Material fatigue is a phenomenon where a material undergoes progressive damage and failure under cyclic loading or repeated stress. This can occur in various materials such as metals, polymers, and composites. Fatigue can cause microscopic cracks to form and grow, eventually leading to catastrophic failure of the material. Research in material fatigue aims to understand the mechanisms of fatigue, predict the fatigue life of materials, and develop strategies to prevent fatigue failure. This research area involves studying the microstructural changes, crack initiation and propagation, and the effects of various factors such as loading frequency, stress amplitude, and environmental conditions on material fatigue. Researchers also develop models and techniques to assess the fatigue resistance of materials and improve their fatigue properties through design modifications or material selection.