Fiber Orientation Distribution Functions and Orientation Tensors for Different Material Symmetries

2015 ◽  
pp. 37-71 ◽  
Author(s):  
Maher Moakher ◽  
Peter J. Basser
Keyword(s):  
Fiber Orientation ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Fiber Orientation Distribution ◽  
Orientation Tensors ◽  
Orientation Distribution Functions

A Statistical Method to Obtain Material Properties From the Orientation Distribution Function for Short-Fiber Polymer Composites

Materials ◽  
2005 ◽  
Author(s):  
David A. Jack ◽  
Douglas E. Smith
Keyword(s):  
Distribution Function ◽  
Orientation Distribution Function ◽  
Material Properties ◽  
Fiber Orientation ◽  
Orientation Distribution ◽  
Short Fiber ◽  
Expectation Values ◽  
Order Tensor ◽  
Fiber Orientation Distribution ◽  
Orientation Tensors

Material behavior of short-fiber composites can be found from the fiber orientation distribution function, with the only widely accepted procedure derived from the application of orientation/moment tensors. The use of orientation tensors requires a closure, whereby the higher order tensor is approximated as a function of the lower order tensor thereby introducing additional computational errors. We present material property expectation values computed directly from the fiber orientation distribution function, thereby alleviating the closure problem inherent to orientation tensors. Material properties are computed from statistically independent unidirectional fiber samples taken from the fiber orientation distribution function. The statistical nature of the distribution function is evaluated with Monte-Carlo simulations to obtain approximate stiffness tensors from the underlying unidirectional composite properties. Examples are presented for simple analytical distributions to demonstrate the effectiveness of expectation values and results are compared to properties obtained through orientation tensors. Results yield a value less than 1.5% for the coefficient of variation and suggest that the orientation tensor method for computing material properties is applicable only for the case of non-interacting fibers.

scholarly journals Study of Meltblown Structures Formed by Robotic and Meltblowing Integrated System: Impact of Process Parameters on Fiber Orientation

2002 ◽  
Vol os-11 (4) ◽  
pp. 1558925002OS-01
Author(s):  
Raoul Farer ◽  
Tushar K. Ghosh ◽  
Abdelfattah M. Seyam ◽  
Eddie Grant ◽  
Subhash K. Batra
Keyword(s):  
Fiber Orientation ◽  
Three Dimensional ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Integrated System ◽  
Rotating Drum ◽  
Throughput Rate ◽  
Approach Angle ◽  
Fiber Orientation Distribution ◽  
Parametric Studies

A novel system that forms two-dimensional (2D) structures on a rotating drum and three-dimensional (3D) structures on 3D molds through proper integration of a laboratory scale meltblown unit with a small die and six-axis robot is briefly described. The system advantages over traditional systems are demonstrated. Parametric studies evaluating the effect of take-up speed, die-to-collector-distance (DCD), polymer throughput rate, and attenuating air pressure on the fiber orientation distribution functions (ODFs) of 2D structures formed by the system are reported. An additional new parameter termed “fiber-stream approach-angle” is introduced and its impact on the ODF of 2D structures is also reported. Under the experimental range studied, the ODFs were significantly impacted by the parameters studied. The fiber-stream approach angle showed the highest impact, among the parameter studied, on the ODF.

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