Elastic response region

To this point, we have limited the discussion to small strains—that is, small deviations from the equilibrium bond distance, such that all imposed deformations are completely recoverable. This is the elastic response region, one that virtually all materials possess (see Figure 5.8). What happens at larger deformations, however, is dependent to some... 

BRs were found to have a rate-sensitive mechanical response with very low tensile and shear strengths [63]. The stress-strain curves of the adhesives were characterized by an initial elastic response followed by a region of large plastic flow. 

Stress-strain relationships for soil are difficult to model due to their complexity. In normal practice, response of soil consists of analyzing compression and shear stresses produced by the structure, applied as static loads. Change in soil strength with deformation is usually disregarded. Clay soils will exhibit some elastic response and are capable of absorbing blast-energy however, there may be insufficient test data to define this response quantitatively. Soil has a very low tensile capacity thus the stress-strain relationship is radically different in the tension region than in compression. 

Figure 1.67 Specific volume as a function of temperature on cooling from the melt for a polymer that tends to crystallize. Region A is liquid, B liquid with elastic response, C supercooled liquid, D glass, E crystallites in a supercooled liquid matrix, F crystallites in a glassy matrix, and G completely crystalline. Paths ABCD, ABEF, and ABG represent fast, intermediate, and very slow cooling rates, respectively. From K. M. Ralls, T. H. Courtney, and J. Wulff, Introduction to Materials Science and Engineering. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

The rubbery region is wholly or partially masked by the crystallinity the elastic response of the melt is, therefore, much less pronounced. 

Due to its structure, a pilus has an intricate force response that differs from that of a single bond as well as those of many other types of biopolymer. As illustrated in Fig. 18.2b, a force-vs.-elongation response of a single pilus can be seen as composed of three regions Region /, in which the response is basically linear, like that of a normal (elastic) spring Region II, in which the... 

Fig. 2.10. Schematic of the stress-strain response of a cylindrical specimen under tensile loading. Elastic response is obtained only in the initial linear region of the loading curve.

Figure 4.3 Specific volume-temperature curves for a semicrystalline polymer. (A) Liquid region (B) viscous liquid with some elastic response (C) rubbery region (D) glassy region (E) crystallites in a rubbery matrix (F) crystallites in a glassy matrix. 

The form of the elastic response varies, but usually includes a power or exponential term to accommodate the toe region. 

Rubbery flow After the rubbery plateau the modulus again decreases from lO to 10 Nm in the section D to E. The effect of applied stress to a polymer in states (3) and (5) is shown in Figure 13.1(c), where there is instantaneous elastic response followed by a region of flow. 

FIGURE 13.13 Schematic representation of a creep curve a, initial elastic response b, region of creep c, irrecoverable viscous flow. This curve can be represented by the four-element model shown in Figure 13.14. 

The phenomena described above are the basis of the structural viscosity and viscoelastic behavior mentioned in Sec. il. The region of elastic response and the region of viscous flow depicted in Fig. 33 correspond to the lirsi and to the second Newtonian plateau of Fig. 5, respectively. Further, the floe destruction region shown in Fig. 34 corresponds to the shear-thinning portion between both plateaus of Fig. 

Figure 5.5. Transitions, plotted as independent variable versus dependent variable, showing a response limited to a partieular range of independent variable. (A) Representation of the thermally driven contraction for an elastic-contractile model protein, such as the cross-linked poly(GVGVP), plotted as the percent contraction (dependent variable) versus temperature (independent variable). The plot shows a poorly responsive range below the onset of the transition, the temperature interval of the inverse temperature transition for hydrophobic association, and another poorly responsive region above the tem-...

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