The vertical ultrasonic surface displacement generated by a laser-induced, thermoelelastic, rectangular surface strip source is formulated. The main features of this source, ultrasonic rise times comparable to those of the generating light pulse derivatives, and a large amplitude, double-pulsed waveform, are advantageous for ultrasonic spectraland time-domain measurements for nondestructive mat...

The optimization problem of ultrasonic testing instrument is studied in this paper. Using ultrasonic nondestructive testing technology to detect quality of products or parts, because the function of conventional ultrasonic testing instruments is custom-built and defined by manufacturers, it is very difficult to meet ever-changing testing requirements such as testing accuracy, testing efficiency...

Bulk and Rayleigh (or surface wave) velocities of ultrasonic waves in chromium coatings on steel were measured and an experimental correlation was found between the surface velocity and the hardness. Since qualitative coating evaluation is commonly made using hardnesses as a guideline, the possibility is herewith presented of using the so und velocities of surface ultrasonic waves for this purp...

Cross fertilization between the quantitative nondestructive evaluation (QNDE) community and the diagnostic medicine community in the area of ultrasonics represents an attractive but challengin~ goal. High resolution, real-time ultrasonic imaging is routinely available not only in major medical centers but even in modest community hospitals. However, quantitative ultrasonic evaluation based on t...

The influence of corrosion on ultrasonic and electromagnetic nondestructive evaluation results has been simulated for 2-layer aluminum aircraft fuselage. Simulations have been performed with respect to ultrasonic time-of-flight measurements aiming on the detection of corrosion at the backwall of the first aluminum layer. Calculations of the eddy current probe response have been performed, where...

abstract-Signals measured in ultrasonic nondestructive evaluation (NDE) of materials are masked by the characteristics of the measuring instruments, the propagation paths taken by the ultrasonic waves, and noise originating from various sources, including the electrical noise. Due to the band-limited characteristics of ultrasonic transducers, the received echoes are degraded by the transducer i...

The pulse compression technique is successfully and widely used in many fields for improving the signal to noise ratio (SNR); which is especially useful when the environment is noisy and the SNR is poor. Since high frequency ultrasound is strongly attenuated in concrete, only low frequency ultrasound can be used in ultrasonic nondestructive testing (NDT) of concrete. In this study the pulse com...

Ultrasonic phased arrays are an emerging technology in nondestructive evaluation (NDE) applications. A phased array is a multi-element piezo-electric device whose elements are individually excited by electric pulses at programmed delay times [1]. Such a delay scheme allows electronically controlled dynamic beam control. One of the advantages of using phased arrays in NDE applications over conve...

In the early 1980’s, the ultrasonic polar scan (UPS) technique was developed to assess the fiber direction of composites in a nondestructive way. In spite of the recognition by several researchers as being a sophisticated and promising methodology for nondestructive testing (NDT) and materials science, little advance was made during the following 30 years. Recently however, the UPS technique ex...