Fatigue delamination growth rates and thresholds of composite laminates under mixed mode loading

Methods for the prediction of fatigue delamination growth in composites and adhesive bonds – A critical review

“…This approach was also adopted by Shivakumar, Chen, and co-workers [116,117] and Zhang, Peng, and co-workers [118,119]. The resistance to delamination growth is caused by a number of different mechanisms, such as: "matrix cracking and fiber bridging in the case of unidirectional composites; tow cracking, multiple delaminations, tow bridging, and tow breaking in the case of woven/braided fiber composites [116]."…”

“…The disadvantage of this method is that the damage state of the fatigue specimen is destroyed, so further fatigue testing is no longer meaningful. Thus in a second paper [119] a new approach was proposed. In this method G R is also determined from the R-curve.…”

Intralaminar fatigue crack growth properties of conventional and interlayer toughened CFRP laminate under mode I loading

“…Here, one of the common problems in these studies is the increase in crack growth resistance owing to the fibre bridging effect for fatigue crack growth [37]. Since the crack growth behaviour depends on the crack length, it is difficult to obtain a minimum threshold value for fatigue crack growth using conventional load-shedding tests [29,38,39]. This effect is significant particularly under mode I loading [39][40][41].…”

Mixed-mode fatigue and fracture behavior of adhesively-bonded composite joints

“…For example, in O'Brien (1990), it is shown that, in general, the slope of the FCG curves decreases with increasing matrix toughness for any mode-mixity. However, this assumption is contradicted by the results presented by others (Mall et al, 1989;Zhang et al, 2012), who attribute changes of the FCG behavior to other factors such as fiber bridging and multiple cracking.…”

“…These methods can be classified into two main approaches: those based on the phenomenological representation of the material/structural behavior (mainly showing that the slope of the FCG curves decreases as the G II /G tot increases. On the other hand, it is reported by Mall et al (1989) that the slope of the FCG curves initially decreases as the G II /G tot increases but increases again in the region close to pure Mode II, whereas Zhang et al (2012) reported an initial increase and eventual decrease as G II /G tot increases.…”