Stress trans fiber

To analyze the stress transfer in the fiber pull-out test of a multiple fiber composite, the specimen is treated as a three-cylinder composite (Zhou and Mai, 1992) where a fiber is located at the center of a coaxial shell of the matrix, which, in turn, is surrounded by a trans-isotropic composite medium with an outer radius fl. 

Nobes CD, Hall A. Rho, rac, and cdc42 GTPases regulate the assembly of multimolecular focal complexes associated with actin stress fibers, lamellipodia, and filopodia. Cell 1995 81 53-62. Nobes CD, Hall A. Rho, rac and cdc42 GTPases regulators of actin structures, cell adhesion and motility. Biochem. Soc. Trans. 1995 23 456-459. 

FIGURE 12.11 Improvements of the mechanical properties of three-dimensional reinforced CMCs by hybrid infiltration routes (a) R.T. flexural stress-strain plots for a three-dimensional carbon fiber reinforced composite before and after cycles of infiltration (comparison between eight cycles with zirconium propoxide and fonr cycles pins a last infiltration with aluminum-silicon ester (b) plot of the mechanical strength as a fnnction of the final open porosity for composites and matrix of equivalent porosity, before and after infiltration (Reprinted from Colomban, R and Wey, M., Sol-gel control of the matrix net-shape sintering in 3D reinforced ceramic matrix composites, J. Eur. Ceram. Soc., 17, 1475, 1997. With permission from Elsevier) (c) R.T. tensile behavior (d) comparison of the R.T. mechanical strength after thermal treatments at various temperatures. (Reprinted from Colomban, R, Tailoring of the nano/microstructure of heterogeneous ceramics by sol-gel routes, Ceram. Trans., 95, 243, 1998. With permission from The American Ceramic Society.)... 

Figure 20.27 SEM micrograph of the fracture surface of a carbon fiber epoxy resin laminate after a fiber buckling mode failure due to a longitudinal compression stress viewed under high magnification showing both tension and compressive fracture in a single fiber. Source Reprinted with permission from Ewins PD, Potter RT, Phil Trans R Soc London, A294, 507-517,1980. Copyright 1980, The Royal Society of Chemistry.

Tanigawa, Y., Hatanaka, S., Mori, H. (1980) Stress-strain behaviour of steel fiber reinforced concrete under compression, Trans, of the Japan Conor. Inst., 2 187-94. 

It was pointed out in Chapter 6 that the polymorphic transitions from one crystalline form to another can be induced by the application of an external stress on an axially oriented crystalline system. Anisotropic dimensional changes usually accompany the transformation. Typical examples are the classical a-p transition of the keratins,(21) and the crystal-crystal transition in poly(l,4-trans-butadienes).(22) The dimensional changes in these cases reflect the different axial or fiber repeat distances of the two polymorphs. The dimensional change would be expected to be... 

Zhurkov et al. [42] derived the degree of chain orientation from the dichroism of deformed-IR bands of PETP (cf. Chapter SIB and Fig. 8.5) they observed that for highly stressed segments an initial orientation with cos d = 0.75 had turned into practically complete orientation (cos — 1.0). The problems posed by an application of this method are discussed in detail by Read et al. [43]. Bouriot [44] deduced from IR measurements a reversible cis-trans transformation of the ethylene glycol segment in PETP fibers under the effect of tensile stresses. In polyamide 66 he observed a reversible increase of free (non-assodated) NH groups and an increase in the average chain orientation with chain tension. 

---