Date of Award
2025
Document Type
Thesis
Publisher
Edith Cowan University
Degree Name
Doctor of Philosophy
School
School of Engineering
First Supervisor
Majid Rad
Second Supervisor
Ana Vafadar
Abstract
Polylactic acid (PLA) has emerged as a promising material for bone scaffolds due to its biocompatibility, controlled degradation, and suitability for additive manufacturing. However, polymeric scaffolds often face challenges in achieving adequate mechanical strength which compromise their effectiveness as load-bearing supports during bone healing. Hence, evaluating and improving their fatigue performance is essential to meet the required strength. Existing studies have mainly focused on mechanical properties of polymeric scaffolds under static loading, while their performance under cyclic loading remains largely unexplored. This research investigates the mechanical and compressive fatigue performance of 3D-printed PLA bone scaffolds and explore the influence of three key factors: pore architecture, 3D printing parameters, and biodegradation. The first phase involves optimization of 3D printing parameters using the Taguchi method. Results revealed that wider extrusion widths enhanced compressive strength, while lower nozzle temperatures improved fatigue resistance. Thermography analysis of cyclic loading demonstrated a negative correlation between scaffold temperature and stiffness. With optimized printing parameters in place, scaffolds with Gyroid, Lidinoid, Fischer-Koch, IWP, and Voronoi geometries were examined under both static and fatigue loading. The Gyroid topology outperformed other topologies when both compressive and fatigue resistance were taken into account. Finally, the influence of biodegradation on mechanical performance was evaluated by immersing scaffolds with varying surface-to-volume ratios in simulated body fluids. Higher ratios led to increased water uptake and faster degradation, resulting in reduced fatigue resistance. Microscopic images revealed embrittlement of scaffolds after immersion period. It was observed that compressive properties of bone scaffolds remained relatively stable. This underscores the need to carefully design scaffold geometry to avoid rapid degradation and embrittlement during service.
DOI
10.25958/94gp-0m36
Access Note
Access to this thesis is embargoed until 25th March 2026
Recommended Citation
Bakhtiari, H. (2025). Mechanical and low-cycle fatigue performance of polymeric bone scaffolds. Edith Cowan University. https://doi.org/10.25958/94gp-0m36