scholarly journals Characteristics of Eddy Current Distribution in Carbon Fiber Reinforced Polymer

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Shaoni Jiao ◽  
Jian Li ◽  
Fei Du ◽  
Lei Sun ◽  
Zhiwei Zeng

The paper studies the characteristics of eddy current (EC) distribution in carbon fiber reinforced polymer (CFRP) laminates so as to guide the research and operation of eddy current testing of CFRP. To this end, an electromagnetic field computation model of EC response to CFRP based on the finite element method is developed. Quantitative analysis of EC distribution in plies of unidirectional CFRP reveals that EC changes slowly along the fiber direction due to the strong electrical anisotropy of the material. Variation of EC in plies of multidirectional CFRP is fast in both directions. The attenuation of EC in the normal direction in unidirectional CFRP is faster than that in isotropic material due to faster diffusion of EC. In multidirectional CFRP, EC increases near the interfaces of plies having different fiber orientations. The simulation results are beneficial to optimizing sensor design and testing parameters, as well as damage detection and evaluation.

2014 ◽  
Vol 800-801 ◽  
pp. 61-65 ◽  
Author(s):  
Kun Xian Qiu ◽  
Cheng Dong Wang ◽  
Qing Long An ◽  
Ming Chen

The new developed carbon fiber reinforced polymer laminates are widely used in main structural components of big commercial aircrafts. Generally drilling is the final operations in manufacturing structure, which is the most important operation during assembly. Defects such as burrs and delamination always appear in the process of drilling, which makes it hard to control the drilling quality. In this research, the drilling defects of T800 CFRP laminates are evaluated by using a brad point drill and a multifacet drill in terms of drilling forces, burr defect and delamination detection. The results show that the spindle speed is the most significant factor affecting the delamination defect followed by the feed rate. High speed drilling and low feed rate could improve the surface quality and reduce the delamination. The multifacet drill showed excellent drilling performance than the brad point drill and generated smaller defects.


Author(s):  
Jonathan Rudd ◽  
Dustin Spayde ◽  
Oliver Myers

In this paper, the experimental sensing results of damage testing using magnetostrictive particulate sensors, embedded in fiber reinforced polymer laminates, are presented. Carbon fiber reinforced polymer (CFRP) laminates (Hexcel AS4/3501-6) are embedded with terfenol-d particles and the ply count is varied to observe the change in the sensing. Sensing is observed using a non-contacting magnetostrictive strain sensor setup. The sensing parameter observed is the voltage induced in the secondary circuit. Two of the three batches presented have laminates that are embedded with .5″×.5″, release agent coated patches that prevent bonding between the terfenol-d and the CFRP layer. The laminate ply count ranges from 2–14 unidirectional plies. Two fabrication methods are used to distribute the particles in the laminate. The experimental results from the three batches reveal that the fabrication technique has a significant effect on the sensing signal. The effect of particle accumulation near the sensor dominates the sensing signal and makes the presence of a delamination difficult to assess. The experiments also show that when the ply count is varied, there is not much variation in the sensing signal.


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