Seminar - Warfighter Protection and Structural Health Monitoring by Prof. Ken Loh
日期：2018 年 12 月 03 日 ( 星期一)
Time：2:00 pm – 3:00 pm
Structural systems – both the structural asset and its human operators – are susceptible to “damage” caused by fatigue, deterioration, changing operating conditions, or unexpected extreme events. For physical structures, undetected damage can propagate and cause catastrophic failure. Thus, structural health monitoring (SHM) is crucial for identifying damage initiation, directing repair, and ensuring system safety/reliability. This presentation outlines a new paradigm shift in SHM, where sensors are designed from a materials perspective stemming from a “bottom-up” design methodology. By manipulating materials at the molecular level and then scaling them up to tangible length scales, one can engineer novel multifunctional materials, which are defined to possess a diverse suite of engineering functionalities. By coupling these materials with tomographic methods, spatial structural sensing could be achieved. This seminar will highlight a few examples. First, carbon-nanomaterial-based thin films are coupled with electrical impedance tomography (EIT) to realize densely distributed 2D sensing. Damage, such as cracks, strain fields, and pH/corrosion, could be identified and localized. Second, subsurface structural sensing could be achieved by embedding passive thin film sensors in structural components and then interrogating them using an electrical capacitance tomography (ECT) measurement strategy and algorithm. Cross-sectional images of structural components could realize defects (e.g., voids or cracks) in the component. In addition, noncontact and subsurface pH/corrosion and strain sensing was also validated. This presentation concludes with examples of how these same methods and technologies could be adapted for human performance and health monitoring.
Dr. Ken Loh is a Professor and Vice Chair of the Department of Structural Engineering at UC San Diego. He is the Director of the Active, Responsive, Multifunctional, and Ordered-materials Research (ARMOR) Lab. He also serves as the Associate Director for the UC San Diego, Jacobs School of Engineering, Center for Extreme Events Research (CEER), while also serves as an affiliate faculty member of the Materials Science & Engineering Program and Center for Wearable Sensors. His research interests are in multifunctional materials, nanocomposites, and smart materials for structural health monitoring. His most notable (and still active) research works include: (1) carbon nanotube-based sensing skins for distributed structural sensing and damage characterization; (2) buried piezoelectric rods for bridge scour monitoring; (3) noncontact tomographic imaging methods for damage and defect characterization; and (4) nano-engineered and self-sensing cementitious composites. Dr. Loh received his B.S. in Civil Engineering from Johns Hopkins University in 2004. His graduate studies were at the University of Michigan, where he completed two M.S. in Structural Engineering (2005) and Materials Science & Engineering (2008), as well as a Ph.D. in Structural Engineering in 2008. He started his Assistant Professor career in January 2009 in the Department of Civil & Environmental Engineering at UC Davis, before moving to UC San Diego in January 2016.