The creep-fatigue interaction has been studied and innovative mathematical models are proposed to predict the operating life of aircraft components, specifically gas turbine blades subject to creep-fatigue at high temperatures. The historical evolution of the creep-fatigue lifetime prediction is given in order to place the present study in the context. A literature review of the life estimation...

Static and completely reversed cyclic creep acceleration characteristics of Al – 22 wt% Ag alloy were investigated using a modified tensile testing machine. Different amplitudes of reversed cyclic stress (σrev) ranging from 7.2 to 10.2 MPa at different working temperatures ranging from 353 K to 413 K were performed. To get a relation between aging temperature and threshold stress (σth) for cycl...

Reactive infiltration processing was used to fabricate bulk NiAl and fiber-reinforced NiAl composites. Homogenous, pore-free materials were obtained by chemical reaction between nickel and aluminum after complete infiltration with liquid aluminum of preforms of nickel wires (containing tungsten wires for the composites) with low surface-to-volume ratio, high permeability, and regular infiltrati...

steady state creep of the alloy was in a thermodynamical steady state, (2) which configuration of the dislocation network was contributing to the creep strength, and (3) which change in the dislocation network was the cause of the creep recovery. Specimens were furnace-cooled under stress and then observed by transmission electron microscopy. The creep stress was reduced during the test and the...

AIM The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue. METHODS Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To chara...

Physiological responses to weaning procedures were studied in 21 foals assigned to one of five treatments: (1) abrupt, total separation of mare and foal, no preweaning creep feed (TSNC); abrupt, total separation with preweaning creep feed (TSC); partial separation of mare and foal allowing fenceline contact, no preweaning creep feed (PSNC); (4) partial separation with creep feed (PSC); and (5) ...

Creep groan is the undesirable vibration observed in brake pad and disc as brakes are applied during low-speed driving. The presence of friction leads to nonlinear behavior even simple models this phenomenon. This paper uses tools from bifurcation theory investigate creep a 3-degrees-of-freedom mathematical model. Three areas operational interest identified, replicating results previous studies...

The compressive creep and the recovery of commercially available composites, 2 kinds for posterior and 2 kinds for anterior use, in water were examined. In posterior composites, creep strain after 500h at a stress level of 8.3 kgf/mm2 was significantly small (within 1%). The results of the compressive creep test showed that posterior composites would be resistant to occlusal stress. Creep strai...

Mechanical strain or stretch of collagen has been shown to be protective of fibrils against both thermal and enzymatic degradation. The details of this mechanochemical relationship could change our understanding of load-bearing tissue formation, growth, maintenance, and disease in vertebrate animals. However, extracting a quantitative relationship between strain and the rate of enzymatic degrad...

It is very important to design a safe factor or estimating the remain lifetime for electric power plant components of steam pipes which mostly manufacture by high chromium steels and work at high temperature and low stress level. The author will develop the mechanisms based on creep damage constitutive equations for high chromium steel under lows stress in initial stage: (1) Creep cavities most...