摘要:

A full theoretical analysis of the optical excitation of Love waves is presented. The explicit formulae relating the frequency spectrum of the Love modes to the space-time modulation of laser radiation are derived. The photoacoustic transformation is assumed to be caused by the inverse piezoeffect in the electric field induced by the spatial separation of laser-generated electrons and holes. It is demonstrated that information on the parameters of the film can be extracted from the measurements of the relative amplitudes of the different order Love modes. As the structure of the Love modes is simpler than that of pseudo-Rayleigh waves, we consider optical monitoring of the Love modes to be a promising method for remote diagnostics of thin coatings when the film or the substrate, or both, are piezoelectrics.

ISSN:1058-9759    

DOI:10.1080/10589759408956412

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

To evaluate the critical size of detectable flaws in ductile cast iron (DCI) for storage casks of spent nuclear fuels using ultrasonic testing (UT), round robin tests have been conducted. One test was to detect artificial defects using the normal and angle beam UT and a second test was to detect natural defects using UT. This paper describes the results of the second test and discussions including the previous test results.

ISSN:1058-9759    

DOI:10.1080/10589759408956413

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Nondestructive evaluation (NDE) is an essential part of structural and material systems, providing information for condition assessment and/or feedback for intelligent controls. An NSF NDE initiative as well as workshops and recent awards/projects are described in this paper.

ISSN:1058-9759    

DOI:10.1080/10589759408956414

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

One of the major challenges in extending the life of ageing aircraft is to develop improved nondestructive inspection techniques for the rapid large-area detection of various types of hidden corrosion in aircraft components. In this paper, a new one-sided ultrasonic technique is proposed to solve the generic problem of detecting hidden corrosion in thin metallic aircraft skins, where the corrosion has originated at the interface between the skin and a second layer in an aircraft component. The technique involves the use of laser-generated ultrasonic Lamb modes whose attenuation in a thin skin is increased by the presence of corrosion. This paper presents a successful demonstration of the technique on a thin-skin elevator component. The potential of the Lamb wave technique for rapid large-area scanning for hidden corrosion is also described.

ISSN:1058-9759    

DOI:10.1080/10589759408956415

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1058-9759    

DOI:10.1080/10589759408956416

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor