

Committee Member

Garrett Pataky

Abstract

This thesis presents a predictive analysis of the stability of square bistable carbon fiber reinforced composite laminates under various loading conditions. The stability of these laminates is essential to their performance and longevity and is influenced by factors such as thickness and length. Analytical and numerical techniques are used to model the behavior of these laminates, and experimental tests are conducted to validate the models. The findings of this research have implications for the design and optimization of square bistable carbon fiber reinforced composites.

The study investigates the relationships between the side length and thickness of square laminates for bistability. The following equations can be used for a relationship between curvature κ and thickness, t for bistable laminations of CFRP DA 409U/G35 150: κ=0.023t^(-1.059) and t=0.788κ^0.943.

These findings provide valuable insights for designing and fabricating bistable laminates in engineering applications.

These findings have significant practical implications for the design and manufacturing of laminates, as they enable engineers to select an appropriate thickness of laminate to achieve a desired curvature. Moreover, the knowledge gained from this study could be utilized to optimize the strength and durability of laminates for various applications, making it a valuable contribution to the field of engineering. Future studied would require generalizing this equation to other CFRP with varying material properties.

The prediction of snap-through force for bistable laminates reveals that the force required for actuation is dependent on both the thickness and side length of the laminate. The non-dimensional study conducted in this research demonstrates that the force is a function of both parameters, and by introducing non-dimensional parameters, the graph of force versus side length collapses into a single curve for different numbers of plies.

The experimental validation of the approach used to predict snap-through force was inconclusive. The difference in the values obtained from finite element analysis and experimentation could be due to inaccurate material properties and fabrication defects during the hand lay-up process. The present findings provide a useful foundation for further research and offer practical implications for the design and development of bistable laminates for various applications.

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