This paper presents an experimental investigation of the ModeⅡdelamination resistance of curved CFRP laminates reinforced with Z-pins.A Pre-Hole Z-pinning(PHZ)process is developed to reduce the in-plane damage of the...This paper presents an experimental investigation of the ModeⅡdelamination resistance of curved CFRP laminates reinforced with Z-pins.A Pre-Hole Z-pinning(PHZ)process is developed to reduce the in-plane damage of the Z-pinned laminates.The microstructural observation of the Z-pinned laminate specimens indicates that the PHZ process can effectively decrease the defects including the Z-pin offset angle and the area of eyelet zone.The influences of the volume fraction and diameter of Z-pin on the fracture toughness and the delamination crack growth rate of the specimens under End Notch Flexure(ENF)loading are then determined experimentally.The test results show that Z-pin increases the interlayer stiffness of the laminate.The delamination crack growth rate is reduced with the increase of Z-pin diameter and volume fraction,and a reduction up to 40%is achieved compared with the specimens without pins.Furthermore,the ModeⅡfracture toughness is significantly improved with the increase of Z-pin volume fraction.When Z-pin volume fraction increases by 1%,the achieved fracture toughness is about 200%higher compared to the unpinned laminates.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFF0500100)the National Natural Science Foundation of China(No.11872310)。
文摘This paper presents an experimental investigation of the ModeⅡdelamination resistance of curved CFRP laminates reinforced with Z-pins.A Pre-Hole Z-pinning(PHZ)process is developed to reduce the in-plane damage of the Z-pinned laminates.The microstructural observation of the Z-pinned laminate specimens indicates that the PHZ process can effectively decrease the defects including the Z-pin offset angle and the area of eyelet zone.The influences of the volume fraction and diameter of Z-pin on the fracture toughness and the delamination crack growth rate of the specimens under End Notch Flexure(ENF)loading are then determined experimentally.The test results show that Z-pin increases the interlayer stiffness of the laminate.The delamination crack growth rate is reduced with the increase of Z-pin diameter and volume fraction,and a reduction up to 40%is achieved compared with the specimens without pins.Furthermore,the ModeⅡfracture toughness is significantly improved with the increase of Z-pin volume fraction.When Z-pin volume fraction increases by 1%,the achieved fracture toughness is about 200%higher compared to the unpinned laminates.
