Loading-unloading curves

Fig. 39—Loading-unloading curve and displacement of the tip for microscratch test. 1-applied normal force 2-X direction displacement.

F. 20 (a, b) Loading-unloading curves of HM PAAm hydrogels with 7 % of SDS (a) and without SDS (b) 2max = 5,C17.3M = 2mol%. Waiting time betwetai the cycles was 7 min. Crosshead speed was 50 mm min . From [34] with permission from Elsevier... 

The dominant efikcts of carbon black on the tensile stress-strain curve of natural rubber can be seen in Kgure 6.29. Loading/unloading curves are compared for unloading from a strain of 2. The stiffening action of carbon black is dearty in evidence. In addition, however, it accentuates two undesirable features ... 

Elastic recovery tests (a) loading-unloading curve and (b) elastic recovery results. 

Ceramic materials are expected to be applied to the structural parts, especially to tribological application, as they have high hardness and high elastic constants. For this application, it is important to know the properties of mechanical behavior on the surface of ceramics. Instrumented indentation is one of the tests that can explain the mechanical properties on the surface, as it expresses the relation between the penetration depth of the indenter and the applied force.For metallic materials, the standard test method in instrumented indentation is already published. We have tried the instrumented indentation tests on ceramic materials. Figure 1 is a typical example of the loading-unloading curve by this test on alumina ceramics. 

An load/unloading curve with an atmospheric plasma spray-coated specimen (A) is shown in Fig. 10, and a stress-strain curve by the indentation method in Fig. 11. In the latter curve, the initial slope, corresponding to the Young s modulus of materials, was different when using a spherical indenter of diameter 1 mm from that using... 

Figure 10. Load unload curve with spherical indenter.

Figure H.1 Typical loading-unloading curve. These curves separate because the specimen has deformed plastically on loading while unloading is mainly elastic.

Figure H.12 Loading-unloading curves of a PMMA-TEOS specimen obtained under periodic load-reload sequence. The model curve is obtained for Fr = 7.6GPa, H = 3.9GPa, C)/ = I.Ox 10 Pas. (Reprinted from Mammeri et al., 2004, with permission from Elsevier.)...

Figure H.14 Normalized loading-unloading curves obtained under two different loads but same loading and unloading times. Specimen is PMMA. Note the superposition of the curves.

There are relatively few papers that have explored the viscoelastic response of UHMWPE to indentation. Typically, indentation tests of viscoelastic materials have included a pause in the load-unload curves at the maximum load to allow creeplike deformation to occur [21]. Researchers have typically inserted a hold time of between 10 and 100... 

Figure 8 Load-unload curves of plaques a)foam 1 and...

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