Correlation of Interlaminar Fatigue Growth Behavior between Embedded Elliptic Cracks and Through Cracks in High Strength GFRP
高強度GFRP積層板における内部欠陥からの層間き裂と貫通層間き裂の疲労進展特性の関係

Go MATSUBARA, Keisuke TANAKA
2006 TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A  
The elliptic growth behavior of interlaminar fatigue cracks from internal circular delamination was investigated with UD laminates (made of unidirectional laminates) and C laminates (made of unidirectional laminates and cloth laminates) of high strength glass fiber reinforced plastics (GFRP). The fatigue growth tests were carried out using specimens with circular delamination by 3 points bending at the stress ratios of R=0.1 and 1, and tests results were compared with those obtained for
more » ... thickness cracks. The interlaminar crack extended in an elliptic shape under mode II and III deformation. In UD laminates, the growth behavior of the elliptic crack under pure mode II and III agreed with that of the through crack under a respective mode. In the case of C laminates, the crack growth behavior of the elliptic crack under pure mode III agreed with that of the through cracks under pure mode III, while the crack growth resistance of pure mode II of the elliptic crack was about 1/2 of that of through cracks. This difference comes from an error in the G-value evaluation of elliptic cracks performed using the macroscopic mechanical propertis on elastic orthotropy. The G value for actual cracks is larger than the evaluated value, because the resin rich region near the crack tip increases the deformation. At a constant crack growth rate under mixed mode loading, the driving force is expressed in terms of a linear combination of the pure mode II CIImax and the pure mode III GIIImax.
doi:10.1299/kikaia.72.712 fatcat:uxj7lodg2rfzxod2xjut6m6mzy