Course Outline

Smart Structures. Concept and overview. Active and passive smart structures. Need for application to civil structures. Merits and possibilities.

Fiber optic sensors. Introduction to fiber optic sensors. Basic functional principles: Michelson interferometry, Fabry-Perot interferometry, Bragg-gratings, light scattering. Classification of sensors by gauge length; advantages and challenges. Long-gauge sensors and global structural monitoring: meaning of a long-gauge sensor measurement; measurement error inherent to gauge length; sensor topologies and local structural monitoring; global structural monitoring; examples from practice. Distributed sensors and integrity monitoring: meaning of a distributed measurement; direct damage detection and integrity monitoring concept; applicability; examples from practice.

Experimental Modal Analysis and Identification. Measurement techniques: stepped sine tests, shock tests, ambient vibration tests. Sensors and exciters. Basic signal analysis. Classical frequency domain identification. Review of Case Studies. Modal analysis of civil structures: motivation and case studies. Bridges and buildings. Historic structures. Laboratory setups. Structural elements. Model Updating. Sensitivity analysis. Non linear optimization. Definition of target function. Optimization algorithms.

Linear Systems and Time Domain Identification. Linear systems in state-space form and transformation from continuous to sampled time. Concepts of observability and controllability. Relation of state space description to the modal model. Classical and arbitrary damping. Time domain identification; Eigensystem Realization Algorithm.

Damage Detection and Localization. Fundamentals of the Kalman filter and its use as a damage detector. Damage localization using null space techniques. Methods for input-output and for cases where only output measurements are available.

Control of Dynamical Systems. Absolute and relative stability analysis. Output feedback stability. Control system design. Specifications. PID control. Sensitivity to perturbance and parameter variation. Complex control structures. Discrete-time control system design. Linear dynamics of multivariable systems. State feedback control. State observers. Reference-model control design. Adaptive control. Structural control. Active, hybrid and semi-active structural control. Response mitigation of civil engineering structures. Demonstration in the lab of Single- and Multiple-DoF systems.

Wireless Sensor Networks. Introduction and motivation for wireless sensor networks for SHM; hardware design of wireless sensors; interface circuits; embedded software design; SHM algorithms; distributed computing; agent-based load sharing; database design and data management; field studies of wireless monitoring systems; extensions of wireless sensing for structural control.

Micro- and Nanotechnologies for Structural Health Monitoring. Motivation for miniaturization; introduction to microelectromechanical systems (MEMS); bulk fabrication; surface fabrication; MEMS sensors for SHM; nanotechnology; imaging methods; thin film fabrication methods; carbon nanotube composites; distributed thin film sensing; electrical impedance tomography.

Smart Materials. Introduction to Smart Materials. Piezoceramic materials. Shape memory alloy. Shape memory effect. Superelasticity. Electro-Rheological (ER) and Magneto-Rheological (MR) fluids. Magnetostrictive materials. Villari effect. Matteucci effect. Wiedemann effect. Applications to Structural Health Monitoring and vibration control. Ultrasonic wave generation and sensing. Guided wave and impedance-based damage detection.

Statistical Pattern Recognition. Probability theory. Multivariate analysis. Principal component analysis. Curse of dimensionality. Statistical inference. Unsupervised learning. Statistical process control. Outlier/novelty detection. Linear regression analysis. Model order selection. Generalization. Classification. Supervised learning. Fisher’s linear discriminant. Neural network. Radial basis function. Support vector machine. Data normalization. Reference-free diagnosis. Case studies and field applications.

NDT Methods. Ultrasounds with frequency analysis; Nonlinear ultrasounds; Laser excited ultrasounds; Eddy current; Strain gauges. Active thermography, THz technology, Electro–mechanical impedance method. Vibration based methods; Guided wave methods; Acoustic Emission; Comparative Vacuum Monitoring; Electromagnetic layer. Damage modeling. Levels of Health Monitoring

Elastic wave based methods in SHM. Spectral Finite Element Methods. Wave propagation in composite structures. Damage assessment in composite plates. Composite structures: potentials and limitations. Wave propagation modeling in plate and shell–like structures. Optimal sensor network – Estimation of optimal array of sensors placement. 3D laser scanning vibrometry techniques for damage detection (with signal processing).

Mechanics of smart dielectric elastomer structures. Fundamentals of large-strain solid mechanics. Electromechanical coupling in soft dielectric elastomers. Evaluation of performance of homogeneous and composite smart dielectric actuators and generators. The role of instabilities. Applications and overview of the current research in the broad area of electro-active polymers.