ORCID Identifier(s)


Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Mechanical Engineering


Mechanical and Aerospace Engineering

First Advisor

Ashfaq Adnan


Fused Deposition Modeling has become the most popular 3-D printing method over the last decade. Due to its potential to save time, cost and, labor, there is a great deal of interest to use this technique for production of functional load carrying parts and assemblies in bio-medical, automotive, aerospace, and oil and gas industries. In general, materials used in FDM process are isotropic; however, parts printed using FDM process show anisotropic mechanical properties with inconsistent properties in the transverse direction to the filaments’ cross-section. This anisotropic behavior is due to the fabrication process, and the inconsistency in the transverse mechanical properties are due to the different processing parameters used in the FDM process. Transverse mechanical properties of FDM parts are developed as the extruded filaments come in contact and partially bond together. The quality of the bond at the interface of the filaments is the most important factor in the development of mechanical properties in the transverse direction. Transient heat transfer, Multiphase fluid flow, molecular diffusion and structural fracture mechanics should be considered to study the development of interfacial mechanical properties between extruded filaments in FDM parts. In this research, Multiphysics Numerical Modeling techniques have been utilized to study and understand the development of interfacial mechanical properties between adjacent filaments. Effect and significance of different parameters used in FDM process are discussed and suggestions are provided for improvement of the transverse mechanical properties of FDM parts. A new diffusion coefficient is also suggested for determination of interfacial material properties of FDM printed filaments.


3D printing, FDM, Fused deposition modeling, Multiphysics, Fracture mechanics, Eigenfunction expansion, Multi phase flow, Solidification


Aerospace Engineering | Engineering | Mechanical Engineering


Degree granted by The University of Texas at Arlington