In CCG (creep crack growth) tests, the LLD (load line displacement) and LLD rates are measured and used to calculate the creep fracture mechanics paparameter C\*. To date the plastic contribution to the LLD has been evaluated by assuming a power-law relationship for plastic deformation or  C\* has been calculated by totally neglecting the contribution of plasticity to the LLD since  since it is often overestimated, leading to negavive values of C\*.  A new approach has recently been proposed to partition the LLD into its elastic, plastic and creep componenets. This method, which requires a finite element simulation of the CCG test, has already been applied for standard compact tesnion, C(T), geometries for 316H stainless steel. In the new methodolgy proposed both plastic and creep strain history effects have been considered and the plastic deformation behaviour accuratley represented by employing the tesnile test data as opposed to a power-law model of its behaviour. In this work the methodology is applied to analyse the results of CCG tests performed on a lower constraint single edge notched tension geometry , SEN(T). The proportion of the LLD due to elasticity, plasticity and creep is quantified and the impact of this analysis to CCG test results is discussed.


Application of a Novel Load Line Displacement Partitioning Technique to Creep Crack Growth Tests on Sen(t) Geometries of Type 316h Stainless Steel

Division / Sponsors: 
Pressure Vessels & Piping (PVP)


Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2020/volume/83815

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