Novel Test Method for Mixed Mode II and III Interlaminar Fracture Toughness

2010 ◽  
Vol 19 (4) ◽  
pp. 349-361 ◽  
Author(s):  
Hiroshi Suemasu ◽  
Atsushi Kondo ◽  
Katsuhisa Gozu ◽  
Yuichiro Aoki
Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2103
Author(s):  
Christophe Floreani ◽  
Colin Robert ◽  
Parvez Alam ◽  
Peter Davies ◽  
Conchúr M. Ó. Brádaigh

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.


2016 ◽  
Vol 1135 ◽  
pp. 35-51 ◽  
Author(s):  
Rita de Cássia Mendonça Sales ◽  
Bianca Lis Rossi Dias Endo ◽  
Maurício Vicente Donadon

Composite materials have been increasingly used in the aerospace industry for the manufacturing of structures, because of the associated properties of low weight and high mechanical resistance. On the other hand, they have low delamination resistance. This paper presents the results of an experimental study performed to obtain the values of interlaminar fracture toughness (G) of a laminate under three different temperatures, using 0º carbon-epoxy prepreg fabric plies and manufactured via Hand lay up cured in autoclave (HLUP). Double Cantilever Beam (DCB) tests were performed to evaluate mode I toughness, Four Point Bend End Notched Flexure (4ENF) for mode II and Mixed Mode Bending (MMB) for mixed mode I / mode II at -54°C, 25°C and 80°C. The data were collected and analyzed using a routine developed in Matlab®. Finally, the relation between GI and GII through the failure envelope and the temperature influence on the interlaminar fracture toughness was assessed.


2010 ◽  
Vol 452-453 ◽  
pp. 453-456
Author(s):  
H. Ghasemnejad ◽  
V. Thomas ◽  
H. Hadavinia

The mixed-Mode interlaminar fracture toughness, GI/IIC, of z-pinned hybrid laminated composites is studied to investigate the effect of 3D-composites on the crack propagation resistance of delaminated composite structures. In this regard, the mixed-Mode interlaminar fracture toughness, GI/IIC, was measured using asymmetric double cantilever beam (ADCB) test method. The hybrid ADCB and z-pinned hybrid composite beams were laid-up from [G0/C0]4, [G0/C90]4, [G90/C0]4 and [G90/C90]4 to study the effect of z-pinning on the interlaminar fracture toughness. From the obtained results from test it was found that the resistance of z-pin fibres against the crack propagation in z-pinned hybrid composites can significantly increase the mixed-mode interlaminar fracture toughness.


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