Continuous-fiber composites

Continuous ethyl acetate process, 10 483 Continuous Exposure Guidance Levels (CEGL), 21 837 Continuous extractors, 10 751 Continuous falling film SO3 sulfonation process, 23 544, 550-552 Continuous fiber composites, fabrication of, 26 766, 767... 

Fig. 6.14. Blunted crack tip and longitudinal splitting in unidirectional continuous fiber composites. After...

Mitaka, Y. (1994). Stress field in a continuous fiber composite with a variable interphase under thermomechanical loadings. J. Eng. Mater. Technol. 116, 367-377. 

Mitaka, Y. and Taya, M. (1985a). Stress field in a coated continuous fiber composite subjected to thermomechanical loadings. J. Composite Mater. 19, 554-578. 

Recall from Section 1.4.5.1 that there are two primary types of carbon fibers polyacrylonitrile (PAN)-based and pitch-based. There are also different structural forms of these fibers, such as amorphous carbon and crystalline (graphite) fibers. Typically, PAN-based carbon fibers are 93-95% carbon, whereas graphite fibers are usually 99+%, although the terms carbon and graphite are often used interchangeably. We will not try to burden ourselves with too many distinctions here, since the point is to simply introduce the relative benefits of continuous-fiber composites over other types of composites, and not to investigate the minute differences between the various types of carbon-fiber-based composites. The interested reader is referred to the abundance of literature on carbon-fiber-reinforced composites to discern these differences. 

D.H. Allen et al A cumulative damage model for continuous fiber composite laminates with matrix cracking and interply delaminations. ASTM Sp. Tech. Pub. 972, 57-80 (1988)... 

Oxidation at exposed fiber ends in continuous fiber composites. 

Notch-impact tests [ 150-154.156 158], and tests using CT specimens [ 159] (sec Section 3) have also been employed in the evaluation of continuous fiber composites, particularly those with woven [159] and nonwoven [157.158] fabric reinforcements, and 3D composites [156],... 

Fracture toughness data (room temperature measurements) for various continuous fiber composites under different loading modes arc presented in Table 4. The data from different sources are reasonably consistent for a given material system with the same fiber content. Small differences may result from the variations in the degree of cross-linking for thermosets and the degree of crystallinity for the thermoplastic matrices. 

Injection-molded plaques of liquid crystalline polymers exhibit a multilayered structure through the thickness of a molding, where in each layer there is a high degree of orientation. Accordingly the fracture test methods of continuous fiber composites can be adopted for the testing of liquid crystalline polymers [176]. 

Fatigue behavior of continuous fiber composites under multiaxial loading... 

The trend is similar to that discussed on page 345 for short fiber composites, but at the same time it is opposite to the general behavior of plain samples of both short fiber and continuous fiber composites, where the fatigue strength decreases when the biaxiality ratio A2 increases. However, on the basis of the limited amount of data available, it is impossible to justify the experimental evidence and further research is indeed needed to clarify the mechanisms responsible for this peculiar behavior. Results on [0/ 45]2s, [0/ 45/90]s, and [02/ 45]s graphite/epoxy cruciform laminates reported by Jones et al. [16] are less clear than those just discussed—in some cases increasing the biaxiality ratio Ai decreased the fatigue life, and for others the life was increased. 

For this article, the term melt infiltrated ceramic matrix composite (MI-CMC) will refer only to continuous fiber composites whose matrices are formed by molten silicon (or silicon alloy) infiltration into a porous SiC- and/or C-containing preform. GE holds nmnerous patents on the composition and fabrication of these materials, only a few of which are listed in reference 10. Such composites can be made from a variety of constituents and processes. A detailed description of the material variations and processes is also given in reference 1, so only an abbreviated description will be given here. 

Yurgatis, S.W. (1987) Measurement of small angle fiber misalignments in continuous fiber composites. Compos. Sci. Technol., 30, 279-293. 

We have mentioned that the PLC phase is continuous for Vf > 0.55. At high draw ratio (A = 15), the PLC fibrils in PC - - VBlO and PC + VB30 are also essentially continuous, so the axial Young s modulus of all the composites can be analyzed in terms of the rule of mixtures valid for continuous fiber composites ... 

According to the theory of continuous fiber composites [40], not only 3 but also the Poisson s ratio are expected to obey the rule of mixtures. This is verified in Figure 14.24, confirming that highly drawn blends of PC and Vectra B behave like continuous fiber... 

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