Masters Theses

Keywords and Phrases

Extended Finite Element Method; UHTC; Ultra-High Temperature Ceramics; XFEM


“The ultra-high temperature ceramic, zirconium diboride (ZrB2) has long been researched for applications in extreme environments. Its high strength (> 400 MPa) and thermal conductivity (> 100 W/m•K) make it a candidate for use in hypersonic fight, but a low fracture toughness (< 3 MPa•m1/2) limits this use. In order to increase the fracture toughness without compromising the strength and thermal conductivity, experimental research has focused on the viability of engineered architectures using multiple materials to create a macrostructure. These architectures allow for the increase of fracture toughness thru crack deflection in the material.

Two architectures in particular, laminate and fibrous monolith, have been studied due to their effectiveness in preventing full failure after initial fracture. However as the materials involved are expensive and costly to produce, computational modeling can provide an opportunity to further study the mechanics involved in the fracture behavior of these materials. A valid model can even be used to design new architectures that could further increase the fracture toughness.

In this research, the extended finite element method (XFEM) was used to model the fracture behavior of monolithic, laminated, and fibrous monolithic materials. Simulations using general XFEM have been set up and the results were compared to experimental results. However, modifications were required to properly account for the fracture behavior of multi-material systems. A code was developed to modify the nodal equations and run the calculations to determine the direction of crack growth”--Abstract, page iii.


Asle Zaeem, Mohsen

Committee Member(s)

Hilmas, Greg
Fahrenholtz, William


Materials Science and Engineering

Degree Name

M.S. in Materials Science and Engineering


The author would like to thank the Air Force Office of Scientific Research for funding this project, designated as project number FA9550-14-1-0385, and the Missouri University of Science and Technology and the Department of Education for their financial help.


Missouri University of Science and Technology

Publication Date

Summer 2020


xiv, 70 pages

Note about bibliography

Includes bibliographic references (pages 64-69).


© 2020 Leiren Danielle Jarvis, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 11748

Electronic OCLC #