Continuum and Crystal Plasticity Coupled Finite Element Modelling to Explore Complex Loading Conditions

Abstract Components in civil nuclear power plants are subject to high temperatures and pressures. Current methods to perform structural integrity assessments on said components are often overly conservative and cannot predict complex loading conditions. This is partially due to these approaches accounting for only macroscopic material behaviour and ignoring behaviour at a granular level. This has led to increased popularity in crystal plasticity finite element (CPFE) modelling due to its ability to simulate macroscopic and mesoscopic behaviour from a mechanistic perspective. A key factor in the accuracy of CPFE modelling is the boundary conditions applied. Periodic conditions allow the simulation of uniaxial stress states however, exploring more complex loading conditions is challenging. This paper presents a multiscale methodology to apply complex loading conditions to a CPFE model. The material used in this study is Type 316H stainless steel. A macroscopic finite element model is produced of the desired component. At the region of interest, the resulting displacements generated are interpolated and applied to the surfaces of a CPFE model. To partially validate this approach, uniaxial and biaxial simulations have been performed. The uniaxial simulations demonstrate that this approach captures uniaxial behaviour accurately at the macro- and meso-scale, as evidenced by comparisons with lattice plane deformation measured by diffraction techniques. The biaxial simulations match qualitatively well with experimental findings, but more quantitative comparisons must be drawn to exhibit the predictive capabilities.