Modeling and Characterization of Damage Processes in Metallic Materials

Abstract

This paper describes a broad effort that is aimed at understanding the fundamental mechanisms of crack growth and using that understanding as a basis for designing materials and enabling predictions of fracture in materials and structures that have small characteristic dimensions. This area of research, herein referred to as Damage Science, emphasizes the length scale regimes of the nanoscale and the microscale for which analysis and characterization tools are being developed to predict the formation, propagation, and interaction of fundamental damage mechanisms. Examination of nanoscale processes requires atomistic and discrete dislocation plasticity simulations, while microscale processes can be examined using strain gradient plasticity, crystal plasticity and microstructure modeling methods. Concurrent and sequential multiscale modeling methods are being developed to analytically bridge between these length scales. Experimental methods for characterization and quantification of near-crack tip damage are also being developed. This paper focuses on several new methodologies in these areas and their application to understanding damage processes in polycrystalline metals. On-going and potential applications are also discussed.

Reengineering Aircraft Structural Life Prediction Using a Digital Twin

“…Additional spirals of development will increase the fidelity of this Digital Twin by incorporating new technologies as they mature. One of the technologies that may be ready in time for the second development spiral includes physics-based models for damage development and progression from NASA's Damage Sciences [45] and the Air Force Office of Scientific Research's Structural Mechanics programs. Another may be the coupling of different physics models, that is, thermal, dynamic, and stress.…”

Scale-Dependent Crack Modeling for Investigation the Effect of Geometrically Necessary Dislocations in Micro/Nano Grain Size of Copper

“…According to its origination, it can be divided into two types, i.e., Statistically Stored Dislocation (SSD) and GNDs. An inhomogeneous distribution of the dislocations density becomes obvious for such cases in research of [23]. The measurements of strain fields, local orientation changes and estimates distribution of GND content near crack tips and its wakes of fatigue cracks can be compared with predicted results of nano/micro scale computational models ( [23]).…”