In situ ultrasonic methods for structural health monitoring have the potential to provide early detection of fatigue cracks in aircraft components, specifically cracks initiating from fastener holes. A dual angle beam technique based upon an incident shear wave and a spiral creeping wave propagating around the hole has been shown to be a viable configuration for monitoring of fastener hole crac...

A corn kernel classification procedure was developed in the frequency domain using a two-dimensional Fourier Transform for inspection of stress cracks. Investigations were also conducted to define suitable conditions and optimum image resolution for viewing stress cracks in corn kernels using a computer vision system. A pre-processing procedure included contrast enhancement, edge enhancement, a...

The stress intensity factor solution for embedded circular cracks, semicircular and part-circular surface cracks in plates, quartercircular corner cracks in rods, and semicircular surface cracks at a hole in a plate are evaluated using a finite element alternating method. This method of superposition employs the standard 20-noded solid element solution for the untracked solid, and the complete ...

0013-7944/$ see front matter 2012 Elsevier Ltd http://dx.doi.org/10.1016/j.engfracmech.2012.04.030 ⇑ Corresponding author. Tel.: +1 858 534 5930; fa E-mail addresses: [email protected] (C. Nielsen) The fracture behavior of poly(methyl methacrylate) (PMMA) is studied using double cleavage drilled compression (DCDC) experiments. Increasing sample thickness is found to increase the stresses requir...

Abstract Especially in the automotive sector, high-strength sheet materials are processed manufacturing industry. These steels often show a pronounced sensitivity to edge cracks. Because of this, many crack testing methods for wide variety stress conditions have been developed describe material. Only hole expansion test according ISO 16630 has standardized. However, standardization some gaps pr...

This paper describes a new technique for fabrication of nondestructive inspection (NDI) standards with real cracks. This includes cracks in holes, on curved surfaces, on shot peened surfaces, in and under coatings and at buried surfaces. The method uses permanently mounted MWM-Array eddy current sensors to detect crack initiation and monitor crack growth. These sensors have been used in fatigue...

In the present study, stress analysis and explicit solution of rectangular plate with arbitrarily located circular hole, subjected to linear normal stresses on two opposite edges, has been investigated. Airy function and hoop stresses occurring at the edge of the circular have been computed. In this method 2D dimension elasticity and Airy stress function was used. The present method for explici...

This article has studied the effect of ratio of stiffness and thickness between piezoelectric actuators and host plat has been explored on optimal pattern for placement of piezoelectric work pieces around a hole in thin isotropic plate under static loading to reduce stress concentration. The piezoelectric actuators reduce directly or indirectly the stress concentration by applying positive and ...