Session: CT-07-01 Computational Applications in Fatigue, Fracture, and Damage Mechanics

Paper Number: 102278

102278 - Microstructure-Sensitive Description of the Residual Stressability of Components With the Aid of Virtual Experiments 

Despite the advantages of macroscopic, phenomenological damage models, their use in practical applications is still uncommon due to the tremendous experimental effort calibrating the damage model parameters. It involves high material input, which can often not be provided by components in use without affecting their properties. Therefore, this paper presents a methodological, simulative approach to determining the damage model parameters with significantly less material input for the actual material state. Virtual experiments are performed on statistically representative volume elements (RVE) of the microstructure to incorporate microstructure-based influences. For the generation of 3D-RVE, the software DRAGen developed in-house at the IMS is used, which generates a geometric microstructure model based on data gathered from microscopy or EBSD images. Microstructural characteristics, such as hierarchical substructures, were implemented for the ferritic-bainitic reactor pressure vessel steel 22NiMoCr3-7. Mechanical properties are assigned to the constituents of the geometrical model by utilizing a phenomenological crystal plasticity model (CP). The CP model parameters were calibrated for the ferritic phase via experimental nanoindentations with corresponding FE simulations and for the bainitic phase via a curve fitting on the experimental flow curve. In addition, damage criteria on the microscale following the macroscopic material behavior are needed for cleavage and ductile fracture mechanism. Finally, the macroscopic damage model parameters are determined by conducting virtual experiments on the microstructure model with prescribed deformation boundary conditions. For this purpose, the RVE is combined with the calibrated CP model and the damage criteria on the microscale. The stress state dependence is considered by varying the deformation boundary conditions in the virtual experiments.

Presenting Author: Maximilian Neite RWTH Aachen University, Steel Institute - Integrity of Materials and Structures

Presenting Author Biography: Maximilian Neite is working as Research Assistant at RWTH Aachen University, Germany. In 2015 he began studying materials engineering in Aachen, and with his master's thesis about AI-based detection of martensite bands, he completed his studies at the Steel Institute in 2020. Since 2021 he has been doing research in the group Integrity of Materials and Structures, focusing on micromechanical modeling of damage behavior.

Authors:

Maximilian Neite RWTH Aachen University, Steel Institute - Integrity of Materials and Structures
Michael Dölz RWTH Aachen University, Steel Institute - Integrity of Materials and Structures
Markus Könemann RWTH Aachen University, Steel Institute - Integrity of Materials and Structures
Sebastian Münstermann RWTH Aachen University, Steel Institute - Integrity of Materials and Structures