In this paper, a two-dimensional computational model is proposed for predicting the initiation position and propagation path of subsurface crack of spur gear tooth flank. In order to simulate the contact of teeth, an equivalent model of two contacting cylinders is used. The problem is assumed to be under linear elastic fracture mechanic conditions and finite element method is used for numerical...

This paper presents a single-domain boundary element method SDBEM for linear elastic fracture mechanics analysis in the 2D anisotropic bimaterial. In this formulation, the displacement integral equation is collocated on the uncracked boundary only, and the traction integral equation is collocated on one side of the crack surface only. The complete fundamental solution Green’s function for aniso...

OBJECTIVES The aim was to evaluate dentinal crack formation after root canal preparation with ProTaper Next system (PTN) with and without a glide path. MATERIALS AND METHODS Forty-five mesial roots of mandibular first molars were selected. Fifteen teeth were left unprepared and served as controls. The experimental groups consist of mesiobuccal and mesiolingual root canals of remaining 30 teet...

Residual compressive stress can improve fretting fatigue strength. In this paper, the effects of residual stress on fretting fatigue of Al 2024-T351 alloy specimens are studied using a numerical approach. The extended finite element method combined with the cyclic cohesive zone model is adopted to model fretting fatigue crack growth behavior. It is shown that residual stress changes the frettin...

A phase-field model based on a modified form of the regularized formulation Griffith’s fracture theory is presented to investigate intergranular and transgranular crack propagations in polycrystalline brittle materials. Grains grain boundaries are incorporated initiation propagation for growth, which elastic anisotropy varies orientation angle, boundary energy related misorientation angle adjac...

Crack is one of the most typical damage types in engineering structures, and therefore is a research focus in the field of structural health monitoring (SHM). The monitoring and evaluation methods for crack-type damage are studied using a Lamb wave-based RAPID algorithm (Reconstruction Algorithm for the Probabilistic Inspection of Damage) in this study, which is based on a correlation analysis....

The structural reliability of many brittle materials such as structural ceramics relies on the occurrence of intergranular, as opposed to transgranular, fracture in order to induce toughening by grain bridging. For a constant grain boundary strength and grain boundary toughness, the current work examines the role of grain strength, grain toughness, and grain angle in promoting intergranular fra...

In this paper we address the issue of a creeping wave by investigating a twodimensional configuration which involves a surface-braking crack in a traction free planar backwall. We assume that this back-wall is irradiated by a shear Gaussian beam which is incident at a critical angle and hits the wall away from the crack edge. We show that the generated wave known in the engineering literature a...

Attached ultrasonic sensors can detect changes caused by crack initiation and growth if the wave path is directed through the area of critical crack formation. Dynamics of cracks opening and closing under load cause nonlinear modulation of received ultrasonic signals, enabling small cracks to be detected by stationary sensors. A methodology is presented based upon the behavior of ultrasonic sig...

Transient mixed-mode elastodynamic crack growth along arbitrary smoothly varying paths is considered. Asymptotically, the crack tip stress field is square root singular with the angular variation of the singular term depending weakly on the instantaneous values of the crack tip speed and on the mode-I and mode-II stress intensity factors. However, for a material particle at a small distance awa...