Standardization of the End-Notched Flexure Test for Mode II Interlaminar Fracture Toughness Determination of Unidirectional Laminated Composites

2015 ◽  
Vol 43 (6) ◽  
pp. 20140437 ◽  
Author(s):  
Barry D. Davidson
Keyword(s):  
Fracture Toughness ◽  
Laminated Composites ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Flexure Test

Study of mode II interlaminar fracture toughness of laminated composites of glass and jute fibres in epoxy for structural applications

2021 ◽  
Vol 3 (4) ◽  
pp. 044002
Author(s):  
Pankaj Singh Chandel ◽  
Y K Tyagi ◽  
Kanishk Jha ◽  
Rajeev Kumar ◽  
Shubham Sharma ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Laminated Composites ◽  
Curing Temperature ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Three Point Bending ◽  
Glass Fibres ◽  
Structural Applications ◽  
Delamination Resistance

Abstract Composites are being used in the place of metals in many industries as they have a lower density and are cheaper than metals. In aerospace industries there is requirement for light weight together with strength, and reinforced fibre composites are superior in some critical properties compared with metals. In this study, laminated composites were fabricated with woven E-glass and jute fibres in an epoxy matrix by a hand layup method. The samples were prepared as per the relevant the America Society for Testing ad Materials (ASTM) standard and tested for mode II interlaminar fracture toughness to investigate delamination resistance. Mode II interlaminar fracture toughness was evaluated by an end-notched flexure test using three-point bending. The fracture toughness G IIC was calculated for a curing temperature range from 40 °C to 70 °C at intervals of 5 °C for different sets of laminated composites. The investigations revealed that when the curing temperature of laminated composites was increased from 40 °C to 70 °C, the interlaminar fracture toughness G IIC was increased in neat woven E-glass laminated composites, decreased in neat jute laminated composites, significantly increased in laminated composites with woven E-glass fibres in compression and jute fibres in tension and slightly increased when woven E-glass fibres were kept in tension and jute fibres in compression.

scholarly journals Determination of Mode II Interlaminar Fracture Toughness of CFRP Composites Using Numerical Simulations

2019 ◽  
Vol 801 ◽  
pp. 71-76
Author(s):  
Frantisek Sedlacek ◽  
Tomas Kalina ◽  
Karel Raz
Keyword(s):  
Numerical Simulation ◽  
Fracture Toughness ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Three Point Bending ◽  
Nonlinear Solver ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper deals with a numerical simulation of the interlaminar fracture toughness of woven carbon fibre reinforced polymer. Composite materials are increasingly used for their unique properties in many branches of engineering. They are also used for flexible components such as springs, couplings, etc. The strength of these parts must be determined not only in terms of their intralaminar properties but also in terms of their interlaminar properties. This paper provides a methodology for determining the main parameters for Mode II interlaminar fracture toughness using numerical simulation. End Notch Flexure (ENF) specimens were created for fitting fracture toughness parameters of the laminate according to ASTM standards. Three point bending ENF tests were carried out on a Zwick/Roell Z050 machine. The numerical simulation was created in Siemens Simcenter 12.0 using NX Nastran nonlinear solver. The results from the numerical simulation correspond to those from the experimental test with an accuracy of 4%.

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.

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