EVOLUTIONARY SENSOR NETWORK DESIGN FOR STRUCTURAL HEALTH MONITORING OF STRUCTURES WITH TIME-EVOLVING DAMAGE

Abstract

Structural health monitoring (SHM) aims to assess damage intensity and provide engineers with data to make informed maintenance and repair decisions. SHM systems collect crucial information for evaluating a structure's current state, enabling appropriate maintenance decisions and loss mitigation. Therefore, it is crucial to acquire damage-sensitive data by using a well-designed SHM system that is optimal in terms of expenses as well as functionality. In this research, we present an optimal sensor placement framework that considers two stages of the structure’s lifespan: (1) an early-stage pre-posterior design, and (2) a periodically updated sensor design in the operational stage. When the sensors are designed initially in the pre-posterior stage, there is no data available to make informed design assumptions for designing the SHM system. As a result, all the uncertainties and damage evolution models for the structure need to be modeled probabilistically based on reasonable assumptions derived from historical perspective and engineering judgment. The early-stage design of an SHM system initiates the data acquisition and serves two primary purposes: (1) helps update the current state of the structure, and (2) supports data-informed maintenance decisions. As the structure degrades over time, despite periodic maintenance, it is bound to approach the limiting or critical damage state. This warrants an even better inference of damage state with the goal of avoiding the worst scenario of failure. In addition, another reason to update the sensor design while in the operational stage is to optimize the SHM system by making it more suitable to the current structural state and benefit from the data acquired through the pre-posterior design. Periodically updating the design yields the best risk to reward for an SHM system in terms of its expenses and functionality. We demonstrate the application of the proposed framework on a realworld complex miter gate structure.