Composite deformation

When a shear stress acts parallel to the fibers, T12, the composite deforms as if the fibers and matrix were coupled in series. Hence, the shear strain, yi2, can be found from a relation similar to Eq. (5.91), and the corresponding shear modulus for the... 

The remarks above can be extended to alloying between similar organic conductors since the compositional deformation of the cell can also be described by a second-rank tensor [107]. For example, computation of the compositional tensor of the alloy (TMTTF)2(SbF6)1 x(AsF6)x (TMTTF is tetramethyltetrathiofulvalene) has been reported by El Amrani [112]. 

Studies from the composite deformation mechanism and interfacial bonding between nanofillers and the polymer matrix have been performed [46-48]. In these reports, the authors performed straining studies to determine the load transfer between carbon nanotubes and the polymer and observed the phenomena of crack propagation and polymer debonding. In some cases, the mechanical deformation processes were followed over the electrospun composite fibers. Microscopic images revealed information on the dispersion and orientation of nanotubes within the fiber and their impact in the mechanical performance regarding strain at break and stress concentration at the pores of the nanotubes. 

All of these issues illustrate the fact that in the wide field of available modelling options there is a narrow path to the effective analysis. We believe that the chosen modelling paradigm allows capturing the essential features of the composite deformations. 

Qian, D. and Dickey, E. C. In-situ transmission electron microscopy studies of polymer-carbon nanotube composite deformation. JMictvsc., 204, 39-45 (2001). 

Additional striations were also observed in 3D SiC/SiC composite deformed by tension-tension fatigue, as shown in Fig. 7.54. Here, the fractured surface of monotonic tension and tension-tension fatigue results are compared. Note that the whole cross-section surface of the monotonic tension-tested specimens is coarse. On the cross-section surface of the tension-tension fatigue tested specimens, two different areas may be seen one area composed of ringed striations, taking up about half of the whole section, while the other area is smooth. 

The second important factor is the calculation of draw ratio 2, for composites. This problem is due to heterogeneity of composite structure, consisting of two phases elasticity modulus of one of them is essentially (in some orders of value) more, than the second. Differently speaking, during composite tension process only one phase is extended, namely, rubber, owing to nominal value X not already does describe adequately composite deformation process. This effect is well known and for its quantitative accounting for there are two models. The first of them uses the equation [7] ... 

Fractography is the visualization, description, and interpretation of a fracture or a fracture surface, often in order to establish structure-property relationships. Artifact-free visualization and as accurate a description as possible are a prerequisite for interpreting a fracture surface and using it to reveal information about material properties, such as composition, deformation under load, and the failure mechanism. 

Thus, this chapter results have shown that the fractal dimension of space, in which nano composites structure is formed, is defined by their crystalhne polymer phase morphology and does not depend on ciystallinity degree. The indicated dimension defines unequivocally partial melting-reciystallization process at nano composites deformation and influences strongly on their mechanical characteristics. 

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