Cracks in concrete cannot be prevented but the size of cracks can controlled. that occur are strongly influenced by nature and characteristics constituent materials, especially cement water. fresh hard phases. grouped into two, non-structural structural cracks. There several types such as crazing, map cracking, plastic cracking due to shrinkage, settlement, drying temperature changes, chemical ...

When cracks form in a thin contracting layer, they sequentially break the layer into smaller and smaller pieces. A rectilinear crack pattern encodes information about the order of crack formation, as later cracks tend to intersect with earlier cracks at right angles. In a hexagonal pattern, in contrast, the angles between all cracks at a vertex are near 120 degrees. Hexagonal crack patterns are...

The mesoscopic concept is a way to deal with complex materials with an internal structure within continuum mechanics. It consists of extending the domain of the balance equations by mesoscopic variables and of introducing a local distribution function of these variables as a statistical element. In our case microcracks are modelled as penny shaped and completely characterized by their diameter ...

Cracks emerge due to various forces or stresses. After discerning the cracks preferably by non-destructive techniques, there is a need to find the reason for their appearance. With very exact analysis of the shape, form and dimension of the cracks and their location on the structural elements, we can deduce the reason for their formation.  This makes, proposing a suitable solution for preventin...

Cracks emerge due to various forces or stresses. After discerning the cracks preferably by non-destructive techniques, there is a need to find the reason for their appearance. With very exact analysis of the shape, form and dimension of the cracks and their location on the structural elements, we can deduce the reason for their formation. This makes, proposing a suitable solution for preventing...

The role of grain bridging in affecting the initial rising portion of the R-curve and the transient, non-steady-state behavior of short cracks during (cyclic) fatigue-crack propagation has been quantitatively examined in a 99.5% pure alumina. Fatigue-crack growth properties for both long and short ( af < 2 mm) cracks emanating from machined notches (root radius, 15–150 m) were investigated, whe...

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...

Non-destructive detection and evaluation of invisible cracks in metal structures is an important matter in several critical environments including ground transportation, air transportation and power plants. In this paper, a high-Q near-field Microwave probe is designed and fabricated using defected ground structures for surface and subsurface crack detection in metal structures. For this purpos...

The fatigue growth of multiple cracks, of arbitrary lengths, emanating from a row of fastener holes in a bonded, riveted, lap joint in a pressurized aircraft fuselage is studied. The effects of residual stresses due to a rivet misfit, and of plastic deformation near the hole, are included. A Schwartz Neumann alternating method which uses the analytical solution for a row of multiple colinear cr...

The relationship between the crack nucleation and stress-induced martensitic transformation in the retained massive austenites (RM’s) of austempered ductile irons (ADIs) was examined in detail by carrying out tensile tests and scanning electron microscope (SEM) observations for an ADI material. The SEM observations revealed that cracks were not nucleated in the peripheral regions of graphite no...