The thesis extends Lennart Krieg's modified linear viscoelastic fatigue life prediction framework to matrix-dominated angle-ply 45 glass-fiber/epoxy composite laminates. To account for matrix nonlinearity, Schapery's nonlinear viscoelastic constitutive theory was integrated into Krieg's fatigue life prediction equation via an augmentation parameter derived from creep-recovery tests. Applying a saturated capped augmentation parameter significantly improved life predictions, reducing root-mean-square errors across stress ratios (e.g. from 0.656 to 0.316 decades for R=0.3). Independent evaluations using dynamic mechanical analysis and stress-sweep testing yielded well-aligned fatigue limit estimates (69 - 77 MPa). Overall, this work provides a successful proof-of-concept for physics-based fatigue prediction in matrix-dominated composites ... Read more

Mission Aviation Fellowship (MAF) provides humanitarian aid using light aircraft to remote communities, separated by geographical obstacles or conflict. HumanAir aims to reduce their operating emissions by 50% while improving economic sustainability and maintaining operational versatility, by designing an innovative new aircraft within a timeframe of only 5 years. This report describes the design process and analysis of the HA-1 aircraft, the proposed solution to the problems encountered by MAF. The HA-1 aircraft achieves an emissions reduction of more than 50% while remaining competitive on cost, facilitated by the use of readily available Jet-A1 fuel instead of scarce leaded AVGAS. Therefore, the HA-1 will replace multiple of MAF’s ageing aircraft with a single sustainable alternative. ... Read more