Mechanical and Aerospace Engineering
Department Seminar Series
4/20 (Monday) Noon – 1:00 pm RH317
Structural Health Monitoring and Nondestructive Testing in Civil Engineering
Civil, Architectural and Environmental Engineering
Recent research on the use of dynamic approaches for the Non-Destructive Evaluation (NDE) and the Structural Health Monitoring (SHM) of structural components that are common in civil infrastructures is presented.
Among other techniques, ultrasonic guided waves (UGWs) are discussed. UGWs offer large monitoring ranges compared to ultrasounds maintaining good sensitivity from a single probe position with the complete coverage of the waveguide cross-section. Compared to global vibrations, often employed for SHM, guided waves provide increased sensitivity to smaller defects due to the larger frequencies. However, these advantages can be fully exploited only once the complexities of guided wave propagation are unveiled for the given test structure. UGWs are useful at the component level but global approaches (for instance based on global vibration) are needed when the understanding of larger systems is necessary.
The seminar will focus on numerical predictions of dynamic vibration in complex structural components and results of several experimental and field tests performed by the author. Numerical simulations are based on a Semi-Analytical Finite Element (SAFE) method. This approach can also be coupled with Boundary Elements to account for leakage induced attenuation. The numerical approach is able to model wave properties (such as speed and attenuation) in waveguides of arbitrary cross-section, with a large number of layers and accounting for viscoelastic material damping. These solutions are essential in the interpretation of experimental results and are necessary to develop a Structural Health Monitoring strategy based on Guided Waves.
Some relevant applications are presented such as defect detection in railroad tracks, stress monitoring and damage detection in concrete bridge structural components and impact location/identification in composite structural components. Finally, the talk includes also additional NDE and SHM activities currently conducted by the presenter.
Ivan Bartoli received his Degree in Civil Engineering from the University of Bologna, Italy in 2001, where he worked until 2002 as a researcher. In 2003 he joined the Structural Engineering Department of the University of California, San Diego where he earned an M.S. degree in 2005, a Ph.D. degree in 2007 and he worked as Assistant Project Scientist until Sept 2010. Dr. Bartoli has joined the Department of Civil Architectural and Environmental Engineering at Drexel University in 2010. His areas of expertise include dynamics and vibrations of structural components, and ultrasonic guided waves for Non-Destructive Evaluation and Structural Health Monitoring of civil structures. He has developed techniques for dynamic testing of civil and aerospace structures, and analytical/numerical modeling of ultrasonic guided wave propagation.