Characterization and prediction of fiber orientation

The orientation of fibers can be represented by the second order orientation tensor defined as,  

10 Length distribution of glass fiber molded by conventional plastica-tion unit and long glass fiber plastication unit. (Reproduced based on the data of reference 65, p. 129.) 

To model and predict the fiber orientation in injection molded parts, Folgar and Hicker modified the theory proposed by Jeffery by introducing a diffusion term as follows  

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