What Is Fatigue Life?
Fatigue life is the number of actuation cycles a Shape memory alloys (SMAs) can sustain before experiencing functional degradation or failure. In SMA actuators, fatigue life is a critical reliability metric, especially in applications requiring repeated cyclic motion.
Factors Affecting Fatigue Life in SMAs
Fatigue life strongly depends on strain amplitude, applied stress level, and microstructural quality. Operating at higher strains or stresses can significantly reduce cycle life, while optimized microstructure, such as controlled crystallographic orientation or monocrystalline structures, can enhance durability.
Understanding fatigue life allows engineers to balance actuation performance, stroke length, and long-term reliability, making it essential for designing robust SMA-based actuators in aerospace, robotics, medical devices, and precision systems.