Thermo-Mechanical Fatigue Crack Growth of RR1000

Thermo-Mechanical Fatigue Crack Growth of RR1000

Non-isothermal conditions during flight cycles have long led to the requirement for thermo-mechanical fatigue (TMF) evaluation of aerospace materials. However, the increased temperatures within the gas turbine engine have meant that the requirements for TMF testing now extend to disc alloys along with blade materials. As such, fatigue crack growth rates are required to be evaluated under non-is...

Hold-time effect on the thermo-mechanical fatigue crack growth behaviour of Inconel 718

In-phase TMF crack growth testing with different lengths of the hold time at the maximum temperature of 550C has been conducted on Inconel 718 specimens. Focus has been on establishing a method for TMF crack growth testing and investigating the effect of high temperature hold times on the TMF crack growth of the material. The tests are compared to isothermal crack propagation tests and show go...

Thermo-Mechanical Fatigue Life Assessment of a Diesel Engine Piston

A cohesive model of fatigue crack growth

We investigate the use of cohesive theories of fracture, in conjunction with the explicit resolution of the near-tip plastic fields and the enforcement of closure as a contact constraint, for the purpose of fatiguelife prediction. An important characteristic of the cohesive laws considered here is that they exhibit unloadingreloading hysteresis. This feature has the important consequence of pre...

Stochastic Analysis of Fatigue Crack Growth

Due to cost and time limitations, experiments for fatigue crack growth are only feasible below certain cycle numbers. In this paper, it is investigated whether or not fatigue crack growth laws allow for an extrapolation of the statistics of the cycle number to reach a certain crack length from limited experimental data, and hence reduce costs.