Energy based study on quasi-static delamination growth treated as a low cycle fatigue process

This work proposes to treat quasi-static mode I delamination growth of CFRP as a low-cycle fatigue process. To this end, mode I quasi-static and fatigue delamination tests were performed. An average physical Strain Energy Release Rate (SERR), derived from an energy balance, is used to characterize the energy released in crack extension. The physical SERR is then compared to the SERRs calculated by the ASTM standard, and the physical background of the standard is questioned. Furthermore, when normalizing the physical SERR for fatigue delamination by the one obtained for quasi-static crack extension, a stress ratio dependence is observed. This stress ratio effect is physically explained to be present due to the relation between quasi-static and fatigue loading at high stress ratios.