NDT (non-destructive testing)
Festive themed damage on this one. A cast-iron Christmas tree stand fell from the garage rafters and the frame took a direct hit on the chainstay. The damage on the surface looked pretty insignificant, but the ultrasound readout showed delamination (the second peak in the middle), and we were fully expecting a fracture all the way through.
We applied a UV dye penetrant to the damage so that the fracture became more visible.
The second photo of the ultrasound shows a single peak which denotes good consolidated carbon where the repair has been made.