Turbo generator shafts are often subjected to cyclic torsion resulting in formation of large longitudinal cracks as well as circumferential cracks. The presence of these cracks could greatly impact the shaft resonance frequencies. In this paper, dynamic response of a shaft with longitudinal and circumferential cracks is investigated through a comprehensive analytical study. The longitudinally c...

This paper presents a simple method based on strain energy density criterion to study the crack initiation angle by finite element method under biaxial loading condition. The crack surface relative displacement method is used to eliminate the calculation of the stress intensity factors which are normally required. The analysis is performed using higher order four node quadrilateral element. The...

Fatigue crack initiation and early short crack propagation behaviour in two microstructural variants of a recently developed Low Solvus, High Refractory (LSHR) disc superalloy at room temperature has been investigated by three-point bending with replication procedure. The results shows that fine gained (FG) LSHR possesses higher fatigue life due to its better crack initiation resistance, limite...

Abstract This work analytically calculates mixed-mode I/II stress intensity factors for an inclined central frictional crack in a Brazilian disc partially compressed with uniform pressure. Wide-range controlling parameters are invoked. The analyzed include the pressure angle, relative length, inclination, and friction coefficient between two surfaces. For discs, there exists critical angle at w...

Compositionally graded glass-filled epoxy sheets with edge cracks initially along the gradient are studied under dynamic loading conditions. Specimens with monotonically varying volume fraction of reinforcement are subjected to mixed-mode loading by eccentric impact relative to the crack plane. The optical method of Coherent Gradient Sensing and high-speed photography are used to map transient ...

A commonly used model for a transversely anisotropic crack rock is that by Hudson (1980, 1981). This model is based on a simplified analysis of a thin circular crack, with displacement and stress conditions specified on the boundary. These papers have a second order correction in addition to the first order term in porosity/crack density. In this paper we compare the results of Hudson with thos...

Crack propagation modeling in quasi-brittle materials such as concrete is essential for improving the reliability and load-bearing capacity assessment. Crack propagation explains many failure characteristics of concrete structures using the fracture mechanics approach. This approach could better explain the softening behavior of concrete structures. A great effort has been made in developing nu...

This paper introduces a novel method for slip angle estimation based on visually observing the traces produced by the wheels of a robot on soft, deformable terrain. The proposed algorithm uses a robust Hough transform enhanced by fuzzy reasoning to estimate the angle of inclination of the wheel trace with respect to the vehicle reference frame. Any deviation of the wheel track from the planned ...

This article studies the retardation effect in plasticity-induced fatigue crack growth rate for a low-medium strength steel, due to appearance of microdeflections path. To this end, finite element method was used model with its kinked tip under several stress intensity factor (SIF) ranges. The results allowed calculation (after small number cycles) propagation multiaxial and uniaxial configurat...