Interlaminar Fracture Toughness of Composite Laminate with Splicing Plies

2011 ◽  
Vol 194-196 ◽  
pp. 1697-1702
Author(s):  
Li Liang ◽  
Pu Rong Jia ◽  
Gui Qiong Jiao
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Tensile Testing ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Fiber Reinforced ◽  
Interlaminar Fracture ◽  
Mode Ii Fracture ◽  
Mode Ii Fracture Toughness ◽  
Delamination Failure

Delamination is one of the important damage modes in the fiber-reinforced composite laminates. The interlaminar fracture toughness is the key parameter in delamination failure analysis of composites. The stress analysis by a finite element modeling has shown that the shear stress is very large near the ply splicing area. So the delamination failure is mainly dependent on the mode II fracture toughness. A new way of loading in tensile testing is proposed for the measurement of mode II fracture toughness. Specific specimen with splicing plies has been designed and used for the experiment. Testing study on the carbon-fiber-reinforced laminate with ply splicing was performed. Steady crack propagation has been seen by the tensile testing of the specimen. Mode II fracture toughness GIIC of the laminate has been determined by the experiment data analysis. The experiment and numerical analysis shows that the tensile testing for the measurement of mode II interlaminar fracture toughness is feasible.

Improvement of Vibration Damping Capacity and Fracture Toughness in Composite Laminates by the Use of Polymeric Interleaves

1999 ◽  
Author(s):  
Ronald F. Gibson ◽  
Hui Zhao
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Critical Thickness ◽  
Vibration Damping ◽  
Thickness Effect ◽  
Damping Capacity ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Mode Ii Fracture Toughness

Abstract It is shown that simultaneous improvement of vibration damping capacity and interlaminar fracture toughness in composite laminates can be achieved by using polymeric interleaves between the composite laminae. The specific case of Mode II interlaminar fracture toughness and flexural damping capacity of interleaved composite laminates is studied. Graphite/epoxy, E-glass/epoxy and E-glass/polyetherimide composite laminates with polymeric interleaves of several different thicknesses and materials were tested using both the end notch flexure (ENF) test for Mode II fracture toughness and the impulse-frequency response test for flexural damping capacity. The Mode II energy release rate GIIc for all three composites increased linearly with increasing interleaf thickness up to a critical thickness, then dropped off with further increases in thickness. The damping loss factor η for all three composites increased linearly with increasing interleaf thickness up to the maximum thickness. Analytical models for predicting the influence of interleaves on GIIc and η are developed, along with a hypothesis for the critical thickness effect with regard to fracture toughness.

Improvement of Vibration Damping Capacity and Fracture Toughness in Composite Laminates by the Use of Polymeric Interleaves

2001 ◽  
Vol 123 (3) ◽  
pp. 309-314 ◽  
Author(s):  
Ronald F. Gibson ◽  
Yu Chen ◽  
Hui Zhao
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Critical Thickness ◽  
Vibration Damping ◽  
Thickness Effect ◽  
Damping Capacity ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Mode Ii Fracture Toughness

It is shown that, under certain conditions, simultaneous improvement of vibration damping capacity and interlaminar fracture toughness in composite laminates can be achieved by using polymeric interleaves between the composite laminae. The specific case of Mode II interlaminar fracture toughness and flexural damping capacity of interleaved composite laminates is studied. Graphite/epoxy, E-glass/epoxy and E-glass/polyetherimide composite laminates with polymeric interleaves of several different thicknesses and materials were tested using both the end notch flexure (ENF) test for Mode II fracture toughness and the impulse-frequency response test for flexural damping capacity. The Mode II energy release rate GIIc for all three composites increased linearly with increasing interleaf thickness up to a critical thickness, then dropped off with further increases in thickness. The damping loss factor η for all three composites increased linearly with increasing interleaf thickness up to the maximum thickness. Analytical models for predicting the influence of interleaves on GIIc and η are developed, along with a hypothesis for the critical thickness effect with regard to fracture toughness.

scholarly journals Woven Glass Fiber Composites with Aligned Carbon Nanotube Sheet Interlayers

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hardik Bhanushali ◽  
Philip D. Bradford
Keyword(s):  
Fracture Toughness ◽  
Glass Fiber ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Fiber Reinforced ◽  
Interlaminar Fracture ◽  
Glass Fiber Reinforced ◽  
Short Beam ◽  
Woven Glass Fiber

This investigation describes the design, fabrication, and testing of woven glass fiber reinforced epoxy matrix laminates with aligned CNT sheets integrated between plies in order to improve the matrix dominated through thickness properties such as the interlaminar fracture toughness at ply interfaces. Using aligned CNT sheets allows for a concentration of millimeter long CNTs at the most likely point of laminate failure. Mode I and Mode II interlaminar fracture toughness of various CNT modified samples were investigated using double cantilever beam (DCB) and end notched flexure (ENF) experiments, respectively. Short beam strength (SBS) and in-plane tensile properties of the CNT modified samples were also investigated. Moderate improvement was observed in Mode I and Mode II fracture toughness at crack initiation when aligned CNT sheets with a basis weight of 0.354 g/m2were used to modify the ply interface. No compromise in the in-plane mechanical properties of the laminate was observed and very little improvement was observed in the shear related short beam strength of the CNT modified laminates as compared to the control samples. Integration of aligned CNT sheets into the composite laminate imparted in-plane and through thickness electrical properties into the nonconductive glass fiber reinforced epoxy composite laminates.

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