Title : Multifunctional Sensing Skins for Structural Health Monitoring for Fifth International Workshop on Structural Control and Monitoring 2008

The integrity and safety of metallic structures can be jeopardized by structural damage (e.g., yielding, cracking, impact, corrosion) that can occur any time. While various sensors have been proposed and validated for structural health monitoring, most sensors only provide data at a discrete point on the structure. Here, a carbon nanotube-polyelectrolyte sensing skin is proposed for monitoring strain, impact, and corrosion of metallic structures. Experimental validation studies have verified that these films exhibit dramatic changes in electrical properties in response to applied strain and corrosion processes. The proposed sensing skin is coupled with an electrical impedance tomographic (EIT) conductivity mapping technique. Unlike point-based sensing transducers, EIT reconstructs two-dimensional skin conductivity distributions for damage identification of large structural components. Since EIT relies solely on boundary electrical measurements, one does not need to physically probe each structural location for data acquisition. Instead, spatially-distributed structural damage can be identified by localized changes in film conductivity detectable via EIT.