An assessment of the effects of microstructure on room temperature fatigue threshold and crack propagation behaviour has been carried out on microstructural variants of U720Li, i.e. as-received U720Li, U720Li-LG (large grain variant) and U720Li-LP (large intragranular coherent γ′ variant). Fatigue tests were carried out at room temperature using a 20Hz sinusoidal cycling waveform at an Rratio=0...

The fundamentals associated with acoustic emission monitoring of fatigue crack initiation and propagation of Ti-6AI-4V were studied. Acoustic emission can detect and locate incipient fatigue crack extensions of approximately 1 0 gm. The technique therefore can serve as a sensitive warning to material failure. There are three distinct stages during which acoustic emission is generated. These sta...

The elements of the concrete structure are most frequently affected by cracking. Crack detection is essential to ensure safety and performance during its service life. Cracks do not have a regular shape, in order to achieve the exact dimensions of the crack; the general mathematical formulae are by no means applicable. The authors have proposed a new method which aims to measure the crack dimen...

The initial stage of fretting fatigue crack growth is significantly influenced by tangential force induced by fretting action along the contact surface where a mixed-mode crack growth is involved. Fretting crack behavior of aluminum alloy 2024 was studied, taking into account the problem of contact asperities. Finite element was used for the determination of the stress field near the contact su...

Stable ductile crack growth in 3 mm thick AISI 304 stainless steel specimens has been investigated experimentally and numerically. Multi-linear Isotropic Hardening method coupled with the Von-Mises yield criterion was adopted for modeling elasto-plastic behavior of the material. Mode-I CT fracture specimens have been tested to generate experimental load-displacement-crack growth data during sta...

The aim of this study is to know the meaning, for the family, of the daily contact with a member user of crack. This is a qualitative, descriptive and phenomenological study, whose empirical data collection was based on phenomenological interviews with two families of crack dependents in a Psychosocial Care Center on Alcohol and other Drugs. The analysis and categorization of experiential descr...

in this paper, in order to analyze the transverse vibration of a uniform bernoulli-euler beam containing one single edge crack, a new continuous model is proposed for the cracked section. to this end, by using the fracture mechanics, the crack is modeled as a continuous disturbance in the stress and strain fields. by applying the hamilton’s principle, the equation of motion and the correspondin...

The present paper is concerned with the effective numerical implementation of the two-dimensional dual boundary element method, for linear elastic crack problems. The dual equations of the method are the displacement and the traction boundary integral equations. When the displacement equation is applied on one of the crack surfaces and the traction equation on the other, general mixed-mode crac...

We investigate theoretically statistics and thermally activated dynamics of crack nucleation and propagation in a two-dimensional heterogeneous material containing quenched randomly distributed defects. We consider a crack tip dynamics accounting for dissipation, thermal noise and the random forces arising from the elastic interactions of the crack opening with the defects. The equation of moti...

New generation jet engines are subject to severe reduced fuel consumption requirements. This usually leads to thin components in which damage issues such as thermomechanical fatigue, creep and crack propagation can be quite important. The combination of stresses due to centrifugal loads and thermal stresses usually leads to mixed-mode loading. Consequently, a suitable crack propagation tool mus...