Mode II fracture behaviour monitoring for composite laminates using embedded fibre Bragg grating sensors

2006 ◽  
Vol 76 (1-2) ◽  
pp. 88-93 ◽  
Author(s):  
Hang-yin Ling ◽  
Kin-tak Lau ◽  
Li Cheng ◽  
Zhongqing Su
Keyword(s):  
Composite Laminates ◽  
Fracture Behaviour ◽  
Bragg Grating ◽  
Mode Ii ◽  
Fibre Bragg Grating ◽  
Mode Ii Fracture

Monitoring mode II fracture behaviour of composite laminates using embedded fiber-optic sensors

2007 ◽  
Vol 38 (4) ◽  
pp. 488-497 ◽  
Author(s):  
Hang-Yin Ling ◽  
Kin-Tak Lau ◽  
Zhongqing Su ◽  
Eric Tsun-Tat Wong
Keyword(s):  
Composite Laminates ◽  
Fiber Optic ◽  
Fracture Behaviour ◽  
Fiber Optic Sensors ◽  
Mode Ii ◽  
Mode Ii Fracture

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.

High Strain Monitoring during Fatigue Loading of Thermoplastic Composites Using Imbedded Draw Tower Fibre Bragg Grating Sensors

2008 ◽  
Vol 56 ◽  
pp. 441-446 ◽  
Author(s):  
Eli Voet ◽  
Geert Luyckx ◽  
Ives De Baere ◽  
Joris Degrieck ◽  
J. Vlekken ◽  
...  
Keyword(s):  
Composite Laminates ◽  
High Strength ◽  
Fatigue Loading ◽  
Strain Sensors ◽  
Thermoplastic Composites ◽  
Bragg Grating ◽  
Fibre Bragg Grating ◽  
Strain Measurements ◽  
Strain Monitoring

This paper presents the experimental study of fibre Bragg grating sensors for measuring strain inside composite laminates during fatigue loading. The optical fibres are imbedded inside thermoplastic CFRP test-coupons which have an ultimate strain of about 1.1%. Tension – tension fatigue cycling at a rate of 5Hz is been carried out at 314MPa with a maximum strain of 0.51%. At such extreme strain levels the use of high strength sensors becomes inevitable. Neither the sensor nor the composite test-coupons showed any significant degradation even after more than 500000 cycles. Fibre optic Bragg grating sensors are known to be very accurate strain sensors but one should be very careful interpreting their response once they are imbedded inside composite materials. In this study high strength fibre Bragg grating sensors with coating are imbedded in composite test coupons and a pretty good correlation was found between the strain measurements of an electrical extensometer and the imbedded sensor during the complete cycling. The high strength sensor show to be very feasible for extreme and long term strain measurements.

Cohesive zone modeling of the autoclave pressure effect on the delamination behavior of composite laminates

2018 ◽  
Vol 37 (24) ◽  
pp. 1468-1480
Author(s):  
Tengfei Chang ◽  
Lihua Zhan ◽  
Wei Tan ◽  
Xintong Wu
Keyword(s):  
Fracture Toughness ◽  
Cohesive Zone ◽  
Composite Laminates ◽  
Cohesive Zone Model ◽  
Cohesive Strength ◽  
Mode Ii ◽  
Zone Model ◽  
Mode Ii Fracture ◽  
Mode Ii Fracture Toughness ◽  
Delamination Behavior

Current manufacturing processes using resin transfer molding or low-pressure prepreg curing may result in different defects and interfacial properties. The effect of autoclave pressure on the delamination behavior of T800/X850 composite laminates is explored. Cohesive zone model was used to model the delamination of unidirectional composite laminates under short-beam bending. Composites with various interlaminar properties were manufactured using autoclave under cure pressure from 0 MPa to 0.6 MPa. Cohesive zone model was validated using the material parameters of the composite cured under 0.6 MPa. The effect of cohesive zone model parameters including cohesive strength, mode I fracture toughness ([Formula: see text]), and mode II fracture toughness ([Formula: see text]) on the delamination behavior and load–displacement response was investigated. Parametric study shows that interlaminar cohesive strength and mode II fracture toughness dominated the initiation of yield and post-yield region, respectively. The correlation between autoclave pressure and mode II fracture toughness was predicted, which is mainly affected by void content.

Sign in / Sign up

Export Citation Format

Share Document