SPRAY-ON COMB TRANSDUCERS FOR HEALTH MONITORING OF HIGH-TEMPERATURE STRUCTURES
Open Access
- Author:
- Malarich, Nathan Albert
- Area of Honors:
- Engineering Science
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Bernhard R Tittmann, Thesis Supervisor
Dr. Charles E. Bakis, Thesis Honors Advisor
Clifford Jesse Lissenden III, Faculty Reader - Keywords:
- structural health monitoring
SHM
comb transducer
spray-on
guided waves
nonlinear - Abstract:
- Currently there is great industrial interest in installing permanent diagnostic sensors for structural health monitoring (SHM) of safety-critical parts. The past half-century has seen broad use of ultrasonic transducers for subsurface viewing and defect detection. However, traditional techniques require a water-based couplant between the transducer and interrogated structure. Thus most current sensors cannot interrogate structures near or above 100°C, such as heat-exchanger pipes and valves in an operating nuclear reactor. A network of permanently-attached guided-wave sensors on these structures could assess the structures’ state of damage and wear in order to prevent catastrophic failure. No sensor exists to monitor the health of a large volume of safety-critical structure for which the specific failure site is unpredictable. This thesis details two steps of progress towards fulfilling that need with a novel leave-in-place nonlinear ultrasonic transducer. The work combines the recent research on guided wave health inspection methods with the research on high-temperature spray-on transducers. First, the spray-on transducer is shown to be capable of fabrication and acoustic wave generation on two different structures: small-diameter heat-exchanger tubing, and a large steel mockup structure. Second, two spray-on transducers propagated along 0.2m of tubing the L(0,4) guided wave mode, a useful guided wave mode for the highly defect-sensitive method of nonlinear testing.