The relation between the strain energy release in fatigue and quasi-static crack growth

• Quasi-static mode I delamination is treated as low-cycle fatigue.
• Delamination is assessed by a parameter derived from the crack extension.
• Fatigue and quasi-static delamination are linked through physical principles.
• The energy released on crack extension depends on decohesion mechanisms.

This work proposes to use an average Strain Energy Release Rate (SERR) to characterise similarly fatigue and quasi-static delamination growth. Mode I quasi-static and fatigue tests were performed. The quasi-static crack extension was considered as a low-cycle fatigue process, discretized to different levels and correlated to the fatigue data. Fracture surfaces were analysed and damage mechanisms were related to average SERRs for each case. The strain energy released in crack extension showed to be dependent on the decohesion mechanisms, and it is demonstrated how the values of the SERR for fatigue and quasi-static loading can be linked through physical principles.