Lifetime prediction of ceramic components - A case study on hybrid rolling contact

- We made lifetime predictions based on experimental fatigue data.
- We showed the effect of environment on the fatigue life of silicon nitride.
- RCF experiments were in accordance with calculated fatigue life estimates.
- Incorporating plasticity in the FEM yielded more realistic results.
- We showed that crack propagation is more likely to occur at R = −1.

In this study, fatigue life predictions were made for silicon nitride components undergoing hybrid ceramic-steel rolling contact. Three-dimensional stress fields were extracted using a bespoke finite element model and subsequently used to calculate stress intensity factors by means of the weight function method. Crack-growth rates were estimated by assuming crack growth to follow a Paris power-law expression whose material parameters were obtained from four-point bending fatigue experiments under fluctuating tensile load (R = 0.1) and fully-reversed alternating load (R = −1).The crack-growth behavior obtained from the calculations was compared with experimental results obtained from twin-disk-type RCF experiments. The calculated lifetime predictions were in accordance with the experimental results. Crack formation and propagation was found more likely to occur in locations undergoing alternating load rather than those undergoing pure fluctuating tensile load.