Inverse Analysis for Damage Identification in CFRP Laminates with Embedded FBG Sensors

2004 ◽  
pp. 993-998
Author(s):  
Shigeki Yashirol ◽  
Tomonaga Okabe ◽  
Nobuo Takeda
Keyword(s):  
Inverse Analysis ◽  
Damage Identification ◽  
Cfrp Laminates ◽  
Fbg Sensors

Cure Monitoring of Composites Based on Embedded Fiber Bragg Gratings

2011 ◽  
Vol 211-212 ◽  
pp. 585-589 ◽  
Author(s):  
Xiao Yan Shen
Keyword(s):  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Cure Process ◽  
Cfrp Laminates ◽  
Cure Monitoring ◽  
Fbg Sensor ◽  
Reinforced Polymer ◽  
Before And After ◽  
Fbg Sensors ◽  
The Difference

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.

Identification of Damage Locations in CFRP Laminates Using Chirped FBG Sensors

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

Damage Identification and Classification in CFRP Laminates – A SEM Based Study

2012 ◽  
Vol 225 ◽  
pp. 138-143
Author(s):  
Mohamed Thariq Hameed Sultan ◽  
Noorfaizal Yidris ◽  
Faizal Mustapha ◽  
Azmin Shakrine M. Rafie ◽  
Dayang Laila Majid
Keyword(s):  
Surface Defects ◽  
Damage Identification ◽  
Large Mass ◽  
Test Procedures ◽  
Cross Sectional ◽  
Cfrp Laminates ◽  
Test Conditions ◽  
Main Factors ◽  
Selection For ◽  
Lower Height

There are two main factors that need to be considered as important parameters that affect the response of a structure: kinetic energy (E=1/2mv^2 ) and potential energy (E=mgh). For instance, if one has a large mass but with lower height, the amount of damage produced on the structure may not be the same as if one has a smaller mass with a higher dropping height although the potential energies will be the same. Therefore, before performing tests on the structures, the selection for the appropriate test apparatus and test procedures must be made carefully to ensure that the test conditions are similar to the actual impact conditions. In this present work, a study was conducted to fully understand the damage progression and growth, not only should the impacted surface be evaluated, but also the cross sectional defects on the impacted area must be accurately identified and examined. In this current work, the impacted test specimens will be observed at different magnifications to distinguish the types of failure mechanisms using Scanning Electron Microscopy (SEM). To perform this, the impacted specimens will be examined by two different approaches: surface defects and cross-sectional defects. This allows the failure mechanism to be observed more precisely.

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