Date of Award

8-2022

Degree Name

Doctor of Philosophy

Department

Mechanical and Aerospace Engineering

First Advisor

Jinseok Kim, Ph.D.

Second Advisor

Judah Ari-Gur, D.Sc.

Third Advisor

Daniel Kujawski, Ph.D., D.Sc.

Fourth Advisor

Peter A. Gustafson, Ph.D.

Keywords

Electromechanics, fracture, meshless methods, peridynamics, piezoelectricity, surface correction method

Abstract

The bond-based peridynamics (BB-PD) is a widely used peridynamic model in the literature. Despite Poisson's ratio restriction, it still serves as a powerful tool to solve challenging engineering problems with a relatively cheap computational cost. Consider the Poisson ratio of the material does not deviate from the ones that BB-PD can model. In that case, it becomes advantageous to use the BB-PD compared to other PD models in terms of computational cost and simplicity. However, the BB-PD suffers from the so-called surface or skin effect where the material response at boundaries becomes softer than the bulk material points. As a remedy, this study presents a new surface correction method that calculates the material parameters discretely during the numerical simulations. As a result, the accuracy of the BB-PD simulations is significantly improved for the problems with regular boundaries and the problems involving fractures where new boundaries emerge as the crack propagates and branches.The piezoelectric ceramics have high stiffness compared to their natural counterparts and can be used efficiently as sensors, actuators, and transducers in various smart devices and structures. However, they have low ultimate tensile strength and fracture toughness, making them susceptible to damage. Furthermore, the piezoelectric ceramics are operated at high electrical and mechanical loads. Therefore, studying piezoelectric materials' damage and cracking mechanisms is crucial to operating them safely. Therefore, this study utilizes the non-ordinary state-based peridynamics (NOSB-PD) to model the fully coupled electromechanical behavior and fracture of the transversely isotropic piezo ceramics. The results obtained from the proposed implicit formulation for the static problems agree well with the analytical solutions available in the literature. Finally, an iterative solution procedure is utilized to perform the mode-I fracture simulations of a pre-notched PZT-4 ceramic plate under combined electromechanical loading. The effect of the direction and magnitude of the applied electric field on the crack propagation under quasi-static conditions are discussed.

Access Setting

Dissertation-Open Access

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