In this study, we investigated a method for the non-destructive detection of cracks based on an ultrasonic transit timing method. This method is considered to be an effective means for crack monitoring over an extensive coverage area. Aluminum specimens were prepared with a range of crack sizes and subjected to a tone burst wave to investigate the relationship between crack depth and the transi...

The interpretation of da ta from nondestructive evaluation (NDE) techniques is a tedious and time-consuming manual process that is subject to such random variables as sc an quality, and inspector expertise and fatigue. The authors are researching methods to automatically recognize defects in ultrasonic images of aircraft structures. A typical wing skin image with an annotated defect is shown in...

Leaky-Rayleigh waves have been studied extensively at liquid-solid interface in the last 30 years [1-4]. Both leaky-Rayleigh and leaky-Lamb waves have found many application in Nondestructive Evaluation, e.g. surface defect characterization, etc [5,6]. Because of the difficulties associated with ultrasonic wave generation and detection in air in the megaHerz region air coupled non destructive e...

All surfaces and interfaces between dissimilar materials are rough. The extent to which this roughness affects the reflection of elastic waves has been the subject of study for many decades. A recent book by Ogilvy [1] provides a comprehensive review and summary of this subject. The problem is of particular interest in ultrasonic nondestructive evaluation. For example, it has been shown that fo...

Usually ultrasonic techniques tend to evaluate the closed cracks as smaller than the actual size. In this paper, we describe two strategic techniques for accurately evaluating the closed cracks by means of ultrasound. First, we show the advanced technique utilizing the thermal stress induced by cooling a cracked part. It is shown that a small amount of temperature decrease is effective to open ...

Polymer Bonded Explosives (PBX) are well-known explosives for the weapons, especially for the parts of some important weapon. Generally, they first are modelled in cylinder. One of the most important issues in PBX cylinder properties is the detection of its flaw. Each PBX cylinder may have flaws that influence the security, machine-performance and other important physical or chemical performanc...

Ultrasonic measurements of materials are usually obtained from an electrical conversion of an acoustic signal by a transducer. ln this paper, a conventional (phase sensitive) transducer and a new phase insensitive acoustoelectric converter called an AEC are contrasted. In particular, the AEC is shown to exhibit superior characteristics for many typical experi~nts and appears to have many applic...