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This paper investigates the consistency in phased array element performance by extracting information from the Full Matrix Capture (FMC) of a reflection from a planar interface. The purpose of this work is to generate a robust methodology for tracking phased array performance over time, therefore, ensuring the reliability of measured data. To achieve this, a calibration method has been developed that...
The resonance frequency of an active element in a piezoelectric ultrasonic transducer is dependent on its length scale. Inspired by natural occurring auditory systems, incorporation of elements with varying length scales in the piezoelectric transducer design can result in a wider operational bandwidth. In this paper, a mathematical algorithm was developed first to define the feature of a fractal...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled devices. This paper presents a methodology for improving the bandwidth of an air-coupled micro-machined ultrasonic transducer (MUT) without sensitivity...
Wider operational bandwidth is an important requirement of an ultrasound transducer across many applications. It has been reported mathematically that by having elements with varying length scales in the piezoelectric transducer design, the device may possess a wider operational bandwidth or a higher sensitivity compared to a conventional device. In this paper, the potential for extending the operational...
An implementation of the Causal Differential Method (CDM) for modelling the effective properties of a random two-phase composite material is presented. Such materials are commonly used as ultrasonic transducer matching layers or backing layers. The method is extended to incorporate a particle size distribution in the inclusion phase. Numerical issues regarding the implementation and convergence of...
Conventionally, in order to acoustically match thickness mode piezoelectric transducers to a low acoustic impedance load medium, multiple quarter wavelength (QW) matching layers are employed at the front face of the device. Typically a number of layers, 2-4 in number, are employed resulting in discrete impedance steps within the acoustic matching scheme. This can result in impedance matching with...
The cost of implementing real-time monitoring and control of industrial processes is a significant barrier for many companies. Acoustic techniques provide complementary information to optical spectroscopic sensors and have a number of advantages: they are relatively inexpensive, can be applied non-invasively, are non-destructive, multi-point measurements are possible, opaque samples can be analysed...
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