Fatigue crack growth behavior of AZ61 magnesium alloy was investigated in low humidity (55% relative humidity) and 3.5% NaCl spray environments under various stress ratios. Fatigue crack growth rates became higher with increasing load ratio for both environments. However, the results of fatigue crack growth test under 3.5% NaCl spray environment showed lower fatigue crack propagation rate compa...

Seasonal cracking of the soil matrix results in poor estimates of runoff and infiltration by simulation models due to the changing soil storage conditions. In this study, soil surface elevation changes were measured every two weeks and soil crack volume was calculated for a two-year period at the USDA-Agricultural Research Service, Riesel Y-2 watershed in central Texas. Soil anchors were placed...

Serial mechanical sectioning and high resolution X-ray tomography have been used to study the three-dimensional morphology of small fatigue cracks growing in a 12 Cr tempered martensitic steam turbine blade material. A range of surface conditions has been studied, namely polished and shot peened (with varying levels of intensity). In the polished (unpeened) condition, inclusions (alumina and ma...

A technique to estimate the depth of surface-breaking cracks in concrete is presented. The surface wave transmission coefficient across the crack plane is determined and used to estimate the depth. A self-compensating testing scheme is applied to eliminate experimental difficulties. Here the self-compensating testing scheme is introduced, and the approach used to estimate crack depth from the m...

structural health monitoring of cracked structures is one of beloved subject of researchers recently. consider of crack behavior in the water and energy pipeline is important because of environmental problems. in this paper consider of crack parameters in the underwater pipe subjected to mechanical transient load is investigated. for this purpose, three- dimensional parametric model of cracked ...

the new non-conventional cutting process by the use of thermal shock is a convenient procedure for cutting the brittle materials such as glasses and ceramics. this method is based on the application of localized thermal shock to brittle materials by the use of hot air jet, which induces thermal stresses at the tip of an existed pre-crack. due to the thermo-elastic behavior of materials, the pre...

Ultrasonic is one of the most common uses of a non-destructive evaluation method for crack detection and characterization. The effectiveness of the acoustic-ultrasound Structural Health Monitoring (SHM) technique for the determination of the depth of the surface crack was presented. A method for ultrasonic sizing of surface cracks combined with the time domain and frequency spectrum was adopted...

Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the ...

We use computer simulations to study the behavior of atomically sharp and blunted cracks in various f.c.c. metals. The simulations use effective medium potentials which contain many-body interactions. We find that when using potentials representing platinum and gold a sharp crack is stable with respect to the emission of a dislocation from the crack tip, whereas for all other metals studied the...

The study of brittle or fatigue fracture that involves contact along the crack faces is difficult for several reasons. On the one hand, material data pertaining to the growth of cracks in a compressive environment are scant, and, on the other, frictional stresses may be transmitted across the contacting crack faces. The analysis of cracks under these conditions is complicated. Nevertheless, sol...