In this paper an analytical crack propagation scenario is proposed which assumes that a crack propagates in the tooth root in both the crack depth direction and the tooth width direction, and which is more reasonable and realistic for non-uniform load distribution cases than the other presented scenarios. An analytical approach is used for quantifying the loss of time-varying gear mesh stiffnes...

The fatigue behaviour of single lap bonded joints under fatigue loading was already investigated and a suitable life prediction model was presented and validated [1-2]. The model is based on the actual damage evolution under fatigue load: a crack initiation followed by its propagation up to a critical length [2, 3]. In the present paper the evolution of fatigue damage in single lap joints is ex...

The objective of this paper is to present a procedure based on moving (or shifting) isoparametric elements for the analysis of dynamic crack propagation. The fracture parameters, such as the stress intensity factors or energy release rates for dynamically propagating cracks, are evaluated by far-field path-independent integrals that were recently derived by the authors. The combined use of the ...

The fatigue micro crack initiation and propagation tests of a TiAl alloy with 8% Nb content were carried out by using scanning electron microscopy in situ technology at room temperature and at 750 C. These results indicated that the fatigue micro crack initiation was mainly caused by the stress concentration at room temperature, but at an elevated temperature (750 C) the multi-cracks were cau...

It is considered that the process of fatigue fracture could be arranged the three classes, i.e., crack initiation, crack propagation and fracture. Of these the second process is important from the following point of view. (1) As has so far been reported in many publications, the importance of crack propagation process in total fatigue life increases in proportion to the increase in the stress c...

in this paper, three-dimensional modeling of the fatigue crack growth profiles was performed in a simple riveted lap joint. simulation results showed that mode i was dominated on the one side of the plates and the crack straightly grew on this side, while the other side of the plates was in a mixed-mode condition and the crack propagation path was not straight on this side. afterward, the fract...

Fatigue crack propagation tests were conducted on the powder metallurgy nickel-base superalloy KM4 at room temperature. Two different heat treatments were investigated, one which produced a relatively coarse grain size around 55 μm, and another which produced a very fine grain size around 6 μm. Tests were conducted at 50 Hz and 1000 Hz in an advanced servohydraulic testing machine at R-ratios b...

The size and the character (low and large angle, special boundaries, tilt and twist boundaries, twins) of the grain boundaries (GBs) in polycrystalline materials influence their strength and their fracture toughness. Recent studies devoted to nanocrystalline (NC) materials have shown a deviation from the Hall-Petch law. Special GBs formed by Σ3 twins in face-centred cubic metals are also known ...