Systematic assessment of the influence of voids on the material performance and failure in additively manufactured polymers.

Fused filament fabrication (FFF) is increasingly used for small-scale manufacturing for niche applications, however, its wide adoption for industrial-scale production of structural components requires significant improvement in the overall quality and functionality of the produced products. While the mechanical properties of FFF components are often influenced by print-to-print variability due to various factors, the presence of voids can significantly compromise structural integrity and influence failure behavior. This study investigates the effects of voids, generated by various process parameters to simulate as-manufactured voids seen, on the mechanical performance and failure of FFF components, with particular focus on fracture toughness and fatigue crack propagation. Various experimental techniques including fracture initiation, fatigue propagation, X-ray computed tomography (CT), fractography, thermography and digital image correlation (DIC) were adopted to investigate the influence of process-induced and in-service voids in FFF components. Compact tension specimens (CTS) were used to evaluate plane-strain fracture toughness and fatigue crack propagation, while double cantilever beam (DCB) was utilized to assess Mode I interlaminar fracture toughness in multi-material FFF components. This work seeks to contribute to the widespread adoption of FFF process for functional applications, focusing on the role of voids. This objective was accomplished by i) enhancing interfacial adhesion of multi-material FFF components to resist crack propagation; ii) investigating how void volume fraction and orientation dictates the fracture and fatigue performance of the FFF components; and iii) investigating void evolution during fatigue crack propagation, thereby giving insights into the lifespan and in-service performance of FFF structures. This study provides essential information for enabling damage tolerant design considerations of FFF components, reducing the chances of catastrophic failure and simplifying supply chain of critical components with shorter lead time.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Doctoral

Grantor

Baylor University.

Year dc:date.issued

2026

Author dc:creator

• Jafor, Md Abu, 1994-

Advisor dc:contributor.advisor

• Fleck, Trevor J.

• Additive manufacturing (AM)
• Polymers.
• Fracture.
• Fatigue.

Statement dc:rights

• Baylor University works are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact libraryquestions@baylor.edu for inquiries about permission.

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/2104/14645

OAI identifier oai:identifier

oai:baylor-ir.tdl.org:2104/14645