Based on the current demand of the high-speed flywheels for storage-energy, this thesis focuses on the systematic study of the damage and fracture of the high-speed flywheels for storage-energy. For the first time the acoustic emission method (AE) is used successfully to measure the damage of the high-speed flywheel for storage-energy. The artificial neural network technology is also used successfully to the damage-type recognition.The following issues have been studied in the research: First, the preparati...