Date of Completion

12-15-2019

Embargo Period

11-29-2019

Advisors

Prof. Jeongho Kim, Prof. Wei Zhang, Prof. Shinae Jang

Field of Study

Civil Engineering

Degree

Master of Science

Open Access

Campus Access

Abstract

In recent times, there has been an increase in the use of bi-materials in many engineering applications. These bi-materials present the advantage of combining the positive attributes of different materials in a single structure. On the other hand, they raise concerns about interface fracture. Often times, cracks develop at the interface (between the two materials) and propagate over time due to internal stresses and external loads, which ultimately results in the collapse of the structure. To be able to develop reliable bi-material systems, a comprehensive knowledge of interface fracture is required. In the dental field, a number of tests have been developed to evaluate fracture behavior at the interface of bi-materials. Out of the numerous tests invented, the Brazil-nut-sandwiched specimen has proven to be the most reliable. This is due to its ability to measure interfacial fracture toughness along a wide range of mode mixities (from mode I to mode II). In this study, a finite element analysis of the Brazil-nut-sandwiched specimen is used to evaluate the interfacial fracture behavior of bi-material dental structures. The goal is to develop a design map to assist dental professionals in understanding mixed-mode behavior in bi-material dental structures. Three different bi-materials are considered: zirconia-resin, glass ceramic-resin, and porcelain-resin. ABAQUS is used for the finite element analysis and validation of the numerical model is done using similar models in existing literature. The study reveals that interface fracture toughness is influenced by a number of factors including, the size of the crack, the loading angle, degree of mismatch in mechanical properties of the materials, and the location of the crack path. Based on the results from the finite element analysis, a design map is developed for the evaluation of interface fracture behavior for selected dental materials. The results predicted by the design map correlated well with the numerical prediction.

Major Advisor

Prof. Jeongho Kim

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