Crack initiation criteria in fretting fatigue

On crack initiation mechanisms in fretting fatigue. The present study investigated the fretting fatigue crack initiation of dovetail structure based on experimental observation and multiple axial criteria. The complexity of modelling fretting fatigue arises due to the presence of multi axial stress state and wear, hence, it is imperative. The fretting fatigue life was found to be infinite below a certain critical contact width. In this work, the multiaxial fatigue damage parameters, swt proposed by smith et al. First parameter, r 5, which is a multiplication of the maximum surface shear stress and slip amplitude at any point in the contact zone, is considered as a criteria for fretting fatigue damage. In addition, fatigue failure process is constituted by crack initiation and propagation, with the former dominating the fretting fatigue lifetime 2. Fretting fatigue failure is generally categorised in two stages. Chapter 7 combines the predicted fretting fatigue crack initiation and. Very high cycle fretting fatigue damage and crack path. The coefficient of friction at the edge of contact, which characterizes the asymptotic stress field, is considered as the primary controlling parameter in the process.

By using the crack analogue model of rigid flatended contact, crack initiation inf, in fretting fatigue is analyzed. Sorry, we are unable to provide the full text but you may find it at the following locations. These three criteria are implemented in dubourgs fatigue. Initiation and propagation behavior of fretting fatigue cracks t. In another paper, extension of ruiz criteria is proposed. The variation of life with contact size can be explained by a variation in amplitude of microslip. The physical basis of these parameters and their use in design calculations is discussed. By using the crack analogue model of rigid flatended contact, crack initiation in fretting fatigue is analyzed. Crack initiation criteria in fretting fatigue sciencedirect. Crack path prediction under fretting fatiguea theoretical and. These will be referred to as the crack initiation and growth criteria respectively. Before the crack nucleation, the reduction of the reaction force is not obvious. The primary objective of employing cp parameters for fretting fatigue cases is related to analyses of crack nucleation location, crack initiation orientation and number to cycles to crack initiation. To study damage nucleation mechanism, szolwinski and farris 20 developed a quantitative tool by combining stress fields with multiaxial fatigue theory.

Two possible explanations for the size effect must be considered. Also, most important, all of the examined criteria predicted nonconservative estimates of. Numerical modeling of fretting fatigue crack initiation and. Numerical modelling of fretting fatigue crack initiation.

Fretting fatigue crack initiation fretting fatigue crack initiation criteria. The configuration has been analysed using elastic stress analysis and stresses. At the contact pressure of 1045 mpa, both the depth of crack initiation area and the fretting fatigue strength do not vary significantly. Prediction of fretting fatigue crack initiation location. Therefore, the damage parameters are evaluated on these planes. In general the fretting fatigue crack initiation is analysed based on mechanistic approach, micro mechanisms approach, and analytical approach.

Crack initiation criteria in fretting fatigue this paper is. Fretting fatigue crack initiation mechanism in ti6al4v. Enhanced ruiz criterion for the evaluation of crack. Crack initiation in order to predict fretting fatigue crack initiation lifetime, many researchers have dealt with stress or strain at a point, the value of parameter at a point or the stress or parameter at some distance beneath the contact surface critical distance approach or an average value over some surface area or volume. The coefficient of friction at the edge of contact which characterizes the. Prediction of fretting fatigue crack initiation and. Figure 4 shows an analytical model of the turbinegenerator.