Combined high and low cycle fatigue life prediction model based on damage mechanics and its application in determining the aluminized location of turbine blade

摘要

A new combined high and low cycle fatigue (CCF) life prediction model based on the damage mechanics theory is proposed in this paper. The model parameters are fitted based on the material data and blade data respectively. Verification tests are carried out to evaluate predicted results in combination with the experimental data. Results illustrate that the new model based on the blade data can predict the blade life with relatively higher accuracy (within 2.2 times of scatter band), which is much better than that based on the material data (within 178.2 times of scatter band). Afterward, in comparison with typical existing models, the newly proposed model can predict the turbine blade life more accurately. What's more, based on the newly proposed model, a novel determination method for permitted aluminized location in the turbine blade is put forward. Then, combined with aluminized blade tests, correlated model parameters are determined and the permitted aluminized location distribution is given by using the novel method. The presented life model and the determination method may have a great value for potential engineering applications.