Multiaxial fatigue: a stress based criterion for hard metals

Fatigue Equivalent Stress State Approach Validation in Non-conservative Criteria: a Comparative Study

“…When the fatigue limit is attained, the fatigue strength yields the value one, for a constant amplitude multiaxial fatigue load. The fatigue strength error index ΔI expressed in percentage ΔI (%) is defined by Goncalves et al (2005) as:…”

“…It is common practice to sum the results of predictions in a histogram, (see Papadopoulos et al (1997); Goncalves et al (2005)). This kind of prediction evaluation is sufficiently representative and readily understandable.…”

“…One difficulty is that most of the existing multiaxial fatigue criteria can only provide good predictions for propor-Latin A m erican Journal of Solids and Structures 12 (2015) [2506][2507][2508][2509][2510][2511][2512][2513][2514][2515][2516][2517][2518][2519] tional (in-phase) loading, like reported by Weber et al (2001); Goncalves et al (2005); Papuga (2011). Another difficulty involves their implementation for general complex multiaxial fatigue loading that permits arbitrary stress histories such as the variation of the principal stress directions during the stress cycle history (Lambert et al (2010); Soh et al (2013); Li et al (2015)).…”

“…Crossland and Sines stress invariant based criteria can provide good predictions for proportional and non-proportional loads. However, they are not conservative for general complex multiaxial fatigue loading as shown in the works of Weber et al (2001); Papadopoulos et al (1997); Goncalves et al (2005);Papuga (2011).…”

On the multiaxial fatigue assessment of complex three-dimensional stress concentrators

“…In this context, the orientation of the critical plane is recommended here to be determined through the Shear StressMaximum Variance Method (s-MVM) [17,18]. In more detail, contrary to other existing techniques such as the Longest Chord [19], Longest Projection [20], Minimum Circumscribed Circle [21], and Minimum Circumscribed Ellipse Method [22][23][24][25], the s-MVM postulates that the orientation of the critical plane can be determined by locating those material planes containing the direction experiencing the maximum variance of the resolved shear stress. This approach is seen to be very efficient from a numerical point of view, since, as soon as the variance and co-variance terms characterising the load history under investigation are known, the computational time required to reach convergence is not affected by the length of the stress signal being post-processed [17] -the Reader is referred to Ref.…”