Interferogram/creep rate

Fig. 4 A scheme of the interferogram/creep rate vs time plots obtained using the LICRM setup...

Thus, the time evolution of the creep process is registered as an interferogram. A displacement velocity e of the mirror rigidly connected with the moving clamp, that is, a specimen creep rate, and its total displacement (total specimen deformation) may be determined using the relations... 

Figure 73 illustrates the jump-like creep process by the interferograms obtained for amorphous polymers and the scheme of stepped deformation. Two parameters were introduced to characterize the stepwise creep (1) deformation increment L corresponding to the period of creep rate variation (the height of the step in the scheme) and (2) the ratio h of the maximum ( max) to minimum (emin) creep rates within the same step L, i.e., jump sharpness. In some cases, the mean value... 

Fig. 73 Typical interferograms (a) and a scheme of the stepwise (jump-like) creep (b) in amorphous polymers [11,321]. One oscillation (beat) corresponds to an increase of deformation on compression by 0.3 jam (usually 0.005%), and the creep rate e is determined by the beat frequency 1/x...

The laser-interferometric technique provided a convenient route for the precise determination, simultaneously with the measurements of creep rates, of a modulus of elasticity as a function of temperature T. Such dependencies can be determined directly from the number of oscillations in the interferograms characterizing the deformation value obtained for 1-2 s after loading and using (10). 

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