It is commonly proposed that the fatigue strength can be enhanced by increasing the tensile strength, but this conclusion needs to be reconsidered according to our study. Here a recrystallized α-Cu-15at.%Al alloy with moderate grain size of 0.62 μm was fabricated by cold rolling and annealing, and this alloy achieved exceptional high fatigue strength of 280 MPa at 10(7) cycles. This value is mu...

In the short crack regime of the fatigue process, grain boundaries in steels are barriers against crack growth. In this paper, we use: (1) a method involving crack density; and (2) a method of dimensional analysis, to evaluate the effects of grain size and grain-boundary resistance on short crack behaviour and fatigue life. The results show that the fatigue life increases with a decrease in gra...

Step-loading fatigue tests have been conducted on two � -TiAl alloys with differing microstructures following quasi-static indentations intended to simulate assembly-related impact damage to lowpressure turbine blades. Fatigue tests were conducted at 600 �C using computer-controlled servohydrau­ lic loading at a frequency of 20 Hz. Reasonably good agreement was achieved between the fatigue data...

Combined in-phase tension/torsion loading was applied to 8-ply 45° 4 E-glass/epoxy composite shafts under monotonic and fatigue conditions to determine the effects of multi-axial loading on its failure. A damage criterion for multi-axial monotonic loading was proposed considering the contribution of both normal and shear stresses on the plane of failure. The experimental data showed an excellen...

Fatigue damage is an irreversible progression which can be represented by the entropy increase, and it is well known that the second law of thermodynamics can describe an irreversible process. Based on the concept of entropy, the second law of thermodynamics can provide the changing direction of system. In the current study, a new entropy increment model is developed based on the frame work of ...

Objectives: Skeletal-muscular disorders affect the biomechanics of the human body, especially the lower extremity, with a negative effect on the biomechanics of exercise. The main aim of this study was to evaluate the effect of fatigue on the kinematic variables of knee joints during countermovement jumps in female students of physical education with valgus knee deformity.  Methods: Fifte...

Especially for ageing aircraft the development of fatigue cracks at fastener holes due to stress concentration and varying loading conditions constitutes a significant maintenance problem. High frequency guided waves offer a potential compromise between the capabilities of local bulk ultrasonic measurements with proven defect detection sensitivity and the large area coverage of lower frequency ...

Submit Manuscript | http://medcraveonline.com Abbreviations: FFR: Fatigue Failure Rate; FFPN: Fleet of N Fatigue-Prone aircraft; AL: Airline; AC: Aircraft; SL: Safe Life; FS: Fail Safe; DT: Damage Tolerance; MIMAR: Modeling in Industrial Maintenance and Reliability; CDF: Cumulative Distribution Functions; RV: Random Variable; ML: Maximum Likelihood; MCh: Markov chain; CD: Crack Detection; FF: F...