Interlaminar fracture toughness of unidirectional carbon fibre-polyimide composites

1992 ◽  
Vol 11 (22) ◽  
pp. 1490-1492 ◽  
Author(s):  
H. Wittich ◽  
J. Krey ◽  
K. Friedrich
Keyword(s):  
Fracture Toughness ◽  
Carbon Fibre ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Polyimide Composites

scholarly journals Mixed-Mode Interlaminar Fracture Toughness of Glass and Carbon Fibre Powder Epoxy Composites—For Design of Wind and Tidal Turbine Blades

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2103
Author(s):  
Christophe Floreani ◽  
Colin Robert ◽  
Parvez Alam ◽  
Peter Davies ◽  
Conchúr M. Ó. Brádaigh
Keyword(s):  
Fracture Toughness ◽  
Carbon Fibre ◽  
Composite Structures ◽  
Mixed Mode ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Pure Mode ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture

Powder epoxy composites have several advantages for the processing of large composite structures, including low exotherm, viscosity and material cost, as well as the ability to carry out separate melting and curing operations. This work studies the mode I and mixed-mode toughness, as well as the in-plane mechanical properties of unidirectional stitched glass and carbon fibre reinforced powder epoxy composites. The interlaminar fracture toughness is studied in pure mode I by performing Double Cantilever Beam tests and at 25% mode II, 50% mode II and 75% mode II by performing Mixed Mode Bending testing according to the ASTM D5528-13 test standard. The tensile and compressive properties are comparable to that of standard epoxy composites but both the mode I and mixed-mode toughness are shown to be significantly higher than that of other epoxy composites, even when comparing to toughened epoxies. The mixed-mode critical strain energy release rate as a function of the delamination mode ratio is also provided. This paper highlights the potential for powder epoxy composites in the manufacturing of structures where there is a risk of delamination.

Delamination Behaviour of Rubber-Toughened Carbon Fibre/Epoxy Composites

2013 ◽  
Vol 392 ◽  
pp. 73-77
Author(s):  
Helen Wu
Keyword(s):  
Fracture Toughness ◽  
Plastic Zone ◽  
Carbon Fibre ◽  
Composite Laminates ◽  
Epoxy Composites ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
The Matrix ◽  
Key Factor ◽  
Modified Epoxy

In this study, core-shell rubber (CSR) and liquid rubber (LR) were used to modify the matrix toughness of unidirectional carbon fibre/epoxy composites. Double cantilever beam (DCB) and end notched flexure (END) tests were performed to evaluate the interlaminar fracture toughness. It was found that LR was identified to be more effective than CSR in improving GICand GIICof the composites, although fracture toughness of the CSR-modified epoxy was better than that of the LR-modified epoxy. SEM observation of post-fracture surfaces of the specimens shows that the degree of plastic deformation of matrix is well related to the rating of fracture toughness of composites for these unmodified and modified composite laminates, and is the key factor controlling the interlaminar fracture toughness of composite laminates. Further, it was confirmed that rigid fibres constrain growth of plastic zone in composites laminates, comparing with toughened bulk epoxy matrix. However, plastic zone is not limited to a single resin layer and it is capable of developing across rigid fibre layers.

scholarly journals Interlaminar Fracture Behavior of Carbon Fiber/Polyimide Composites Toughened by Interleaving Thermoplastic Polyimide Fiber Veils

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2695
Author(s):  
Bangwei Lan ◽  
Yi Liu ◽  
Song Mo ◽  
Minhui He ◽  
Lei Zhai ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Fracture Behavior ◽  
Elevated Temperatures ◽  
Areal Density ◽  
Thermally Stable ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Maximum Improvement ◽  
Polyimide Composites

Carbon fiber reinforced thermosetting polyimide (CF/TSPI) composites were interleaved with thermally stable thermoplastic polyimide (TPPI) fiber veils in order to improve the interlaminar fracture toughness without sacrificing the heat resistance. Both of the mode I and mode II interlaminar fracture toughness (GIC and GIIC) for the untoughened laminate and TPPI fiber veils interleaved laminates were characterized by the double cantilever beam (DCB) test and end notch flexure (ENF) test, respectively. It is found that the TPPI fiber veils interleaved laminates exhibit extremely increased fracture toughness than the untoughened one. Moreover, the areal density of TPPI greatly affected the fracture toughness of laminates. A maximum improvement up to 179% and 132% on GIC and GIIC is obtained for 15 gsm fiber veils interleaved laminate, which contributes to the existence of bicontinuous TPPI/TSPI structure in the interlayer according to the fractography analysis. The interlaminar fracture behavior at elevated temperatures for 15 gsm fiber veils interleaved laminate were also investigated. The results indicated that the introduction of thermally stable TPPI fiber veils could enhance the fracture toughness of CF/TSPI composites by exceeding 200% as compared to the untoughened one even as tested at 250 °C.

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