An experimental study on the crack initiation from notches connected to interfaces of bonded bi-materials

• We conduct a systematic experimental study on bi-material (polymer/aluminum) specimens with notches and interfaces.
• Variations in notch angles, bonding strengths and loading locations.
• Notch angles and bonding strengths have significant effects on crack initiation load.
• Loading point locations affect the local mode-mixity at notch tips and crack initiation load.
• Real-time videos show the in situ stress and crack developments during experiments.

A systematic experimental study was conducted to investigate the interaction between cracks, notches and interfaces of bonded aluminum and polymer joints. Bi-material specimens with sharp V-notches with variation in notch angles (30°, 90° and 120°), bonding strengths and loading locations were tested under three-point bonding. The notch angle and the bonding strength have significant effect on the crack initiation load. For weakly bonded polymer/metal specimens, crack initiation load increases with the increase of the notch angle. The loading point locations also affect the crack initiation load due to change in local mode-mixity at the notch tip.