This study presents a new procedure based on Artificial Neural Network (ANN) for identification of double cracks in Functionally Graded Beams (FGBs). A cantilever beam is modeled using Finite Element Method (FEM) for analyzing a double-cracked FGB and evaluation of its first four natural frequencies for different cracks depths and locations. The obtained FEM results are verified against availab...

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...

Tidal cracks are linear features that appear parallel to coastlines in fast ice regions due to the actions of periodic and non-periodic sea level oscillations. They can influence energy and heat exchange between the ocean, ice, and atmosphere, as well as human activities. In this paper, the LINE module of Geomatics 2015 software was used to automatically extract tidal cracks in fast ice regions...

Propagation of monochromatic elastic waves across cracks is investigated in 1D, both theoretically and numerically. Cracks are modeled by nonlinear jump conditions. The mean dilatation of a single crack and the generation of harmonics are estimated by a perturbation analysis, and computed by the harmonic balance method. With a periodic and finite network of cracks, direct numerical simulations ...

Volumetric images of small mortar cylinders under load are acquired by X-ray microtomography. The images are binarized at different threshold values, and the connected components are extracted at each threshold with a 3D spaceand time-efficient program. Statistics of volume and surface area of separated concrete segments and cracks are collected and analyzed. Under increasing load, the concrete...

Vertical cracks are among the most problematic types of defects from the thermal nondestructive testing (NDT) point of view. Nowadays, the fast thermal inspection techniques most commonly utilize infrared cameras and pulsed heating provided by flash lamps. The flash lamps illuminate the whole surface of a sample, and the resulting heat flow is mostly perpendicular to the surface. Therefore, the...

We develop two closely-related fast and simple numerical algorithms to address the inverse problem of identifying a collection of disjoint linear cracks in a twodimensional homogeneous electrical conductor from exterior boundary voltage/current measurements. We allow the possibility that the cracks are partially conductive. Our approach also allows us to determine the actual number of cracks pr...

015504-1 The shear wave speed is an upper limit for the speed of cracks loaded in tension in linear elastic solids. We have discovered that in a nonlinear material, cracks in tension (mode I) exceed this sound speed and travel in an intersonic range between shear and longitudinal wave speeds. The experiments are conducted in highly stretched sheets of rubber; intersonic cracks can be produced s...

We generalize lattice models of brittle fracture to arbitrary nonlinear force laws and study the existence of arrested semi-infinite cracks. Unlike what is seen in the discontinuous case studied to date, the range in driving displacement for which these arrested cracks exist is very small. Also, our results indicate that small changes in the vicinity of the crack tip can have an extremely large...