In this paper we review the state of the art in an emerging new technology: embedded ultrasonic non-destructive evaluation (NDE). Embedded ultrasonic NDE permits active structural health monitoring, i.e. the on-demand interrogation of the structure to determine its current state of structural health. The enabling element of embedded ultrasonic NDE is the piezoelectric wafer active sensor (PWAS)...

Ultrasonic testing and evaluation procedures typically depend on reference reflectors to establish detection sensitivity and evaluation of test data. Rules and regulations governing safety-related components emphasize on test procedures that assure the detectability of discontinuities at all over the component and oriented in any arbitrary direction. Existing procedures, however, do not provide...

ABSTRACT. A full scale wing panel fatigue test was undertaken in 2007 as a part of the DARPA Structural Integrity Prognosis System (SIPS) program. Both local and global ultrasonic sensors were installed on the wing panel and data were recorded periodically over a period of about seven weeks. The local ultrasonic sensors interrogated a small number of selected fastener holes, and the global ultr...

This paper presents the development of delay pulse circuit with 1ns resolution for both driving ultrasonic array transducers and digital receive beamforming for ultrasonic phased array system. The circuit which can supply pulses with a 1ns time resolution employs the phase shifting with phase locked loop (PLL). In this way, 6 phase clocks with 1ns phase difference are generated, which are used ...

This paper presents an analytical method to predict the acoustic pressure field produced in the air by concentric, annular sources. The sources correspond to a multi-element, ultrasonic, air-coupled array, which should be used further for non-destructive testing (NDT) purposes. After validation of the model based on the comparison of the predicted acoustic pressure with experimental results, a ...

The use of plastic as a pipe material for the transport of gas and water has increased over the last few years, attributed to the significant advantages of this material such as corrosion resistance, strengthto-weight ratio, lightness, flexibility and cost. Consequently, these pipes have a long predicted service life. One of the pipes’ joining processes is electrofusion welding. As for all kind...

The study of the cross-talk and its effects in the performance of a matrix array of piezoelectric elements is an important issue. This corresponds to the study of the cross mode of vibration of each one of the piezoelectric elements that form the ultrasonic array. The aim is to detect and measure the cross-talk that is generated for the cross mode of vibration. In order to accomplish this task,...

In this paper a non-destructive method for inspecting jet-engine turbine blades for root cracking is developed. This method utilises 2D ultrasonic arrays to enable the detection and characterisation of sub-surface cracks in three-dimensions. The majority of modern turbine blades are manufactured from single crystals of nickel based superalloys which exhibit high elastic anisotropy. This complic...

*Corr. Author’s Address: University of Coimbra’s Mechanical Engineering Research Center, Department of Electrical Engineering and Computers, University of Coimbra, 3030-290 Coimbra, Portugal, [email protected] 135 FPGA-Based Control System of an Ultrasonic Phased Array Santos, M.J.S.F. Santos, J.B. Mário João Simões Ferreira dos Santos* Jaime Batista dos Santos University of Coimbra’s Mechanica...

For ultrasound in the hundred kilohertz regime concrete is a very inhomogeneous propagation material. The prescribed definition of aggregates with regard to the respective percentage, the size distribution and the material composition together with the percentage of air inclusions can be realized as a computer model to serve as a platform for elastic wave propagation simulations. As a simulatio...