Crack identification in CFRP laminates using small-diameter FBG sensors

Author(s):  
Tadahito Mizutani ◽  
Yoji Okabe ◽  
Nobuo Takeda
2001 ◽  
Author(s):  
Yoji Okabe ◽  
Tadahito Mizutani ◽  
Shigeki Yashiro ◽  
Nobuo Takeda
Keyword(s):  

2011 ◽  
Vol 211-212 ◽  
pp. 585-589 ◽  
Author(s):  
Xiao Yan Shen

Cure-induced strain is produced inevitably during the fabrication of the composite. To measure the strain, undamaged methods such as using fiber Bragg grating(FBG) sensor are employed. In this paper, nine unidirectional carbon fiber-reinforced polymer(CFRP) laminates are autoclaved produced, with FBGs embedded in different layers through the thickness (0-layer, 5-layer, 10-layer and 13-layer). The experiment measures the difference of the FBGs’ Bragg wavelengths before and after the cure which is linearly relevant to the cure-induced strain, to explore the distribution of strains through the thickness. The experimental results indicate a certain strain in neural plane of approximately 370με under the designed size of the laminates. The results also show that the cure-induced strains in different layers through the thickness are less than 1000με even including all errors, however they do not display distinct regular in thickness direction. Moreover, through the FBG sensors and the thermocouples, the cure process with the strain and temperature variations is understood well. The result verifies that the cure-induced strain is mainly generated at the end of the cure when the temperature cools down.


2002 ◽  
Vol 2002.8 (0) ◽  
pp. 227-228
Author(s):  
Ryohei TSUJI ◽  
Yoji OKABE ◽  
Nobuo TAKEDA
Keyword(s):  

2005 ◽  
Vol 53 (615) ◽  
pp. 166-173 ◽  
Author(s):  
Hisao Tamaue ◽  
Junichiro Kuwahara ◽  
Yoji Okabe ◽  
Nobuo Takeda ◽  
Seiji Kojima
Keyword(s):  

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