title: Application of conformal map theory for design of 2-D ultrasonic array structure for NDT imaging application: a feasibility study.
abstract: Two-dimensional ultrasonic phased arrays are becoming increasingly popular in nondestructive evaluation (NDE). Sparse array element configurations are required to fully exploit the potential benefits of 2-D phased arrays. This paper applies the conformal mapping technique as a means of designing sparse 2-D array layouts for NDE applications. Modeling using both Huygens' field prediction theory and 2-D fast Fourier transformation is employed to study the resulting new structure. A conformal power map was used that, for fixed beam width, was shown in simulations to have a greater contrast than rectangular or random arrays. A prototype aperiodic 2-D array configuration for direct contact operation in steel, with operational frequency ~3 MHz, was designed using the array design principle described in this paper. Experimental results demonstrate a working sparse-array transducer capable of performing volumetric imaging.
authors.forename: Sivaram N
authors.initials: SN
authors.lastname: Ramadas
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Jackson
authors.forename: Jerzy
authors.initials: J
authors.lastname: Dziewierz
authors.forename: Richard
authors.initials: R
authors.lastname: O'Leary
authors.forename: Anthony
authors.initials: A
authors.lastname: Gachagan
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D019220:High-Energy Shock Waves; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods; D008962:Models, Theoretical; D012542:Scattering, Radiation; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*