Finite element analysis of notched bar skeletal point stresses and dimension changes due to creep

摘要

In this investigation, finite element calculations have been performed to obtain the creep stress distributions generated in circumferentially notched bar test-pieces. They have also been made to determine the relation between axial extension and notch throat diameter changes. It has been found that an approximate skeletal point can be identified where the stress state is insensitive to the power law stress dependence of creep. Consistent trends in skeletal point stress ratios to those given in an existing Code of Practice for notch bar creep testing have been obtained. Nevertheless updated values, particularly for sharp notches, are proposed and these have now been inserted into a new version of the Code of Practice. In contrast, the link between extension and notch throat diameter changes has been found to depend on the creep stress index as well as the notch geometry. It is anticipated that the analysis can be used to establish the multi-axial creep stress deformation and rupture behaviour of materials.