The fatigue micro crack initiation and propagation tests of a TiAl alloy with 8% Nb content were carried out by using scanning electron microscopy in situ technology at room temperature and at 750 C. These results indicated that the fatigue micro crack initiation was mainly caused by the stress concentration at room temperature, but at an elevated temperature (750 C) the multi-cracks were cau...

From an engineering point of view, prediction of fatigue crack nucleation in automotive rubber parts is an essential prerequisite for the design of new components. We have derived a new predictor for fatigue crack nucleation in rubber. It is motivated by microscopic mechanisms induced by fatigue and developed in the framework of Configurational Mechanics. As the occurrence of macroscopic fatigu...

An experimental study was conducted to examine the room-temperature fatigue crack-growth characteristics of shape-memory NiTi matrix composites reinforced with 10 and 20 vol.% of TiC particles. Microstructural characterization of these hot-isostatically-pressed materials shows that the TiC particles do not react with the NiTi matrix and that they lack any texture. Overall fatigue crack-growth c...

Artificial aging degrades the fatigue crack growth (FCG) resistance of heat treatable aluminum alloys, particularly in the near-threshold regime. Consequently, applications of aluminum alloys in tensiondominated structures that require fatigue damage tolerance are limited to the naturally aged T3 temper. Degraded FCG resistance compromises the benefit from higher strength by artificial aging. W...

In the present investigation, fatigue crack growth tests under mixed-mode (I and II) overload have been conducted on HSLA steel and subsequently genetic programming has been applied to predict post overload fatigue life. It is observed that the proposed model predicts fatigue life of HSLA steel with reasonable accuracy.

Improving the design and performance of medical stents for implantation in the human body is of current interest. This paper describes a study of fatigue-crack propagation behavior in the superelastic alloy Nitinol. Specifically, the objective of this work was to study the effect of environment on cyclic crack-growth resistance in an approximately 50Ni-50Ti (atom %) alloy and to provide the nec...

The increasing incidence of military aircraft engine failures that can be traced to high-cycle fatigue (HCF) has prompted a reassessment of the design methodologies for HCF-critical components, such as turbine blades and disks. Because of the high-frequency vibratory loading involved, damage-tolerant design methodologies based on a threshold for no crack growth offer a preferred approach. As im...

The evaluation of energy release rate and centre Crack Opening Displacement (COD) for circumferential Through-Wall Cracked (TWC) pipes is an important issue in the assessment of critical crack length for unstable fracture. The ability to predict crack growth continues to be an important component of research for several structural materials. Crack growth predictions can aid the understanding of...

The effects of alloy production method on microstructure and hence fatigue crack growth rate and fracture mechanism have been examined for a variety of fine-grained/high dispersoid Al-Li-Mg-Zr and Al-Li-Cu-Mg-Zr alloys. Microstructures have been assessed by scanning and transmission electron microcopy, together with electron back scattered diffraction pattern assessment. In these fine-grained/h...

Various stresses add to the railway rails and accumulate fatigue damage due to daily use. Fracture mechanics clarification concerning the growth behavior of cracks is needed, in order to decide the inspection period and the cycle [1], . Though the crack progression and influence of residual stress on fatigue strength has been researched [3] for many years, they are not clear now. The aims of th...