Fatigue crack growth (FCG) testing is used to evaluate the safety and reliability of materials by subjecting samples with a pre-existing crack to repeated loading and unloading. The crack growth rate is monitored and provides information on the resistance of materials to stable crack growth under this cyclic loading. Fatigue crack growth rates, from the very slow threshold regime to the fast growth rate region, are typically developed using constant load or K-controlled parameters.
The typical output of these tests is a curve displaying the crack growth rate as the cyclic stress intensity factor (ΔK) is varied. Fatigue crack growth test reports include the following information:
- da/dN versus ΔK data
- A plot of da/dN vs ΔK
- Threshold, and/or Paris Law values, as appropriate
SMaRT routinely conducts FCG testing in compliance with the following international and industry standards (working to other standards are available upon request):
- BS ISO 12108 Metallic materials – Fatigue testing – Fatigue crack growth method