Cyclic stress-strain diagram

Fig. 10.29. Cyclic stress-strain diagram. A static stress-strain curve is shown for comparison...

If we perform cyclic experiments at different strain amplitudes and plot the stabilised values of the stress amplitude, we arrive at the cyclic stress-strain diagram sketched in figure 10.29. Usually, it does not coincide with the result of a monotonous tensile or compressive test. If cyclic hardening occurs,... 

The statement made in [643] that the knee at 47 to 245 N/mm in the static stress-strain diagram represents an upper limit for cyclic loading cannot be confirmed. For example, while knee-stress in EPl-GF laminates reaches approx. 81 % of that of EP3-GF, the cyclic load limit is at only approx. 50%, Fig. 4.93. 

FIGURE 4.8 The stress - strain (a - e) diagrams at loading up to failure (1) and at cyclic load exertion (2-4) for EP-2 2 - the first loading cycle 3 - the second loading cycle 4 - the third loading cycle [39]. 

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