Crack path prediction in rolled aluminum plates with fracture toughness orthotropy and experimental validation

• Crack growth criterion for cracks in materials with orthotropic fracture toughness.
• Fracture toughness testing and crack path experiments in Al-7075-T651 plate specimens.
• Implementation of the orthotropic fracture toughness in the numerical model.
• Numerically predicted crack paths are in good agreement with experimental paths.
• Anisotropic material properties are crucial for the accurate prediction of crack paths.

The paper presents a numerical procedure for the accurate calculation of crack paths in plane structures. The J-integral is used to determine crack tip loading quantities such as stress intensity factors or the energy release rate. Crack paths are predicted applying a modified maximum energy release rate approach accounting for the fracture toughness orthotropy in rolled plates of aluminum alloy Al-7075-T651 where the anisotropy of elastic constants is negligible. Experiments with CT-specimens are carried out to determine the fracture toughnesses in and perpendicular to the rolling direction. The numerically predicted crack paths for differently shaped specimens are in good agreement with those obtained from experiments.