CREEP AND DAMAGE ANALYSIS OF A SERVICED TEE INTERSECTION IN A BOILER HEADER - COMPARISON BETWEEN NUMERICAL AND EXPERIMENTAL RESULTS

In the last few years modelling of damage phenomena under creep condit ion has been developed in order to take into account the microstructur al material evolution in life predictions of high temperature componen ts. The new analytical methods based on ''Continuum Damage Mechanics'' and experimental creep and creep-rupture data aim at describing both stress-strain and damage field in structures in order to predict crack initiation. These models are implemented in computer finite element p rograms and should be subjected to rigorous experimental verification for a practical use in power plant assessment activities. In the prese nt paper the numerical results obtained from some creep and damagement analyses of a header component (10 CrMo 910 steel) are shown and comp ared with the experimental ones. The creep analyses have been performe d by the computer code ABAQUS and the damage evaluation has been carri ed out by means of proper in-house developed user's subroutine and pos t processor.