-This paper presents an overview of the finite element alternating technique for the analysis of interacting cracks. To illustrate the ease and accuracy of this method the technique is used to analyse several problems associated with both widespread fatigue and multi-site damage, a problem which is attracting worldwide attention. Whilst this paper presents an overview of the technique for both ...

Abstract: Cracks in solids can be detected by ultrasound if they are open. However, their detection is not easy when they are closed with a closure stress, and it is a fundamental problem in ultrasonic testing. Subharmonics with half the input frequency is potentially useful in the detection and evaluation of such cracks. We developed analytical and numerical theories accounting for the crack p...

In some applications such as quality control of metal components or inspection of large metal structures, inspection systems with rapid scanning capability are required. Of particular interest are systems capable of real-time detection and sizing of surface breaking cracks in metals. Since such systems have to perform the data processing in the course of scanning, they should be based on NDE te...

Vibrothermography, also known as Sonic IR and thermosonics, is a method for finding cracks through thermal imaging of vibration-induced crack heating. Due to large experimental variability and equipment which has, up to now, yielded mostly qualitative results, little data has been available to help quantify the vibrothermographic effect. This paper quantitatively evaluates the relationship betw...

In the context of fine structure extraction, lots of methods have been introduced, and, particularly in pavement crack detection. We can distinguish approaches based on a threshold, employing mathematical morphology tools or neuron networks and, more recently, techniques with transformations, like wavelet decomposition. The goal of this paper is to introduce a 2D matched filter in order to defi...

Considerable interest has existed in the literature for a long time in support of real-time crack detection NonDestructive Techniques (NDT) in a variety of applications. Various authors [1, 15, 16, and 17] have suggested different approaches in finding a solution to this problem. In this paper we suggest a Soft Computing approach using Fuzzy Logic as an effective method to take up this problem....

The objective of this study was the development of the automated system for crack detection on square steel bars used in the automotive industry for axle and shaft construction. The automated system for thermographic crack detection uses brief pulsed eddy currents to heat steel components under inspection. Cracks, if present, will disturb the current flow and so generate changes in the temperat...

Introduction: There are several electromagnetic techniques that can be used for detecting surface-breaking cracks in metals, including potential drop, AC field measurement and eddy current methods. Each method possesses its own advantages and limitations in a specific application. In recent years, the use of microwaves has shown an increasing potential and success as a new technique for non-des...

Bacteria used in self-healing of concrete crack need to be embedded into the concrete in the form of dormant spores. However, quantification of viable spores is still a challengeable task due to the lack of rapid, efficient and accurate methods. Considering that viable spores have a higher refractive index than vegetative cells and the refractivity issubject to decrease during the germination p...