Smart Infrastructure Health Monitoring & Wireless Sensor Networks: Stochastic Subspace Identification (SSI), Operational Modal Analysis, and Sensor Energy Harvesting Kinetics
Smart Infrastructure Health Monitoring (SHM) and Wireless Sensor Networks (WSN) provide a continuous, real-time diagnostic framework for evaluating structural integrity, damage accumulation, and operational performance across critical civil infrastructure. By deploying low-power MEMS accelerometers, strain gauges, and tilt sensors, engineers transition from schedule-based visual inspections to automated, data-driven condition assessment, detecting subtle stiffness degradation and modal parameter shifts long before visible structural distress manifests. Under operational conditions, ambient excitation (such as wind, traffic, and wave action) is modeled as an unmeasured stationary white noise process. The dynamic system response is identified using Covariance-Driven Stochastic Subspace Identification (SSI-COV) , expressed in discrete-time state-space form: $$\mathbf{x}_{k+1} = \mathbf{A} \mathbf{x}_k + \mathbf{w}_k$$ $$\mathbf{y}_k = \mathbf{C} \mathbf{x}_k + \mathbf{v}_k$$ Whe...