Creep-plasticity-fatigue calculations in the design of porous double layers for new transpiration cooling systems

New porous double layer (PDL) transpiration cooling technologies can allow gas turbine entry temperatures to be increased beyond current limits towards higher engine efficiency. However, PDL systems require inclined film holes with stress concentration factors in excess of 3.8. Combination of thermoelastic Finite Element (FE) analysis with Neuber type local strain approaches gives similar cyclic strain range predictions with cyclic plasticity-creep FE analysis. Fatigue crack initiation at film holes occurs with a low number of cycles due to excessive plasticity. Our study establishes links between elastic-inelastic analyses and between material phenomena-PDL geometry and indicates pathways of improving life.

Automated summary

The study establishes the connections between elastic-inelastic analyses and between material phenomena-PDL geometry, indicating pathways for improving life. Fatigue crack initiation at film holes occurs with a low number of cycles due to excessive plasticity.