| Abstrakt: |
Papers devoted to the development of methods of describing the behavior of materials during creep and stress relaxation in terms of uniaxial strain data are usually based on the idea of the existence of a mechanical equation of state, i.e., an equation relating deformation or rate of deformation, temperature, stress, and time for such processes. The idea of a mechanical equation of state was first put forward by Nadai [1] and Zener and Holloman [2]. Holloman [3] has reported some experimental evidence for the existence of such an equation of state. However, Orowan [4], Dorn et al. [5], and Johnson et al. [6] have obtained data which are not in agreement with this idea. Freudenthal [7] has considered the physical basis of these processes and their mathematical description, and has not rejected the basic possibility of conversion of the data of one type of test into another. He ascribes the various difficulties in this area to insufficient knowledge about the nature of these processes. Guiu and Pratt [8] have come to the same conclusion and have noted the complexity of the processes taking place in the material under test. |
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