Influence of Fiber Length

Critical fiber length—dependence on fiber strength and diameter and fiber-matrix bond strength (or matrix shear yield strength) 

For a number of glass and carbon fiber-matrix combinations, this critical length is on the order of 1 mm, which ranges between 20 and 150 times the fiber diameter. 

Fibers for which I (normally I 15/ ) are termed continuous discontinuous or short fibers have lengths shorter than this. For discontinuous fibers of lengths significantly less than f, the matrix deforms around the fiber such that there is virtually no 

Stress-position profiles when the fiber length I (a) is equal to the critical length Z (b) is greater than the critical length, and (c) is less than the critical length for a fiber-reinforced composite that is subjected to a tensile stress equal to the fiber tensile strength aj. 

Tensile Stress-Strain Behavior—Longitudinal Loading 

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Thomason JL, Vlug MA. Influence of fiber length and concentration on the properties of glass fiber-reinforced polypropylene 1. Tensile and flexural modulus. Composites Part A Applied Science and Manufacturing. 1996 27(6) 477-84. 

Influence of Fiber Length on the Mechanical Properties for Glass Fiber Reinforced Polypropylenes. Kyouka Plastics (the Journal of Japan Reinforced Platics Society, in Japanese), Vol.44, No.5, pp. 197-203 ISSN 0452-9685... 

The studies in the literature indicate that several different vegetable fibers have been mixed with glass fibers and incorporated into a number of polar and non-polar polymers, including thermoplastics, thermosets and even natmal rubber. The influence of fiber content and relative amounts, fiber length, modification of both fibers and matrices and the use of compatibilizers on the mechanical and thermal behaviour of these systems was described. 

M. Pervaiz, M. Sain, and A. Ghosh, Evaluation of the influence of fibre length and concentration on mechanical performance of hemp fibre reinforced polypropylene composite. 7. Nat. Fibers 2, 67-84 (2006). 

Dimensional Stability. Dimensional stabiHty refers to how a fiber changes length under the influence of load or heat. Conventionally described in terms of fiber shrinkage (ASTM D885-64) at a defined temperature, the term has also come to mean time dependent length change or creep. 

FIG U RE 1.37 Effects of extraction time and fiber length on two-phase LPME of mirtazapine stereoisomers.156 Influence of extraction time (A) and acceptor-to-donor phases volume ratio (B) on the efficiency of LPME. Plots for the (+)-(5)-mirtazapine (white bars) and (-)-(R)-mirtazapine (black bars) enantiomers (response in area counts). Extraction conditions (A) 1 mL plasma sample 0.1 mL 10 M NaOH 3.0 ml deionized water 7.0 cm fiber length 22 /rL toluene (B) 30 min of extraction 1 mL plasma sample 0.1 mL 10 M NaOH 3.0 mL deionized water toluene. (Reproduced with permission from Elsevier.)... 

Marolzke, Ch. (1993). Influence of the fiber length on the stress transfer from glass and carbon fibers into a thermoplastic matrix in the pull-out test. Composite Interfaces 1, 15.3-166. 

Practically any natural plant can be utilized as a source of papermaking fibers, but there is considerable variation in the quality of paper realized from alternate plant sources. Factors such as fiber length, content of non-fibrous components such as parenchyma tissue, contaminants such as silica, etc. greatly influence the quality of the final sheet. Procurement of sufficient quantities of the raw material and seasonal fluctuations in supply can also pose problems. It is also necessary to use alternate pulping equipment to handle the plant materials since the material tends to mat down in the digester making it difficult to get uniform circulation of the cooking chemicals. 

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