Notched strength of carbon fibre/epoxy composite laminates with a circular hole

1999 ◽  
Vol 65 (7) ◽  
pp. 295-300 ◽  
Author(s):  
P. K. Govindan Potti ◽  
B. Nageswara Rao ◽  
V. K. Srivastava
2000 ◽  
Vol 65 (10) ◽  
pp. 295-300 ◽  
Author(s):  
P. K. Govindan Potti ◽  
B. Nageswara Rao ◽  
V. K. Srivastava

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 109 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Mohini Sain

The effect of unidirectional (UD) carbon fibre hybridisation on the tensile properties of flax fibre epoxy composite was investigated. Composites containing different fibre ply orientations were fabricated using vacuum infusion with a symmetrical ply structure of 0/+45/−45/90/90/−45/+45/0. Tensile tests were performed to characterise the tensile performance of plain flax/epoxy, carbon/flax/epoxy, and plain carbon/epoxy composite laminates. The experimental results showed that the carbon/flax fibre hybrid system exhibited significantly improved tensile properties over plain flax fibre composites, increasing the tensile strength from 68.12 MPa for plain flax/epoxy composite to 517.66 MPa (670% increase) and tensile modulus from 4.67 GPa for flax/epoxy to 18.91 GPa (305% increase) for carbon/flax hybrid composite. The failure mechanism was characterised by examining the fractured surfaces of tensile tested specimens using environmental scanning electron microscopy (E-SEM). It was evidenced that interactions between hybrid ply interfaces and strain to failure of the reinforcing fibres were the critical factors for governing tensile properties and failure modes of hybrid composites.


1998 ◽  
Vol 58 (3-4) ◽  
pp. 591-602 ◽  
Author(s):  
Takayuki Kusaka ◽  
Masaki Hojo ◽  
Yiu-Wing Mai ◽  
Tomoaki Kurokawa ◽  
Taketoshi Nojima ◽  
...  

2004 ◽  
Vol 108 (1083) ◽  
pp. 263-269
Author(s):  
P. K. G. Potti ◽  
B. N. Rao ◽  
V. K. Srivastava

Abstract A statistical approach is followed for prediction of tolerences of notched strength of composite laminates using the recently proposed improved inherent flaw model (IFM). In order to examine the validity of this approach, the existing fracture data on graphite/epoxy composite laminates containing central holes and cracks were used. The notched strength estimations are found to be within the range of tested values.


Studies have shown that the angle of fiber orientation significantly affects the mechanical properties of a composite laminate. Due to this, accurate prediction of the laminate response because of the loading effect is crucial. Many investigations on the properties of composite materials have been conducted. However, there is still the lack of study related to Kevlar/Epoxy laminate. Therefore, this study aims to investigate the effect of the angle of fiber orientation to woven and unidirectional (UD) Kevlar/Epoxy laminates under compression state. The study was conducted in two stages comprising of numerical validation and failure analysis. For the failure analysis, a flat plate and flat plate with circular hole under compression were modelled using ANSYS. Two of the most common failure models, Maximum Stress Theory and Tsai-Wu Failure criteria were selected for the failure prediction. The laminates were made of 24 layers woven Kevlar/Epoxy and the stacking sequence was (θ4 /04 /-θ4 )s. The angle of fiber orientations, θ, have been varied from 0° to 90° and failure loads for both flat plate and flat plate with circular hole were determined. The trend of displacement and failure behaviour for both types of plate were compared. The results show that the angle of fiber orientation affects significantly the trend of the displacement and failure curves of UD and woven Kevlar/Epoxy. The curves for UD and woven; flat plate and flat plate with circular hole are different and unique in nature; and thus should be treated individually. These analysis and findings are important in aiding the engineers at designing a stronger woven Kevlar/Epoxy composite laminate. Therefore, it can be concluded that the current study has contributed towards enhancing knowledge about the compressive failure behaviour of unidirectional and woven Kevlar/Epoxy composite laminates


Sign in / Sign up

Export Citation Format

Share Document