Hysteresis Loop-Variable Amplitude Loads

The same material of the previous sample problem is now subjected to a history of variable amplitude strains, as shown in Fig. 6.31a. Construct the corresponding hysteresis loops of the material. Cycle ABA is the same as before, but now the material ahead of the notch root once returned in A is partially unloaded to point C = (0.002 —284) following the previously calculated path. Once in C the load is reversed so that Eq. (6.7) is used and solved by partial differences with the same strain step As = 0.002. Results are listed in Table 6.5. The new reloading path is 

Total strain Stress amplitude Ait/2 Plastic strain amplitude Cycles to failure 

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