Engineering application of enhanced C*-Q* two parameter approaches for predicting creep crack initiation times

摘要: Abstract Enhanced C*-Q* two parameter approaches were developed into engineering application where the creep crack initiation was defined by a critical distance of 0.2 or 0.5 mm. coupled stress-regime strain rate and Fermi's function ductility as well constraint effect used. Two methods proposed to evaluate (CCI) times based on enhanced approaches. (1) Simple method I, i.e. directly applying 4d calculate CCI times. (2) Four-stages II, divide 0.2 mm 4 stages, in each stage, d = 0.05 mm could be applied obtain time, then total four stages. The estimation initial stress state selection criterion prediction model for plane also proposed. By comparing between predictions from II R5 method, finite element simulation experimental data, it indicated that I (with average length a+1.5d) accurate conservative. Method more convenient than while accurate. Hence, recommended apply these according actual condition demand.