Investigation of intergranular stresses for validation of a novel multi-scale modelling framework

In nuclear power plants complex thermomechanical loading will occur leading to damage of critical components. Finite element modelling is conventionally used and employs empirically based continuum models to underpin integrity and lifetime assessments. Laws such as these have a longstanding pedigree, they are not based on the underlying physical behaviour of the component or structure. Recent research at Bristol has focussed on developing a multi-scale numerical framework to model problems such as these. A meso-scale, physically motivated model at the grain level is used to capture key material behaviour, which is then linked to a more conventional continuum model. This permits the modelling of larger, realistic plant components. This study aims to validate our multiscale modelling framework and provide confidence to apply it to more complex cases. We propose the measurement of notched specimens to study intergranular stresses upon multiaxial loading of 316H austenitic stainless steel. Evolution of these intergranular stresses during displacement controlled dwell will also be investigated. Therefore, this study aims to measure the elastic lattice strain at multiple positions in notched specimens of different acuities under thermomechanical loads. Additionally, the results obtained will also prove useful in exploring the evolution of these intergranular stresses during time-dependent plastic deformation.