In order to investigate the methods to heal fatigue cracks in metals, tubular specimens of 1045 steel with axial and radial fatigue cracks were treated under the eddy current. The optical microscope was employed to examine the change of fatigue cracks of specimens before and after the eddy current treatment. The results show that the fatigue cracks along the axial direction of the specimen coul...

The age-related deterioration in the quality (e.g., strength and fracture resistance) and quantity (e.g., bone-mineral density) of human bone, together with increased life expectancy, is responsible for increasing incidence of bone fracture in the elderly. The present study describes ex vivo fracture experiments to quantitatively assess the effect of aging on the fracture toughness properties o...

In this paper we study the crack initiation in a hyper-elastic body governed by a Gri th's type energy. We prove that, during a load process through a time dependent boundary datum of the type t→ tg(x) and in absence of strong singularities (this is the case of homogeneous isotropic materials) the crack initiation is brutal, i.e., a big crack appears after a positive time ti > 0. On the contrar...

In this paper we study the crack initiation in a hyper-elastic body governed by a Griffith’s type energy. We prove that, during a load process through a time dependent boundary datum of the type t → tg(x) and in absence of strong singularities (this is the case of homogeneous isotropic materials) the crack initiation is brutal, i.e., a big crack appears after a positive time ti > 0. On the cont...

Crack tip deformations and fracture parameters in functionally graded glass-filled epoxy beams are experimentally evaluated under static and dynamic loading conditions. Beams with unidirectional, monotonic elastic gradients and cracks along the gradient are examined. SEN samples with increasing or decreasing Young’s modulus ahead of the crack tip are studied in symmetric four-point bending and ...

This article presents an experimental study on the fatigue behaviour of cracks emanating from cold-expanded holes utilizing thermoelastic stress analysis (TSA) and synchrotron X-ray diffraction (SXRD) techniques with the aim of resolving the long-standing ambiguity in the literature regarding potential relaxation, or modification, of beneficial compressive residual stresses as a result of fatig...

An elastic finite element analysis was conducted to evaluate the stress distribution in the initiation zone of the adhesive rupture during the 3-point bending test. This test is used to measure the adherence between a polyepoxy adhesive and aluminum alloy with different surface treatments. The purpose is to compare, in the high stress concentration areas, the stress fields calculated using fini...

A general methodology for fatigue reliability degradation of railroad wheels is proposed in this paper. Both fatigue crack initiation and crack propagation life are included in the proposed methodology using previously developed multiaxial fatigue models by the same authors. A response surface method in conjunction with design of experiments is used to develop a closed form approximation of the...