Fatigue crack propagation in microcapsule-toughened epoxy

Fatigue crack propagation in microcapsule - toughened epoxy

The addition of liquid-filled urea-formaldehyde (UF) microcapsules to an epoxy matrix leads to significant reduction in fatigue crack growth rate and corresponding increase in fatigue life. Mode-I fatigue crack propagation is measured using a tapered doublecantilever beam (TDCB) specimen for a range of microcapsule concentrations and sizes: 0, 5, 10, and 20% by weight and 50, 180, and 460 lm di...

Fatigue Crack Propagation in Transformation-Toughened Zirconia Ceramic

Fatigue crack propagation under tension-tension loading is observed in ( I trunsjormcition-tougheried purtiully stabilized zirconia (PSZ) certimic wnt~iining 9 mol% M g O . Such subcritical crack p m v t h behavior is clernonstrciterl to be licully induced, based on u comparison with behuvior unrler ,sirstciinerl loading (ut the maximum loud in thejiitigue cycle) and at varying c~clic~,fi-riluc...

Retardation and repair of fatigue cracks in a microcapsule toughened epoxy composite – Part I: Manual infiltration

As a first step towards a new crack healing methodology for cyclic loading, this paper examines two promising crack-tip shielding mechanisms during fatigue of a microcapsule toughened epoxy. Artificial crack closure is achieved by injecting precatalyzed monomer into the crack plane to form a polymer wedge at the crack tip. The effect of wedge geometry is also considered, as dictated by crack lo...

Retardation and repair of fatigue cracks in a microcapsule toughened epoxy composite—Part II: In situ self-healing

Successful arrest and retardation of fatigue cracks is achieved with an in situ self-healing epoxy matrix composite that incorporates microencapsulated dicyclopentadiene (DCPD) healing agent and Grubbs first generation Ru catalyst. Healing agent is released into the crack plane by the propagating crack, where it polymerizes to form a polymer wedge, generating a crack tip shielding mechanism. Du...

High Temperature Fatigue Crack Propagation in INCONEL718