Stress ratio effect on cyclic debonding in adhesively bonded composite joints

Dynamic fractures of adhesively bonded carbon fibre-reinforced polymeric joints

“…For instance, FCGR curves showed similar tendencies when they were plotted as a function of DG; however, when curves were plotted as a function of G max , it was observed that as R decreased, a high crack growth occurred. Similar changes of graphs were also reported in Mall, Ramamurthy, and Rezaizdeh (1987). In Pirondi and Nicoletto (2004), the influence of R and the frequency on the FCGR-curve were analysed, concluding that the effect of the frequency is much lower than that of R; it was explained that such behaviour was due to viscoelastic properties of the adhesive.…”

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

“…Furthermore Mall et al [82], and Rezaizadeh and Mall [37] found that the use of G max produced different curves for different R-ratios, whereas when they used ∆G, the curves collapsed into a single line regardless of R-ratio. The observed disappearance of the R-ratio effect in this case may have been material dependant however, as other researchers have reported an R-ratio effect even when using ∆G [2,29].…”

Cyclic-fatigue crack growth in composite and adhesively-bonded structures: The FAA slow crack growth approach to certification and the problem of similitude

“…However, if the term is used as the CDF then no attention is paid to the minimum value of the SERR, , in the fatigue cycle. Indeed, authors [30] have shown that there are instances when taking G max as the CDF may lead, very misleadingly, to an apparent strong dependence of the measured fatigue behaviour upon the R-ratio employed.…”