Microscale Testing and Characterization Techniques for Benchmarking Crystal. . .
119
Fig. 12 Progression from experimentally captured digital microstructure to meshed structure
ready for simulation. Digital segmentation based on identifying individual features such as grains is
performed, followed by assigning properties to each feature and generating a mesh for performing
a CPFEM simulation
of these features can be assigned properties based on their orientation, and a
finite element mesh can be developed to model the microstructure using the CPFE
method.
While this framework for generating explicit benchmarks from combined
mechanical testing and 3D dataset generation seems straightforward, the collection
of experimental data to instantiate a simulation is nontrivial. Two major limitations
reside in the amount of data that can be handled in 3D datasets and the volumes that
can be captured in computational models. CPFEM requires a fine mesh to capture
grain-level details and an even finer mesh to account for intragranular features such
as twins that are common in René 88DT. For René 88DT, this creates the challenge
to design and test a sample volume that contains a reasonable number of grains
to model at the spatial resolution of about 0.5 μm necessary to accurately capture
the twin structures present. Designing and mechanically testing appropriately
sized samples is the primary focus of this chapter, but initial attempts at pairing
of these tests with explicit 3D datasets of the entire sample shows considerable
promise. Realizing this promise will require development of a technique to
protect and section freestanding samples using protective layers that eliminate
sectioning artifacts. 3D serial sectioning methods and emerging nondestructive
characterization techniques like HEDM have considerable promise, especially with
the on-going development of infrastructure for big data management.
119
Fig. 12 Progression from experimentally captured digital microstructure to meshed structure
ready for simulation. Digital segmentation based on identifying individual features such as grains is
performed, followed by assigning properties to each feature and generating a mesh for performing
a CPFEM simulation
of these features can be assigned properties based on their orientation, and a
finite element mesh can be developed to model the microstructure using the CPFE
method.
While this framework for generating explicit benchmarks from combined
mechanical testing and 3D dataset generation seems straightforward, the collection
of experimental data to instantiate a simulation is nontrivial. Two major limitations
reside in the amount of data that can be handled in 3D datasets and the volumes that
can be captured in computational models. CPFEM requires a fine mesh to capture
grain-level details and an even finer mesh to account for intragranular features such
as twins that are common in René 88DT. For René 88DT, this creates the challenge
to design and test a sample volume that contains a reasonable number of grains
to model at the spatial resolution of about 0.5 μm necessary to accurately capture
the twin structures present. Designing and mechanically testing appropriately
sized samples is the primary focus of this chapter, but initial attempts at pairing
of these tests with explicit 3D datasets of the entire sample shows considerable
promise. Realizing this promise will require development of a technique to
protect and section freestanding samples using protective layers that eliminate
sectioning artifacts. 3D serial sectioning methods and emerging nondestructive
characterization techniques like HEDM have considerable promise, especially with
the on-going development of infrastructure for big data management.