EFFICIENT CYCLE JUMPING TECHNIQUES FOR THE MODELING OF MATERIALS AND STRUCTURES UNDER CYCLIC MECHANICAL AND THERMAL LOADING

Highly efficient cycle jumping algorithms have been developed for the calculation of stress and damage histories for both cyclic mechanical and cyclic thermal loading. The techniques have been shown to be suita ble for cyclic plasticity; creep-cyclic plasticity interaction; and cr eep dominated material behaviour. The cycle jumping algorithms have be en validated by comparison of the predictions made using both the cycl e jumping technique, and the full calculation involving the integratio n of the equations around all cycles. Excellent agreement has been ach ieved, and significant reductions in computer processing time of up to 90% have been obtained by using the cycle jumping technique. A furthe r cycle jumping technique has been developed for full component analys is, using a viscoplastic damage finite element solver, which enables s tress redistribution to be modelled. The behaviour and lifetime of a s lag tap component has been predicted when subjected to cyclic thermal loading. Cyclic plasticity damage and micro-crack initiation is predic ted to occur at the water cooling duct after 2,974 cycles, with damage and micro-crack evolution arresting after 60,000.