A Preliminary Round‐Robin Study of Ultrasonic Phased‐Array Transducer Variability

Phased‐array transducers are playing an increasing role in ultrasonic inspections, and methods for comparing the performances of such transducers are needed. In this paper we discuss a preliminary set of performance tests designed to document the operational capabilities of two types of 10‐MHz phased array transducers. “Type‐I” transducers have 15 elements, including a focused, circular, removable center element (RCE) and 14 outer planar, concentric annular rings. “Type‐II” transducers have 110 elements with a compound spherical surface to promote focusing. A series of tests were performed to measure such characteristics as peak response amplitude from a FBH target, center frequency, bandwidth, and beam‐diameter at the focus. These could be measured in essentially the same way for both the RCE transducer and the Type‐I or Type‐II phased elements driven in concert to form a focused beam. Additional tests were specific to either the RCE or the phased array. For phased‐arrays, these included an examination o...