Composite stress-strain diagram

Figure 5.102 Tensile stress-strain diagrams for two SMC compounds 25 wt% fiber, bottom, and 65 wt% fiber, top. Reprinted, by permission, from Composite Materials Technology, P. K. Mallick and S. Newman, eds., p. 45. Copyright 1990 by Carl Hanser Verlag.

Figure 5.108 Schematic comparison of stress-strain diagrams for common reinforcing fibers (HMG = high modulus graphite) and whiskers. Reprinted, by permission, from A. Kelly, ed.. Concise Encyclopedia of Composite Materials, revised edition, p. 312. Copyright 1994 by Elsevier Science Publishers, Ltd.

Figure 5.123 Schematic tensile stress-strain diagram for a symmetric (0, 90°) cross-plied laminate tested at 2 = 0°. Reprinted, by permission, from P. K. Mallick, Fiber-Reinforced Composites, p. 187. Copyright 1988 by Marcel Dekker, Inc.

Fig. 5 Stress-strain diagram of rubber composite mixed at different temperatures containing 5 phr organoclay in a XNBR matrix. Circles indicate crossover points...

Fig. 13 Variation of 200% modulus (a), tensile strength (b), and elongation at break (c) with the amount of organoclay and XNBR. Stress-strain diagram of the organoclay-rubber composites (d)...

Fig. 10. Stress-strain diagram of a unidirectional epoxy composite with Kevlar 49, tested under tension and compression 80)...

As shown above, the ZrO/Ni composites examined by disk-bend testing are found to deform in a nonlinear manner, so that composition-dependent fracture strengths cannot be obtained directly from the stress-strain diagram in Fig. 3. Under the circumstances, we now make a micromechanical analysis to estimate actual stresses to be developed by plastic deformation of the ductile constituent on the basis of an established "mean-field" model [12]. In the following, the macrostress a) is related to the microstresses and (o) such... 

Figure 7 A typical stress-strain diagram of composite 39-b, measured by the TIT technique.

Fig. 14.12 shows the stress—strain—normalized resistance plot for the specimen with 12-mm notch spacing. We know that the nominal strain at fracture for the composite material is around 0.0147. Due to the notches, the strain concentration would be three times that of the smooth specimen. Thus any damage around the notch should start at one-third of the applied strain on the smooth specimen. This is indeed the case as seen in Fig. 14.13. A sharp change in the slope of the stress—strain curve is seen at a nominal strain of 0.005 = l/3eu- Before this knee the resistivity variation is nonlinear with respect to the applied strain. With the onset of damage at e = 0.005 (at the edges of the notches) a sharp increase in resistivity is seen. After this point the resistivity response is linear with the applied strain. Another jump in resistivity can be seen, probably due to damage initiation at the other notch, however, the stress—strain diagram does not detect this. After the second jump the sensor responds very...

The close relation between the composition and the mechanical properties of these polymers is reflected in the stress-strain diagrams measured at 300 K and 348 K (Figs. 47 and 48). Hence, at ambient temperature for the spedfied experimental conditions a distinct increase of initial modulus (11. 45 and 1 MNm ), stress-hysteresis (ratio of area bounded by a strain cycle to the total area underneath the elongation curve 60,80 and 90 %) and extension set (30,65 and 100 %) can be obsened with increasing hard segment content of polyester urethane (a) to (c). 

A typical stress-strain diagram for a composite material, in which strong and brittle fibres are reinforcing a ductile matrix, is shown in Figure 2.8, together with separate diagrams for fibres and matrix. The failure of a composite material occurs shortly after the failure of fibres and the post-failure behaviour of the matrix is highly non-linear. 

Figure 2.8 Typical stress-strain diagram for fibre, matrix and composite material, after Tsai and Hahn (1980).

If the failure strain in the matrix is larger than in the fibre, the fibres fracture before the matrix fails. This is frequently the case in composites with metallic or polymeric matrix. Figure 9.3 shows the resulting stress-strain diagram. It is assumed that the matrix yields plastically before the fibre breaks. The material deforms elastically until the matrix yields. On further increasing the strain, the strengthening fibres fracture, and the stress-strain curve drops to a small stress value that lies below that of the pure matrix material because of the reduced volume. Eventually, failure by fracturing of the matrix occurs. The fracture strain is smaller than in a pure matrix material. This is due... 

Figure 9.10 schematically shows the stress-strain diagram of a ceramic matrix composite. First cracks in the matrix occur at a stress of [Pg.311]

Figure 18.12 Stress-strain diagrams of some mortars compositions with respect to temperature.

Stress-strain diagram of SWCNT- and DWCNT/epox y composite with interphase B as epoxy/CT interphase. 

Sketch a stress-strain diagram for a composite with a smaller volume fraction of the fibers to that shown in Figure 10.2 in which the yield strength of the composite is lower than the fracture strength of the matrix. 

The most important physical-mechanical characteristics of the coatings are shown in Table 5.2. Typical diagrams of the stress-strain relationship for coatings with optimal composition on concrete substratum are plotted in Figures 5.1 and 5.2. 

If the bonding is located on a section subjected to frequent shear strains that can cause slanting cracks, the tensile stress exerted on the composite at a distance a should be calculated after having transferred the diagram of the flexural moment, dimension aj. This transfer should take place in the direction leading to an increase of the absolute value of the flexural moment. 

Hence, for out-of-plane loading Young s modulus for the hollow composite increases when the cell wall becomes thicker and when the wall length is shorter. Figure 3.8 shows the schematic diagrams by Gibson and Ashby (1999) of the strain-stress curves... 

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