Real-time health monitoring of mechanical structures

The paper presents development and experimental validation of a real-time health monitoring and nondestructive evaluation (NDE) method for residual life prediction of ductile-alloy structures. Application areas include fatigue crack damage in mechanical structures such as those in aircraft, surface ship, submarines, civil infrastructures, and power plants. The technical approach relies on fusion of heterogeneous information derived from physics-based models of fatigue damage and real-time sensor data. This ultrasonic-sensor-based NDE method requires theoretical formulation and experimental validation: (i) a stochastic damage model under fatigue crack initiation and propagation; and (ii) filter algorithms for on-line damage estimation and remaining life. The analytical part of the work is supported by laboratory experimentation on a special-purpose fatigue test apparatus that is equipped with computer-based ultrasonic, optical, and mechanical sensing devices.