The third Sandia Fracture Challenge: peridynamic blind prediction of ductile fracture characterization in additively manufactured metal

• Published in: International journal of fracture Vol. 218; no. 1-2; pp. 97 - 109
• Main Authors: Behzadinasab, Masoud, Foster, John T.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.07.2019; Springer Nature B.V
• Subjects: Additive manufacturing; Austenitic stainless steels; Automotive Engineering; Bearing strength; Brittle materials; Characterization and Evaluation of Materials; Chemistry and Materials Science; Civil Engineering; Classical Mechanics; Computer simulation; Crack initiation; Crack propagation; Damage; Damage assessment; Deformation; Ductile fracture; Ductile-brittle transition; Elastoplasticity; Failure; Fracture mechanics; Iterative methods; Laboratories; Load carrying capacity; Materials Science; Mathematical models; Mechanical Engineering; Modelling; Nucleation; Parameter uncertainty; Predictions; Sandia Fracture Challenge 2017; Stability; Stability analysis; Tensile tests; Peridynamics; Ductile fracture; Sandia Fracture Challenge; Nonlocal; Material instability; Additively manufactured metal
• ISSN: 0376-9429; 1573-2673
• DOI: 10.1007/s10704-019-00363-z

In the context of the third Sandia Fracture Challenge (SFC3), the details of the blind predictions performed by the University of Texas team are provided in this article. Over the past two decades, the peridynamic theory has shown great promise in modeling autonomous crack nucleation and growth in materials. While peridynamics has been commonly applied to simulate failure of brittle materials, its ability in predicting ductile fracture has remained mostly untested. This fracture challenge was seen as an opportunity to assess the state of the art of the peridynamic theory in predicting the response of an additively manufactured 316L stainless steel bar with a complex geometry under the dynamic tensile experiments performed by Sandia National Laboratories. The performance of a recently proposed, generalized, ordinary finite deformation constitutive correspondence model, coupled with a recent state-based damage correspondence model was explored over this problem. For finite deformation material modeling, the classical elastoplastic framework of Simo was implemented within the ordinary correspondence theory. Damage modeling was achieved by incorporating the Johnson-Cook failure criterion using the damage correspondence framework. An iterative inverse technique was applied to calibrate the model parameters using the longitudinal and notched tensile tests data provided by Sandia National Laboratories. A blind prediction of the deformation and failure behavior of the SFC3 geometry was performed by embedding the calibrated model in a peridynamic simulation. Uncertainty was introduced into the model parameters to quantify material variability. The results are compared to the experiments conducted at Sandia National Laboratories. While our modeling approach led to qualitatively good results and a correctly predicted crack path, it underpredicted the load-carrying capacity of the structure and simulated an early fracture. Our post-experiment analysis identifies material instability issues associated with the model as the primary sources of error.