title: Use of parabolic reflector to amplify in-air signals generated during impact-echo testing.
abstract: The impact-echo method is a commonly used nondestructive testing technique for elastic plates in civil engineering. The impact-echo mode corresponds to the frequency at zero group velocity of S(1) Lamb mode. Recent development of the air-coupled impact-echo (ACIE) method introduces the possibility for rapid scanning of large structures and increases the practicality of in situ measurements. However, sensors used in ACIE are susceptible to ambient noise, which complicates in situ ACIE measurements. This letter presents the results of ACIE measurements taken using a parabolic reflector together with standard measurement microphones to increase the signal to noise ratio for ACIE measurements. The signal gain and effects of sensor location with respect to impact location are discussed.
authors.affiliation: Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, USA. xdai@utexas.edu
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Dai
authors.forename: Jinying
authors.initials: J
authors.lastname: Zhu
authors.forename: Yi-Te
authors.initials: YT
authors.lastname: Tsai
authors.forename: Michael R
authors.initials: MR
authors.lastname: Haberman
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D003252:Construction Materials; D004548:Elasticity; D004738:Engineering / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D008422:Materials Testing; D008962:Models, Theoretical; D009038:Motion; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013997:Time Factors; D014160:Transducers, Pressure