Mechanical Engineering ETDs

Publication Date

Fall 11-15-2017


The exceptional combination of properties offered by carbon fiber composites has propelled their incorporation into high performance markets such as aerospace, wind energy, luxury cars and sporting goods. While the use of carbon fiber in these sectors is expected to continue to increase, the high price and energy cost associated with carbon fiber production acts as a significant barrier of entry into larger volume markets, such as the automotive industry. One method of navigating this transition is through the use of recycled carbon fiber composites.

Carbon fiber reclamation can produce fibers with up to 90% and 100% of the strength and stiffness, respectively, and 25% and 10-20% of the cost and production energy, respectively, of virgin fibers. In this study, we investigate the structure and properties of recycled carbon fibers and their composites. The surface of the recycled fibers was characterized with both SEM and XPS, and the mechanical properties were characterized with single fiber tensile tests. Aligned fiber mats were processed using a centrifugal alignment technique. Alignment was characterized using image processing, and the composite mechanical properties were investigated using tensile tests. Finally, theoretical modeling of tensile strength and stiffness of composites were performed. Fiber orientation and length distributions, FOD and FLD, respectively, were taken from experimental image analysis of fiber mats and were input to the model. Effect of FOD and FLD as well as fiber-matrix shear strength were investigated. The modeling provided crucial information that can be used to guide the design of the recycled fiber composites.


Recycled carbon fiber, fiber alignment, discontinuous fiber composites

Degree Name

Mechanical Engineering

Level of Degree


Department Name

Mechanical Engineering

First Committee Member (Chair)

Mehran Tehrani

Second Committee Member

Yu-Lin Shen

Third Committee Member

Mahmoud R. Taha

Document Type