title: Temperature effects in ultrasonic Lamb wave structural health monitoring systems.
abstract: There is a need to better understand the effect of temperature changes on the response of ultrasonic guided-wave pitch-catch systems used for structural health monitoring. A model is proposed to account for all relevant temperature-dependent parameters of a pitch-catch system on an isotropic plate, including the actuator-plate and plate-sensor interactions through shear-lag behavior, the piezoelectric and dielectric permittivity properties of the transducers, and the Lamb wave dispersion properties of the substrate plate. The model is used to predict the S(0) and A(0) response spectra in aluminum plates for the temperature range of -40-+60 degrees C, which accounts for normal aircraft operations. The transducers examined are monolithic PZT-5A [PZT denotes Pb(Zr-Ti)O3] patches and flexible macrofiber composite type P1 patches. The study shows substantial changes in Lamb wave amplitude response caused solely by temperature excursions. It is also shown that, for the transducers considered, the response amplitude changes follow two opposite trends below and above ambient temperature (20 degrees C), respectively. These results can provide a basis for the compensation of temperature effects in guided-wave damage detection systems.
authors.affiliation: NDE and Structural Health Monitoring Laboratory, Department of Structural Engineering, University of California, 9500 Gilman Drive, M.C. 0085, La Jolla, San Diego, California 92093-0085, USA. flanza@ucsd.edu
authors.forename: Francesco
authors.initials: F
authors.lastname: Lanza di Scalea
authors.forename: Salvatore
authors.initials: S
authors.lastname: Salamone
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation*; D006304:Health Status; D006801:Humans; D008962:Models, Theoretical; D013696:Temperature; D014465:Ultrasonics