Effective fiber length volume fraction

A7.1.1 Effect of Volume Fraction on Effective Fiber Length... 

In this expression, Ef and Em are the Young modulus of respectively the fiber and the matrix, and f is the fiber volume fraction. //0 is the fiber orientation factor this factor is equal to 1 for perfectly oriented fibers and 1/6 for a random orientation, tj, is the so-called effective length coefficient (10), which mainly depends on the aspect ratio of the fiber. Indeed ... 

Figure 13-2. Ventricular function (Frank-Starling) curves. The abscissa can be any measure of preload—fiber length, filling pressure, pulmonary capillary wedge pressure, etc. The ordinate is a measure of useful external cardiac work—stroke volume, cardiac output, etc. In congestive heart failure, output is reduced at all fiber lengths and the heart expands because ejection fraction is decreased. As a result, the heart moves from point A to point B. Compensatory sympathetic discharge or effective treatment allows the heart to eject more blood, and the heart moves to point C on the middle curve.

Eiber lengths between 5 and 10 mm are conveniently selected for the microindentation test (111). Eor a carbon fiber/epoxy system, as the fiber volume fraction increases from 10 to 50 vol%, the indentation displacement distance decreases from 44 to 36 pm but the interfacial shear strength increases from 33 to 46 MPa. When the interphase-to-matrix modulus ratio increases from 1.0 to 7.5, the interfacial shear stress increases by only 10%. Likewise, the interphase thickness and fiber diameter have marginal effects on the interfacial shear stress. Three types of thermoplastic polymers (polyester, polyamide, and polypropylene) were tested for their interfacial shear strength to the glass fiber by Desaeger and... 

Rensner and Werther (1993) determined the effective measuring volume of a single fiber optical probe (d = 0.6 mm) for FCC and quartz sand as a function of particle concentration. In both cases (i.e., quartz and FCC), the 50% transmission length was less than 1 mm for the solids volume fraction p = 0.002 and less than 0.1 mm for = 0.2. Concerning the calibration of particle concentration probes Amos et al. (1996) did detailed analysis and experiments. 

The effects of volume fraction and length of biofibers on flexural properties of kenaf/starch and bagasse/starch biocomposites were investigated by Shibata et al. [18]. The flexural modulus of both composites increased with increase of fiber volume fraction up to 60% for kenaf and 66% for bagasse. 

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