Fatigue crack initiation and early short crack propagation behaviour in two microstructural variants of a recently developed Low Solvus, High Refractory (LSHR) disc superalloy at room temperature has been investigated by three-point bending with replication procedure. The results shows that fine gained (FG) LSHR possesses higher fatigue life due to its better crack initiation resistance, limite...

In 2004, a team comprised of researchers and service providers launched the Safer Crack Use, Outreach, Research and Education (SCORE) project in the Downtown Eastside of Vancouver, British Columbia, Canada. The project was aimed at developing a better understanding of the harms associated with crack cocaine smoking and determining the feasibility of introducing specific harm reduction strategie...

This paper reviews the capabilities of a plasticity-induced crack-closure model to predict fatigue lives of metallic materials using “small-crack theory” for various materials and loading conditions. Crack tip constraint factors, to account for three-dimensional stateof-stress effects, were selected to correlate large-crack growth rate data as a function of the effective-stress-intensity factor...

An understanding of how fatigue cracks grow in bone is of importance as fatigue is thought to be the main cause of clinical stress fractures. This study presents new results on the fatigue-crack growth behavior of small surface cracks (approximately 75-1000 microm in size) in human cortical bone, and compares their growth rates with data from other published studies on the behavior of both surf...

An investigation of asymptotic crack tip singular ®elds and their domain of validity is carried out for mode I cracks in solids characterized by the phenomenological strain gradient plasticity theory proposed by Fleck NA, Hutchinson JW. (Strain gradient plasticity. In: Hutchinson JW, Wu TY, editors. Advances in applied mechanics, vol. 33. New York: Academic Press, 1997. pp. 295±361.) Separable ...

The mean and the life-limiting behavior under fatigue of the nickel-based superalloy, IN100, separated (or converged) as a function of stress level and dwell loading. This behavior was related to the control of the life-limiting behavior by the smallcrack growth regime, producing its much slower response to stress level and dwell-time, relative to the mean-lifetime behavior. The lifetime probab...

The evolution of surface damage in bilayers due to cyclic spherical indentation in the presence of incompressible lubricant is studied using an all-transparent glass/polycarbonate system as amodel formore practical applications such as dental crowns and rolling contact fatigue. In situ observations and post-mortem material sectioning reveal that inner cone cracks evolve sequentially from the co...

The growth of transverse cracks under expanding spherical contact in a model system consisted of soda-lime glass bonded to a polycarbonate substrate is observed in situ from below or from the polished edge of the bilayer. Abrasion or chemical etching is employed on the coating surfaces to control the initial fracture. In the limit case of monoliths, the crack mouth becomes fully engulfed by the...

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Pekka Tukiainen Name of the doctoral dissertation Mode I fracture behaviour of Norway spruce and silver birch in the radial-tangential and tangential-radial crack orientations: Publisher School of Chemical Technology Unit Department of Forest Products Technology Series Aalto University publication series DOCTORAL DISSERTATIONS...

Shielding interaction effects of two parallel edge cracks in finite thickness plates subjected to remote tension load is analyzed using a developed finite element analysis program. In the present study, the crack interaction limit is evaluated based on the fitness of service (FFS) code, and focus is given to the weak crack interaction region as the crack interval exceeds the length of cracks (b...