OS09W0347 Suppression effect for mode I propagation of delamination cracks in a laminated composite by using thin SMA plates

Abstract

The use of thin actuator plates bonded to surfaces of FRP laminates to suppress the growth of delamination cracks is investigated. A composite beam analysis was performed to estimate the effect of strains induced by actuators on the strain energy release rate of delamination cracks. When compared at the same value of actuation strain, the apparent crack growth resistance, G_<app>/G_C , is larger for smaller FRP thickness and for smaller FRP fracture toughness, G_C , under both mode I and II loadings. Mode I delamination suppression tests were conducted by using thin SMA actuators. The value of the apparent crack growth resistance, G_<Iapp>, under actuation strains of about 0.001 was 2.7 times larger than fracture toughness of FRP, G_<IC>, and was also about 1.6 times as large as that just before actuation.