Events Calendar

Astani CEE Ph.D. Seminar

Speaker: Charles DeVore, CE Graduate Student

Talk Title: Experimental Verification of Substructure Identification for Damage Detection

Abstract:
Damage detection for civil structures is limited by several factors including, among others, poor signal to noise ratios, a large number of unknown parameters and a limited set of measured responses. Global structural health monitoring (SHM) techniques that track modal parameters often fail to detect damage because they remain insensitive to common forms of structural damage. Moreover, a high-dimensional search space of identified parameters makes global inverse problems ill-conditioned. To overcome some of these limitations, many researchers have advanced substructure identification as a methodology to directly detect local stiffness changes using the local neighborhood of measured responses, thereby improving damage detection and SHM scalability in civil structures.

Building on substructure identification methods previously developed by Zhang and Johnson (2011), this paper develops a substructure identification estimator that identifies the story stiffness and damping parameters of a four-story shear building. Concurrent with the estimator derivation, identified parameter confidence intervals are developed; identification performance is predicted through a first-order error analysis. Using the proposed estimator, experimental testing is performed on a 12 ft four-story steel structure subject to base excitation. The floors of the structure are steel masses and the columns are bolted threaded rods. While additional threaded rods can be added/removed to change the story stiffness, these tests examined several configurations in which small stiffness changes are induced by loosening floor-level connections. These changes simulate damage and are successfully detected by substructure identification within computed confidence intervals. The substructure identified parameters are compared against global modal measures and found to be more sensitive to damage. Furthermore, the estimator's performance follows predictions from the error analysis and motivates future work with identification assisted by structural control.

Location: John Stauffer Science Lecture Hall (SLH) - 102

Audiences: Everyone Is Invited

Contact: Evangeline Reyes