The fracture of restored teeth is a significant obstacle to lifelong oral health. Recent studies suggest that fatigue cracks originate at flaws introduced during cavity preparation and that fatigue crack growth is a principle cause of restored tooth fractures. In this study, the rate of fatigue crack growth in bovine dentin was estimated under mode I cyclic loading. Double cantilever beam (DCB)...

In this paper, the stress intensity factor (SIF) variations along an arbitrarily developing crack front, the non-planar fatigue-crack growth patterns, and the fatigue life of a round bar with an initially straight-fronted surface crack, are studied by employing the 3D symmetric Galerkin boundary element method-finite element method (SGBEM-FEM) alternating method. Different loading cases, involv...

Fatigue crack growth has been observed recently in ferroelectrics under cyclic electric loading[ Does the crack grow by electric breakdown\ or by the stress _eld near the crack tip< The present paper provides a mechanistic explanation for the electric!_eld!induced fatigue crack growth[ The non!uniform electric _eld near an insulated crack tip might cause domain switching which in turn produces ...

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...

In the short crack regime of the fatigue process, grain boundaries in steels are barriers against crack growth. In this paper, we use: (1) a method involving crack density; and (2) a method of dimensional analysis, to evaluate the effects of grain size and grain-boundary resistance on short crack behaviour and fatigue life. The results show that the fatigue life increases with a decrease in gra...

Fatigue crack growth is examined in P/M 2124 aluminum alloys reinforced with SiC particles (SiCp) and whiskers (SiCw) over a wide spectrum of growth rates from 10 to 10 m per cycle. Effects of aging treatment, orientation of crack growth direction with respect to the rolling direction, mean stress (or stress ratio), and reinforcement volume percent on the fatigue crack growth threshold are inve...

16 This paper presents a novel large-area strain sensing technology for monitoring fatigue cracks in 17 steel bridges. The technology is based on a soft elastomeric capacitor (SEC), which serves as a 18 flexible and large-area strain gauge. Previous experiments have verified the SEC’s capability to 19 monitor low-cycle fatigue cracks experiencing large plastic deformation and large crack openin...

A study has been made of the fatigue-crack propagation properties of a series of laminated Nbreinforced Nb3Al intermetallic-matrix composites with varying microstructural scale but nominally identical reinforcement volume fraction (20 pct Nb). It was found that resistance to fatigue-crack growth improved with increasing metallic layer thickness (in the range 50 to 250 mm) both in the crack-divi...

Interest in extending the high cycle fatigue life of structures has increased in the last decade of the 20th century. Since a long fatigue life depends on keeping cyclic loads near or below the fatigue threshold, understanding near-threshold behavior is now all the more important. This paper reviews the status of the ‘threshold of fatigue’ and to a lesser extent its relation to the ‘fatigue lim...

Fretting fatigue induced by combined localized cyclic contact motion and external bulk fatigue loadings may result in premature and dramatic failure of the contacting components. Depending on fretting and fatigue loading conditions, crack nucleation and possibly crack propagation can be activated. This paper proposes a procedure for estimating these two damage thresholds. The crack nucleation b...