Influence of compressive cyclic loading on crack propagation in AM60B magnesium alloy under random and constant amplitude cyclic loadings

Reconsiderations of fatigue crack growth at negative stress ratios: Finite element analyses

“…Moreover, it is often used for experimental investigations with tension-compression loading (e.g. [7,8] and for numerical investigations of plasticity induced crack closure (e.g. [26,27]).…”

“…Furthermore, many available literature results of experimental investigations with tension-compression loading were performed with relatively thin specimen e.g. with t = 2.3mm [2], t = 3mm [7] or t = 4.74mm [8]. For these values of t it can be assumed that the behavior at the surface of the specimens (plane stress condition) has a dominant influence on the crack growth rate.…”

“…[1][2][3]) and variable amplitude loading (e.g. [4][5][6][7][8]). However, the number of studies about the basic effects of compressive loads is limited and therefore important aspects are not clarified by the current body of research.…”

“…As mentioned above Zhang et al [10,23] investigated the influence of the crack length on the compressive crack tip loading. Mehrzadi and Taheri [7] investigated the stress distribution in front of the crack tip. They concluded that the compressive stress distribution in front of the crack tip must be relevant for the crack growth rate.…”

“…However, in none of these works [7,10,24] crack advance was considered. The present study focusses on three important aspects of FCG at negative stress ratios, namely (i) the verification of σ tip as an appropriate parameter to define the minimum crack tip loading at R < 0 (ii) the identification of the deformation mechanism and their interrelation to the crack tip loading (iii) some basic aspects of load interaction effects.…”